panida navasumrit - Academia.edu (original) (raw)
Papers by panida navasumrit
Toxicology and Applied Pharmacology, 2017
Early-life exposure to arsenic increases risk of developing a variety of non-malignant and malign... more Early-life exposure to arsenic increases risk of developing a variety of non-malignant and malignant diseases. Arsenic-induced carcinogenesis may be mediated through epigenetic mechanisms and pathways leading to inflammation. Our previous study reported that prenatal arsenic exposure leads to increased mRNA expression of several genes related to inflammation, including COX2, EGR1, and SOCS3. This study aimed to investigate the effects of arsenic exposure on promoter DNA methylation and mRNA expression of these inflammatory genes (COX2, EGR1, and SOCS3), as well as the generation of 8-nitroguanine, which is a mutagenic DNA lesion involved in inflammation-related carcinogenesis. Prenatally arsenic-exposed newborns had promoter hypomethylation of COX2, EGR1, and SOCS3 in cord blood lymphocytes (p b 0.01). A follow-up study in these prenatally arsenic-exposed children showed a significant hypomethylation of these genes in salivary DNA (p b 0.01). In vitro experiments confirmed that arsenite treatment at short-term high doses (10-100 μM) and long-term low doses (0.5-1 μM) in human lymphoblasts (RPMI 1788) caused promoter hypomethylation of these genes, which was in concordance with an increase in their mRNA expression. Additionally, the level of urinary 8-nitroguanine was significantly higher (p b 0.01) in exposed newborns and children, by 1.4-and 1.8-fold, respectively. Arsenic accumulation in toenails was negatively correlated with hypomethylation of these genes and positively correlated with levels of 8-nitroguanine. These results indicated that early-life exposure to arsenic causes hypomethylation of COX2, EGR1, and SOCS3, increases mRNA expression of these genes, and increases 8-nitroguanine formation. These effects may be linked to mechanisms of arsenic-induced inflammation and cancer development later in life.
Bhutan Health Journal
Major progress has been made in improving the health of vulnerable populations, especially childr... more Major progress has been made in improving the health of vulnerable populations, especially children and pregnant women in low and middle income countries after the launch of the Millennium Development Goals in 2000. While fewer children die, many now face the prospect of years lived with disability (YLD) from chronic non-communicable diseases (NCDs). The estimate for the total YLD for children under-5 years of age for South-East Asia was 2,780,104 in 2015. To improve the health outcomes for children globally, the World Health Organization’s Department of Public Health, Environment and Social Determinants of Health has designated a number of collaborating centres, each with differing areas of expertise. The collaborating centres have formed a network to address children’s environmental health (CEH) issues at the local, national, regional and international levels. However, many gaps in knowledge exist. To further this aim, the 1st Regional Workshop of South-East Asian Children’s Envir...
Inorganic arsenic (iAs) is a naturally occurring metalloid present in drinking water and polluted... more Inorganic arsenic (iAs) is a naturally occurring metalloid present in drinking water and polluted air exposing millions of people globally. Epidemiological studies have linked iAs exposure to the development of numerous diseases including cognitive impairment, cardiovascular failure and cancer. Despite intense research, an effective therapy for chronic arsenicosis has yet to be developed. Laboratory studies have been of great benefit in establishing the pathways involved in iAs toxicity and providing insights into its mechanism of action. However, the in vivo analysis of arsenic toxicity mechanisms has been difficult by the lack of reliable in vivo biomarkers of the effects of iAs. To resolve this issue we have applied the use of our recently developed stress reporter models to study iAs toxicity. The reporter mice Hmox1 (oxidative stress/inflammation; HOTT) and p21 (DNA damage) were exposed to iAs at acute and chronic, environmentally relevant, doses. We observed induction of the o...
&... more <p>The vertical atmospheric potential gradient is particularly affected by high aerosol loading in cities as the air’s conductivity is reduced through aerosol attachment of free ions. The reduction of ion concentrations decreases the conductivity and, as the air-earth current remains constant, the potential difference increases. Aerosol size distributions can be affected by the relative humidity dependent on the aerosol hygroscopicity, if an aerosol is sufficiently hygroscopic, it will grow as humidity increases. As larger aerosols are, in principle, more prone to effectively scavenge ions, an increase in relative humidity may increase the size of hygroscopic aerosols, decrease ion concentrations and hence increased measured potential gradient. Measurements of atmospheric potential gradient in Lisbon, Portugal, demonstrated an increase in potential gradient associated with increasing relative humidity (in the range 60-90%), mainly for wind directions corresponding to marine air.</p><p>A JCI 131 field mill (Chilworth) and Maximet 500 (Gill) weather station were positioned on the roof of the University of Bristol School of Chemistry between May and September 2016. Particle number concentration was determined using a condensation particle counter (TSI 3010) with an upper limit of 10,000 particles cm<sup>-3</sup>. A dilution system was put in place to increase this range to 14,000 cm<sup>-3</sup>. The same field mill and weather station were used in Thailand. Measurements at 1 Hz (averaged to 1-minute samples) were taken on the roof of a 6-floor building, approximately 100 m from a busy toll road in Lak Si, northern Bangkok. Aerosol concentrations were taken with a Condensation Particle Counter (Grimm Aerosol Technik) at the same height. The measurement period began on March 8th 2018 after which there were 8 weeks of particle number count data.</p><p>In the Bristol measurement between 50% and 80% relative humidity, the median potential gradient increased, but above this it sharply decreases, which may be due to…
jurnal ecolab
Pembakaran dupa yang merupakan bagian dari ritual agama dan budaya mayoritas komunitas Oriental, ... more Pembakaran dupa yang merupakan bagian dari ritual agama dan budaya mayoritas komunitas Oriental, diketahui berpotensi menyebabkan efek berbahaya akibat emisi yang menghasilkan berbagai jenis polutan. Telah dilakukan identifikasi senyawa Polycylic Aromatic Hydrocarbons (PAHs) yang berasal dari emisi hasil pembakaran beberapa tipe dupa dalam sebuah ruang eksperimen. Studi ini dilakukan di Chulabhorn Research Institute, Thailand dengan tujuan untuk mengetahui tingkat emisi PAHs yang terikat dalam partikulat pada sampel-sampel dupa dari tiga negara (Indonesia, Thailand, dan Vietnam) yang dipilih secara acak. Dari hasil analisis PAHs menggunakan High Performance Liquid Chromatography dengan Fluorescence Detector (HPLC-FLD) diketahui bahwa komponen dominan dalam sampel dupa Indonesia dan Thailand adalah fluorenthane (Flu) dengan konsentrasi masing-masing 8.2±1.0 dan 3.5±0.5 µg/m 3 , sementara sampel Vietnam didominasi oleh komponen chrysene (CHR) (34.5±10.6 µg/m 3). Sampel dupa Vietnam mengemisikan total PAHs ~5 kali lebih tinggi dari dupa Indonesia dan ~8 kali lebih tinggi dari dupa Thailand. Seluruh sampel mengemisikan Benzo[a]pyrene (BaP) dalam level serupa, meskipun konsentrasi dalam dupa Vietnam masih ~1.3 kali lebih tinggi dari dupa Indonesia dan ~1.8 kali dari dupa Thailand. Sementara untuk nilai BaP ekivalen, dupa Vietnam ~3.7 kali dan ~7kali lebih tinggi dari sampel Indonesia dan Thailand.
<p>Airborne particulate matter is known to be deleterious to human health and excee... more <p>Airborne particulate matter is known to be deleterious to human health and exceeds exposure limits in many large cities. Some heavy metals and metalloids are known carcinogens and have been measured as constituents of PM in Bangkok air. There is growing interest in the sub-micron and ultrafine (< 100 nm) fractions due to their deeper penetration in the lung. Identifying distribution of metals over the size range can provide information on the metals source as well as providing information on the likely exposure to those particles.</p> <p>Three sites, owned and managed by the Thailand Pollution Control Department, were identified to provide contrasting particulate samples in a measurement campaign during 2018. The Ayutthaya site was located within the grounds of a school, 80 km to the north of Bangkok. The site was chosen as concentrations due to city traffic would be lower and could be considered a reference site. The Bang Phli site was situated in an industrial area 50 km to the south-east of Bangkok, in an area near industry. The Chok Chai site was in central Bangkok near to a busy road.</p> <p>At each site, three 3-day weekend and 3-day weekday gravimetric samples of size differentiated mass were drawn using an Electrical Low Pressure Impactor (ELPI; Dekati, Finland) over 12 size fractions in six different study visits. These were chosen to enable three measurements over the rainy season and three in the dry season. Each size fraction was weighed and then analysed by inductively coupled plasma mass spectroscopy to find the concentration of 17 elements (Mg, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sb, Ba and Pb). The ELPI also measured particle number concentration at 1 Hz.&#160;</p> <p>The number concentration of aerosol was highest in the Chok Chai roadside site, and lowest in the Ayutthaya background site. Al concentration was the highest in all three locations, with an average concentration over all measurements of 1909, 1012 and 1576 ng m<sup>-3</sup> in Ayutthaya, Bang Phli and Chok Chai respectively. Concentrations of Al, Cr, Mg and Fe were typically higher than 100 ng m<sup>-3</sup> in all sites, Cu and Zn higher than 10 ng m<sup>-3</sup> and the rest lower.</p> <p>The shape of the metal distributions was consistent across all three sites for specific metals. Mg, Al, Cr, Mo, Ni and Cu could be described as having a flat distribution across all measured size distributions V, Mn, Cd, Sb, Pb, Zn As and Se had a peak in the sub-micron range, while Fe, Ba and Co peaked above 1 &#181;m.</p> <p>Some seasonal effects could be seen across all three locations, these included an increase in Al, Cr and Fe during four measurements in dry season (November, 2018). This was particularly observed at Ayutthaya, where total measurements of Al were between 4862 and 5961 ng m<sup>-3</sup>, when all other measurements were between 98 and 264 ng m<sup>-3</sup>, suggesting a strong local source.</p>
Chemical Research in Toxicology
Environmental Health
Background: Growing evidence indicates that in utero arsenic exposures in humans may increase the... more Background: Growing evidence indicates that in utero arsenic exposures in humans may increase the risk of adverse health effects and development of diseases later in life. This study aimed to evaluate potential health risks of in utero arsenic exposure on genetic damage in newborns in relation to maternal arsenic exposure. Methods: A total of 205 pregnant women residing in arsenic-contaminated areas in Hanam province, Vietnam, were recruited. Prenatal arsenic exposure was determined by arsenic concentration in mother's toenails and urine during pregnancy and in umbilical cord blood collected at delivery. Genetic damage in newborns was assessed by various biomarkers of early genetic effects including oxidative/nitrative DNA damage (8-hydroxydeoxyguanosine, 8-OHdG, and 8-nitroguanine), DNA strand breaks and micronuclei (MN) in cord blood. Results: Maternal arsenic exposure, measured by arsenic levels in toenails and urine, was significantly increased (p < 0.05) in subjects residing in areas with high levels of arsenic contamination in drinking water. Cord blood arsenic level was significantly increased in accordance with maternal arsenic exposure (p < 0.001). Arsenic exposure in utero is associated with genotoxic effects in newborns indicated as increased levels of 8-OHdG, 8-nitroguanine, DNA strand breaks and MN frequency in cord blood with increasing levels of maternal arsenic exposure. Maternal toenail arsenic level was significantly associated with all biomarkers of early genetic effects, while cord blood arsenic levels associated with DNA strand breaks and MN frequency. Conclusions: In utero arsenic exposure is associated with various types of genetic damage in newborns potentially contributing to the development of diseases, including cancer, later in life.
Waste Disposal & Sustainable Energy
Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in various building mat... more Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in various building materials, plastic and other polymers, airplanes, electronics, etc. All or some of their congeners have been already banned in many countries, due to their persistency and adverse health effects. In this study, we are focusing on e-wastes as a source of emission of PBDEs in ambient air during reclamation processes. The ambient air particulate matter (PM) samples were collected at and near an e-waste reclamation site in Bangkok, Thailand. Results showed the presence of various homologues, viz: tri-, tetra-, penta-, hexa-, and hepta-PBDEs in both PM2.5 and total suspended particle (TSP) samples. The comparison of samples as a function of distance from the reclamation site indicated elevated levels of PBDEs in close proximity to the e-waste site. Interestingly, a shift in the congener pattern was observed with lower brominated PBDEs being more prevalent in nearby off-site samples as compared to the PM collected at the e-waste site. The total penta-PBDEs concentration is almost double in the e-waste site PM2.5 compared to the control site samples. For TSP, tetra, penta, and hepta-PBDEs congeners are at higher concentrations at the e-waste sites and its vicinity compared to reference sites. Overall, a clear trend can be observed indicating a debromination of PBDEs to more toxic tri and tetra congeners during the reclamation process and PBDEs are being translocated from treated materials to ambient air PM. BDE 30 is uniquely detected in our studies as a dominant final debromination product, that can be used as a marker of thermal e-waste activity. This work indicates potential hazards related to the reclamation of e-wastes and remediation of sites containing PBDEs. In particular, thermal treatment methods can lead to congener transformation and increased emissions of more toxic lower brominated congeners.
Reviews on environmental health, Jan 27, 2018
As one of the largest waste streams, electronic waste (e-waste) production continues to grow in r... more As one of the largest waste streams, electronic waste (e-waste) production continues to grow in response to global demand for consumer electronics. This waste is often shipped to developing countries where it is disassembled and recycled. In many cases, e-waste recycling activities are conducted in informal settings with very few controls or protections in place for workers. These activities involve exposure to hazardous substances such as cadmium, lead, and brominated flame retardants and are frequently performed by women and children. Although recycling practices and exposures vary by scale and geographic region, we present case studies of e-waste recycling scenarios and intervention approaches to reduce or prevent exposures to the hazardous substances in e-waste that may be broadly applicable to diverse situations. Drawing on parallels identified in these cases, we discuss the future prevention and intervention strategies that recognize the difficult economic realities of informa...
Toxicology Reports
Naturally occurring depsidones from the marine fungus Aspergillus unguis are known to have substa... more Naturally occurring depsidones from the marine fungus Aspergillus unguis are known to have substantial anticancer activity, but their mechanism of action remains elusive. The purpose of this study was to examine the anti-aromatase activity of two common depsidones, unguinol and aspergillusidone A, in a co-culture system of human primary breast adipose fibroblasts and hormonal responsive T47D breast tumor cells. Using this in vitro model it was shown that these depsidones inhibit the growth of T47D tumor cells most likely via inhibition of aromatase (CYP19) activity. The IC 50 values of these depisidones were compared with the aromatase inhibitors letrozole and exemestane. Letrozole and exemestane had IC 50 values of respectively, 0.19 and 0.14 μM, while those for Unguinol and Aspergillusidone A were respectively, 9.7 and 7.3 μM. Our results indicate that among the depsidones there maybe aromatase inhibitors with possible pharmacotherapeutical relevance.
Medical Sciences, 2016
The aim of this study was to investigate prevalence and related factors of androgen receptor (AR)... more The aim of this study was to investigate prevalence and related factors of androgen receptor (AR) expression in Thai breast cancer patients. A descriptive study was done in 95 patients, who were admitted to Charoenkrung Pracharak Hospital, Bangkok (2011-2013). Statistical relationships were examined between AR protein expression, tumor status, and patient characteristics. Compared with those from Western countries, ethnic Thai patients were younger at age of diagnosis and had a higher proliferative index (high Ki-67 expression), which indicates unfavorable prognosis. In addition, 91% of the Thai breast tumors that were positive for any of the following receptors, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) also expressed the AR protein, while in triple negative breast tumors only 33% were AR positive. ER and PR expression was positively related with AR expression, while AR expression was inversely correlated to Ki-67 expression. AR status was strongly correlated with ER and PR status in Thai patients. There is an inverse relationship between Ki-67 and AR, which suggests that AR may be a prognostic factor for breast cancer.
Environmental Research, 2017
Chemico Biological Interactions, Apr 15, 2008
Traffic related urban air pollution is a major environmental health problem in many large cities.... more Traffic related urban air pollution is a major environmental health problem in many large cities. Children living in urban areas are exposed to benzene and other toxic pollutants simultaneously on a regular basis. Assessment of benzene exposure and oxidative DNA damage in schoolchildren in Bangkok compared with the rural schoolchildren was studied through the use of biomarkers. Benzene levels in ambient air at the roadside adjacent to Bangkok schools was 3.95-fold greater than that of rural school areas. Personal exposure to benzene in Bangkok schoolchildren was 3.04-fold higher than that in the rural schoolchildren. Blood benzene, urinary benzene and urinary muconic acid (MA) levels were significantly higher in the Bangkok schoolchildren. A significantly higher level of 8-hydroxy-2-deoxyguanosine (8-OHdG) in leukocytes and in urine was found in Bangkok children than in the rural children. There was a significant correlation between individual benzene exposure level and blood benzene (r s = 0.193, P < 0.05), urinary benzene (r s = 0.298, P < 0.05), urinary MA (r s = 0.348, P < 0.01), and 8-OHdG in leukocyte (r s = 0.130, P < 0.05). In addition, a significant correlation between urinary MA and 8-OHdG in leukocytes (r s = 0.241, P < 0.05) was also found. Polymorphisms of various xenobiotic metabolizing genes responsible for susceptibility to benzene toxicity have been studied; however only the GSTM1 genotypes had a significant effect on urinary MA excretion. Our data indicates that children living in the areas of high traffic density are exposed to a higher level of benzene than those living in rural areas. Exposure to higher level of benzene in urban children may contribute to oxidative DNA damage, suggesting an increased health risk from traffic benzene emission.
Reviews on Environmental Health, 2016
Early life exposure to inorganic arsenic is associated with a wide range of malignant and chronic... more Early life exposure to inorganic arsenic is associated with a wide range of malignant and chronic disease outcomes in humans. Prenatal arsenic exposure may give rise to adverse effects on child health and development as arsenic readily passes through the placenta in human beings. The impact of maternal arsenic exposure on fetal gene expression was conducted in pregnant women living in Southern Thailand. Arsenic exposed newborns had significantly higher levels of arsenic in cord blood, and a set of genes associated with numerous biological pathways, including cell signaling, apoptosis, inflammatory and stress response. A slight increase in promoter methylation of
Environmental health perspectives, Jan 26, 2015
Millions of individuals worldwide, particularly those living in rural and developing areas, are e... more Millions of individuals worldwide, particularly those living in rural and developing areas, are exposed to harmful levels of inorganic arsenic (iAs) in their drinking water. Inorganic As exposure during key developmental periods is associated with a variety of adverse health effects including those that are evident in adulthood. There is considerable interest in identifying the molecular mechanisms that relate early-life iAs exposure to the development of these latent diseases, particularly in relationship to cancer. This work summarizes research on the molecular mechanisms that underlie the increased risk of cancer development in adulthood that is associated with early-life iAs exposure. Epigenetic reprogramming that imparts functional changes in gene expression, the development of cancer stem cells, and immunomodulation are plausible underlying mechanisms by which early-life iAs exposure elicits latent carcinogenic effects. Evidence is mounting that relates early-life iAs exposure...
Toxicology and applied pharmacology, 2015
Aflatoxin B1 (AFB1) is one of the major risk factors for liver cancer globally. A recent study sh... more Aflatoxin B1 (AFB1) is one of the major risk factors for liver cancer globally. A recent study showed that sulforaphane (SF), a potent inducer of phase II enzymes that occurs naturally in widely consumed vegetables, effectively induces hepatic glutathione S-transferases (GSTs) and reduces levels of hepatic AFB1-DNA adducts in AFB1-exposed Sprague Dawley rats. The present study characterized the effects of SF pre-treatment on global gene expression in the livers of similarly treated male rats. Combined treatment with AFB1 and SF caused reprogramming of a network of genes involved in signal transduction and transcription. Changes in gene regulation were observable 4h after AFB1 administration in SF-pretreated animals and may reflect regeneration of cells in the wake of AFB1-induced hepatotoxicity. At 24h after AFB1 administration, significant induction of genes that play roles in cellular lipid metabolism and acetyl-CoA biosynthesis was detected in SF-pretreated AFB1-dosed rats. Induc...
Toxicology and Applied Pharmacology, 2017
Early-life exposure to arsenic increases risk of developing a variety of non-malignant and malign... more Early-life exposure to arsenic increases risk of developing a variety of non-malignant and malignant diseases. Arsenic-induced carcinogenesis may be mediated through epigenetic mechanisms and pathways leading to inflammation. Our previous study reported that prenatal arsenic exposure leads to increased mRNA expression of several genes related to inflammation, including COX2, EGR1, and SOCS3. This study aimed to investigate the effects of arsenic exposure on promoter DNA methylation and mRNA expression of these inflammatory genes (COX2, EGR1, and SOCS3), as well as the generation of 8-nitroguanine, which is a mutagenic DNA lesion involved in inflammation-related carcinogenesis. Prenatally arsenic-exposed newborns had promoter hypomethylation of COX2, EGR1, and SOCS3 in cord blood lymphocytes (p b 0.01). A follow-up study in these prenatally arsenic-exposed children showed a significant hypomethylation of these genes in salivary DNA (p b 0.01). In vitro experiments confirmed that arsenite treatment at short-term high doses (10-100 μM) and long-term low doses (0.5-1 μM) in human lymphoblasts (RPMI 1788) caused promoter hypomethylation of these genes, which was in concordance with an increase in their mRNA expression. Additionally, the level of urinary 8-nitroguanine was significantly higher (p b 0.01) in exposed newborns and children, by 1.4-and 1.8-fold, respectively. Arsenic accumulation in toenails was negatively correlated with hypomethylation of these genes and positively correlated with levels of 8-nitroguanine. These results indicated that early-life exposure to arsenic causes hypomethylation of COX2, EGR1, and SOCS3, increases mRNA expression of these genes, and increases 8-nitroguanine formation. These effects may be linked to mechanisms of arsenic-induced inflammation and cancer development later in life.
Bhutan Health Journal
Major progress has been made in improving the health of vulnerable populations, especially childr... more Major progress has been made in improving the health of vulnerable populations, especially children and pregnant women in low and middle income countries after the launch of the Millennium Development Goals in 2000. While fewer children die, many now face the prospect of years lived with disability (YLD) from chronic non-communicable diseases (NCDs). The estimate for the total YLD for children under-5 years of age for South-East Asia was 2,780,104 in 2015. To improve the health outcomes for children globally, the World Health Organization’s Department of Public Health, Environment and Social Determinants of Health has designated a number of collaborating centres, each with differing areas of expertise. The collaborating centres have formed a network to address children’s environmental health (CEH) issues at the local, national, regional and international levels. However, many gaps in knowledge exist. To further this aim, the 1st Regional Workshop of South-East Asian Children’s Envir...
Inorganic arsenic (iAs) is a naturally occurring metalloid present in drinking water and polluted... more Inorganic arsenic (iAs) is a naturally occurring metalloid present in drinking water and polluted air exposing millions of people globally. Epidemiological studies have linked iAs exposure to the development of numerous diseases including cognitive impairment, cardiovascular failure and cancer. Despite intense research, an effective therapy for chronic arsenicosis has yet to be developed. Laboratory studies have been of great benefit in establishing the pathways involved in iAs toxicity and providing insights into its mechanism of action. However, the in vivo analysis of arsenic toxicity mechanisms has been difficult by the lack of reliable in vivo biomarkers of the effects of iAs. To resolve this issue we have applied the use of our recently developed stress reporter models to study iAs toxicity. The reporter mice Hmox1 (oxidative stress/inflammation; HOTT) and p21 (DNA damage) were exposed to iAs at acute and chronic, environmentally relevant, doses. We observed induction of the o...
&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;... more &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;The vertical atmospheric potential gradient is particularly affected by high aerosol loading in cities as the air&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#8217;s conductivity is reduced through aerosol attachment of free ions. The reduction of ion concentrations decreases the conductivity and, as the air-earth current remains constant, the potential difference increases. Aerosol size distributions can be affected by the relative humidity dependent on the aerosol hygroscopicity, if an aerosol is sufficiently hygroscopic, it will grow as humidity increases. As larger aerosols are, in principle, more prone to effectively scavenge ions, an increase in relative humidity may increase the size of hygroscopic aerosols, decrease ion concentrations and hence increased measured potential gradient. Measurements of atmospheric potential gradient in Lisbon, Portugal, demonstrated an increase in potential gradient associated with increasing relative humidity (in the range 60-90%), mainly for wind directions corresponding to marine air.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;A JCI 131 field mill (Chilworth) and Maximet 500 (Gill) weather station were positioned on the roof of the University of Bristol School of Chemistry between May and September 2016. Particle number concentration was determined using a condensation particle counter (TSI 3010) with an upper limit of 10,000 particles cm&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;sup&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;-3&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/sup&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;. A dilution system was put in place to increase this range to 14,000 cm&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;sup&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;-3&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/sup&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;. The same field mill and weather station were used in Thailand. Measurements at 1 Hz (averaged to 1-minute samples) were taken on the roof of a 6-floor building, approximately 100 m from a busy toll road in Lak Si, northern Bangkok. Aerosol concentrations were taken with a Condensation Particle Counter (Grimm Aerosol Technik) at the same height. The measurement period began on March 8th 2018 after which there were 8 weeks of particle number count data.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;In the Bristol measurement between 50% and 80% relative humidity, the median potential gradient increased, but above this it sharply decreases, which may be due to…
jurnal ecolab
Pembakaran dupa yang merupakan bagian dari ritual agama dan budaya mayoritas komunitas Oriental, ... more Pembakaran dupa yang merupakan bagian dari ritual agama dan budaya mayoritas komunitas Oriental, diketahui berpotensi menyebabkan efek berbahaya akibat emisi yang menghasilkan berbagai jenis polutan. Telah dilakukan identifikasi senyawa Polycylic Aromatic Hydrocarbons (PAHs) yang berasal dari emisi hasil pembakaran beberapa tipe dupa dalam sebuah ruang eksperimen. Studi ini dilakukan di Chulabhorn Research Institute, Thailand dengan tujuan untuk mengetahui tingkat emisi PAHs yang terikat dalam partikulat pada sampel-sampel dupa dari tiga negara (Indonesia, Thailand, dan Vietnam) yang dipilih secara acak. Dari hasil analisis PAHs menggunakan High Performance Liquid Chromatography dengan Fluorescence Detector (HPLC-FLD) diketahui bahwa komponen dominan dalam sampel dupa Indonesia dan Thailand adalah fluorenthane (Flu) dengan konsentrasi masing-masing 8.2±1.0 dan 3.5±0.5 µg/m 3 , sementara sampel Vietnam didominasi oleh komponen chrysene (CHR) (34.5±10.6 µg/m 3). Sampel dupa Vietnam mengemisikan total PAHs ~5 kali lebih tinggi dari dupa Indonesia dan ~8 kali lebih tinggi dari dupa Thailand. Seluruh sampel mengemisikan Benzo[a]pyrene (BaP) dalam level serupa, meskipun konsentrasi dalam dupa Vietnam masih ~1.3 kali lebih tinggi dari dupa Indonesia dan ~1.8 kali dari dupa Thailand. Sementara untuk nilai BaP ekivalen, dupa Vietnam ~3.7 kali dan ~7kali lebih tinggi dari sampel Indonesia dan Thailand.
<p>Airborne particulate matter is known to be deleterious to human health and excee... more <p>Airborne particulate matter is known to be deleterious to human health and exceeds exposure limits in many large cities. Some heavy metals and metalloids are known carcinogens and have been measured as constituents of PM in Bangkok air. There is growing interest in the sub-micron and ultrafine (< 100 nm) fractions due to their deeper penetration in the lung. Identifying distribution of metals over the size range can provide information on the metals source as well as providing information on the likely exposure to those particles.</p> <p>Three sites, owned and managed by the Thailand Pollution Control Department, were identified to provide contrasting particulate samples in a measurement campaign during 2018. The Ayutthaya site was located within the grounds of a school, 80 km to the north of Bangkok. The site was chosen as concentrations due to city traffic would be lower and could be considered a reference site. The Bang Phli site was situated in an industrial area 50 km to the south-east of Bangkok, in an area near industry. The Chok Chai site was in central Bangkok near to a busy road.</p> <p>At each site, three 3-day weekend and 3-day weekday gravimetric samples of size differentiated mass were drawn using an Electrical Low Pressure Impactor (ELPI; Dekati, Finland) over 12 size fractions in six different study visits. These were chosen to enable three measurements over the rainy season and three in the dry season. Each size fraction was weighed and then analysed by inductively coupled plasma mass spectroscopy to find the concentration of 17 elements (Mg, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sb, Ba and Pb). The ELPI also measured particle number concentration at 1 Hz.&#160;</p> <p>The number concentration of aerosol was highest in the Chok Chai roadside site, and lowest in the Ayutthaya background site. Al concentration was the highest in all three locations, with an average concentration over all measurements of 1909, 1012 and 1576 ng m<sup>-3</sup> in Ayutthaya, Bang Phli and Chok Chai respectively. Concentrations of Al, Cr, Mg and Fe were typically higher than 100 ng m<sup>-3</sup> in all sites, Cu and Zn higher than 10 ng m<sup>-3</sup> and the rest lower.</p> <p>The shape of the metal distributions was consistent across all three sites for specific metals. Mg, Al, Cr, Mo, Ni and Cu could be described as having a flat distribution across all measured size distributions V, Mn, Cd, Sb, Pb, Zn As and Se had a peak in the sub-micron range, while Fe, Ba and Co peaked above 1 &#181;m.</p> <p>Some seasonal effects could be seen across all three locations, these included an increase in Al, Cr and Fe during four measurements in dry season (November, 2018). This was particularly observed at Ayutthaya, where total measurements of Al were between 4862 and 5961 ng m<sup>-3</sup>, when all other measurements were between 98 and 264 ng m<sup>-3</sup>, suggesting a strong local source.</p>
Chemical Research in Toxicology
Environmental Health
Background: Growing evidence indicates that in utero arsenic exposures in humans may increase the... more Background: Growing evidence indicates that in utero arsenic exposures in humans may increase the risk of adverse health effects and development of diseases later in life. This study aimed to evaluate potential health risks of in utero arsenic exposure on genetic damage in newborns in relation to maternal arsenic exposure. Methods: A total of 205 pregnant women residing in arsenic-contaminated areas in Hanam province, Vietnam, were recruited. Prenatal arsenic exposure was determined by arsenic concentration in mother's toenails and urine during pregnancy and in umbilical cord blood collected at delivery. Genetic damage in newborns was assessed by various biomarkers of early genetic effects including oxidative/nitrative DNA damage (8-hydroxydeoxyguanosine, 8-OHdG, and 8-nitroguanine), DNA strand breaks and micronuclei (MN) in cord blood. Results: Maternal arsenic exposure, measured by arsenic levels in toenails and urine, was significantly increased (p < 0.05) in subjects residing in areas with high levels of arsenic contamination in drinking water. Cord blood arsenic level was significantly increased in accordance with maternal arsenic exposure (p < 0.001). Arsenic exposure in utero is associated with genotoxic effects in newborns indicated as increased levels of 8-OHdG, 8-nitroguanine, DNA strand breaks and MN frequency in cord blood with increasing levels of maternal arsenic exposure. Maternal toenail arsenic level was significantly associated with all biomarkers of early genetic effects, while cord blood arsenic levels associated with DNA strand breaks and MN frequency. Conclusions: In utero arsenic exposure is associated with various types of genetic damage in newborns potentially contributing to the development of diseases, including cancer, later in life.
Waste Disposal & Sustainable Energy
Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in various building mat... more Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in various building materials, plastic and other polymers, airplanes, electronics, etc. All or some of their congeners have been already banned in many countries, due to their persistency and adverse health effects. In this study, we are focusing on e-wastes as a source of emission of PBDEs in ambient air during reclamation processes. The ambient air particulate matter (PM) samples were collected at and near an e-waste reclamation site in Bangkok, Thailand. Results showed the presence of various homologues, viz: tri-, tetra-, penta-, hexa-, and hepta-PBDEs in both PM2.5 and total suspended particle (TSP) samples. The comparison of samples as a function of distance from the reclamation site indicated elevated levels of PBDEs in close proximity to the e-waste site. Interestingly, a shift in the congener pattern was observed with lower brominated PBDEs being more prevalent in nearby off-site samples as compared to the PM collected at the e-waste site. The total penta-PBDEs concentration is almost double in the e-waste site PM2.5 compared to the control site samples. For TSP, tetra, penta, and hepta-PBDEs congeners are at higher concentrations at the e-waste sites and its vicinity compared to reference sites. Overall, a clear trend can be observed indicating a debromination of PBDEs to more toxic tri and tetra congeners during the reclamation process and PBDEs are being translocated from treated materials to ambient air PM. BDE 30 is uniquely detected in our studies as a dominant final debromination product, that can be used as a marker of thermal e-waste activity. This work indicates potential hazards related to the reclamation of e-wastes and remediation of sites containing PBDEs. In particular, thermal treatment methods can lead to congener transformation and increased emissions of more toxic lower brominated congeners.
Reviews on environmental health, Jan 27, 2018
As one of the largest waste streams, electronic waste (e-waste) production continues to grow in r... more As one of the largest waste streams, electronic waste (e-waste) production continues to grow in response to global demand for consumer electronics. This waste is often shipped to developing countries where it is disassembled and recycled. In many cases, e-waste recycling activities are conducted in informal settings with very few controls or protections in place for workers. These activities involve exposure to hazardous substances such as cadmium, lead, and brominated flame retardants and are frequently performed by women and children. Although recycling practices and exposures vary by scale and geographic region, we present case studies of e-waste recycling scenarios and intervention approaches to reduce or prevent exposures to the hazardous substances in e-waste that may be broadly applicable to diverse situations. Drawing on parallels identified in these cases, we discuss the future prevention and intervention strategies that recognize the difficult economic realities of informa...
Toxicology Reports
Naturally occurring depsidones from the marine fungus Aspergillus unguis are known to have substa... more Naturally occurring depsidones from the marine fungus Aspergillus unguis are known to have substantial anticancer activity, but their mechanism of action remains elusive. The purpose of this study was to examine the anti-aromatase activity of two common depsidones, unguinol and aspergillusidone A, in a co-culture system of human primary breast adipose fibroblasts and hormonal responsive T47D breast tumor cells. Using this in vitro model it was shown that these depsidones inhibit the growth of T47D tumor cells most likely via inhibition of aromatase (CYP19) activity. The IC 50 values of these depisidones were compared with the aromatase inhibitors letrozole and exemestane. Letrozole and exemestane had IC 50 values of respectively, 0.19 and 0.14 μM, while those for Unguinol and Aspergillusidone A were respectively, 9.7 and 7.3 μM. Our results indicate that among the depsidones there maybe aromatase inhibitors with possible pharmacotherapeutical relevance.
Medical Sciences, 2016
The aim of this study was to investigate prevalence and related factors of androgen receptor (AR)... more The aim of this study was to investigate prevalence and related factors of androgen receptor (AR) expression in Thai breast cancer patients. A descriptive study was done in 95 patients, who were admitted to Charoenkrung Pracharak Hospital, Bangkok (2011-2013). Statistical relationships were examined between AR protein expression, tumor status, and patient characteristics. Compared with those from Western countries, ethnic Thai patients were younger at age of diagnosis and had a higher proliferative index (high Ki-67 expression), which indicates unfavorable prognosis. In addition, 91% of the Thai breast tumors that were positive for any of the following receptors, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) also expressed the AR protein, while in triple negative breast tumors only 33% were AR positive. ER and PR expression was positively related with AR expression, while AR expression was inversely correlated to Ki-67 expression. AR status was strongly correlated with ER and PR status in Thai patients. There is an inverse relationship between Ki-67 and AR, which suggests that AR may be a prognostic factor for breast cancer.
Environmental Research, 2017
Chemico Biological Interactions, Apr 15, 2008
Traffic related urban air pollution is a major environmental health problem in many large cities.... more Traffic related urban air pollution is a major environmental health problem in many large cities. Children living in urban areas are exposed to benzene and other toxic pollutants simultaneously on a regular basis. Assessment of benzene exposure and oxidative DNA damage in schoolchildren in Bangkok compared with the rural schoolchildren was studied through the use of biomarkers. Benzene levels in ambient air at the roadside adjacent to Bangkok schools was 3.95-fold greater than that of rural school areas. Personal exposure to benzene in Bangkok schoolchildren was 3.04-fold higher than that in the rural schoolchildren. Blood benzene, urinary benzene and urinary muconic acid (MA) levels were significantly higher in the Bangkok schoolchildren. A significantly higher level of 8-hydroxy-2-deoxyguanosine (8-OHdG) in leukocytes and in urine was found in Bangkok children than in the rural children. There was a significant correlation between individual benzene exposure level and blood benzene (r s = 0.193, P < 0.05), urinary benzene (r s = 0.298, P < 0.05), urinary MA (r s = 0.348, P < 0.01), and 8-OHdG in leukocyte (r s = 0.130, P < 0.05). In addition, a significant correlation between urinary MA and 8-OHdG in leukocytes (r s = 0.241, P < 0.05) was also found. Polymorphisms of various xenobiotic metabolizing genes responsible for susceptibility to benzene toxicity have been studied; however only the GSTM1 genotypes had a significant effect on urinary MA excretion. Our data indicates that children living in the areas of high traffic density are exposed to a higher level of benzene than those living in rural areas. Exposure to higher level of benzene in urban children may contribute to oxidative DNA damage, suggesting an increased health risk from traffic benzene emission.
Reviews on Environmental Health, 2016
Early life exposure to inorganic arsenic is associated with a wide range of malignant and chronic... more Early life exposure to inorganic arsenic is associated with a wide range of malignant and chronic disease outcomes in humans. Prenatal arsenic exposure may give rise to adverse effects on child health and development as arsenic readily passes through the placenta in human beings. The impact of maternal arsenic exposure on fetal gene expression was conducted in pregnant women living in Southern Thailand. Arsenic exposed newborns had significantly higher levels of arsenic in cord blood, and a set of genes associated with numerous biological pathways, including cell signaling, apoptosis, inflammatory and stress response. A slight increase in promoter methylation of
Environmental health perspectives, Jan 26, 2015
Millions of individuals worldwide, particularly those living in rural and developing areas, are e... more Millions of individuals worldwide, particularly those living in rural and developing areas, are exposed to harmful levels of inorganic arsenic (iAs) in their drinking water. Inorganic As exposure during key developmental periods is associated with a variety of adverse health effects including those that are evident in adulthood. There is considerable interest in identifying the molecular mechanisms that relate early-life iAs exposure to the development of these latent diseases, particularly in relationship to cancer. This work summarizes research on the molecular mechanisms that underlie the increased risk of cancer development in adulthood that is associated with early-life iAs exposure. Epigenetic reprogramming that imparts functional changes in gene expression, the development of cancer stem cells, and immunomodulation are plausible underlying mechanisms by which early-life iAs exposure elicits latent carcinogenic effects. Evidence is mounting that relates early-life iAs exposure...
Toxicology and applied pharmacology, 2015
Aflatoxin B1 (AFB1) is one of the major risk factors for liver cancer globally. A recent study sh... more Aflatoxin B1 (AFB1) is one of the major risk factors for liver cancer globally. A recent study showed that sulforaphane (SF), a potent inducer of phase II enzymes that occurs naturally in widely consumed vegetables, effectively induces hepatic glutathione S-transferases (GSTs) and reduces levels of hepatic AFB1-DNA adducts in AFB1-exposed Sprague Dawley rats. The present study characterized the effects of SF pre-treatment on global gene expression in the livers of similarly treated male rats. Combined treatment with AFB1 and SF caused reprogramming of a network of genes involved in signal transduction and transcription. Changes in gene regulation were observable 4h after AFB1 administration in SF-pretreated animals and may reflect regeneration of cells in the wake of AFB1-induced hepatotoxicity. At 24h after AFB1 administration, significant induction of genes that play roles in cellular lipid metabolism and acetyl-CoA biosynthesis was detected in SF-pretreated AFB1-dosed rats. Induc...