85 results on '"Wai KM"'
Search Results
52. Patterns and Predictors of Successful Treatment Discontinuation in Retinal Vein Occlusions With Macular Edema in the Real World.
- Author
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Lo T, Lent-Schochet D, Luu KY, Kuriyan AE, Weiss MY, Rachitskaya AV, Singh RP, Wai KM, Campbell JP, Gupta K, Nudleman E, Chen KC, and Yiu G
- Subjects
- Angiogenesis Inhibitors therapeutic use, Follow-Up Studies, Humans, Intravitreal Injections, Retina, Retrospective Studies, Tomography, Optical Coherence, Treatment Outcome, Visual Acuity, Macular Edema diagnosis, Macular Edema drug therapy, Macular Edema etiology, Retinal Vein Occlusion complications, Retinal Vein Occlusion diagnosis, Retinal Vein Occlusion drug therapy
- Abstract
Background and Objective: To identify factors associated with successful treatment discontinuation in eyes with retinal vein occlusions (RVOs) and macular edema (ME) in real-world settings., Patients and Methods: Retrospective study of 214 eyes with RVO and ME with 24-month follow-up at five academic centers. Regression analyses identified factors associated with (1) successful treatment discontinuation for at least 6 months without fluid recurrence and (2) best-corrected visual acuity (BCVA) at 24 months., Results: Forty percent of eyes with branch RVO and 35% with central RVO (CRVO) / hemi-retinal RVO (HRVO) successfully discontinued therapy without fluid recurrence, with median time to discontinuation of 6 and 7 months, respectively. Lower 6-month central subfield thickness was associated with greater likelihood of treatment discontinuation within 24 months for eyes with CRVO/HRVO (P = .001), whereas better 6-month BCVA was associated with better 24-month BCVA for all RVO subtypes (P < .001)., Conclusion: Early anatomic response at 6 months is associated with greater likelihood of stopping treatments. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:84-92.]., (Copyright 2021, SLACK Incorporated.)
- Published
- 2021
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53. Can COVID-19 Move Myanmar in the Right Direction? Perspectives on Older People, Mental Health, and Local Organizations.
- Author
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Akhter-Khan SC and Wai KM
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- Aged, Betacoronavirus, COVID-19, Coronavirus Infections economics, Financial Support, Humans, Mental Health economics, Myanmar epidemiology, Pandemics economics, Pneumonia, Viral economics, SARS-CoV-2, Coronavirus Infections epidemiology, Coronavirus Infections psychology, Mental Health statistics & numerical data, Organizations economics, Pneumonia, Viral epidemiology, Pneumonia, Viral psychology
- Published
- 2020
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54. In-utero arsenic exposure and growth of infants from birth to 6 months of age: a prospective cohort study in rural Bangladesh.
- Author
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Wai KM, Ser PH, Ahmad SA, Yasmin R, Ito Y, Konishi S, Umezaki M, and Watanabe C
- Subjects
- Adult, Bangladesh, Female, Humans, Infant, Infant, Newborn, Male, Pregnancy, Prenatal Exposure Delayed Effects chemically induced, Prospective Studies, Rural Population, Young Adult, Arsenic adverse effects, Growth drug effects, Maternal Exposure adverse effects, Prenatal Exposure Delayed Effects classification
- Abstract
Arsenic exposure in postnatal life impacts the growth of children, but little is known about the effect of in-utero arsenic exposure on growth very early in childhood. The aim of this study was to examine the associations between in-utero arsenic exposure and the growth of infants from birth to 6 months of age using monthly follow-up data. A prospective cohort study was conducted in rural areas of Bangladesh with 108 mother-infant pairs. This study identified a negative association between in-utero arsenic exposure and head circumference of infants 1-6 months of age (coefficient = -1.20, 95% confidence interval [CI]: -1.97, -0.42), and the effect was more pronounced in the earlier ages of 1-3 months (coefficient = -0.88, 95% CI: -1.70, -0.05). Because head circumference is considered as a surrogate of brain size, our findings suggest that in-utero arsenic exposure influences brain growth during an important developmental period.
- Published
- 2020
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55. Relationship between Selected Trace Elements and Hematological Parameters among Japanese Community Dwellers.
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Wai KM, Sawada K, Kumagai M, Itai K, Tokuda I, Murashita K, Nakaji S, and Ihara K
- Subjects
- Adult, Aged, Anemia, Cadmium blood, Cobalt blood, Copper blood, Cross-Sectional Studies, Female, Hemoglobins, Humans, Iron blood, Japan, Male, Middle Aged, Selenium blood, Sex Factors, Zinc blood, Residence Characteristics, Trace Elements blood
- Abstract
This study aimed (1) to assess serum trace elements concentrations and hematological parameters, (2) to evaluate the sex differences in the associations between serum trace elements levels and hematological parameters, and (3) to identify the associations between serum trace elements concentrations and risk of anemia among Japanese community dwellers. This is a community-based cross-sectional study that utilized the data of the 2014 Iwaki Health Promotion Project. Participants were 1176 community dwellers (>18 years) residing in the Iwaki District, Aomori Prefecture, Japan. We assessed the data of serum trace elements concentrations of cadmium (Cd), cobalt (Co), copper (Cu), selenium (Se), zinc (Zn), and iron (Fe) as well as the hematological parameters of red blood cells (RBC) counts, hemoglobin, packed cells volume (PCV), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH). Serum concentrations of Zn (871.5 μg/L vs. 900.1 μg/L) and Fe (946.8 μg/L vs. 1096.1 μg/L) were significantly lower in females than in males, while serum concentrations of Co (0.4 μg/L vs. 0.3 μg/L) and Cu (1062.4 μg/L vs. 965.3 μg/L) were significantly higher in females. By multivariate linear regression, serum Se concentration was significantly, positively associated with PCV (β = 1.04; 95% confidence interval (CI): 0.17, 1.92; p = 0.016) among the study participants. Serum Zn also had positive associations with hemoglobin (β = 0.42; 95% CI: 0.07, 0.77; p = 0.020), PCV (β = 1.79; 95% CI: 0.78, 2.81; p < 0.001), and RBCs count (β = 15.56; 95% CI: 7.31, 31.69; p = 0.002). On the other hand, serum Co concentration was negatively associated with the hematological parameters, particularly in females. Moreover, serum Zn concentration had a decreased risk of anemia (lowest vs. highest quartiles: odds ratio (OR) = 0.42; 95% CI: 0.23, 0.76; p = 0.005) while higher Co concentrations had an increased risk of anemia (lowest vs. highest quartiles: OR = 1.95; 95% CI: 1.04, 3.67; p = 0.037). However, no significant association was found between serum Cu level and hematological parameters. There were substantial sex differences in serum trace elements, implying that trace elements metabolism differed between males and females. Zn can play a protective role in the development of anemia. Surprisingly, increased Co concentration increased the risk of anemia among our study population, which called for further studies to confirm and to consider for speciation analysis.
- Published
- 2020
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56. External Cesium-137 doses to humans from soil influenced by the Fukushima and Chernobyl nuclear power plants accidents: a comparative study.
- Author
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Wai KM, Krstic D, Nikezic D, Lin TH, and Yu PKN
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- Algorithms, Environmental Exposure, Humans, Models, Theoretical, Organ Specificity radiation effects, Cesium Radioisotopes adverse effects, Cesium Radioisotopes analysis, Chernobyl Nuclear Accident, Fukushima Nuclear Accident, Radiation Dosage, Soil chemistry, Soil Pollutants, Radioactive adverse effects, Soil Pollutants, Radioactive analysis
- Abstract
External exposure to gamma-photon irradiation from soil contamination due to nuclear power plant (NPP) accidents has significant contribution to human radiation exposure in the proximity of the NPP. Detailed absorbed doses in human organs are rarely reported in the literature. We applied the Monte Carlo Neutron Particle (MCNP) transport code to calculate and compare the absorbed doses in different human organs. The absorbed doses by gamma-photon radiation were from cesium-137 (
137 Cs) in soil contaminated by the two major NPP accidents. More serious and wide-spread impacts of the Chernobyl NPP accident on soil contamination in Ukraine, Belarus, Russia and countries as far as Sweden and Greece were due to the inland location, radiative plume transport pathway and high137 Cs emission strength (9 times the Fukushima emission). Based on our MCNP calculations, the largest absorbed dose was found in skin. The maximum calculated external137 Cs annual effective dose received from the Chernobyl accident was 10 times higher relative to the Fukushima accident. Our calculated effective doses at various influenced areas were comparable to those available in the literature. The calculated annual effective doses at areas near the Fukushima and Chernobyl NPPs exceeded the ICRP recommendation of 1 mSv yr-1 .- Published
- 2020
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57. Protective role of selenium in the shortening of telomere length in newborns induced by in utero heavy metal exposure.
- Author
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Wai KM, Umezaki M, Umemura M, Mar O, and Watanabe C
- Subjects
- Cohort Studies, Female, Humans, Infant, Newborn, Myanmar, Pregnancy, Telomere, Metals, Heavy toxicity, Selenium pharmacology, Telomere Shortening
- Abstract
The effects of toxic heavy metals, such as arsenic (As), cadmium (Cd), and lead (Pb), on telomere length (TL) have been reported previously. Although selenium (Se) is considered as an anti-oxidant which may detoxify the effects, there are no data on whether Se could protect against the TL-shortening effects of heavy metals. Thus, the aim of this study was to evaluate the protective role of Se against heavy metal-induced TL shortening. A birth cohort study was conducted in Myanmar in 2016, including 408 mother-infant pairs. First, pregnant women in the third trimester were interviewed concerning their socioeconomic, and pregnancy and birth characteristics using a pre-validated questionnaire. Maternal spot urine samples were collected after the interview. During the follow-up period (1-3 months), blood samples were collected from the umbilical cord at birth by local health workers. Metal concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS). TL was measured by quantitative real-time polymerase chain reaction (PCR). Relative TL was calculated as the ratio of telomere genes to single-copy genes. To evaluate the effect of Se on TL shortening, molar ratios were calculated. Linear regression analyses were performed to examine the associations between heavy metals and TL, individually and after adjustment for Se level. The effects of As, Cd, and Pb exposure on TL were smaller after adjustment for the Se level, especially for Pb (unadjusted β = -0.10; 95% CI: 0.18, -0.01; adjusted β = -0.03; 95% CI: 0.13, 0.05). On stratifying the data by Se concentration, there was no significant association between Cd or Pb exposure and TL in the high-Se group. Our study indicated a protective effect of Se against the TL shortening induced by heavy metal exposure, where the effect sizes were smaller after adjusting for the Se level, compared to individual metal exposure., Competing Interests: Declaration of competing interest There is no conflict of interest to be declared., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2020
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58. Relationship between pedestrian-level outdoor thermal comfort and building morphology in a high-density city.
- Author
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Wai KM, Yuan C, Lai A, and Yu PKN
- Abstract
Urban compact buildings impose large frictional drag on boundary-layer air flow and create stagnant air within the building environment. It results in exacerbating the street-level outdoor thermal comfort (OTC). It is common to perform in-situ measurements of the OTC in different urban forms and to study their relationship. However, it is impossible to do so from a planning perspective because of the absence of physical planned urban forms. Our objective was to quantify the thermal environment and OTC in different planned complex urban forms by well-validated numerical models. We coupled a computational fluid dynamics (CFD) model to an OTC (Rayman) model to study the OTC. The κ-ω SST turbulent model was adopted for the CFD simulations, with accuracy of the turbulent model validated by wind tunnel measurements. The highest calculated air temperature within the street canyon of a planned bulky urban form could reach more than 5 °C higher than the surrounding environment. Within the tested urban forms, our coupled model predicted mean radiant temperature comparable with measurements in the literature. The model also produced sensible street-level physiologically equivalent temperatures (PETs) when comparing with those listed in the human thermal sensation categories. In the morning, the predicted PETs within all the urban forms were lower than that in open areas, which indicated that the shading of buildings effectively reduced the PET increase due to solar irradiance. At noon, increases in PETs by more than 10 °C relative to the morning situation indicated that when the buildings acted as heat sources after insolation absorption, increase in the air temperature at the street intersection and in the street canyon made an important contribution to the receiver PETs. The reduction in building lengths and increase in the low-level porosity were the most effective ways to reduce the heat stress at the pedestrian-level., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2020
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59. Subfoveal choroidal thickness as a prognostic factor in exudative age-related macular degeneration.
- Author
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Kumar JB, Wai KM, Ehlers JP, Singh RP, and Rachitskaya AV
- Subjects
- Aged, Aged, 80 and over, Bevacizumab therapeutic use, Biomarkers analysis, Female, Fovea Centralis pathology, Humans, Male, Middle Aged, Prognosis, Ranibizumab therapeutic use, Receptors, Vascular Endothelial Growth Factor therapeutic use, Recombinant Fusion Proteins therapeutic use, Regression Analysis, Retrospective Studies, Angiogenesis Inhibitors therapeutic use, Choroid pathology, Macular Degeneration drug therapy, Macular Degeneration pathology
- Abstract
Aims: To investigate the relationship between subfoveal choroidal thickness (SFCT), visual acuity (VA), optical coherence tomography (OCT) features and total anti-vascular endothelial growth factor (VEGF) treatments to determine whether SFCT serves as a prognostic factor in age-related macular degeneration (AMD)., Methods: This is a retrospective case series of 62 consecutive treatment-naive patients with exudative AMD followed for 1 year and treated with treat-and-extend or pro re nata anti-VEGF protocols. SFCT was measured at three locations using Cirrus HD-OCT (the foveal centre and 500 um nasal and temporal to the fovea) at presentation, 3, 6 and 12 months. Demographic characteristics, OCT imaging biomarkers and VA were recorded., Results: Mean SFCT at baseline was 187 µm (range: 70-361 µm). There was a trend of decreasing SFCT at 1 year (173 µm) compared with 3 months (175 µm) and baseline (188 µm) (p=0.2). There was no correlation between baseline SFCT and presence of subretinal fluid (p=0.2), intraretinal fluid (p=0.6) or subretinal hyper-reflective material (p=0.4) at baseline. The mean number of injections at 1 year was 6.6 (range: 2-12). Increased SFCT at baseline showed statistically significant correlation with a higher number of intravitreal injections at 1 year (p=0.004). Eyes with SFCT>1 SD above the mean required 50% more injections compared with others. There was no association between SFCT on presentation with baseline and 1 year VA (p=0.7 and p=0.2)., Conclusions: SFCT in naïve patients with exudative AMD may be an important prognostic tool in determining treatment burden. Patients with thicker subfoveal choroid may require increased intravitreal injections., Competing Interests: Competing interests: JBK and KMW report no financial disclosures. JPE reports grants from National Institutes of Health/National Eye Institute, grants from Ohio Department of Development, grants from Research to Prevent Blindness, during the conduct of the study; other from Bioptigen, grants and personal fees from Thrombogenic, personal fees from Leica, personal fees from Zeiss, grants and personal fees from Alcon, grants and personal fees from Genentech, grants from Regeneron, personal fees from Allergan, personal fees from Santen, personal fees from Roche, outside the submitted work. RPS reports grants and personal fees from Regeneron, grants and personal fees from Genentech/Roche, grants and personal fees from Alcon/Novartis, grants from Apellis, personal fees from Optos, personal fees from Zeiss and personal fees from Biogen. AVR is a consultant for Allergan and Zeiss., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2019
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60. Characterization of Patients With Geographic Atrophy in Routine Clinical Practice.
- Author
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Conti F, Han MM, Song W, Wai KM, Silva FQ, and Singh RP
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- Aged, Aged, 80 and over, Blindness epidemiology, Choroidal Neovascularization complications, Choroidal Neovascularization physiopathology, Cross-Sectional Studies, Female, Humans, Incidence, Male, Middle Aged, Vision, Low epidemiology, Visual Acuity physiology, Geographic Atrophy complications, Geographic Atrophy diagnosis, Geographic Atrophy physiopathology
- Abstract
Background and Objective: Geographic atrophy (GA) affects millions of patients with age-related macular degeneration (AMD) worldwide, leading to significant, irreversible visual impairment. This study aims to characterize the visual impairment of patients with GA in a routine clinical practice., Patients and Methods: This single-center, cross-sectional study used a novel natural language processing to select 1,045 GA cases utilizing the macula examination records from 19,359 patients with AMD., Results: Patients were classified based on the diagnosis of the fellow-eye as follow: 502 in group 1 (GA:GA), 403 in group 2 (GA : choroidal neovascularization), and 234 in group 3 (GA : early / intermediate AMD). Best-corrected visual acuity (BCVA) in the affected eye was 50.3 (± 22.1) letters in group 1, 52.5 (± 21.3) letters in group 2, and 48.5 (± 23.6) letters in group 3 (P < .05). Visual impairment (ineligibility for an unrestricted driver license) was present in 70.5% of group 1, 59.7% of group 2, and 39.6% of group 3. Legal blindness (BCVA < 20 letters in the best-seeing eye) was seen in 2.2% of group 1, 3% of group 2, and 0.8% of group 3., Conclusion: Differences in visual impairment between subgroups of patients with GA can be seen in routine clinical practice. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:93-98.]., (Copyright 2019, SLACK Incorporated.)
- Published
- 2019
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61. Impact of prenatal heavy metal exposure on newborn leucocyte telomere length: A birth-cohort study.
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Wai KM, Umezaki M, Kosaka S, Mar O, Umemura M, Fillman T, and Watanabe C
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- Adult, Arsenic urine, Cadmium blood, Cohort Studies, Female, Humans, Infant, Newborn, Lead blood, Metals, Heavy blood, Pregnancy, Telomere, Environmental Pollutants toxicity, Maternal Exposure statistics & numerical data, Metals, Heavy toxicity
- Abstract
Arsenic, cadmium and lead are toxic environmental contaminants. They were shown to be associated with telomere length (TL) in adults. Although they can cross the placental barrier, the effect of prenatal exposure of these metals on newborn TL is unknown. The aim of this study was to examine whether prenatal exposure to heavy metals has an impact on newborn leucocyte TL. A birth-cohort study was conducted with 409 pregnant women and their newborns in Myanmar. During the first visit, face-to-face interviews were conducted, and maternal spot urine sampling was performed. Cord blood samples were collected during follow-up. Urinary heavy metal concentration was measured by ICP-MS and adjusted for creatinine. Relative TL was measured by quantitative real-time polymerase chain reaction. The extent of prenatal arsenic, cadmium and lead exposure and their associations with newborn leucocyte TL were assessed using multivariate linear regression. The median values of maternal urinary arsenic, cadmium, and lead concentrations were 73.9, 0.9, and 1.8 μg/g creatinine, respectively. Prenatal arsenic and cadmium exposure was significantly associated with newborn TL shortening (lowest vs highest quartile, coefficient = - 0.13, 95% CI: - 0.22, - 0.03, p = 0.002, and coefficient = - 0.17, 95% CI: - 0.27, - 0.07, p = 0.001, respectively), and the associations remained robust after adjusting for confounders. There was no significant association between prenatal lead exposure and newborn TL. The present study identified the effect of arsenic and cadmium exposure on TL shortening, even in utero exposure at a lower concentration., (Copyright © 2018 Elsevier Ltd. All rights reserved.)
- Published
- 2018
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62. Impact of Time to Anti-Vascular Endothelial Growth Factor Intervention on Visual Outcomes for Patients Diagnosed With Retinal Vein Occlusion.
- Author
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Hsueh J, Wai KM, Conti FF, Conti TF, and Singh RP
- Subjects
- Aged, Angiogenesis Inhibitors administration & dosage, Female, Follow-Up Studies, Humans, Intravitreal Injections, Male, Middle Aged, Retinal Vein Occlusion diagnosis, Retrospective Studies, Time Factors, Tomography, Optical Coherence, Treatment Outcome, Bevacizumab administration & dosage, Ranibizumab administration & dosage, Receptors, Vascular Endothelial Growth Factor administration & dosage, Recombinant Fusion Proteins administration & dosage, Retinal Vein Occlusion drug therapy, Vascular Endothelial Growth Factor A antagonists & inhibitors, Visual Acuity
- Abstract
Background and Objectives: To analyze the impact of time to treatment with anti-vascular endothelial growth factor (VEGF) for patients with macular edema (ME) secondary to retinal vein occlusions (RVO) in routine clinical practice., Patients and Methods: One hundred fifty-five eyes with ME secondary to RVO were identified. Patients were divided into initiation of anti-VEGF treatment at 28 days or fewer after symptom onset (Group A), between 28 and 84 days (Group B), and 84 days or more (Group C)., Results: A significant central subfield thickness (CST) decrease at 12 months was observed in Groups A, B, and C (-184.14 µm, -204.55 µm, and -170.71 µm, respectively; P < .001). At 12 months, Groups A and B showed significant BCVA improvement (19.14 and 21.11, respectively; P ≤ .001), whereas Group C showed no significant improvement from baseline (4.01; P < .28)., Conclusions: Anatomical response as measured by CST did not differ between groups, whereas delays in treatment resulted in smaller BCVA improvement with anti-VEGF treatment. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:832-837.]., (Copyright 2018, SLACK Incorporated.)
- Published
- 2018
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63. Observational evidence of a long-term increase in precipitation due to urbanization effects and its implications for sustainable urban living.
- Author
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Wai KM, Wang XM, Lin TH, Wong MS, Zeng SK, He N, Ng E, Lau K, and Wang DH
- Abstract
Although projected precipitation increases in East Asia due to future climate change have aroused concern, less attention has been paid by the scientific community and public to the potential long-term increase in precipitation due to rapid urbanization. A ten-year precipitation dataset was analysed for both a rapidly urbanized megacity and nearby suburban/rural stations in southern China. Rapid urbanization in the megacity was evident from satellite observations. A statistically significant, long-term, increasing trend of precipitation existed only at the megacity station (45.6mm per decade) and not at the other stations. The increase was attributed to thermal and dynamical modifications of the tropospheric boundary layer related to urbanization, which was confirmed by the results of our WRF-SLUCM simulations. The results also suggested that a long-term regional increase in precipitation, caused by greenhouse gas-induced climate change, for instance, was not evident within the study period. The urbanization-induced increase was found to be higher than the precipitation increase (18.3mm per decade) expected from future climate change. The direct climate impacts due to rapid urbanization is highlighted with strong implications for urban sustainable development and the planning of effective adaptation strategies for issues such as coastal defenses, mosquito-borne disease spread and heat stress mortality., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2017
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64. Prenatal Heavy Metal Exposure and Adverse Birth Outcomes in Myanmar: A Birth-Cohort Study.
- Author
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Wai KM, Mar O, Kosaka S, Umemura M, and Watanabe C
- Subjects
- Adult, Cohort Studies, Female, Gestational Age, Humans, Infant, Low Birth Weight, Infant, Newborn, Myanmar, Odds Ratio, Pregnancy, Pregnancy Trimester, Third, Congenital Abnormalities etiology, Maternal Exposure adverse effects, Metals, Heavy adverse effects, Metals, Heavy urine, Pregnancy Complications etiology, Premature Birth chemically induced, Prenatal Exposure Delayed Effects
- Abstract
Arsenic, cadmium and lead are well-known environmental contaminants, and their toxicity at low concentration is the target of scientific concern. In this study, we aimed to identify the potential effects of prenatal heavy metal exposure on the birth outcomes among the Myanmar population. This study is part of a birth-cohort study conducted with 419 pregnant women in the Ayeyarwady Division, Myanmar. Face-to-face interviews were performed using a questionnaire, and maternal spot urine samples were collected at the third trimester. Birth outcomes were evaluated at delivery during the follow up. The median values of adjusted urinary arsenic, cadmium, selenium and lead concentration were 74.2, 0.9, 22.6 and 1.8 μg/g creatinine, respectively. Multivariable logistic regression revealed that prenatal cadmium exposure (adjusted odds ratio (OR) = 1.10; 95% confidence interval (CI): 1.01-1.21; p = 0.043), gestational age (adjusted OR = 0.83; 95% CI: 0.72-0.95; p = 0.009) and primigravida mothers (adjusted OR = 4.23; 95% CI: 1.31-13.65; p = 0.016) were the predictors of low birth weight. The present study identified that Myanmar mothers were highly exposed to cadmium. Prenatal maternal cadmium exposure was associated with an occurrence of low birth weight., Competing Interests: The authors declare no conflicts of interest.
- Published
- 2017
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65. Public health risk of mercury in China through consumption of vegetables, a modelling study.
- Author
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Wai KM, Dai J, Yu PKN, Zhou X, and Wong CMS
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- China, Environmental Monitoring, Humans, Risk Assessment, Environmental Exposure, Food Contamination analysis, Mercury analysis, Methylmercury Compounds analysis, Models, Theoretical, Public Health, Vegetables chemistry
- Abstract
Sample measurement of mercury (Hg) contents is a common method for health risk assessment of Hg through vegetable consumption in China. In the present work, we undertook the first modelling study which produced consistent health-risk maps for the whole eastern China. Regional maps of Probable Daily Intake (PDI) of Total mercury (THg) and Methylmercury (MeHg) over the studied area were produced, which were important for the researchers and policy-makers to evaluate the risk and to propose mitigation measures if necessary. The model predictions of air-borne Hg(0) concentrations agreed well with the observations and simulated Hg distribution over China as reported elsewhere. Our calculated PDIs of THg in vegetables were also comparable to those reported in the literature. There was 19% of the studied area with PDIs > 0.08µgkg
-1 bw d-1 [half of the reference dose (RfD)]. The PDI for THg (MeHg) varied from 0.034 (0.007) to 0.162 (0.035)µgkg-1 bw d-1 with an average of 0.058 (0.013)µgkg-1 bw d-1 . The highest calculated PDIs of THg over China was equal to the RfD, while the calculated PDIs of MeHg were well below the RfD of 0.1µgkg-1 bw d-1 . The health risk was of concern through consumption of THg in leafy vegetables, rice/wheat and fish in Liaoning Provinces, Hunan, Zhejiang and Guizhou Provinces, with the associated PDIs exceeding the RfD. Despite this, the heath risk of MeHg exposure for the general population in southern China from the same foodstuff consumption was not a concern. The contribution of consumption through leafy vegetation should be considered when THg and MeHg exposures to the population are evaluated. The results improve our understanding in managing public health risk in China especially in large cities with high population, and thus have important contribution to enhance sustainable urbanization as one of the principle goals under the framework of the Nature-Based Solution (NBS)., (Copyright © 2017 Elsevier Inc. All rights reserved.)- Published
- 2017
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66. Aerosol pollution and its potential impacts on outdoor human thermal sensation: East Asian perspectives.
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Wai KM, Ng EYY, Wong CMS, Tan TZ, Lin TH, Lien WH, Tanner PA, Wang CSH, Lau KKL, He NMH, and Kim J
- Subjects
- Beijing, Cities, Environmental Monitoring, Hong Kong, Humans, Models, Biological, Models, Theoretical, Seoul, Taiwan, Thermosensing, Aerosols analysis, Air Pollutants analysis, Air Pollution analysis
- Abstract
Aerosols affect the insolation at ground and thus the Aerosol Optical Depth (AOD, a measure of aerosol pollution) plays an important role on the variation of the Physiological Equivalent Temperature (PET) at locations with different aerosol climatology. The aerosol effects upon PET were studied for the first time at four East Asian cities by coupling a radiative transfer model and a human thermal comfort model which were previously well evaluated. Evident with the MODIS and AERONET AOD observations, the aerosol pollution at Beijing and Seoul was higher than at Chiayi (Taiwan) and Hong Kong. Based on the AERONET data, with background AOD levels the selected temperate cities had similar clear-sky PET values especially during summertime, due to their locations at similar latitudes. This also applied to the sub-tropical cities. Increase in the AOD level to the seasonal average one led to an increase in diffuse solar radiation and in turn an increase in PET for people living in all the cities. However, the heavy aerosol loading environment in Beijing and Seoul in summertime (AODs > 3.0 in episodic situations) reduced the total radiative flux and thus PET values in the cities. On the contrary, relatively lower episodic AOD levels in Chiayi and Hong Kong led to strong diffuse and still strong direct radiative fluxes and resulted in higher PET values, relative to those with seasonal averaged AOD levels. People tended to feel from "hot" to "very hot" during summertime when the AOD reached their average levels from the background level. This implies that in future aerosol effects add further burden to the thermal environment apart from the effects of greenhouse gas-induced global warming. Understanding the interaction between ambient aerosols and outdoor thermal environment is an important first step for effective mitigation measures such as urban greening to reduce the risk of human heat stress. It is also critical to make cities more attractive and enhancing to human well-being to achieve enhancing sustainable urbanization as one of the principal goals for the Nature-based Solutions., (Copyright © 2017 Elsevier Ltd. All rights reserved.)
- Published
- 2017
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67. Comparison of Ranibizumab and Bevacizumab for Macular Edema Secondary to Retinal Vein Occlusions in Routine Clinical Practice.
- Author
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Khan M, Wai KM, Silva FQ, Srivastava S, Ehlers JP, Rachitskaya A, Babiuch A, Deasy R, Kaiser PK, Schachat AP, Yuan A, and Singh RP
- Subjects
- Aged, Angiogenesis Inhibitors administration & dosage, Female, Fluorescein Angiography, Follow-Up Studies, Fundus Oculi, Humans, Intravitreal Injections, Macular Edema diagnosis, Macular Edema etiology, Male, Retinal Vein Occlusion complications, Retinal Vein Occlusion diagnosis, Retrospective Studies, Tomography, Optical Coherence, Treatment Outcome, Vascular Endothelial Growth Factor A antagonists & inhibitors, Visual Acuity, Bevacizumab administration & dosage, Macula Lutea pathology, Macular Edema drug therapy, Ranibizumab administration & dosage, Retinal Vein Occlusion drug therapy
- Abstract
Background and Objective: To determine outcomes of intravitreal ranibizumab (IVR) (Lucentis; Genentech, South San Francisco, CA) versus bevacizumab (IVB) (Avastin; Genentech, South San Francisco, CA) for treatment of macular edema (ME) secondary to retinal vein occlusion (RVO) in routine clinical practice., Patients and Methods: A retrospective study identified treatment-naïve patients with ME secondary to RVO where treatment with either IVB or IVR was initiated. Retreatment criteria were based on ophthalmic examination and/or spectral-domain optical coherence tomography findings., Results: Central RVO/hemi-RVO cohort: At 12 months, change in visual acuity (VA) (IVR: +12.9 letters, IVB +6.9 letters; P = .53), central subfield thickness (CST) (IVR: -144.1 μm, IVB: -153.9 μm; P = .88), and number of injections (IVR: 5.40 injections, IVB: 5.64 injections; P = .70) were not different between groups. Branch RVO cohort: At 12-month follow-up, no differences in change in VA (IVR: +15.2 letters, IVB: +10.6 letters; P = .46), CST (IVR: -23.1 μm, IVB: -91.4 μm; P = .16), or number of injections (IVR: 5.93 injections, IVB: 5.13 injections; P = .15) were noted., Conclusion: There is no notable difference in outcome between IVR and IVB when treating ME from RVO in routine clinical practice. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:465-472.]., (Copyright 2017, SLACK Incorporated.)
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- 2017
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68. Impact of initial visual acuity on anti-VEGF treatment outcomes in patients with macular oedema secondary to retinal vein occlusions in routine clinical practice.
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Wai KM, Khan M, Srivastava S, Rachitskaya A, Silva FQ, Deasy R, Schachat AP, Babiuch A, Ehlers JP, Kaiser PK, Yuan A, and Singh RP
- Subjects
- Aged, Aged, 80 and over, Bevacizumab, Female, Follow-Up Studies, Humans, Intravitreal Injections, Macular Edema etiology, Macular Edema physiopathology, Male, Middle Aged, Ranibizumab, Retinal Vein Occlusion complications, Retinal Vein Occlusion physiopathology, Retrospective Studies, Tomography, Optical Coherence, Vascular Endothelial Growth Factor A antagonists & inhibitors, Angiogenesis Inhibitors therapeutic use, Macular Edema drug therapy, Retinal Vein Occlusion drug therapy, Visual Acuity physiology
- Abstract
Aim: To determine the impact of initial visual acuity (VA) on anti-vascular endothelial growth factor (VEGF) treatment outcomes in patients with macular oedema secondary to retinal vein occlusions in routine clinical practice., Methods: A retrospective study was conducted at a single academic institution to identify 177 treatment naïve patients with macular oedema secondary to branch retinal vein occlusion (BRVO), hemiretinal vein occlusion (HRVO) and central retinal vein occlusion (CRVO) treated with intravitreal anti-VEGFs. Exclusion criteria included prior intravitreal injection or presence of active confounding ocular disease. Patients were stratified by initial VA; main outcomes measured were average change in VA and mean absolute change in central subfield thickness (CST) at 6 and 12 months., Results: Patients with BRVO with initial VA of 20/40 or better had no significant changes in average letters gained and CST from baseline (+2.6 letters, p=0.42; -48.94 µm, p=0.12) compared with patients with initial VA between 20/50 and 20/300 (+13.2 letters, p<0.001; -98.20 µm, p<0.001) after 12 months. Patients with CRVO/HRVO with initial VA of 20/320 or worse had the most improvement in average letters gained and CST from baseline (+42.2 letters, p<0.001; -182.84 µm, p=0.004) with anti-VEGF therapy compared with patients with initial VA between 20/50 and 20/300 (+9.4 letters, p=0.016; -160.87 µm, p<0.001) and patients with initial VA of 20/40 or better (-9.6 letters, p=0.14; -47.92 µm, p=0.38)., Conclusions: For macular oedema secondary to retinal vein occlusion, anti-VEGF treatment can result in a greater improvement in average letters gained and in CST for those with poor initial VA compared with those with better initial VA., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)
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- 2017
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69. Correlates of sex trading among male non-injecting drug users in Myanmar: a cross-sectional study.
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Saw YM, Saw TN, Wai KM, Poudel KC, and Win HH
- Subjects
- Adolescent, Adult, Cross-Sectional Studies, HIV Infections epidemiology, Humans, Male, Middle Aged, Myanmar epidemiology, Risk Factors, Sexual Behavior statistics & numerical data, Sexual Partners, Substance-Related Disorders psychology, Young Adult, Sex Work psychology, Substance-Related Disorders epidemiology
- Abstract
Background: Sex trading is a recognized risk factor for human immune deficiency virus infection and other sexually transmitted infections among non-injecting drug users (NIDUs). However, very little research has addressed the factors associated with sex trading among male NIDUs in Myanmar., Methods: A cross-sectional study was conducted from January to February 2010 using the respondent-driven sampling method. In total, 210 NIDUs aged between 18 and 49 years, with no history of injecting drug use, and who used non-injected illicit drugs in the last 6 months were recruited. Face-to-face interviews were conducted using a structured questionnaire to collect information on participants' sexual and drug use behaviors. Binary and multivariate logistic regressions were applied to analyze the resulting data., Results: Of 210 NIDUs, 84 (40%) reported involvement in the sex trade during the last 3 months. In the adjusted model, factors associated with sex trade involvement included homosexual preference (adjusted odds ratio [AOR] 4.90; 95% confidence interval [CI] 1.61-14.95), having more than two partners (AOR = 3.88; 95% CI 1.55-9.72), had a regular job (AOR = 5.10; 95% CI 1.65-15.72), use of stimulant drugs rather than opiate (AOR = 2.38; 95% CI 1.10-5.15), and who used drugs more than twice per day., Conclusions: More than one third of NIDUs were involved in sex trading. This study suggested that further comprehensive intervention programs that aim to reduce risk factors of trading sex among NIDUs may consider including NIDUs who used stimulant drugs, had regular/full-time jobs, used drugs more than twice per day, and had homosexual preferences.
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- 2016
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70. Evaluation and Referral of Diabetic Eye Disease in the Endocrinology and Primary Care Office Settings.
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Silva FQ, Adhi M, Wai KM, Olansky L, Lansang MC, and Singh RP
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Female, Follow-Up Studies, Humans, Male, Middle Aged, Ohio, Retrospective Studies, Young Adult, Diabetic Retinopathy therapy, Endocrinology, Office Visits statistics & numerical data, Practice Patterns, Physicians', Primary Health Care methods, Referral and Consultation
- Abstract
Background and Objective: The purpose of this study was to identify whether endocrinologists and primary care physicians (PCP) adequately screen for ophthalmic symptoms/signs within office visits and provide timely ophthalmology referrals in patients with diabetes., Patients and Methods: Patients between the ages of 18 years and 80 years with diabetes who underwent an office visit with an endocrinologist or a PCP between January 1, 2014, and December 31, 2014, were identified. Demographics, ophthalmic assessments, and referral information were collected., Results: A total of 1,250 patient records were reviewed. Providers asked about ophthalmic symptoms/signs in 95.5% and 71% of endocrinology and primary care office encounters, respectively (P < .0001). Past and/or future ophthalmology appointments were verified in 86.1% and 49.7% of patients during endocrinology and PCP visits, respectively (P < .0001)., Conclusions: Ophthalmic complications from diabetes are not adequately screened, especially within the primary care setting, and further quality improvement measures may improve adherence to recommended screening protocols. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:930-934.]., (Copyright 2016, SLACK Incorporated.)
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- 2016
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71. Global Atmospheric Transport and Source-Receptor Relationships for Arsenic.
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Wai KM, Wu S, Li X, Jaffe DA, and Perry KD
- Subjects
- Arctic Regions, Asia, Atmosphere, Humans, North America, South America, Air Pollutants analysis, Arsenic analysis, Models, Theoretical
- Abstract
Arsenic and many of its compounds are toxic pollutants in the global environment. They can be transported long distances in the atmosphere before depositing to the surface, but the global source-receptor relationships between various regions have not yet been assessed. We develop the first global model for atmospheric arsenic to better understand and quantify its intercontinental transport. Our model reproduces the observed arsenic concentrations in surface air over various sites around the world. Arsenic emissions from Asia and South America are found to be the dominant sources for atmospheric arsenic in the Northern and Southern Hemispheres, respectively. Asian emissions are found to contribute 39% and 38% of the total arsenic deposition over the Arctic and Northern America, respectively. Another 14% of the arsenic deposition to the Arctic region is attributed to European emissions. Our results indicate that the reduction of anthropogenic arsenic emissions in Asia and South America can significantly reduce arsenic pollution not only locally but also globally.
- Published
- 2016
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72. Correction: Are Husbands Involving in Their Spouses' Utilization of Maternal Care Services?: A Cross-Sectional Study in Yangon, Myanmar.
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Wai KM, Shibanuma A, Oo NN, Fillman TJ, Saw YM, and Jimba M
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- 2016
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73. Are Husbands Involving in Their Spouses' Utilization of Maternal Care Services?: A Cross-Sectional Study in Yangon, Myanmar.
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Wai KM, Shibanuma A, Oo NN, Fillman TJ, Saw YM, and Jimba M
- Subjects
- Adult, Cross-Sectional Studies, Female, Humans, Male, Myanmar, Pregnancy, Maternal-Child Health Services, Spouses
- Abstract
Introduction: Husbands can play a crucial role in pregnancy and childbirth, especially in patriarchal societies of developing countries. In Myanmar, despite the critical influence of husbands on the health of mothers and newborns, their roles in maternal health have not been well explored. Therefore, the aim of this study was to identify the factors associated with husbands' involvement in maternal health in Myanmar. This study also examined the associations between husbands' involvement and their spouses' utilization of maternal care services during antenatal, delivery and postnatal periods., Methods: A community-based, cross sectional study was conducted with 426 husbands in Thingangyun Township, Yangon, Myanmar. Participants were husbands aged 18 years or older who had at least one child within two years at the time of interview. Face to face interviews were conducted using a pretested structured questionnaire. Factors associated with the characteristics of husband's involvement as well as their spouses' utilization of maternal care services were analyzed by multivariable logistic regression models., Results: Of 426 husbands, 64.8% accompanied their spouses for an antenatal visit more than once while 51.6% accompanied them for a postnatal visit. Husbands were major financial supporters for both antenatal (95.8%) and postnatal care (68.5%). Overall, 69.7% were involved in decision making about the place of delivery. Regarding birth preparedness, the majority of husbands prepared for skilled birth attendance (91.1%), delivery place (83.6%), and money saving (81.7%) before their spouses gave birth. In contrast, fewer planned for a potential blood donor (15.5%) and a safe delivery kit (21.1%). In the context of maternal health, predictors of husband's involvement were parity, educational level, type of marriage, decision making level in family, exposure to maternal health education and perception of risk during pregnancy and childbirth. Increased utilization of maternal health services was found among spouses of husbands who accompanied them to antenatal visits (AOR 5.82, 95% CI, 3.34-10.15) and those who had a well birth plan (AOR 2.42, 95% CI, 1.34-4.39 for antenatal visit and AOR 2.88, 95% CI, 1.52-5.47 for postnatal visit)., Conclusion: The majority of husbands supported their spouses' maternal care services use financially; however, they were less involved in birth preparedness and postnatal care. Exposure to maternal health education and their maternal health knowledge were main predictors of their involvement. Women were more likely to use maternal care services when their husbands company them for ANC visits and had a well-birth plan in advance.
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- 2015
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74. Reduction of Solar UV Radiation Due to Urban High-Rise Buildings--A Coupled Modelling Study.
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Wai KM, Yu PK, and Lam KS
- Subjects
- Humans, Facility Design and Construction, Models, Theoretical, Sunlight, Ultraviolet Rays
- Abstract
Solar UV radiation has both adverse and beneficial effects to human health. Using models (a radiative transfer model coupled to a building shading model), together with satellite and surface measurements, we studied the un-obstructed and obstructed UV environments in a sub-tropical urban environment featured with relatively high pollution (aerosol) loadings and high-rise buildings. Seasonal patterns of the erythemal UV exposure rates were governed by solar zenith angles, seasonal variations of aerosol loadings and cloud effects. The radiative transfer modelling results agreed with measurements of erythemal UV exposure rates and spectral irradiances in UVA and UVB ranges. High-rise buildings and narrow road width (height to width, H/W, ratios up to 15) reduced the modelled total UV (UVA+UVB) radiation and leave 10% of the un-obstructed exposure rate at ground-level at noon. No more than 80% of the un-obstructed exposure rate was received in the open area surrounded by 20-storey buildings. Our modelled reduction of UVB radiation in the urban environment was consistent with similar measurements obtained for Australia. However, our results in more extreme environments (higher H/W ratios) were for the first time reported, with 18% of the un-obstructed exposure rate remained at the ground-level center of the street canyon.
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- 2015
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75. Trans-oceanic transport of 137Cs from the Fukushima nuclear accident and impact of hypothetical Fukushima-like events of future nuclear plants in Southern China.
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Wai KM and Yu PK
- Subjects
- China, Pacific Ocean, Air Pollutants, Radioactive analysis, Cesium Radioisotopes analysis, Fukushima Nuclear Accident, Radiation Monitoring, Water Pollutants, Radioactive analysis
- Abstract
A Lagrangian model was adopted to assess the potential impact of (137)Cs released from hypothetical Fukushima-like accidents occurring on three potential nuclear power plant sites in Southern China in the near future (planned within 10 years) in four different seasons. The maximum surface (0-500 m) (137)Cs air concentrations would be reached 10 Bq m(-3) near the source, comparable to the Fukushima case. In January, Southeast Asian countries would be mostly affected by the radioactive plume due to the effects of winter monsoon. In April, the impact would be mainly on Southern and Northern China. Debris of radioactive plume (~1 mBq m(-3)) would carry out long-range transport to North America. The area of influence would be the smallest in July due to the frequent and intense wet removal events by trough of low pressure and tropical cyclone. The maximum worst-case areas of influence were 2382000, 2327000, 517000 and 1395000 km(2) in January, April, July and October, respectively. Prior to the above calculations, the model was employed to simulate the trans-oceanic transport of (137)Cs from the Fukushima nuclear accident. Observed and modeled (137)Cs concentrations were comparable. Sensitivity runs were performed to optimize the wet scavenging parameterization. The adoption of higher-resolution (1° × 1°) meteorological fields improved the prediction. The computed large-scale plume transport pattern over the Pacific Ocean was compared with that reported in the literature., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2015
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76. Assessment of HIV testing among young methamphetamine users in Muse, Northern Shan State, Myanmar.
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Saw YM, Poudel KC, Kham NP, Chan N, Cope JE, Wai KM, Tun S, and Saw TN
- Subjects
- Adolescent, Cross-Sectional Studies, Drug Users, Female, HIV Infections epidemiology, Humans, Logistic Models, Male, Myanmar epidemiology, Sexual Behavior statistics & numerical data, Substance-Related Disorders, Young Adult, Dopamine Agents administration & dosage, HIV Infections diagnosis, Methamphetamine administration & dosage, Patient Acceptance of Health Care
- Abstract
Background: Methamphetamine (MA) use has a strong correlation with risky sexual behaviors, and thus may be triggering the growing HIV epidemic in Myanmar. Although methamphetamine use is a serious public health concern, only a few studies have examined HIV testing among young drug users. This study aimed to examine how predisposing, enabling and need factors affect HIV testing among young MA users., Methods: A cross-sectional study was conducted from January to March 2013 in Muse city in the Northern Shan State of Myanmar. Using a respondent-driven sampling method, 776 MA users aged 18-24 years were recruited. The main outcome of interest was whether participants had ever been tested for HIV. Descriptive statistics and multivariate logistic regression were applied in this study., Results: Approximately 14.7% of young MA users had ever been tested for HIV. Significant positive predictors of HIV testing included predisposing factors such as being a female MA user, having had higher education, and currently living with one's spouse/sexual partner. Significant enabling factors included being employed and having ever visited NGO clinics or met NGO workers. Significant need factors were having ever been diagnosed with an STI and having ever wanted to receive help to stop drug use., Conclusions: Predisposing, enabling and need factors were significant contributors affecting uptake of HIV testing among young MA users. Integrating HIV testing into STI treatment programs, alongside general expansion of HIV testing services may be effective in increasing HIV testing uptake among young MA users.
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- 2014
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77. Epidemiology of trauma in an acute care hospital in Singapore.
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Wui LW, Shaun GE, Ramalingam G, and Wai KM
- Abstract
Background: Trauma injury is the leading cause of mortality and hospitalization worldwide and the leading cause of potential years of productive life lost. Patients with multiple injuries are prevalent, increasing the complexity of trauma care and treatment. Better understanding of the nature of trauma risk and outcome could lead to more effective prevention and treatment strategies., Materials and Methods: A retrospective review of 1178 trauma patients with Injury Severity Score (ISS) ≥ 9, who were admitted to the Acute and Emergency Care of an acute care hospital between January 2011 and December 2012. The statistical analysis included calculation of percentages and proportions and application of test of significance using Pearson's chi-square test or Fisher's exact test where appropriate., Results: Over the study period, 1178 patients were evaluated, 815 (69.2%) males and 363 (30.8%) females. The mean age of patients was 52.08 ± 21.83 (range 5-100) years. Falls (604; 51.3%) and road traffic accidents (465; 39.5%) were the two most common mechanisms of injury. Based on the three most common mechanisms of injury, i.e. fall on the same level, fall from height, and road traffic accident, the head region (484; 45.40%) was the most commonly injured in the body, followed by lower limbs (377; 35.37%) and thorax (299; 28.05%)., Conclusion: Fall was the leading cause of injury among the elderly population with road traffic injuries being the leading cause among the younger group. There is a need to address the issues of injury control and prevention in these areas.
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- 2014
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78. Astrocytic TGF-β signaling limits inflammation and reduces neuronal damage during central nervous system Toxoplasma infection.
- Author
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Cekanaviciute E, Dietrich HK, Axtell RC, Williams AM, Egusquiza R, Wai KM, Koshy AA, and Buckwalter MS
- Subjects
- Animals, Astrocytes parasitology, Astrocytes pathology, Chemokines genetics, Chemokines immunology, Glial Fibrillary Acidic Protein, Humans, Mice, Mice, Transgenic, Nerve Tissue Proteins genetics, Nerve Tissue Proteins immunology, Neurons parasitology, Neurons pathology, Signal Transduction genetics, Toxoplasma genetics, Toxoplasmosis, Cerebral genetics, Toxoplasmosis, Cerebral pathology, Transforming Growth Factor beta genetics, Up-Regulation genetics, Up-Regulation immunology, Astrocytes immunology, Neurons immunology, Signal Transduction immunology, Toxoplasma immunology, Toxoplasmosis, Cerebral immunology, Transforming Growth Factor beta immunology
- Abstract
The balance between controlling infection and limiting inflammation is particularly precarious in the brain because of its unique vulnerability to the toxic effects of inflammation. Astrocytes have been implicated as key regulators of neuroinflammation in CNS infections, including infection with Toxoplasma gondii, a protozoan parasite that naturally establishes a chronic CNS infection in mice and humans. In CNS toxoplasmosis, astrocytes are critical to controlling parasite growth. They secrete proinflammatory cytokines and physically encircle parasites. However, the molecular mechanisms used by astrocytes to limit neuroinflammation during toxoplasmic encephalitis have not yet been identified. TGF-β signaling in astrocytes is of particular interest because TGF-β is universally upregulated during CNS infection and serves master regulatory and primarily anti-inflammatory functions. We report in this study that TGF-β signaling is activated in astrocytes during toxoplasmic encephalitis and that inhibition of astrocytic TGF-β signaling increases immune cell infiltration, uncouples proinflammatory cytokine and chemokine production from CNS parasite burden, and increases neuronal injury. Remarkably, we show that the effects of inhibiting astrocytic TGF-β signaling are independent of parasite burden and the ability of GFAP(+) astrocytes to physically encircle parasites., (Copyright © 2014 by The American Association of Immunologists, Inc.)
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- 2014
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79. Origin and distribution of trace elements in high-elevation precipitation in southern China.
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Zhou J, Wang Y, Yue T, Li Y, Wai KM, and Wang W
- Subjects
- Air Pollutants analysis, Altitude, China, Environmental Monitoring methods, Spectrophotometry, Atomic methods, Rain chemistry, Snow chemistry, Trace Elements analysis
- Abstract
Introduction: During a 2009 investigation of the transport and deposition of trace elements in southern China, 37 event-based precipitation samples were collected at an observatory on Mount Heng, China (1,269 m asl)., Methods: Concentrations of trace elements were analyzed using inductively coupled plasma-mass spectrometry and the wet deposition fluxes were established. A combination of techniques including enrichment factor analysis, principal component analysis, and back trajectory models were used to identify pollutant sources., Results: Trace element concentrations at Mount Heng were among the highest with respect to measured values reported elsewhere. All elements were of non-marine origin. The elements Pb, As, Cu, Se, and Cd were anthropogenic, while Fe, Cr, V, Ba, Mn, and Ni were of mixed crustal/anthropogenic origin. The crustal and anthropogenic contributions of trace elements were 12.8 % (0.9 ~ 17.4 %) and 87.2 % (82.6 ~ 99.1 %), with the maximum crustal fraction being 17.4 % for Fe. Coal combustion, soil and road dust, metallurgical processes, and industrial activities contributed to the element composition., Conclusions: Summit precipitation events were primarily distant in origin. Medium- to long-range transport of trace elements from the Yangtze River Delta and northern China played an important role in wet deposition at Mount Heng, while air masses from south or southeast of the station were generally low in trace element concentrations.
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- 2012
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80. Evaluation of trace elements contamination in cloud/fog water at an elevated mountain site in Northern China.
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Liu XH, Wai KM, Wang Y, Zhou J, Li PH, Guo J, Xu PJ, and Wang WX
- Subjects
- China, Dust analysis, Time Factors, Altitude, Trace Elements analysis, Water chemistry, Water Pollutants, Chemical analysis, Weather
- Abstract
Totally 117 cloud/fog water samples were collected at the summit of Mt. Tai (1534m a.s.l.)-the highest mountain in the Northern China Plain. The results were investigated by a combination of techniques including back trajectory model, regional air quality and dust storm models, satellite observations and Principal Component Analysis. Elemental concentrations were determined by Inductively Coupled Plasma Mass Spectrometry, with stringent quality control measures. Higher elemental concentrations were found at Mt. Tai compared with those reported by other overseas studies. The larger proportions and higher concentrations of toxic elements such as Pb and As in cloud/fog water compared with those in rainwater at Mt. Tai suggests higher potential hazards of cloud/fog water as a source of contamination in polluted areas to the ecosystem. Peak concentrations of trace elements were frequently observed during the onset of cloud/fog events when liquid water contents of cloud/fog water were usually low and large amount of pollutants were accumulated in the ambient air. Inverse relationship between elemental concentrations and liquid water contents were only found in the samples with high electrical conductivities and liquid water contents lower than 0.3gm(-3). Affected mainly by the emissions of steel industries and mining activities, air masses transported from south/southwest of Mt. Tai were frequently associated with higher elemental concentrations. The element Mn is attributed to play an important role in the acidity of cloud/fog water. The composition of cloud/fog water influenced by an Asian dust storm event was reported, which was seldom found in the literature., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2012
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81. Observational and modeling study of dry deposition on surrogate surfaces in a South China city: implication of removal of atmospheric crustal particles.
- Author
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Wai KM, Leung KY, and Tanner PA
- Subjects
- China, Atmosphere, Models, Theoretical, Particle Size
- Abstract
Dry deposition samples collected during 1999-2001 at a South China site using surrogate surfaces were analyzed by capillary electrophoresis. Collector surface properties played important roles to the dry deposition. The deposition velocities for various species ranged from 0.02 to 1.69 cm s(-1), in general agreement with literature values. More than 90% of Ca(2+) was deposited by sedimentation and its comparable values of dry or wet removal residence times imply that dry deposition is an important atmospheric removal process for the ubiquitous crustal species in South China, compared with precipitation scavenging. Relatively good agreement was found when the species deposition velocities were modeled based on up-to-date knowledge of particle dry deposition. The total depositions for anthropogenic and crustal species in northern China are likely to be much higher than those in the south, including our site where the fluxes of the acidic species SO(4)(2-) and NO(3)(-) were 4.4 and 2.2 g m(-2) year(-1), respectively. The sum of dry deposition for cations Na(+), Ca(2+), Mg(2+), and K(+) contributes 44% of the total flux, which is equivalent to the value estimated in Europe.
- Published
- 2010
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82. Ezetimibe treatment of pediatric patients with hypercholesterolemia.
- Author
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Clauss S, Wai KM, Kavey RE, and Kuehl K
- Subjects
- Adolescent, Child, Cholesterol blood, Cholesterol, HDL blood, Cholesterol, LDL blood, Ezetimibe, Female, Humans, Hypercholesterolemia blood, Hypercholesterolemia genetics, Hyperlipidemia, Familial Combined blood, Male, Triglycerides blood, Anticholesteremic Agents therapeutic use, Azetidines therapeutic use, Hypercholesterolemia drug therapy, Hyperlipidemia, Familial Combined drug therapy
- Abstract
Objective: To review the efficacy of ezetimibe monotherapy for treatment of hypercholesterolemia in pediatric patients., Study Design: This is a retrospective review of all pediatric patients who received ezetimibe monotherapy as treatment for hypercholesterolemia and for whom follow-up clinical and lipid results were available. Of 36 identified patients, 26 had lipoprotein profiles suggestive of familial hypercholesterolemia (FH), and 10 had profiles suggestive of familial combined hyperlipidemia (FCHL)., Results: After a mean 105 days of treatment with ezetimibe (range, 32-175 days), total cholesterol (TC) levels decreased from 7.3 +/- 1.0 mmol/L to 5.7 +/- 1.0 mmol/L (P < .0001), and low-density lipoprotein cholesterol (LDL-C) levels decreased from 5.3 +/- 0.9 mmol/L to 3.9 +/- 0.8 (P < .0001) in patients with FH. In patients with FCHL, TC levels decreased from 6.4 +/- 2.0 mmol/L to 5.6 +/- 0.4 mmol/L (P < or = .002), and LDL-C levels decreased from 4.7 +/- 1.0 mmol/L to 3.8 +/- 0.6 mmol/L (P < or = .005). For all patients, the mean decrease in individual LDL-C values was 1.5 +/- 0.9 mmol/L or 28%. There was no significant change in triglyceride or high-density lipoprotein cholesterol levels with ezetimibe. Patients were maintained on ezetimibe with no adverse effects attributable to the medication for as long as 3.5 years. At a mean of 13.6 months (range, 1-44 months) after the initiation of ezetimibe, LDL-C levels remained decreased at 4.0 +/- 0.6 mmol/L., Conclusions: In this small retrospective series of children and adolescents with hypercholesterolemia, ezetimibe was safe and effective in lowering LDL-C levels.
- Published
- 2009
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83. 2-year study of chemical composition of bulk deposition in a south China coastal city: comparison with east Asian cities.
- Author
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Wai KM, Tanner PA, and Tam CW
- Subjects
- Cations, China, Cities, Environmental Monitoring, Hong Kong, Hydrogen-Ion Concentration, Japan, Rain, Seasons, Time Factors, Air Pollutants analysis, Ammonia analysis, Calcium analysis, Nitrates analysis, Sulfates analysis
- Abstract
Using the emission strengths of the precursor gases, the nature of soil in China, the ventilation power and half value rainout region length, the nss-SO42-, NO3-, Ca2+, and NH4+ concentrations, and pH of rainwater at Hong Kong and other cities of China and Japan are compared and rationalized. The chemical composition of Hong Kong bulk deposition from 1998 to 2000 is taken from our collection and analysis of 156 daily samples. The volume-weighted average (VWA) pH is 4.2 over the whole study period. Nonsea salt- (nss-) sulfate is the most abundant species in the samples, and the pH mostly depended upon the concentrations of the major species nss-SO42, NO3-, Ca2+, and NH4+. All species concentrations show higher levels in the cold season (especially NO3- and Ca2+), which indicates the dominant dilution effects in the warm season due to heavy rainfall and the influence of the continental outflow of pollutants during the cold season. For Hong Kong bulk deposition, the VWA pH is slightly lower in the cold season, and there is a slight decrease in VWA pH over the period from 1994 to 2000. The impact of acid rain in Hong Kong is briefly discussed.
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- 2005
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84. Calculating the statistical significance of physical clusters of co-regulated genes in the genome: the role of chromatin in domain-wide gene regulation.
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Chang CF, Wai KM, and Patterton HG
- Subjects
- Cluster Analysis, Gene Expression Profiling, Genes, Fungal, Histone Deacetylases metabolism, Nuclear Proteins physiology, Repressor Proteins physiology, Reproducibility of Results, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae metabolism, Saccharomyces cerevisiae Proteins physiology, Silent Information Regulator Proteins, Saccharomyces cerevisiae metabolism, Sirtuin 2, Sirtuins metabolism, Telomere genetics, Chromatin physiology, Gene Expression Regulation, Models, Statistical, Software
- Abstract
Physical clusters of co-regulated, but apparently functionally unrelated, genes are present in many genomes. Despite the important implication that the genomic environment contributes appreciably to the regulation of gene expression, no simple statistical method has been described to identify physical clusters of co-regulated genes. Here we report the development of a model that allows the direct calculation of the significance of such clusters. We have implemented the derived statistical relation in a software program, Pyxis, and have analyzed a selection of Saccharomyces cerevisiae gene expression microarray data sets. We have identified many gene clusters where constituent genes exhibited a regulatory dependence on proteins previously implicated in chromatin structure. Specifically, we found that Tup1p-dependent gene domains were enriched close to telomeres, which suggested a new role for Tup1p in telomere silencing. In addition, we identified Sir2p-, Sir3p- and Sir4p-dependent clusters, which suggested the presence of Sir-mediated heterochromatin in previously unidentified regions of the yeast genome. We also showed the presence of Sir4p-dependent gene clusters bordering the HMRa heterothallic locus, which suggested leaky termination of the heterochromatin by the boundary elements. These results demonstrate the utility of Pyxis in identifying possible higher order genomic features that may contribute to gene regulation in extended domains.
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- 2004
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85. Monitoring long-term variation of aerosol composition: a dual particle-size approach applied to Hong Kong.
- Author
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Wai KM and Tanner PA
- Subjects
- Hong Kong, Particle Size, Aerosols analysis, Air Pollutants analysis, Environmental Monitoring
- Abstract
The 1990's time series in Hong Kong for various components of total suspended particulate matter (TSP) and PM10 have been analyzed in order to assess two distinct types of anthropogenic input. The first of these relates to the immense reclamation and construction activities for new developments and airport construction. The concentrations of crustal components in PM > 10 (= TSP - PM10) were found to peak at the time of this maximum activity. A second type of anthropogenic input, ambient lead from petrol vehicles, has decreased in Hong Kong and now represents a regional background. Ambient bromine now arises mainly from the seasalt source.
- Published
- 2002
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