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An improved version of a recently developed stochastic cluster dynamics (SCD) method (Marian and Bulatov, 2012) [6] is introduced as an alternative to rate theory (RT) methods for solving coupled ordinary differential equation (ODE) systems for irradiation damage simulations. SCD circumvents by design the curse of dimensionality of the variable space that renders traditional ODE-based RT approaches inefficient when handling complex defect population comprised of multiple (more than two) defect species. Several improvements introduced here enable efficient and accurate simulations of irradiated materials up to realistic (high) damage doses characteristic of next-generation nuclear systems. The first improvement is a procedure for efficiently updating the defect reaction-network and event selection in the context of a dynamically expanding reaction-network. Next is a novel implementation of the τ-leaping method that speeds up SCD simulations by advancing the state of the reaction network in large time increments when appropriate. Lastly, a volume rescaling procedure is introduced to control the computational complexity of the expanding reaction-network through occasional reductions of the defect population while maintaining accurate statistics. The enhanced SCD method is then applied to model defect cluster accumulation in iron thin films subjected to triple ion-beam (Fe3+, He+ and H+) irradiations, for which standard RT or spatially-resolved kinetic Monte Carlo simulations are prohibitively expensive.

Purpose: Pediatric constraint-induced movement therapy (CIMT) is an evidence-based treatment that has a long history of demonstrating efficacy for children with hemiparesis. The purpose of this study is to determine the effectiveness of a culturally responsive CIMT program for children with hemiplegic cerebral palsy (CP) developed for the Vietnam healthcare system., Methods: Thirty children with hemiplegic CP (mean age = 2.88 years, age range: 1 to 8 yrs, 60% male) were recruited to a CIMT program (7.5 h/week, 4 weeks) developed for the cultural context of Vietnam. Motor abilities of the affected arm and participation in daily activities were evaluated at 3 time points (one-week prior to CIMT (baseline), one-week before (pre) and after (post) CIMT) using the Quality of Upper Extremity Skill Test (QUEST) and Pediatric Motor Activity Log-Revised (PMAL-R). Individual goals were measured using the Goal Attainment Scale (GAS)., Results: There were significant increases in the "How often scale" and "How Well" scales of the PMAL-R (0.75 and 0.75, p  < 0.00)). Score of Grasp and Dissociated Movement items on the QUEST increased significantly (6.47 and 7.63, p  < 0.001). Group GAS T-Scores were 52.19 indicating that children met individual goals., Conclusions: A model of CIMT was successfully developed and delivered within the Vietnamese healthcare system. Future studies should explore the optimal model for CIMT in various regions of world where the delivery of rehabilitation services may vary.

We aimed to elucidate the toxic effects and biological activities of 3-phenoxybenzoic acid (3PBA) and its metabolite products., Numerous in silico methods were used to identify the toxic effects and biological activities of 3PBA, including PASS online, molecular docking, ADMETlab 2.0, ADMESWISS, MetaTox, and molecular dynamic simulation., Ten metabolite products were identified via Phase II reactions (O-glucuronidation, O-sulfation, and methylation)., All of the investigated compounds were followed by Lipinski's rule, indicating that they were stimulants or inducers of hazardous processes., Because of their high gastrointestinal absorption and ability to reach the blood-brain barrier, the studied compounds' physicochemical and pharmacokinetic properties matched existing evidence of harmful effects, including haematemesis, reproductive dysfunction, allergic dermatitis, toxic respiration, and neurotoxicity., The studied compounds have been linked to the apoptotic pathway, the reproductivity system, neuroendocrine disruptors, phospholipid-translocating ATPase inhibitors, and JAK2 expression., An O-glucuronidation metabolite product demonstrated higher binding affinity and interaction with CYP2C9, CYP3A4, caspase 3, and caspase 8 than 3PBA and other metabolite products, whereas metabolite products from methylation were predominant and more toxic., Our in silico findings partly meet the 3Rs principle by minimizing animal testing before more study is needed to identify the detrimental effects of 3PBA on other organs (liver, kidneys)., Future research directions may involve experimental validation of in silico predictions, elucidation of molecular mechanisms, and exploration of therapeutic interventions., These findings contribute to our understanding of the toxicological profile of 3PBA and its metabolites, which has implications for risk assessment and regulatory decisions.

Healthcare fraud, waste and abuse are costly problems that have huge impact on society. Traditional approaches to identify non-compliant claims rely on auditing strategies requiring trained professionals, or on machine learning methods requiring labelled data and possibly lacking interpretability. We present Clais, a collaborative artificial intelligence system for claims analysis. Clais automatically extracts human-interpretable rules from healthcare policy documents (0.72 F1-score), and it enables professionals to edit and validate the extracted rules through an intuitive user interface. Clais executes the rules on claim records to identify non-compliance: on this task Clais significantly outperforms two baseline machine learning models, and its median F1-score is 1.0 (IQR = 0.83 to 1.0) when executing the extracted rules, and 1.0 (IQR = 1.0 to 1.0) when executing the same rules after human curation. Professionals confirm through a user study the usefulness of Clais in making their workflow simpler and more effective., (© 2024. The Author(s).)

Diabetes mellitus remains a major global health issue, and great attention is directed at natural therapeutics. This systematic review aimed to assess the potential of flavonoids as antidiabetic agents by investigating their inhibitory effects on α-glucosidase and α-amylase, two key enzymes involved in starch digestion. Six scientific databases (PubMed, Virtual Health Library, EMBASE, SCOPUS, Web of Science, and WHO Global Index Medicus) were searched until August 21, 2022, for in vitro studies reporting IC 50 values of purified flavonoids on α-amylase and α-glucosidase, along with corresponding data for acarbose as a positive control. A total of 339 eligible articles were analyzed, resulting in the retrieval of 1643 flavonoid structures. These structures were rigorously standardized and curated, yielding 974 unique compounds, among which 177 flavonoids exhibited inhibition of both α-glucosidase and α-amylase are presented. Quality assessment utilizing a modified CONSORT checklist and structure-activity relationship (SAR) analysis were performed, revealing crucial features for the simultaneous inhibition of flavonoids against both enzymes. Moreover, the review also addressed several limitations in the current research landscape and proposed potential solutions. The curated datasets are available online at https://github.com/MedChemUMP/FDIGA ., (© 2024. The Author(s).)

Background: Mitochondrial DNA (mtDNA) analysis has been used in forensics and requires well-established population databases for statistical interpretations. However, high-quality mtDNA data from Vietnamese population samples have been limited., Aim: To examine the mtDNA sequences and haplogroup compositions of a Vietnamese population to provide an mtDNA dataset that can further be used to construct a Vietnamese-specific reference database., Subjects and Methods: A total of 173 Vietnamese individuals were analysed for two hypervariable regions (HVI and HVII) of mtDNA. Forensic parameters were calculated and haplogroup assignment was performed based on the resulting mtDNA haplotypes. Genetic relationships between the Vietnamese and other Asian populations were investigated through principal component analysis (PCA) and pairwise F st ., Results: The Vietnamese population sample consisted of 145 different haplotypes with a random match probability of 0.96%, a power of discrimination of 0.9904, and a haplotype diversity of 0.9962. The samples were assigned to 83 haplogroups that were commonly reported in Asia. PCA and pairwise F st revealed close relationships of the Vietnamese population with other Asian populations, especially with populations in proximity., Conclusion: The results from this study can contribute to the current genetic information content as a supplementary mtDNA reference dataset for forensic investigations and phylogenetic research.

This paper uses Vietnam - where overexploitation of wildlife resources is a major threat to biodiversity conservation - as a case study to examine how government officials perceive the impacts of COVID-19 on wildlife farming, as well as the opportunities and challenges presented for sustainable wildlife management. Findings show Vietnamese government officials perceive COVID-19 to have had mixed impacts on wildlife conservation policies and practice. While the pandemic strengthened the legal framework on wildlife conservation, implementation and outcomes have been poor, as existing policies are unclear, contradictory, and poorly enforced. Our paper also shows policymakers in Vietnam are not in favor of banning wildlife trade. As our paper documents the immediate impacts of the pandemic on wildlife farming, more research is necessary to analyse longer-term impacts., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 Elsevier Ltd. All rights reserved.)

Pesticide residue in food, especially in vegetables, is one of the important parameters to assess food safety. This study evaluates the pesticide use in vegetables from two provinces in Central Vietnamand and present data on pesticides detected in vegetables sampled from the sites. The potential health risk associated with the contamination of four commonly used pesticides in different vegetables is also discussed. Both household surveys and monitoring campaigns were conducted. The survey showed that improper pesticide application, storage, and waste disposal prevailed at the study sites. Only 20% of the respondent were aware of pesticide toxicity. As a result, pesticides were detected in 81% out of 290 vegetable samples collected at harvesting time. Up to 23% of samples had pesticide residues above the Maximum Residue Limit values. The highest total pesticide concentration quantified in vegetables in Thua Thien Hue was 11.9 mg/kg (green onions), and in Quang Binh was 38.6 mg/kg (mustard greens). Median residue levels of individual pesticides in vegetables ranged from 0.007 to 0.037 mg/kg. Among the ten target pesticides, cypermethrin, difenoconazole, and fenobucarb were detected at the highest frequencies (72%, 41%, and 37%, respectively). Pesticide residues varied between seasons at both study provinces. Pesticide contamination in the wet season was significantly higher than in the dry season. This study also discovered a potential health risk associated with fipronil residues in vegetables in Thua Thien Hue province. The paper provides recommendations for mitigation measures (both technological and social) in reducing potential health risks linked to pesticide use in vegetables in the region., Competing Interests: The authors have declared that no competing interests exist.

Background: Dystrophic epidermolysis bullosa (DEB) is a rare inherited disorder characterized by skin fragility leading to trauma-induced subepidermal blisters and healing with scarring. DEB is caused by mutations in COL7A1, the gene encoding for type VII collagen (COLVII). The DEB inheritance trait is divided into dominant dystrophic epidermolysis bullosa (DDEB) and recessive dystrophic epidermolysis bullosa (RDEB)., Methods: Whole-exome sequencing (WES) was performed for identifying mutations in six affected individuals of five Vietnamese families., Results: Three novel variants in total of eight variants were found in five families. The first novel variant causing glycine substitution (c.8279G>A, p.G2760E), the remaining two novel variants resulted in splice site affecting (c.4518+2delT and c.5821-2A>G). Functional analysis indicated that the splice site at c.4518+2delT resulted in a skipping of exon 43, leading to an in-frame deletion of 12 amino acids., Conclusion: Our finding expands the spectrum of COL7A1 mutations and reports altered splicing at c.4518+2delT during the processing of the pre-mRNA. This study provides an additional scientific basis for diagnosis, genetic counseling, and prognosis purposes of EB patients., (© 2021 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

Biodegradable periodic mesoporous organosilica (BPMO) has recently emerged as a promising type of mesoporous silica-based nanoparticle for biomedical applications. Like mesoporous silica nanoparticles (MSN), BPMO possesses a large surface area where various compounds can be attached. In this work, we attached boronophenylalanine ( 10 BPA) to the surface and explored the potential of this nanomaterial for delivering boron-10 for use in boron neutron capture therapy (BNCT). This cancer therapy is based on the principle that the exposure of boron-10 to thermal neutron results in the release of a-particles that kill cancer cells. To attach 10 BPA, the surface of BPMO was modified with diol groups which facilitated the efficient binding of 10 BPA, yielding 10 BPA-loaded BPMO ( 10 BPA-BPMO). Surface modification with phosphonate was also carried out to increase the dispersibility of the nanoparticles. To investigate this nanomaterial's potential for BNCT, we first used human cancer cells and found that 10 BPA-BPMO nanoparticles were efficiently taken up into the cancer cells and were localized in perinuclear regions. We then used a chicken egg tumor model, a versatile and convenient tumor model used to characterize nanomaterials. After observing significant tumor accumulation, 10 BPA-BPMO injected chicken eggs were evaluated by irradiating with neutron beams. Dramatic inhibition of the tumor growth was observed. These results suggest the potential of 10 BPA-BPMO as a novel boron agent for BNCT.

Streptococcus dysgalactiae subsp. equisimilis (SDSE) causes cellulitis, bacteremia, and invasive diseases, such as streptococcal toxic shock syndrome. Although SDSE infection is more prevalent among elderly individuals and those with diabetes mellitus than infections with Streptococcus pyogenes (Group A streptococci; GAS) and Streptococcus agalactiae (Group B streptococci; GBS), the mechanisms underlying the pathogenicity of SDSE remain unknown. SDSE possesses a gene hylD encoding a hyaluronate lyase (HylD), whose homologue (HylB) is involved in pathogenicity of GBS, while the role of HylD has not been characterized. In this study, we focused on the enzyme HylD produced by SDSE; HylD cleaves hyaluronate (HA) and generates unsaturated disaccharides via a β-elimination reaction. Hyaluronate-agar plate assays revealed that SDSE promoted dramatic HA degradation. SDSE expresses both HylD and an unsaturated glucuronyl hydrolase (UGL) that catalyzes the degradation of HA-derived oligosaccharides; as such, SDSE was more effective at HA degradation than other β-hemolytic streptococci, including GAS and GBS. Although HylD shows some homology to HylB, a similar enzyme produced by GBS, HylD exhibited significantly higher enzymatic activity than HylB at pH 6.0, conditions that are detected in the skin of both elderly individuals and those with diabetes mellitus. We also detected upregulation of transcripts from hylD and ugl genes from SDSE wild-type collected from the mouse peritoneal cavity; upregulated expression of ugl was not observed in ΔhylD SDSE mutants. These results suggested that disaccharides produced by the actions of HylD are capable of triggering downstream pathways that catalyze their destruction. Furthermore, we determined that infection with SDSE ΔhylD was significantly less lethal than infection with the parent strain. When mouse skin wounds were infected for 2 days, intensive infiltration of neutrophils was observed around the wound areas infected with SDSE wild-type but not SDSE ΔhylD . Our investigation suggested that HylD and UGL play important roles in nutrient acquisition from hosts, followed by the bacterial pathogenicity damaging host tissues., (Copyright © 2020 Nguyen, Ogura, Matsue, Takemoto, Mukai, Nakajima, Hoang, Iwata, Sakai, Wada, Hashimoto, Okamoto and Ichimura.)

This is the first study on polychlorinated biphenyls (PCBs) in fish from the Cau Hai lagoon, a part of the largest coastal lagoon in Southeast Asia. Seven selected PCB congeners and organochlorine pesticides in sediments and edible fish tissues were quantified by GC-MS. The sum of ICES-7 PCB and DDTs concentrations in fish species consumed regularly and of economic value were in ranges 26-43 ng g -1 lw and 182-277 ng g -1 lw, respectively. The ratio between the parent DDT compound and the sum of metabolites, DDE and DDD, was most of the time smaller than 1, suggesting primarily an historical contamination of the lagoon. An agglomerative hierarchical clustering indicates sites located in the north-western part of the Cau Hai lagoon were characterized by above-average concentrations of DDE and DDT. Comparing to previous data, a large decrease in ∑DDT residues can be seen over the past 20 years., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Concentrations of Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, U, V and Zn were quantified in surface sediments collected from 13 different sampling sites from Cau Hai lagoon in Central Vietnam, and in 8 wild and farmed-fishes involving both pelagic and benthic species. Multivariate analysis shows that these trace elements are mainly associated with lithogenic matter, and are most likely the result of alteration and erosion processes in the lagoon. Enrichment factors and geo-accumulation indices reveal substantial sediment enrichments for both As and Bi with respect to the mean composition in the upper continental crust. As is enriched in the edible portion of fish tissue with values up to 10 times higher than the allowed limits set up by Health Canada. Target hazard quotient and target carcinogenic risk for As were assessed through fish diet and were greater than 1 and 10 -4 , respectively, indicating potential health risks for fish consumers in Cau Hai lagoon., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

We introduce for the first time a paper-based analytical device (PAD) for the non-enzymatic detection of glucose by modifying a screen-printed carbon electrode with cobalt phthalocyanine, graphene and an ionic liquid (CoPc/G/IL/SPCE). The modifying composite was characterized by UV-visible spectroscopy, energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The disposable devices show excellent conductivity and fast electron transfer kinetics. The results demonstrated that the modified electrode on PADs had excellent electrocatalytic activity towards the oxidation of glucose with NaOH as supporting electrolyte (0.1M). The oxidation potential of glucose was negatively shifted to 0.64V vs. the screen-printed carbon pseudo-reference electrode. The paper-based sensor comprised a wide linear concentration range for glucose, from 0.01 to 1.3mM and 1.3-5.0mM for low and high concentration of glucose assay, respectively, with a detection limit of 0.67µM (S/N = 3). Additionally, the PADs were applied to quantify glucose in honey, white wine and human serum. The disposable, efficient, sensitive and low-cost non-enzymatic PAD has great potential for the development of point-of-care testing (POCT) devices that can be applied in healthcare monitoring., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Kawasaki disease (KD) is a multisystem vasculitis that predominantly targets the coronary arteries in children. Phenotypic similarities between KD and recurrent fever syndromes point to the potential role of inflammasome activation in KD. Mutations in NLRP3 are associated with recurrent fever/autoinflammatory syndromes. We show that the KD-associated genetic polymorphism in inositol-triphosphate 3-kinase C (ITPKC) (rs28493229) has important functional consequences, governing ITPKC protein levels and thereby intracellular calcium, which in turn regulates NLRP3 expression and production of IL-1β and IL-18. Analysis of transcript abundance, protein levels, and cellular response profiles from matched, serial biospecimens from a cohort of genotyped KD subjects points to the critical role of ITPKC in mediating NLRP3 inflammasome activation. Treatment failure in those with the high-risk ITPKC genotype was associated with the highest basal and stimulated intracellular calcium levels and with increased cellular production of IL-1β and IL-18 and higher circulating levels of both cytokines. Mechanistic studies using Itpkc-deficient mice in a disease model support the genomic, cellular, and clinical findings in affected children. Our findings provide the mechanism behind the observed efficacy of rescue therapy with IL-1 blockade in recalcitrant KD, and we identify that regulation of calcium mobilization is fundamental to the underlying immunobiology in KD., (Copyright © 2016 by The American Association of Immunologists, Inc.)

Objective: Peroxisome proliferator-activated receptor-alpha (PPARα) is a nuclear receptor that has critical roles in the treatment of atherosclerosis, hyperlipidemia and hepatic steatosis., Results: Squalene is a novel nature PPARα agonist, identified from reporter gene assay and qPCR analysis. Cultured hepatocytes stimulated with squalene exhibited significantly decreased cellular triacylglycerols and cholesterol concentrations, while cellular uptake of fatty acids was increased. Quantitative PCR analysis revealed that expression of genes related to fatty acid uptake, fatty acid oxidation, ketogenesis and reverse cholesterol transport metabolism were upregulated, while that of genes related to fatty acid synthesis were suppressed in cell treated with squalene., Conclusion: Squalene is hypolipidemic by activation of PPARα via a ligand-mediated mechanism that regulates the expression of lipid metabolism genes in hepatocytes.

In oocytes, where centrosomes are absent, the chromosomes direct the assembly of a bipolar spindle. Interactions between chromosomes and microtubules are essential for both spindle formation and chromosome segregation, but the nature and function of these interactions is not clear. We have examined oocytes lacking two kinetochore proteins, NDC80 and SPC105R, and a centromere-associated motor protein, CENP-E, to characterize the impact of kinetochore-microtubule attachments on spindle assembly and chromosome segregation in Drosophila oocytes. We found that the initiation of spindle assembly results from chromosome-microtubule interactions that are kinetochore-independent. Stabilization of the spindle, however, depends on both central spindle and kinetochore components. This stabilization coincides with changes in kinetochore-microtubule attachments and bi-orientation of homologs. We propose that the bi-orientation process begins with the kinetochores moving laterally along central spindle microtubules towards their minus ends. This movement depends on SPC105R, can occur in the absence of NDC80, and is antagonized by plus-end directed forces from the CENP-E motor. End-on kinetochore-microtubule attachments that depend on NDC80 are required to stabilize bi-orientation of homologs. A surprising finding was that SPC105R but not NDC80 is required for co-orientation of sister centromeres at meiosis I. Together, these results demonstrate that, in oocytes, kinetochore-dependent and -independent chromosome-microtubule attachments work together to promote the accurate segregation of chromosomes.

Background: Dysregulated immune responses may contribute to the clinical complications that occur in some patients with dengue., Findings: In Vietnamese pediatric dengue cases randomized to early prednisolone therapy, 81 gene-transcripts (0.2% of the 47,231 evaluated) were differentially abundant in whole-blood between high-dose (2 mg/kg) prednisolone and placebo-treated patients two days after commencing therapy. Prominent among the 81 transcripts were those associated with T and NK cell cytolytic functions. Additionally, prednisolone therapy was not associated with changes in plasma cytokine levels., Conclusion: The inability of prednisolone treatment to markedly attenuate the host immune response is instructive for planning future therapeutic strategies for dengue.

We developed a sensitive and rapid real-time reverse transcription-polymerase chain reaction (RT-PCR) assay to detect influenza A H5N1 virus in clinical samples. This assay was evaluated with samples from H5N1-infected patients and demonstrated greater sensitivity and faster turnaround time than nested RT-PCR.

Salmonella enterica serovar Typhi strains resistant to ampicillin, chloramphenicol, tetracyclines, streptomycin, and cotrimoxazole, isolated from sporadic cases and minor outbreaks in Vietnam between 1995 and 2002, were typed and compared. Plasmid fingerprinting, Vi bacteriophage typing, XbaI pulsed-field gel electrophoresis, and PstI ribotyping showed that endemic, epidemic multidrug-resistant typhoid fever was due, for at least 74.1% of the isolates, to one or two clones of serovar Typhi harboring a single resistance plasmid. PstI ribotyping was used as a basic technique to ensure that a serovar Typhi expansion was clonal.

Background: Recent outbreaks of avian influenza A (H5N1) in poultry throughout Asia have had major economic and health repercussions. Human infections with this virus were identified in Vietnam in January 2004., Methods: We report the clinical features and preliminary epidemiologic findings among 10 patients with confirmed cases of avian influenza A (H5N1) who presented to hospitals in Ho Chi Minh City and Hanoi, Vietnam, in December 2003 and January 2004., Results: In all 10 cases, the diagnosis of influenza A (H5N1) was confirmed by means of viral culture or reverse transcriptase-polymerase chain reaction with primers specific for H5 and N1. None of the 10 patients (mean age, 13.7 years) had preexisting medical conditions. Nine of them had a clear history of direct contact with poultry (median time before onset of illness, three days). All patients presented with fever (temperature, 38.5 to 40.0 degrees C), respiratory symptoms, and clinically significant lymphopenia (median lymphocyte count, 700 per cubic millimeter). The median platelet count was 75,500 per cubic millimeter. Seven patients had diarrhea. In all patients, there were marked abnormalities on chest radiography. There was no definitive evidence of human-to-human transmission. Eight patients died, one patient has recovered, and one is recovering., Conclusions: Influenza A (H5N1) infection, characterized by fever, respiratory symptoms, and lymphopenia, carries a high risk of death. Although in all 10 cases the infection appears to have been acquired directly from infected poultry, the potential exists for genetic reassortment with human influenzaviruses and the evolution of human-to-human transmission. Containment of influenza A (H5N1) in poultry throughout Asia is therefore urgently required., (Copyright 2004 Massachusetts Medical Society)

Background: HIV prevalence among sex workers in Ho Chi Minh City has increased rapidly, from 6.5% in 1999 to 18.1% in 2000. This study examined whether injecting drug use among street-based sex workers (SSWs) in Ho Chi Minh City is a high-risk factor for HIV infection., Goal: The goal of this study was to determine the correlates and prevalence of intravenous drug users among SSWs in Ho Chi Minh City., Study Design: A cross-sectional study was conducted among SSWs in Ho Chi Minh City during December 2000. The SSWs were interviewed and tested for HIV-1., Results: HIV-1 seroprevalence was 16.3%. Regression analysis indicated that injecting drugs and being younger than 25 years of age were independently associated with HIV seropositivity., Conclusion: Young SSWs who inject drugs are at the greatest risk of contracting HIV and acting as a bridge for HIV to the sexually active population.

To ascertain hepatitis B virus (HBV) infection rates for Vietnam, we surveyed HBV markers in two districts of Thanh Hoa province. We randomly selected 536 infants (9- < or = 18 months old), 228 children (4 to < or = 6 years old), 219 adolescents (14 to < or = 16 years old), and 596 adults (25 to < or = 40 years old). On questioning, none of those surveyed had received vaccine against HBV. Hepatitis B virus surface antigen (HBsAg) and total HBV core antibody (anti-HBc) were measured in all specimens, and HBV e antigen (HBeAg) in those positive for HBsAg, and HBV surface antibody (anti-HBs) were measured in all others. Current infection (HBsAg+) rates were infants = 12.5%, children = 18.4%, adolescents = 20.5%, and adults = 18.8%. Current or previous infection (HBsAg+, anti-HBc+, or anti-HBs+) increased with age (infants = 19.6%, children = 36.4%, adolescents = 55.3%, adults = 79.2%). Rates of HBeAg among those HBsAg+ were infants = 85.1%, children = 88.1%, adolescents = 71.1%, and adults = 30.4%. The epidemiology of HBV in Vietnam resembles that of many southeast Asian nations before introduction of vaccine. Immunization of newborns will have enormous impact on HBV-related morbidity and mortality there.

To investigate the nature of recent HIV outbreaks among injecting drug users (IDUs) near the Vietnam-China border, we genetically analyzed 24 HIV-positive blood specimens from 2 northern provinces of Vietnam (Lang Son and quang Ninh) adjacent to the China border, where HIV outbreaks among IDUs were first detected in late 1996. Genetic subtyping based on gag (p17) and env (C2/V3) sequences revealed that CRF01&#95;AE is a principal strain circulating throughout Vietnam, including the provinces near the China border. The majority of CRF01&#95;AE sequences among IDUs in Quang Ninh and Lang Son showed significant clustering with those found in nearby Pingxiang City of China's Guangxi Province, sharing a unique valine substitution 12 amino acids downstream of the V3 loop. This particular subtype E variant, uniquely found among IDUs in northern Vietnam and southeastern China, is designated E(v). The genetic diversity of CRF01&#95;AE distributed in Quang Ninh (1.5 +/- 0.6%) and Pingxiang City (1.9 +/- 1.2%) was remarkably low, indicating the emerging nature of HIV spread in these areas. It is also noted that the genetic diversity of CRF01&#95;AE among IDUs was consistently lower than that in persons infected sexually, suggesting that fewer closely related CRF01&#95;AE variants were introduced into IDUs and, conversely, that multiple strains of CRF01&#95;AE had been introduced via the sexual route. The data in the present study provide additional evidence that HIV outbreaks among IDUs in northern Vietnam were caused by the recent introduction of a highly homogeneous CRF01&#95;AE variant (E(v)) closely related to that prevailing in nearby southern China.

To investigate the molecular epidemiology of a recent HIV-1 outbreak in northern Vietnam and its relation to the epidemic in surrounding areas, we analyzed 17 HIV-positive blood specimens from 3 heterosexuals, 2 sexually transmitted disease patients, and 12 injecting drug users (IDUs), collected in 4 provinces near Hanoi in 1998. These were compared with the specimens from Ho Chi Minh City (n = 10) and An Giang Province (n = 10) in southern Vietnam and with published sequences from neighboring countries. Genetic subtyping based on the env C2/V3 sequences revealed that HIV-1 subtype E predominated throughout Vietnam in all risk populations; the exception was one typical United States-European-type HIV-1 subtype B detected in a patient in Ho Chi Minh City, the first case of HIV infection identified in Vietnam in 1990. The HIV-1 subtype E sequences identified in 9 of the 12 IDUs from northern provinces were closely related phylogenetically to those in IDUs in nearby Guangxi Province of China, and also shared a common amino acid signature downstream of the env V3 loop region. The low interperson nucleotide diversity among IDUs in northern Vietnam supports the view that HIV-1 subtype E was introduced recently among IDUs in northern Vietnam. These data indicate a linkage between HIV-1 circulating among IDUs in northern Vietnam and southern China, and suggest recent transborder introductions as the likely source of HIV-1 subtype E in northern Vietnam.

Objective: To measure the prevalence of and trends in HIV infections in populations defined by sentinel surveillance in Vietnam., Methods: Surveillance was conducted in eight provinces in 1994, expanded to 12 in 1995 and to 20 in 1996. Sentinel populations were sexually transmitted disease (STD) patients, female sex workers (FSW), injecting drug users (IDU), tuberculosis (TB) patients, pregnant women, and military conscripts. Samples were collected twice yearly for high-risk populations and once yearly for low-risk populations., Results: The overall HIV epidemic in Vietnam comprises several different smaller epidemics. It is primarily associated with injecting drug use, but its extent varies widely throughout the country. In 1998, HIV prevalence rates ranged from 0 to 85% (median, 13.1%), with an aggregate prevalence rate (APR; i.e., the sum of HIV-positive study subjects divided by the sum of all study subjects tested in sentinel provinces) of 17% among IDUs; this ranged from 0 to 14.7% (median, 0.8%), with the APR of 2.4% among FSWs; and from 0 to 6% (median, 0%), with the APR of 0.9% among STD patients. The APRs among antenatal women and army conscripts were less than 0.15%. APRs increased significantly from 1994 to 1998 among STD patients (p < .001), FSWs (p < .001), TB patients (p < .001), and pregnant women (p < .05) in original sentinel provinces. HIV prevalence also increased significantly among younger age groups of IDUs and FSWs., Conclusion: Vietnam's HIV epidemic is increasing predominantly and most rapidly among IDUs. However, prevalence rates among FSWs and STD patients are rising but are still low among pregnant women and army conscripts. Vietnam, at present, is still in the early phase of the HIV epidemic and has time to take effective and appropriate actions.

Previous serological studies have demonstrated that some 60% of intravenous drug abusers (IVDAs) in urban areas of the former South Vietnam are infected with HTLV-II. In the present report we have attempted to characterize the viruses using restriction fragment length polymorphism (RFLP) and nucleotide sequence analysis of the provirus long terminal repeat (LTR) region. RFLP analysis of nine samples demonstrated that all were infected with the HTLV-IIb subtype. The HTLV-IIa subtype was not detected. Phylogenetic analysis of the nucleotide sequences demonstrated that the viruses clustered closely with HTLV-IIb isolates present in IVDAs from the New York City area. The present molecular analysis together with the previously reported absence of HTLV-II infection in North Vietnam supports the view that HTLV-II may have been introduced from the United States to this part of Asia by military personnel during the Vietnam conflict.

A high rate of human T-lymphotropic virus type II (HTLV-II) infection has been documented in intravenous drug abusers (IVDAs) in South Vietnam. We have investigated the molecular characteristics of the virus and have shown that one HTLV-II subtype is predominant in Ho Chi Minh City. This molecular subtype, HTLV-IIb, was identified in a number of South Vietnamese by nucleotide sequence analysis of the long terminal repeat (LTR) region. HTLV-IIa was not found. These findings suggest that HTLV-IIb is endemic in IVDAs in South Vietnam, although IVDAs in urban areas in North America are predominantly infected with HTLV-IIa.

A long-term survey of leprosy patients of all clinical types, starting at the time of diagnosis, was carried out to monitor clinical, bacteriological and immunological parameters at regular intervals during multiple drug therapy (MDT). The patients were assigned to two groups for treatment following WHO guidelines: paucibacillary (PB) and multibacillary (MB). Immunoglobulin levels, specific antibodies, skin-test responses to different soluble mycobacterial antigens (new tuberculins), and in vitro proliferative responses to mitogens and to antigens were measured during treatment, as were clinical changes, the bacterial index, and clinical improvement. No exact relations between disease activity and IgM antibody levels, both IgM immunoglobulin and specific IgM antibody to a species-specific antigen (ND-O-BSA), could be seen for MB patients. Changes in in vitro cell-mediated immunity and skin-test response seemed to be more directly related to the bacterial load and could reflect the improvement of bacteriological and clinical parameters during MDT.

Cataract is the first blinding disease in VIETNAM. Its frequency was studied in Central VIETNAM. Trachoma and xerophthalmia are very common. The evaluation of the prevention program against blindness in Central Areas of VIETNAM is set up. The authors point out an important improvement of the situation. Nevertheless they stress the necessity of carrying on the anti-trachomatous and anti-xerophthalmic campaign. A higher number of cataract operations could be performed since a sufficient number of operating kits was allowed.

Levels of serum immunoglobulins were measured in healthy Vietnamese and in leprosy patients. Healthy Vietnamese had higher levels of IgG, IgA, IgM, and IgE than did healthy Dutch controls, as well as higher levels of three of the four subclasses of IgG (IgG1, IgG2, IgG3). Lepromatous leprosy patients had significant increases in all classes and subclasses of immunoglobulins, except for IgG2, in comparison with local controls. Tuberculoid leprosy patients had more IgG1, IgG3, and IgG4 than did local controls and had higher total IgG levels. The patients had no increase in autoantibodies against tissue antigens compared to local or Dutch controls.

The relationship between immunoglobulin allotypes and leprosy was studied in 91 unrelated patients and 100 healthy controls from Vietnam. Twenty Vietnamese patients with tuberculosis were also typed for the Gm, A2m and Km allotypes. The results were compared with those from the healthy controls. No significant association was found for the allotypes G1m(z,a,x,f) G2m(n), G3m(g,b), A2m(1,2) and Km(1,3) between the two groups of patients and the controls. Heterogeneity in the distribution of G2m(n), G3m(b), A2m(2) and Km(3) was found when 60 polar-lepromatous (LL) patients and 27 borderline-tuberculoid (BT) patients were separated out of the 91 leprosy patients. In the LL patients there appeared to be a significantly higher frequency of G2m(n), G3m(b) and A2m(2) in comparison with the BT patients (P less than 0.05). A significantly lower frequency of Km(3) was found in the LL patients in comparison with the healthy control group (P less than 0.05). The frequencies of the Gm-A2m haplotypes and of the occurrence of the Km(1) and Km(3) in the Vietnamese population were calculated on the basis of the results in the 100 samples of healthy controls. The main haplotype is Gmaf;n;b (frequency 0.676), occurring with A2m1 (0.200), as well as with A2m2 (0.476).

White blood cell counts and the percentages and absolute numbers of lymphocytes in the peripheral blood of active lepromatous (BT, BB, BL) leprosy patients, patients with borderline leprosy, and normal controls were determined. Lepromatous patients showed decreased leukocyte counts and elevated percentages of lymphocytes, resulting in normal absolute lymphocyte counts. The proportion of peripheral blood mononuclear cells forming "active" rosettes, standard (4 degrees C overnight) rosettes, and "high affinity" (29 degrees C for 1 hr) rosettes with sheep erythrocytes, and rosettes with EAC were determined. Lepromatous patients, compared with normal controls, had decreased "active" rosettes, standard rosettes, and "high affinity" rosettes with sheep erythrocytes with an increase in the nonrosetting proportion. Both lepromatous and borderline leprosy patients showed increased percentages of EAC rosettes compared with normal controls.