Volume 11 (2017): Issue 4 (August 2017)

Phthalates are found in products made of plastic. Because of concerns regarding the hazards of phthalate exposure, including endocrine disruption, many countries have regulations to restrict their use in products used by children. However, in Thailand, no such restrictions exist, and data relating to phthalate exposure are scarce.

To determine the level of exposure of Thai children and adolescents to phthalates, and study its associations with sociodemographic data and the exposure to potential sources of phthalates.

Healthy children aged 2–18 y were enrolled into the present cross-sectional study between January 2016 and December 2016 inclusive. Their anthropometric indices and Tanner staging were determined. Urinary concentrations of the phthalate metabolites, monomethyl phthalate (MMP) and mono-n-butyl phthalate (MBP), were determined in spot samples by high-performance liquid chromatography to estimate the level of phthalate exposure. Associations between sociodemographic data, exposure to potential sources of phthalates, and phthalate metabolite concentrations were analyzed.

We included 103 boys and 118 girls with a mean age of 9.4 ± 3.64 (range 2.8–17.1) y and detected MMP in 28.5% and MBP in 88.6%. The geometric means (interquartile range) of urinary MMP and MBP were 3400 (2489, 4642) and 214.4 (164, 279) μg/g creatinine (Cr), respectively. Significant associations were found between exposure to floor cleaning products and Cr-adjusted urinary MMP level (P < 0.05), and paint and Cr-adjusted urinary MMP and MBP levels (P < 0.05). Prepuberty was significantly associated with urinary Cr-adjusted MMP level.

Urinary phthalate metabolite levels were high in a proportion of Thai children and adolescents. Exposure to floor cleaning products and paint is associated with phthalate exposure, and advanced Tanner stage is negatively associated with urinary Cr-adjusted MBP.

The Migraine-Specific Quality of Life Questionnaire version 2.1 (MSQv2.1) is used to evaluate the impact of symptoms on the quality of life (QoL) of migraineurs.

To evaluate primarily the concurrent validity, test–retest reliability, and internal consistency, and secondarily the sensitivity to change of a Thai version of the MSQv2.1.

The original English version of the MSQv2.1 was translated into a Thai version. The Thai version of the MSQv2.1 was assessed for content and language equivalence. Validity of the Thai version of the MSQv2.1 was assessed using migraine characteristics in a prospective study conducted at the Chulalongkorn Comprehensive Headache Centre of King Chulalongkorn Memorial Hospital. Test–retest reliability and internal consistency were tested in migraineurs. Sensitivity to change was evaluated in another group of migraineurs using an 8-week follow-up.

We recruited 30 migraineurs to test the validity, test–retest reliability, and internal consistency of the Thai version of the MSQv2.1 and 11 migraineurs to test its sensitivity to change. The Thai version of the MSQv2.1 scores were significantly correlated with migraine symptoms (inverse coefficient range from –0.62 to –0.39) except for associated symptoms, which had no correlation with any of the dimensions or overall QoL score. Spearman’s correlation coefficient for test–retest reliability was 0.56–0.83, and Cronbach’s α for internal consistency was 0.91–0.96. Headache, including average pain duration per attack, pain severity score (numeric rating scale), associated symptoms and dimensions, and overall QoL score of the Thai version of MSQv2.1 improved over time (P < 0.05). Moreover, improvement in headache correlated (coefficient range 0.67–0.77) with improvement in overall QoL score and some dimensions of the Thai version of the MSQv2.1 (coefficient range 0.66–0.77).

The Thai version of the MSQv2.1 had validity, acceptable internal consistency, moderate-to-strong test–retest reliability, and strong correlation between improvement in headache severity and overall QoL score. A future study with a larger sample size and longer follow-up is required for better estimates of internal consistency and sensitivity to change.

Antioxidant levels increase to protect cell homeostasis when oxidant generation is increased by drug or inhibitor treatment. If the oxidant–antioxidant equilibrium is disrupted, oxidative stress will occur.

To determine the effects of various potassium channel inhibitors in the disruption of oxidant–antioxidant equilibrium in breast cancer cell lines with various phenotypes.

MCF-7 or MDA-MB-231 breast cancer cells were treated with tetraethylammonium chloride (5 mM; TEA), 4-aminopyridine (5 mM; 4-AP), margatoxin (25 nM; MgTX), or astemizole (200 nM; AST). After treatment, total antioxidant, oxidant, and oxidative stress levels were determined.

Incubation with TEA, 4-AP, MgTX, and AST increased oxidative stress in both MCF-7 and MDA-MB-231 cells (P < 0.001). Specific inhibitors of calcium-activated potassium channels and ether á go-go 1-related potassium channels produce greater oxidative stress than other inhibitors in MCF-7 breast cancer cells, whereas in MDA-MB-231 cells, the nonselective channel inhibitor 4-AP produces the greatest oxidative stress.

Potassium channel inhibitors used in our study disrupted the antioxidant–oxidant equilibrium and increased oxidative stress in the cancer cell lines. Although all of the channel inhibitors increased oxidative stress in cells, TEA and AST were the most effective inhibitors in MCF-7 cells. 4-AP was the most effective inhibitor in MDA-MB-231 cells. Voltage-gated potassium channels are attractive targets for anticancer therapy, and their inhibitors may enhance the effects of anticancer drugs.

Driving performance is influenced by human, vehicular, and environmental factors.

To investigate the effects of distraction tasks, such as sending a text message (STM) and searching a navigation device (SN), on the driving performance of experienced taxi drivers.

Twelve male taxi drivers (age: 56.3 ± 4.4 y; experience: 28.4 ± 6.4 y) and 14 female taxi drivers (age: 55.5 ± 3.5 y; experience: 19.4 ± 5.0 y) drove in a simulator at a constant speed (90 km/h) for 2 min while maintaining a gap of 30 m from the car in front, also traveling at 90 km/h. Participants were instructed to drive only for the first 1 min (control phase). For an additional 1 min (task phase), they were instructed to drive only, drive + STM, or drive + SN.

Compared with driving only, during driving + STM or driving + SN, the drivers’ skin conductance level was relatively increased, suggesting that the distraction task increased the drivers’ workload and sympathetic nervous system activity. Compared with driving only, during driving + STM or driving + SN, the average distance from the car in front, speed deviation, and anterior–posterior and medial–lateral coefficients of variation increased, suggesting that maintaining the instructed gap and speed, and the longitudinal and transverse control of the car, was more difficult because of the distraction task.

Even for highly experienced taxi drivers, distraction tasks increased workload, increased the difficulty of vehicle control, and detracted from safe driving.

To our knowledge, no study reported so far has investigated appropriate vancomycin dosing, which is important for treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection in Thai patients of various ages and with varying degrees of renal function.

To predict vancomycin dosing for MRSA in Thai patients of various ages and with varying degrees of renal functions.

Monte Carlo simulation and minimal inhibitory concentration (MIC) distribution of MRSA from a hospital in Thailand were used to predict the area under the curve in 24 h/MIC >400 and trough concentration (C_trough) <20 mg/L of 9 vancomycin dosage regimens for Thai patients stratified by age and renal function.

Vancomycin dosing at least 2.5 g per day can attain cumulative fraction of response (CFR) of ≥90% in every age group. Vancomycin dosage achieving CFR of ≥90% for simulated patients with creatinine clearance (CL_cr) was calculated using the Cockcroft–Gault equation. Appropriate vancomycin doses for Thai patients infected with MRSA with CL_cr of <40, 40–60, >60–80, and >80 mL/min were 1.5 g every 24 h, 1.25 g every 12 h, 1 g every 8 h, and 1.75 g every 12 h, respectively. However, more than a half of patients simulated using these regimens have a vancomycin C_trough of >20 mg/L.

Although vancomycin doses attaining a CFR of ≥90% can treat MRSA infection effectively, the regimens may cause kidney injury. The regimens have a probability of target attainment of 100%, and most patients can attain C_trough of <20 mg/L.

Understanding the contribution of efflux pumps to the resistance of antibiotics is useful when considering strategies for antimicrobial therapy.

To assess the role of efflux activity on the resistance of antibiotics commonly used in hospitals.

We analyzed the efflux activity of 120 clinical isolates of Acinetobacter baumannii using an Hoechst 33342 (H33342) dye-accumulation assay. We compared the indicators for efflux activity of susceptible and non-susceptible groups of each of 16 tested antibiotics. To determine the role of efflux activity on resistance to an antibiotic, we used 3 criteria based on the results of the H33342-accumulation assay.

The evaluation suggests that efflux activity contributed to resistance to the following 11 antibiotics: cefepime, cefotaxime, ceftazidime, ciprofloxacin, gentamicin, imipenem, meropenem, piperacillin, piperacillin/tazobactam, ticarcillin/ clavulanic acid, and tigecycline. However, ampicillin/sulbactam, minocycline, and trimethoprim/sulfamethoxazole did not meet the criteria, suggesting resistance may not be mediated by efflux activity. A significant difference in efflux activity was observed between bacteria belonging to the multidrug-resistant Acinetobacter baumannii (MDRAB) group and those belonging to the non-MDRAB group.

Efflux activity may contribute to multidrug resistance and particularly resistance to numerous antibiotics used in hospitals. These antibiotics would be good candidates for combination therapeutic regimens consisting of an antibiotic and an efflux pump inhibitor as an adjuvant to combat drug efflux.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency poses problems for the treatment of Plasmodium vivax malaria, as the 8-aminoquinolines, used to eliminate liver hypnozoites, cause hemolysis in G6PD-deficient individuals.G6PD deficiency is an X-linked disorder that can be linked to other conditions determined by genes located nearby on the Xq28 band of the X chromosome, including red–green color blindness. A Karen population has undergone recent positive selection for G6PD deficiency with extended long-range haplotypes around G6PD.

To determine the association between G6PD deficiency and color blindness in a Karen population that lives in an area endemic for P. vivax and that is already known to display long-range haplotypes around G6PD because of the recent positive selection of the Mahidol G6PD deficiency allele.

We examined the phenotypic association between G6PD deficiency and color blindness.

Of 186 male participants successfully assessed for color blindness using the Ishihara 38 plates test, 10 (5.4%) were red–green color blind, while 1 individual was totally color blind. There was a nonsignificant trend toward negative association (repulsion) between G6PD deficiency and red–green color blindness; 34/35 individuals with the Mahidol variant of G6PD deficiency had normal vision, while 9 of the 10 red–green color blind individuals were G6PD normal. A single individual had both conditions.

Despite the long-range haplotype associated with G6PD deficiency in this population, color blindness is not informative in terms of predicting G6PD deficiency in this population. The most likely explanation is that there are multiple genetic causes of red–green color blindness.

Human cases of highly pathogenic avian-origin influenza A/H5N1 infection continue to be reported to the World Health Organization, and recent outbreaks of human cases of other zoonotic influenza strains highlight the continued need for strategies to mitigate influenza pandemic potential.

A Phase II–III randomized, placebo-controlled, observer-blind trial was conducted to assess the immunogenicity, reactogenicity, and safety of two 1.9 μg hemagglutinin doses of AS03_B-adjuvanted H5N1 (AS03_B-H5N1; A/Indonesia) vaccine in children (6 months to <18 years old) of Thailand, the United States, and Canada (Year 1, published elsewhere). After database lock in Year 1, the trial was unblinded, and children who had been randomized to receive placebo and continued to fulfill the eligibility criteria were invited to participate in an open-label, one-way, crossover safety extension phase, in which they received AS03_B-H5N1 vaccine. Here we report the safety analysis in Year 2.

A total of 155 children were vaccinated in Year 2. The most frequent solicited adverse event (AE) during 7 days post vaccination was injection site pain. Irritability or fussiness was reported in about one-third of younger children (aged <6 years) during 7 days post vaccination and was the most common solicited general AE in this age group. Postvaccination temperature (≥38°C) was reported in 4 (5.1%) children. The most common solicited general AEs in older children (aged ≥6 years) were muscle aches, headache, and fatigue. The AS03_B-H5N1 vaccine had a clinically acceptable safety profile up to 385 days post vaccination.

Safety in the crossover phase was acceptable and consistent with that observed in vaccine recipients in the randomized, blinded phase of the study.

ClinicalTrials.gov: NCT01310413.

Maxillofacial injury is a common injury in trauma patients. The incidence, associated injuries and causes have been never reported for King Chulalongkorn Memorial Hospital (KCMH).

To report the incidence, associated injuries, age groups, treatments, and behavioral risks in maxillofacial patients who were admitted to KCMH in the past decade.

We conducted a retrospective descriptive analysis of patients from January 1, 2006, to December 31, 2015, to evaluate the age groups, causes, sites of facial bone fracture, associated injuries, treatments, and behavioral risks.

There were 1,275 patients (79% male and 21% female). The most common age group was 21–30 years (30.6%), followed by 11–20 years (19.5%) and 31–40 years (18.8%). The most common cause of injury was motorcycle accident (39.7%), and the most common associated injury was head injury (58%). The total number of fractures were 1,526, with the most common fracture site being the zygomaticomaxillary complex (38.6%), followed by mandible (21.8%) and nasal bone (17.8%). Most fractures were treated using open reduction and internal fixation with plates and screws.

The main cause of maxillofacial injury is motorcycle accident even though the government launched a policy named “Decade of Action for Road Safety 2011–2020” to reduce road traffic deaths. Thailand continues to need stronger law enforcement to reduce risky motorcycle driving behavior.