Maternal and Perinatal Factors Associated With Childhood Brain Tumors: A Case-Control Study in Vietnam.

INTRODUCTION: Brain cancer is the leading cause of cancer-related deaths in children and the majority of childhood brain tumors are diagnosed without determination of their underlying etiology. Little is known about risk factors for childhood brain tumors in Vietnam. The objective of this case-control study was to identify maternal and perinatal factors associated with brain tumors occurring in young Vietnamese children and adolescents. METHODS: We conducted a hospital-based case-control study at Viet Duc University Hospital in Hanoi, Vietnam. Cases consisted of children with brain tumors aged 0-14 years old admitted to the hospital from January 2020 to July 2022 while the controls were age and sex-matched hospitalized children diagnosed with head trauma. Perinatal characteristics were abstracted from hospital medical records and maternal medical, behavioral, and sociodemographic factors were collected through in-person interviews. Conditional logistic regression models were used to examine maternal and perinatal factors associated with childhood brain tumors. RESULTS: The study sample included 220 children (110 cases and 110 controls) whose average age was 8.9 years and 41.8% were girls. Children born to mothers aged greater than 30 years at the time of the child's birth had a higher risk of childhood brain tumors compared to those born to mothers aged from 18 to 30 years old (OR = 2.55; 95% CI: 1.13-5.75). Additionally low maternal body mass index prior to the current pregnancy of <18.5 kg/m2 significantly increased the odds of having a child with a brain tumor in relation to normal maternal body mass index from 18.5-22.9 kg/m2 (OR = 3.19; 95% CI: 1.36 - 7.50). CONCLUSION: Advanced maternal age and being markedly underweight were associated with an increased odds of having a child with a brain tumor. A population-based study with larger sample size is needed to confirm and extend the present findings.

Field and laboratory investigation of highly pathogenic avian influenza H5N6 and H5N8 in Quang Ninh province, Vietnam, 2020 to 2021

Background@#Avian influenza (AI) is a contagious disease that causes illness and death in poultry and humans. High pathogenicity AI (HPAI) H5N6 outbreaks commonly occur in Quang Ninh province bordering China. In June 2021, the first HPAI H5N8 outbreak occurred at a Quang Ninh chicken farm. @*Objectives@#This study examined the risk factors associated with HPAI H5N6 and H5N8 outbreaks in Quang Ninh. @*Methods@#A retrospective case-control study was conducted in Quang Ninh from Nov 2021 to Jan 2022. The cases were households with susceptible poultry with two or more clinical signs and tested positive by real-time reverse transcription polymerase chain reaction. The controls were households in the same village as the cases but did not show clinical symptoms of the disease. Logistic regression models were constructed to assess the risk factors associated with HPAI outbreaks at the household level. @*Results@#There were 38 cases with H5N6 clade 2.3.4.4h viruses (n = 35) and H5N8 clade 2.3.4.4b viruses (n = 3). Compared to the 112 controls, raising poultry in uncovered or partially covered ponds (odds ratio [OR], 7.52; 95% confidence interval [CI], 1.44–39.27), poultry traders visiting the farm (OR, 8.66; 95% CI, 2.7–27.69), farms with 50–2,000 birds (OR, 3.00; 95% CI, 1.06–8-51), and farms with ≥ 2,000 birds (OR, 11.35; 95% CI, 3.07–41.94) were significantly associated with HPAI outbreaks. @*Conclusions@#Combining biosecurity measures, such as restricting visitor entry and vaccination in farms with more than 50 birds, can enhance the control and prevention of HPAI in Quang Ninh and its spread across borders.

Antibiotic resistance and heteroresistance in Helicobacter pylori isolates from symptomatic Vietnamese children: A prospective multicenter study.

BACKGROUND: Antibiotic resistance of Helicobacter pylori (H. pylori) is increasing worldwide, with geographical variations, impacting the treatment outcomes. This study assessed the antibiotic resistance patterns of H. pylori in Vietnamese children. MATERIALS AND METHODS: Symptomatic children undergoing gastroduodenoscopy at two tertiary Children's Hospitals in Ho Chi Minh City were recruited. Antral and corpus biopsies were obtained and cultured separately. Susceptibility to amoxicillin (AMO), clarithromycin (CLA), metronidazole (MET), levofloxacin (LEV), and tetracycline (TET) was determined using E-test. Polymerase chain reaction was performed on another antral biopsy to detect the urease gene, cytotoxin-associated gene A (cagA), vacuolating cytotoxin A (vacA) genotypes, and 23S rRNA mutations conferring CLA resistance. RESULTS: Among 123 enrolled children, a high primary resistance rate was found for CLA (68.5%, 61/89), followed by LEV (55.1%), MET (31.5%), AMO (25.8%), and TET (1.1%). Secondary resistance rates were 82.1% (7/28), 71.4%, 53.6%, and 3.6% for CLA, LEV, MET, and TET, respectively. Multidrug resistance was frequent (67.7%), with common patterns including CLA + LEV (20.3%) and CLA + MTZ + LEV (15.2%). Heteroresistance was detected in eight children (6.5%). The A2143G mutation was detected in 97.5% (119/122) of children. 86.1% of children had positive cagA strains and 27.9% had multiple vacA genotypes. No factor was significantly associated with antibiotic resistance. CONCLUSIONS: The alarming rate of antibiotic resistance for H. pylori, especially for CLA, with emerging multi- and hetero-resistant strains, pose a major treatment challenge that precludes CLA use as empirical therapy. Biopsies from both antrum and corpus can improve H. pylori culture, allowing tailored treatment based on antimicrobial susceptibility.

Emergence of amoxicillin resistance and identification of novel mutations of the pbp1A gene in Helicobacter pylori in Vietnam.

BACKGROUND: Amoxicillin-resistant Helicobacter pylori (H. pylori) strains seem to have increased over time in Vietnam. This threatens the effectiveness of H. pylori eradication therapies with this antibiotic. This study aimed to investigate the prevalence of primary resistance of H. pylori to amoxicillin and to assess its association with pbp1A point mutations in Vietnamese patients. MATERIALS AND METHODS: Naive patients who presented with dyspepsia undergoing upper gastrointestinal endoscopy were recruited. Rapid urease tests and PCR assays were used to diagnose H. pylori infection. Amoxicillin susceptibility was examined by E-tests. Molecular detection of the mutant pbp1A gene conferring amoxicillin resistance was carried out by real-time PCR followed by direct sequencing of the PCR products. Phylogenetic analyses were performed using the Tamura-Nei genetic distance model and the neighbor-joining tree building method. RESULTS: There were 308 patients (46.1% men and 53.9% women, p = 0.190) with H. pylori infection. The mean age of the patients was 40.5 ± 11.4 years, ranging from 18 to 74 years old. The E-test was used to determine the susceptibility to amoxicillin (minimum inhibitory concentration (MIC) ≤ 0.125 µg/ml) in 101 isolates, among which the rate of primarily resistant strains to amoxicillin was 25.7%. Then, 270 sequences of pbp1A gene fragments were analysed. There were 77 amino acid substitution positions investigated, spanning amino acids 310-596, with the proportion varying from 0.4 to 100%. Seven amino acid changes were significantly different between amoxicillin-sensitive (AmoxS) and amoxicillin-resistant (AmoxR) samples, including Phe366 to Leu (p <  0.001), Ser414 to Arg (p <  0.001), Glu/Asn464-465 (p = 0.009), Val469 to Met (p = 0.021), Phe473 to Val (p <  0.001), Asp479 to Glu (p = 0.044), and Ser/Ala/Gly595-596 (p = 0.001). Phylogenetic analyses suggested that other molecular mechanisms might contribute to amoxicillin resistance in H. pylori in addition to the alterations in PBP1A. CONCLUSIONS: We reported the emergence of amoxicillin-resistant Helicobacter pylori strains in Vietnam and new mutations statistically associated with this antimicrobial resistance. Additional studies are necessary to identify the mechanisms contributing to this resistance in Vietnam.

Electronic structures and spectroscopic signatures of diiron intermediates generated by O2 activation of nonheme iron(II)-thiolate complexes.

The activation of O2 at thiolate-ligated iron(II) sites is essential to the function of numerous metalloenzymes and synthetic catalysts. Iron-thiolate bonds in the active sites of nonheme iron enzymes arise from either coordination of an endogenous cysteinate residue or binding of a deprotonated thiol-containing substrate. Examples of the latter include sulfoxide synthases, such as EgtB and OvoA, that utilize O2 to catalyze tandem S-C bond formation and S-oxygenation steps in thiohistidine biosyntheses. We recently reported the preparation of two mononuclear nonheme iron-thiolate complexes (1 and 2) that serve as structural active-site models of substrate-bound EgtB and OvoA (Dalton Trans. 2020, 49, 17745-17757). These models feature monodentate thiolate ligands and tripodal N4 ligands with mixed pyridyl/imidazolyl donors. Here, we describe the reactivity of 1 and 2 with O2 at low temperatures to give metastable intermediates (3 and 4, respectively). Characterization with multiple spectroscopic techniques (UV-vis absorption, NMR, variable-field and -temperature Mössbauer, and resonance Raman) revealed that these intermediates are thiolate-ligated iron(III) dimers with a bridging oxo ligand derived from the four-electron reduction of O2. Structural models of 3 and 4 consistent with the experimental data were generated via density functional theory (DFT) calculations. The combined experimental and computational results illuminate the geometric and electronic origins of the unique spectral features of diiron(III)-µ-oxo complexes with thiolate ligands, and the spectroscopic signatures of 3 and 4 are compared to those of closely-related diiron(III)-µ-peroxo species. Collectively, these results will assist in the identification of intermediates that appear on the O2 reaction landscapes of iron-thiolate species in both biological and synthetic environments.

Evaluating Preschool Visual Attentional Selective-Set: Preliminary ERP Modeling and Simulation of Target Enhancement Homology.

We reanalyzed, modeled and simulated Event-Related Potential (ERP) data from 13 healthy children (Mean age = 5.12, Standard Deviation = 0.75) during a computerized visual sustained target detection task. Extending an ERP-based ACT-R (Adaptive Control of Thought-Rational) neurocognitive modeling approach, we tested whether visual sustained selective-set attention in preschool children involves the enhancement of neural response to targets, and it shows key adult-like features (neurofunctional homology). Blinded automatic peaks analysis was conducted on vincentized binned grand ERP averages. Time-course and distribution of scalp activity were detailed through topographic mapping and paths analysis. Reaction times and accuracy were also measured. Adult Magnetic Resonance Imaging-based mapping using ACT-R dipole source modeling and electric-field spiking simulation provided very good fit with the actual ERP data (R2 > 0.70). In most electrodes, between 50 and 400 ms, ERPs concurrent with target presentation were enhanced relative to distractor, without manual response confounds. Triangulation of peak analysis, ACT-R modeling and simulation for the entire ERP epochs up to the moment of manual response (~700 ms, on average) suggested converging evidence of distinct but interacting processes of enhancement and planning for response release/inhibition, respectively. The latter involved functions and structures consistent with adult ERP activity which might correspond to a large-scale network, implicating Dorsal and Ventral Attentional Networks, corticostriatal loops, and subcortical hubs connected to prefrontal cortex top-down working memory executive control. Although preliminary, the present approach suggests novel directions for further tests and falsifiable hypotheses on the origins and development of visual selective attention and their ERP correlates.