[Show abstract][Hide abstract] ABSTRACT: Adducts were synthesized from thiokol and epoxy resin using triethylamine as a catalyst, and their structure and molecular weights were determined. The synthesized adducts, which possessed an epoxide group on their chain as a modifier to enhance the toughness of the epoxy resin, were well dispersed in the epoxy matrix, resulting in the successful manufacture of laminate composites made from glass fiber/epoxy resin (GF/EP). The microstructure and mechanical properties, such as the tensile strength, impact resistance and mode I interlaminar fracture toughness, were investigated and compared with those of the GF/EP system. The addition of the adduct to the epoxy matrix led to an increase in both the mode I interlaminar fracture toughness and IZOD impact resistance of the GF/EP.
[Show abstract][Hide abstract] ABSTRACT: Objective: To investigate the profile of drug resistance-associated mutations in pol gene of antiretroviral therapy-naïve HIV-1 infected children enrolled in National Hospital Pediatrics in Northern Vietnam. Methods: Genotyping was performed on 134 antiretroviral therapy-naïve plasma samples from HIV-1 infected children. HIV-1 pol gene was amplified using primers for protease and reverse transcriptase and sequenced using the BigDye chemistry. The mutations were analyzed based on the Stanford University HIV-1 Drug Resistance Database and ISA-USA list. Results: All the children were infected with HIV-1 CRF01_AE subtype. Major protease inhibitor resistance mutations were found in 2 children (2.3%) and reverse-transcriptase inhibitor resistance mutations were found in 5 children (7.7%). The protease inhibitor mutations were observed M46L and L90M and reverse-transcriptase inhibitor mutations were M184I, K65R, Q151M, T69N, L210W, Y181C, M230L and K101E. Conclusions: This is the first study reporting the prevalence of drug resistance-associated mutation in naïve HIV-1 infected children in Northern Vietnam. These data also emphasize the importance of genotypic resistance testing of HIV-1 infected children before initiating treatment in order to achieve better clinical outcome.
No preview · Article · Sep 2015 · Asian Pacific Journal of Tropical Disease
[Show abstract][Hide abstract] ABSTRACT: Three different types of additives, thiokol, epoxidized natural rubber (ENR) and epoxidized linseed oil (ELO), were dispersed in an epoxy matrix before being used in glass fiber (GF) composites, and their effects on the mechanical and dielectric properties of epoxy resin and glass fiber reinforced epoxy composites (GF/EP) were examined. The addition of each of 7 phr ENR, 9 phr ELO and 5 phr thiokol into the epoxy resin increased the fracture toughness significantly by 56.9, 43.1, and 80.0%, respectively, compared to the unmodified resin. The mode I interlaminar fracture toughness of the GF/EP at propagation was also improved by 26.9, 18.3 and 32.7% when each of 7 phr ENR, 9 phr ELO, and 5 phr thiokol, respectively, was dispersed in the epoxy matrix. Scanning electron microscopy showed that the additives reduced crack growth in the GF/EP, whereas their dielectric measurements showed that all these additives had no additional effect on the real permittivity and loss factor of the GF/EP.
[Show abstract][Hide abstract] ABSTRACT: Differences between urban and rural settings can be seen as a very important example of gaps between groups in a population. The aim of this paper is to compare an urban and a rural area regarding child growth during the first two years of life as related to mother's use of antenatal care (ANC), breastfeeding and reported symptoms of illness.
The studies were conducted in two Health and Demographic Surveillance Sites, one rural and one urban in Hanoi, Vietnam.
We found that children in the urban area grow faster than those in the rural area. There were statistical associations between growth and the education of the mother as well as household resources. There were positive correlations between the number of ANC visits and child growth. We also saw a positive association between growth and early initiation (first hour of life) of breastfeeding but the reported duration of exclusive breastfeeding was not statistically significantly related to growth. Reporting symptoms of illness was negatively correlated to growth, i.e. morbidity is hampering growth.
All predictors of growth discussed in this article, ANC, breastfeeding and illness, are associated with social and economic conditions. To improve and maintain good conditions for child growth it is important to strengthen education of mothers and household resources particularly in the rural areas. Globalization and urbanization means obvious risks for increasing gaps not least between urban and rural areas. Improvement of the quality of programs for antenatal care, breastfeeding and integrated management of childhood illness are also needed in Vietnam.
[Show abstract][Hide abstract] ABSTRACT: icroscopic Observation Drug Susceptibility (MODS) has been shown to be an effective and rapid technique for early diagnosis of tuberculosis (TB). Thus far only a limited number of studies evaluating MODS have been performed in children and in extra-pulmonary tuberculosis. This study aims to assess relative accuracy and time to positive culture of MODS for TB diagnosis in children admitted to a general pediatric hospital in Vietnam.
Specimens from children with suspected TB were tested by smear, MODS and Lowenstein-Jensen agar (LJ). 1129 samples from 705 children were analyzed, including sputum (n = 59), gastric aspirate (n = 775), CSF (n = 148), pleural fluid (n = 33), BAL (n = 41), tracheal fluid (n = 45), other (n = 28). 113 TB cases were defined based on the "clinical diagnosis" (confirmed and probable groups) as the reference standard, in which 26% (n = 30) were diagnosed as extra-pulmonary TB. Analysis by patient shows that the overall sensitivity and specificity of smear, LJ and MODS against "clinical diagnosis" was 8.8% and 100%, 38.9% and 100%, 46% and 99.5% respectively with MODS significantly more sensitive than LJ culture (P = 0.02). When analyzed by sample type, the sensitivity of MODS was significantly higher than LJ for gastric aspirates (P = 0.004). The time to detection was also significantly shorter for MODS than LJ (7 days versus 32 days, P<0.001).
ODS is a sensitive and rapid culture technique for detecting TB in children. As MODS culture can be performed at a BSL2 facility and is inexpensive, it can therefore be recommended as a routine test for children with symptoms suggestive of TB in resource-limited settings.
[Show abstract][Hide abstract] ABSTRACT: This study aimed to evaluate the effectiveness of gancyclovir (GCV) treatment for severe cytomegalovirus (CMV)-associated pneumonia in immunocompetent children.
We enrolled patients with CMV-associated severe pneumonia admitted to the Vietnam National Hospital of Pediatrics, Hanoi, Vietnam, from January 2010 to December 2011. On admission, though respiratory bacteria and viruses were not detected in tracheal aspirates, more than 5 x 103 copies/mL of CMV-DNA were detected in both tracheal aspirates and in blood plasma. GCV was given intravenously at a dose of 10 mg/kg/24 h for a duration of 14 days at most. The dose was then reduced to 5 mg/kg/24 h until CMV-DNA was not detected in plasma. The main study variables included clinical symptoms, complete blood count, hepatic and renal function, chest X-ray, CMV viral load, duration of GCV treatment and outcome.
Forty-three patients were enrolled in the study. The median age of patients was 57 (interquartile range [IQR] 45--85) days. Clinical and laboratory findings included anemia (67.4%), leukocytosis (90.7%), hepatosplenomegaly (60.5%), elevated liver enzymes (74.4%), decreased ratio of CD4:CD8-positive T lymphocytes (69.4%), and decreased serum IgG concentration (25.7%). The median duration of GCV treatment was 12 days (IQR 7-21). Thirty-seven patients (86.0%) showed normal chest X-rays at the end of treatment. One infant died (2.3%); the other children (97.7%) were discharged in good condition. There was no severe toxicity associated with GCV treatment.
GCV is safe and effective for the treatment of severe CMV-associated pneumonia in children.
[Show abstract][Hide abstract] ABSTRACT: Fulminant cardiopulmonary failure is a severe complication of hand, foot and mouth diseases due to enterovirus 71 infection, with a high mortality rate. The treatment is mainly supportive with aggressive cardiopulmonary resuscitation. We report the use of continuous veno-venous hemofiltration in a patient with pulmonary edema and shock due to enterovirus 71 infection. To the best of our knowledge, this is the first report of the use of continuous veno-venous hemofiltration to successfully treat a patient with fulminant cardiopulmonary failure due to enterovirus 71 infection.
A 36-month-old Asian girl presented to our hospital with pulmonary edema, refractory hypotension and severe cardiac dysfunction due to enterovirus 71 infection. In addition to the standard management and care, we performed continuous veno-venous hemofiltration to overcome refractory shock and our patient eventually made a full recovery. At a three-month follow-up, a full assessment revealed no neurological sequelae.
In the management of patients with enterovirus 71-related fulminant cardiopulmonary failure, early continuous veno-venous hemofiltration may be considered as an alternative treatment to improve patient survival and to prevent severe neurological disabilities.
Full-text · Article · Jun 2012 · Journal of Medical Case Reports
[Show abstract][Hide abstract] ABSTRACT: Good infant growth is important for future health. Assessing growth is common in pediatric care all over the world, both at the population and individual level. There are few studies of birth weight and growth studies comparing urban and rural communities in Vietnam. The first aim is to describe and compare the birth weight distributions and physical growth (weight and length) of children during their first year in one rural and one urban area of Hanoi Vietnam. The second aim is to study associations between the anthropometric outcomes and indicators of the economic and educational situations.
Totally 1,466 children, born from 1st March, 2009 to June 2010, were followed monthly from birth to 12 months of age in two Health and Demographic Surveillance Sites; one rural and one urban. In all, 14,199 measurements each of weight and length were made. Birth weight was recorded separately. Information about demographic conditions, education, occupation and economic conditions of persons and households was obtained from household surveys. Fractional Polynomial models and standard statistical methods were used for description and analysis.
Urban infants have higher birth weight and gain weight faster than rural infants. The mean birth weight for urban boys and girls were 3,298 grams and 3,203 grams as compared to 3,105 grams and 3,057 grams for rural children. At 90 days, the urban boys were estimated to be 4.1% heavier than rural boys. This difference increased to 7.2% at 360 days. The corresponding difference for girls was 3.4% and 10.5%. The differences for length were comparatively smaller. Both birth weight and growth were statistically significantly and positively associated with economic conditions and mother education.
Birth weight was lower and the growth, weight and length, considerably slower in the rural area, for boys as well as for girls. The results support the hypothesis that the rather drastic differences in maternal education and economic conditions lead to poor nutrition for mothers and children in turn causing inferior birth weight and growth.
[Show abstract][Hide abstract] ABSTRACT: Influenza virus infection causes severe respiratory disease such as that due to avian influenza (H5N1). Influenza A viruses proliferate in human epithelial cells, which produce inflammatory cytokines/chemokines as a "cytokine storm" attenuated with the viral nonstructural protein 1 (NS1). Cytokine/chemokine production in A549 epithelial cells infected with influenza A/H1N1 virus (PR-8) or nonstructural protein 1 (NS1) plasmid was examined in vitro. Because tumor necrosis factor-α (TNF-α) and regulated upon activation normal T-cell expressed and secreted (RANTES) are predominantly produced from cells infected with PR-8 virus, the effects of mRNA knockdown of these cytokines were investigated. Small interfering (si)TNF-α down-regulated RANTES expression and secretion of RANTES, interleukin (IL)-8, and monocyte chemotactic protein-1 (MCP-1). In addition, siRANTES suppressed interferon (IFN)-γ expression and secretion of RANTES, IL-8, and MCP-1, suggesting that TNF-α stimulates production of RANTES, IL-8, MCP-1, and IFN-γ, and RANTES also increased IL-8, MCP-1, and IFN-γ. Furthermore, administration of TNF-α promoted increased secretion of RANTES, IL-8, and MCP-1. Administration of RANTES enhanced IL-6, IL-8, and MCP-1 production without PR-8 infection. These results strongly suggest that, as an initial step, TNF-α regulates RANTES production, followed by increase of IL-6, IL-8, and MCP-1 and IFNs concentrations. At a later stage, cells transfected with viral NS1 plasmid showed production of a large amount of IL-8 and MCP-1 in the presence of the H(2)O(2)-myeloperoxidse (MPO) system, suggesting that NS1 of PR-8 may induce a "cytokine storm" from epithelial cells in the presence of an H(2)O(2)-MPO system.
Full-text · Article · Dec 2011 · Microbiology and Immunology
[Show abstract][Hide abstract] ABSTRACT: Mitochondrial acetoacetyl-CoA thiolase (T2) deficiency is an inborn error of metabolism affecting isoleucine catabolism and ketone body utilization. This disorder is clinically characterized by intermittent ketoacidotic episodes with no clinical symptoms between episodes. In general, T2 gene mutations are heterogeneous. No common mutations have been identified and more than 70 mutations have been identified in 70 patients with T2 deficiency (including unpublished data). We herein identified a common mutation, R208X, in Vietnamese patients. We identified R208X homozygously in six patients and heterozygously in two patients among eight Vietnamese patients. This R208X mutation was also identified heterozygously in two Dutch patients, however, R208X mutant alleles in the Vietnamese have a different haplotype from that in the Dutch, when analyzed using Msp I and Taq I polymorphisms in the T2 gene. The R208X mutant allele was not so frequent in the Vietnamese since we could not find that mutant allele in 400 healthy Vietnamese controls using the Nla III restriction enzyme assay. DNA diagnosis of T2 deficiency may be applicable to the Vietnamese population.
No preview · Article · May 2010 · Molecular Genetics and Metabolism
[Show abstract][Hide abstract] ABSTRACT: A clinical picture of patients with acute respiratory distress syndrome (ARDS) induced by highly pathogenic avian influenza
A (H5N1) has been reported. We reviewed 37 sets of clinical data for pediatric patients with ARDS at the National Hospital
of Pediatrics (Hanoi, Vietnam); 12 patients with H5N1-positive and 25 with H5N1-negative ARDS were enrolled. The H5N1-negative
patients had a clinical picture and mortality rate similar to that for the pediatric ARDS patients. However, the H5N1-positive
patients had ARDS with normal ventilation capacity at the time of hospital admission, then rapidly proceeded to severe respiratory
failure. The survival probability and days until final outcome in groups of H5N1-positive (n=12) vs. H5N1-negative (n=25)
patients were 17% versus 52% and 12.3±5.7 days (median, 11 days) versus 21.5±13.8 days (median, 22 days), respectively. Our
observations clarified the clinical picture of H5N1-induced fulminant ARDS and also confirmed that relatively older age (∼6
years of age), high fever at onset, and leukopenia and/or thrombocytopenia at the time of hospital admission are risk parameters
for H5N1-induced fulminant ARDS
Full-text · Article · Sep 2009 · The Journal of Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.