Displaying publications 41 - 60 of 70 in total

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  1. Fulltext The mechanism of formation, structure and physiological relevance of covalent hemoglobin attachment to the erythrocyte membrane
    Welbourn EM, Wilson MT, Yusof A, Metodiev MV, Cooper CE
    Free Radic Biol Med, 2017 02;103:95-106.
    PMID: 28007575 DOI: 10.1016/j.freeradbiomed.2016.12.024
    Covalent hemoglobin binding to membranes leads to band 3 (AE1) clustering and the removal of erythrocytes from the circulation; it is also implicated in blood storage lesions. Damaged hemoglobin, with the heme being in a redox and oxygen-binding inactive hemichrome form, has been implicated as the binding species. However, previous studies used strong non-physiological oxidants. In vivo hemoglobin is constantly being oxidised to methemoglobin (ferric), with around 1% of hemoglobin being in this form at any one time. In this study we tested the ability of the natural oxidised form of hemoglobin (methemoglobin) in the presence or absence of the physiological oxidant hydrogen peroxide to initiate membrane binding. The higher the oxidation state of hemoglobin (from Fe(III) to Fe(V)) the more binding was observed, with approximately 50% of this binding requiring reactive sulphydryl groups. The hemoglobin bound was in a high molecular weight complex containing spectrin, ankyrin and band 4.2, which are common to one of the cytoskeletal nodes. Unusually, we showed that hemoglobin bound in this way was redox active and capable of ligand binding. It can initiate lipid peroxidation showing the potential to cause cell damage. In vivo oxidative stress studies using extreme endurance exercise challenges showed an increase in hemoglobin membrane binding, especially in older cells with lower levels of antioxidant enzymes. These are then targeted for destruction. We propose a model where mild oxidative stress initiates the binding of redox active hemoglobin to the membrane. The maximum lifetime of the erythrocyte is thus governed by the redox activity of the cell; from the moment of its release into the circulation the timer is set.
    Matched MeSH terms: Carbon Monoxide/metabolism
  2. Exhaled carbon monoxide levels among Malaysian male smokers with nicotine dependence
    Guan NC, Ann AY
    Southeast Asian J Trop Med Public Health, 2012 Jan;43(1):212-8.
    PMID: 23082572
    We studied the use of exhaled carbon monoxide (CO) to identify nicotine dependence among adult Malaysian male smokers. We conducted a cross-sectional study among 107 male smoking staff at a university hospital. We measured their exhaled CO using a piCO+ Smokerlyzer and diagnosed nicotine dependence using a Mini-International Neuropsychiatric Interview (MINI). The optimal cut-off value for exhaled CO was determined. The correlation between exhaled CO level and the Fagerstrom Test for Nicotine Dependence (FTND) was also assessed. The mean exhaled CO level among subjects with nicotine dependence (15.78 ppm) was significantly higher than subjects without nicotine dependence (9.62 ppm). The cut-off value used to identify smokers with nicotine dependence was set at 10 ppm (specificity = 0.721, sensitivity = 0.731, positive predictive value = 0.817 and negative predictive value = 0.617). Psychometric properties were stable with various durations of smoking. Exhaled CO correlated positively with FTND scores (Pearson's rho = 0.398, p = 0.01). Our findings show exhaled CO can be used to identify nicotine dependence among adult Malaysian male smokers.
    Matched MeSH terms: Carbon Monoxide*
  3. Indoor air quality in an automotive assembly plant in Selangor, Malaysia
    Edimansyah BA, Rusli BN, Naing L, Azwan BA, Aziah BD
    Southeast Asian J Trop Med Public Health, 2009 Jan;40(1):187-92.
    PMID: 19323052
    The purpose of this study was to determine the indoor air quality (IAQ) status of an automotive assembly plant in Rawang, Selangor, Malaysia using selected IAQ parameters, such as carbon dioxide (CO2), carbon monoxide (CO), temperature, relative humidity (RH) and respirable particulate matter (PM10). A cross-sectional study was conducted in the paint shop and body shop sections of the plant in March 2005. The Q-TRAK Plus IAQ Monitor was used to record the patterns of CO, CO2, RH and temperature; whilst PM10 was measured using DUSTTRAK Aerosol Monitor over an 8-hour time weight average (8-TWA). It was found that the average temperatures, RH and PM10 in the paint shop section and body shop sections exceeded the Department of Safety and Health (DOSH) standards. The average concentrations of RH and CO were slightly higher in the body shop section than in the paint shop section, while the average concentrations of temperature and CO2 were slightly higher in the paint shop section than in the body shop section. There was no difference in the average concentrations of PM10 between the two sections.
    Matched MeSH terms: Carbon Monoxide/analysis
  4. Fulltext Nicotine Dependence among Adolescents Single and Dual Cigarette Users
    Mohd Radzi NA, Saub R, Mohd Yusof ZY, Dahlui M, Sujak SL
    Children (Basel), 2021 Feb 14;8(2).
    PMID: 33672960 DOI: 10.3390/children8020144
    The prevalence of concurrent use of combustible and electronic cigarettes (dual-use) is on the rise among Malaysian adolescents. This study compares nicotine dependence among exclusive cigarette users, e-cigarette users, and dual adolescent users. A total of 227 adolescent smokers completed a self-administrated questionnaire with items based on Hooked on Nicotine Checklist (HONC) incorporated. Endorsement of at least one HONC item indicates nicotine dependence. Exhaled carbon monoxide readings and salivary cotinine data were also collected. Over half (52.9%) of the participants were exclusive e-cigarette users (EC). The prevalence of exclusive conventional cigarette smokers (CC) and dual users was 11.9% and 35.2%, respectively. Adolescents who have mothers with secondary school education were more likely to become addicted to nicotine (Adjusted Odd Ratio (aOR) = 2.72; 95% CI = 1.17-6.32). Adolescents' "mother's education" level predicted nicotine dependence. This highlighted the need to target families within the identified demography with a more supportive anti-tobacco program.
    Matched MeSH terms: Carbon Monoxide
  5. Data on combustion, performance and emissions of a 6.8 L, 6-cylinder, Tier II diesel engine
    Wan Mansor WN, Abdullah S, Jarkoni MNK, Vaughn JS, Olsen DB
    Data Brief, 2020 Dec;33:106580.
    PMID: 33304969 DOI: 10.1016/j.dib.2020.106580
    A diesel engine has been a desirable machine due to its better fuel efficiency, reliability, and higher power output. It is widely used in transportations, locomotives, power generation, and industrial applications. The combustion of diesel fuel emits harmful emissions such as unburned hydrocarbons (HC), particulate matter (PM), nitrogen oxides (NOx), and carbon monoxides (CO). This article presents data on the efficiency, combustion, and emission of a 4-stroke diesel engine. The engine is a 6.8 L turbocharged 6-cylinder Tier II diesel engine fitted with a common rail injection system. The test was carried out at the Powerhouse Energy Campus, Colorado State University Engines and Energy Conversion facility. The ISO Standard 8178:4 Cycle D2 cycle was adopted for this study consists of five test runs at 1800 rpm. During the testing, CO, carbon dioxide (CO2), oxygen (O2), NOx, PM, unburned HC as a total HC (THC), methane (CH4), formaldehyde (CH2O), and volatile organic compound (VOC) emissions were measured. At the same time, the data acquisition system recorded the combustion data. The engine's performance is characterized by the brake specific fuel combustion (BSFC) and thermal efficiency. A dataset of correlations among the parameters was also presented in this article.
    Matched MeSH terms: Carbon Monoxide
  6. Parasuicide and suicide: demographic features and changing trend among cases in Hospital Sungai Bakap 2001-2005
    Teo GS, Teh LC, Lim JH
    Malaysian Journal of Psychiatry, 2008;17:3-12.
    Parasuicide has become an increasingly common response to emotional distress in young adults. The general pattern of parasuicide shows variations among the developing countries. The objectives of this study were to determine the pattern of parasuicide and suicide beside comparing the characteristics between different ethnic groups. The study was a retrospective case review of all parasuicide cases treated in Hospital Sungai Bakap and all suicides from the hospital mortuary from January 2001 to December 2005. We collected data concerning demographic data, information on method used and the circumstances. A total of 189 cases of parasuicide were analysed. There was a significant increase of parasuicide from 26.5 per 100,000 persons in 2001 to 32.1 per 100,000 persons in 2005. Seventy two percent of the cases were female. Indians constituted 64 % of the cases, followed by the Chinese (19 %), Malays (13 %) and foreigners (4 %). The age group 18-30 years ranked at the top, constituting 59.7% of the cases. Majority of the cases were by intentional poisoning and only 2 cases (1.1 %) were intentional injuries by sharp objects. In the past 5 years, the agents implicated were drugs (43.9 %), pesticides (23.5 %), household products (11.8 %), and others (20.8 %). Intentional Paracetamol poisoning had doubled from 11.7 % in 2001 to 23.4 % in 2005 while the use of pesticides had decreased from 32 % in 2001 to 17 % in 2005. Only 2 % of the cases had history of underlying disorders like schizophrenia and personalities disorders. As for suicide, the rates remained relatively unchanged at 5 per 100,000 populations. In this study, the demographic characteristics of suicide differ from parasuicide as suicides were associated with higher percentage of males and Chinese. There were 2 peaks in the age group of 31-40 and above 60 years old. The highest mode of suicide was hanging (53.5 %), followed by pesticide poisoning (25.6 %) and inhaled carbon monoxide (9.3 %).There is a need to improve on prevention and interventions for parasuicide and decrease suicide prevalence. Keywords: parasuicide, suicide, self-harm, Penang
    Matched MeSH terms: Carbon Monoxide
  7. Comparison of air conditioning ducting measurement data and effect of indoor air data at office building
    Amir Abdullah, M.D., Leman, A.M., Norhidayah, A., Syafiq Syazwan, M.M.
    Journal of Occupational Safety and Health, 2012;9(3):23-30.
    MyJurnal
    A poor Indoor Air Quality (IAQ) is a crucial problem which produces by the improper maintenance of Mechanical Ventilation and Air Conditioning (MVAC) ducting. A budget constraint intimidates for the practise of monitoring of the MVAC ducting. Thus IAQ measurements were conducted at the room where the air supplied by centralized air conditioning. It has been performed at four different offices that supply by two different Air Handling Unit (AHU). Walkthrough survey was conducted and the area samplings were selected for data collection. This paper examines the result of comparison of air ducting and air quality at academic office building, Universiti Tun Hussein Onn Malaysia (UTHM). The parameters involved were Temperature (°C), Relative Humidity (RH), Carbon Dioxide (CO2) and Carbon Monoxide (CO). Pictures were also captured to demonstrate the real conditions inside the ducting by using Mechanical Robot. Thus, duct cleaning was recommended to be an exceptional platform for the IAQ improvement.
    Matched MeSH terms: Carbon Monoxide
  8. Fulltext Delayed neuropsychiatry sequelae (DNS) Of carbon monoxide (CO) poisoning - a case report
    Arasalingam, Shamini, Ahmad Faizal Shamsuddin, Hatta Sidi, Hjh Rabai'ah Mohd Salleh
    ASEAN Journal of Psychiatry, 2015;16(1):131-134.
    MyJurnal
    Objective: Several cases of suicide attempt by charcoal burning producing CO have been reported in Malaysia. This case report highlights a case of delayed delayed neuropsychiatry sequelae (DNS) in CO poisoning.
    Method: We report a young Chinese homemaker who presented with DNS who was detained in a Malaysian forensic psychiatric ward.
    Results: After approximately two weeks of admission, in a familicide attempt, she had started to exhibit subtle changes in her behaviour, including social withdrawal, impaired memory, and there was lack of emotional distress.
    Conclusion: We report an interesting DNS as one of the two forms of chronic sequelae of CO poisoning, whereas the other type of neuropsychiatric sequelae is the persistently progressive type.
    Matched MeSH terms: Carbon Monoxide Poisoning
  9. Fulltext De novo transcriptome resources of the lichens, Dirinaria sp. UKM-J1 and UKM-K1 collected from Jerantut and Klang, Malaysia
    Bharudin I, Abdul Rahim SN, Abu Bakar MF, Ibrahim SN, Kamaruddin S, Latif MT, et al.
    Data Brief, 2018 Aug;19:2416-2419.
    PMID: 30229114 DOI: 10.1016/j.dib.2018.07.020
    Lichen is a symbiotic organism that exists as a single composite body consisting of a mycobiont (fungus) and a photobiont (algae or a cyanobacterium). Many lichen species are considered as extremophiles due to their tolerance to radiation, desiccation, temperature and pollution. However, not all lichen species are tolerant to harsh environmental conditions as several species are sensitive for example to nitrogen, sulphur, acidity, heavy metals, halogens (e.g. fluoride) and ozone. Thus, to better understand why some lichens can withstand exposure to pollutants as opposed to those that are susceptible, we focused on the lichen species of Dirinaria known for their wide distribution in the tropics, subtropics and pantropical, and moderate tolerance to air pollution. Their moderate tolerance to air pollution affords them to thrive in good air quality environments as well as polluted air environments. Lichen samples of Dirinaria sp., UKM-J1 and UKM-K1, were respectively collected from two areas with different levels of air quality based on Air Pollutant Index or API (with index pollutant criteria of PM10, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide) in the outskirt of Jerantut (UKM-J1), a rural area in the middle of Peninsular Malaysia and the township of Klang (UKM-K1), in a busy area of the Klang Valley, Malaysia. API was monitored throughout 2012-2013 whereby the sample collection site in Klang showed markedly higher concentrations of pollutants in all the index pollutant criteria as compared to that of Jerantut. We performed transcriptome sequencing using Illumina RNA-seq technology and de novo assembly of the transcripts from the lichen samples. Raw reads from both libraries were deposited in the NCBI database with the accession number SRP138994.
    Matched MeSH terms: Carbon Monoxide
  10. Local and transboundary factors' impacts on trace gases and aerosol during haze episode in 2015 El Niño in Malaysia
    Samsuddin NAC, Khan MF, Maulud KNA, Hamid AH, Munna FT, Rahim MAA, et al.
    Sci Total Environ, 2018 Jul 15;630:1502-1514.
    PMID: 29554768 DOI: 10.1016/j.scitotenv.2018.02.289
    Southeast Asian haze is a semi-natural phenomenon that chokes the region each year during the dry monsoon season. Smoke-haze episodes caused by the vegetation and peat fires in Indonesia severely affected large parts of Malaysia during the 2015 El Niño phenomenon. This study aimed to evaluate the factors that influenced the concentrations of aerosol and trace gases during the 2015 haze and non-haze period on a semi-urban site in the southern part of Malaysian peninsula that facing Sumatra (Muar, Site A), and on an urban site near to Kuala Lumpur, influenced by the city centre (Cheras, Site B). Local land use data and the cluster of air mass weighted backward trajectory were used to identify the potential factors from local sources and the transboundary region, respectively. The annual median concentrations of PM10 for semi-urban and urban sites were 45.0μg/m3 and 47.0μg/m3, respectively for the study period (Jan-Dec 2015) from the hourly observation dataset. The highest PM10 concentrations during the haze were 358μg/m3 and 415μg/m3 for the two sites, respectively, representing absolutely unhealthy air. However, the trace gases were within the safe threshold. The average concentrations of PM10 and carbon monoxide were two fold higher during the haze than the non-haze episodes on both sites. Nitrogen dioxide was more influenced by haze compared with sulphur dioxide and ozone. The results of the land use change suggest that the local factor can also partially affect the air pollution on the urban area (Site B) but more visible in 2015. The results of the backward trajectory and the wildfire radiative power showed that the smoke-haze episodes that affected Malaysia in 2015 were mainly initiated in the Indonesian Sumatra and Kalimantan regions. This study provides a very useful information towards the impacted region during El Niño haze episode.
    Matched MeSH terms: Carbon Monoxide
  11. Modeling air quality in main cities of Peninsular Malaysia by using a generalized Pareto model
    Masseran N, Razali AM, Ibrahim K, Latif MT
    Environ Monit Assess, 2016 Jan;188(1):65.
    PMID: 26718946 DOI: 10.1007/s10661-015-5070-9
    The air pollution index (API) is an important figure used for measuring the quality of air in the environment. The API is determined based on the highest average value of individual indices for all the variables which include sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and suspended particulate matter (PM10) at a particular hour. API values that exceed the limit of 100 units indicate an unhealthy status for the exposed environment. This study investigates the risk of occurrences of API values greater than 100 units for eight urban areas in Peninsular Malaysia for the period of January 2004 to December 2014. An extreme value model, known as the generalized Pareto distribution (GPD), has been fitted to the API values found. Based on the fitted model, return period for describing the occurrences of API exceeding 100 in the different cities has been computed as the indicator of risk. The results obtained indicated that most of the urban areas considered have a very small risk of occurrence of the unhealthy events, except for Kuala Lumpur, Malacca, and Klang. However, among these three cities, it is found that Klang has the highest risk. Based on all the results obtained, the air quality standard in urban areas of Peninsular Malaysia falls within healthy limits to human beings.
    Matched MeSH terms: Carbon Monoxide/analysis
  12. CO2 gasification reactivity of biomass char: catalytic influence of alkali, alkaline earth and transition metal salts
    Lahijani P, Zainal ZA, Mohamed AR, Mohammadi M
    Bioresour Technol, 2013 Sep;144:288-95.
    PMID: 23880130 DOI: 10.1016/j.biortech.2013.06.059
    This study investigates the influence of alkali (Na, K), alkaline earth (Ca, Mg) and transition (Fe) metal nitrates on CO2 gasification reactivity of pistachio nut shell (PNS) char. The preliminary gasification experiments were performed in thermogravimetric analyzer (TGA) and the results showed considerable improvement in carbon conversion; Na-char>Ca-char>Fe-char>K-char>Mg-char>raw char. Based on TGA studies, NaNO3 (with loadings of 3-7 wt%) was selected as the superior catalyst for further gasification studies in bench-scale reactor; the highest reactivity was devoted to 5 wt% Na loaded char. The data acquired for gasification rate of catalyzed char were fitted with several kinetic models, among which, random pore model was adopted as the best model. Based on obtained gasification rate constant and using the Arrhenius plot, activation energy of 5 wt% Na loaded char was calculated as 151.46 kJ/mol which was 53 kJ/mol lower than that of un-catalyzed char.
    Matched MeSH terms: Carbon Monoxide/analysis
  13. Forecasting peak asthma admissions in London: an application of quantile regression models
    Soyiri IN, Reidpath DD, Sarran C
    Int J Biometeorol, 2013 Jul;57(4):569-78.
    PMID: 22886344 DOI: 10.1007/s00484-012-0584-0
    Asthma is a chronic condition of great public health concern globally. The associated morbidity, mortality and healthcare utilisation place an enormous burden on healthcare infrastructure and services. This study demonstrates a multistage quantile regression approach to predicting excess demand for health care services in the form of asthma daily admissions in London, using retrospective data from the Hospital Episode Statistics, weather and air quality. Trivariate quantile regression models (QRM) of asthma daily admissions were fitted to a 14-day range of lags of environmental factors, accounting for seasonality in a hold-in sample of the data. Representative lags were pooled to form multivariate predictive models, selected through a systematic backward stepwise reduction approach. Models were cross-validated using a hold-out sample of the data, and their respective root mean square error measures, sensitivity, specificity and predictive values compared. Two of the predictive models were able to detect extreme number of daily asthma admissions at sensitivity levels of 76 % and 62 %, as well as specificities of 66 % and 76 %. Their positive predictive values were slightly higher for the hold-out sample (29 % and 28 %) than for the hold-in model development sample (16 % and 18 %). QRMs can be used in multistage to select suitable variables to forecast extreme asthma events. The associations between asthma and environmental factors, including temperature, ozone and carbon monoxide can be exploited in predicting future events using QRMs.
    Matched MeSH terms: Carbon Monoxide/analysis
  14. Comparison of the carbon-sequestering abilities of pineapple leaf residue chars produced by controlled combustion and by field burning
    Leng LY, Husni MH, Samsuri AW
    Bioresour Technol, 2011 Nov;102(22):10759-62.
    PMID: 21958525 DOI: 10.1016/j.biortech.2011.08.131
    This study was undertaken to compare the chemical properties and yields of pineapple leaf residue (PLR) char produced by field burning (CF) with that produced by a partial combustion of air-dried PLR at 340 °C for 3 h in a furnace (CL). Higher total C, lignin content, and yield from CL as well as the presence of aromatic compounds in the Fourier Transform Infrared spectra of the char produced from CL suggest that the CL process was better in sequestering C than was the CF process. Although the C/N ratio of char produced from CL was low indicating a high N content of the char, the C in the char produced from CL was dominated by lignin suggesting that the decomposition of char produced from CL would be slow. To sequester C by char application, the PLR should be combusted in a controlled process rather than by burning in the field.
    Matched MeSH terms: Carbon Monoxide/analysis
  15. Site-Directed Mutagenesis of Cytochrome P450 2D6 and 2C19 Enzymes: Expression and Spectral Characterization of Naturally Occurring Allelic Variants
    Dong AN, Pan Y, Palanisamy UD, Yiap BC, Ahemad N, Ong CE
    Appl Biochem Biotechnol, 2018 Sep;186(1):132-144.
    PMID: 29524040 DOI: 10.1007/s12010-018-2728-0
    Genetic polymorphism of the cytochrome P450 (CYP) genes particularly affects CYP2D6 and CYP2C19 to a functionally relevant extent, and it is therefore crucial to elucidate the enzyme kinetic and molecular basis for altered catalytic activity of these allelic variants. This study explored the expression and function of the reported alleles CYP2D6*2, CYP2D6*10, CYP2D6*17, CYP2C19*23, CYP2C19*24, and CYP2C19*25 with respect to gene polymorphisms. Site-directed mutagenesis (SDM) was carried out to generate these six alleles. After DNA sequencing, the CYP2D6 and CYP2C19 wild types alongside with their alleles were each independently co-expressed with NADPH-CYP oxidoreductase (OxR) in Escherichia coli. The expressed proteins were analyzed using Western blotting, reduced carbon monoxide (CO) difference spectral scanning, and cytochrome c reductase assay. Results from Western blot revealed the presence of all CYP wild-type and allelic proteins in E. coli membrane fractions. The reduced CO difference spectra scanning presented the distinct peak of absorbance at 450 nm, and the cytochrome c reductase assay has confirmed that spectrally active OxR was expressed in each protein preparation. As a conclusion, the results obtained from this study have proven the CYP variants to be immunoreactive and spectrally active and are suitable for use to examine biotransformation and interaction mechanism of the enzymes.
    Matched MeSH terms: Carbon Monoxide/chemistry
  16. Stop smoking clinics in Malaysia: characteristics of attendees and predictors of success
    Wee LH, Shahab L, Bulgiba A, West R
    Addict Behav, 2011 Apr;36(4):400-3.
    PMID: 21195553 DOI: 10.1016/j.addbeh.2010.11.011
    INTRODUCTION: As Stop Smoking Clinics (SSCs) become more common across the globe, it is important to know how far one can make broad generalisations concerning characteristics of smokers who attend these clinics and factors that predict their success. This involves accumulation of data from different countries.
    OBJECTIVE: The aim of this study was to identify characteristics of smokers and factors leading up to quitting with clinics in Malaysia.
    METHOD: Records from 629 smokers who had sought help from five selected SSCs in Malaysia from January 2006 to June 2007 were analysed.
    RESULTS: The characteristics of smokers attending Malaysian smoking clinics were broadly similar to those in Western countries. Consistent with the findings from other countries, older age and longest duration of previous quit attempts were associated with successful smoking cessation. Greater baseline carbon-monoxide readings (OR 0.96, 95% CI 0.93-0.99; p=0.013), but not Fagerstrom Test for Nicotine Dependence (FTND), predicted failure to quit at six-month in multivariate analysis. Success rates varied greatly between clinics even after adjusting for all other predictors.
    CONCLUSION: In these rare data from a non-Western culture some predictors of successful smoking cessation appeared to generalise from Western smokers but the universal validity of the FTND in particular needs to be examined further.
    Matched MeSH terms: Carbon Monoxide/analysis
  17. Clinical and high resolution computed tomography characteristics of patients with rheumatoid arthritis lung disease
    Mohd Noor N, Mohd Shahrir MS, Shahid MS, Abdul Manap R, Shahizon Azura AM, Azhar Shah S
    Int J Rheum Dis, 2009 Jul;12(2):136-44.
    PMID: 20374331 DOI: 10.1111/j.1756-185X.2009.01376.x
    Introduction: Rheumatoid arthritis (RA) is a systemic disease of unknown cause. A variety of pulmonary disorders have been described in association with RA. Among the most common are interstitial lung disease
    (ILD) and bronchiectasis.
    Objectives: This study aims to determine the characteristics of RA patients with lung disease in relation to clinical characteristics, pulmonary function test (PFT) and high resolution computed tomography (HRCT) thorax.
    Method: This is a 6-months cross-sectional study involving 63 consecutive RA patients in an outpatient rheumatology clinic. Patients had a mean disease duration of 5 years and above. Disease activity and severity
    was assessed by Disease Activity Score 28 (DAS28), Health Assessment Questionnaire (HAQ) and Rheumatoid Arthritis Articular Damage (RAAD) score. Full pulmonary function test (PFT) and HRCT of thorax were performed.
    Conclusions: The prevalence of RA-ILD is 44% and 67% of patients are asymptomatic. There was significant higher proportion (68%) in patients of Chinese ethnicity who have ILD. Diffusion capacity of carbon monoxide
    was abnormal in all patients and forced expiratory flow (FEF)25–75% was low in 16%. Restrictive pattern was 66.7% by PFT. The most common HRCT findings were reticulation (46%) followed by ground glass opacities
    (38.1%) and bronchiectasis (28.6%). There was no association between ILD and male gender, duration of the disease, smoking, rheumatoid factor, extra-articular manifestations, disease activity or severity.
    Key words: high resolution computed tomography, interstitial lung disease, lung function test, rheumatoid arthritis.
    Study site: Rheumatology clinic, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia
    Matched MeSH terms: Carbon Monoxide/metabolism
  18. Fulltext Stability of the antimalarial drug dihydroartemisinin under physiologically relevant conditions: implications for clinical treatment and pharmacokinetic and in vitro assays
    Parapini S, Olliaro P, Navaratnam V, Taramelli D, Basilico N
    Antimicrob Agents Chemother, 2015 Jul;59(7):4046-52.
    PMID: 25918150 DOI: 10.1128/AAC.00183-15
    Artemisinins are peroxidic antimalarial drugs known to be very potent but highly chemically unstable; they degrade in the presence of ferrous iron, Fe(II)-heme, or biological reductants. Less documented is how this translates into chemical stability and antimalarial activity across a range of conditions applying to in vitro testing and clinical situations. Dihydroartemisinin (DHA) is studied here because it is an antimalarial drug on its own and the main metabolite of other artemisinins. The behaviors of DHA in phosphate-buffered saline, plasma, or erythrocyte lysate at different temperatures and pH ranges were examined. The antimalarial activity of the residual drug was evaluated using the chemosensitivity assay on Plasmodium falciparum, and the extent of decomposition of DHA was established through use of high-performance liquid chromatography with electrochemical detection analysis. The role of the Fe(II)-heme was investigated by blocking its reactivity using carbon monoxide (CO). A significant reduction in the antimalarial activity of DHA was seen after incubation in plasma and to a lesser extent in erythrocyte lysate. Activity was reduced by half after 3 h and almost completely abolished after 24 h. Serum-enriched media also affected DHA activity. Effects were temperature and pH dependent and paralleled the increased rate of decomposition of DHA from pH 7 upwards and in plasma. These results suggest that particular care should be taken in conducting and interpreting in vitro studies, prone as their results are to experimental and drug storage conditions. Disorders such as fever, hemolysis, or acidosis associated with malaria severity may contribute to artemisinin instability and reduce their clinical efficacy.
    Matched MeSH terms: Carbon Monoxide/chemistry
  19. Applied chemometric approach in identification sources of air quality pattern in Selangor, Malaysia
    Ang KH
    Sains Malaysiana, 2018;47:471-479.
    In recent years, Malaysia has experienced quite a few number of chronic air pollution problems and it has become a
    major contributor to the deterioration of human health and ecosystems. This study aimed to assess the air quality data
    and identify the pattern of air pollution sources using chemometric analysis through hierarchical cluster analysis (HCA),
    discriminant analysis (DA), principal component analysis (PCA) and multiple linear regression analysis (MLR). The air
    quality data from January 2016 until December 2016 was obtained from the Department of Environment Malaysia. Air
    quality data from eight sampling stations in Selangor include the selected variables of nitrogen dioxide (NO2
    ), ozone (O3
    ),
    sulfur dioxide (SO2
    ), carbon monoxide (CO) and particulate matter (PM10). The HCA resulted in three clusters, namely low
    pollution source (LPS), moderate pollution source (MPS) and slightly high pollution source (SHPS). Meanwhile, DA resulted
    in two and four variables for the forward stepwise mode and the backward stepwise mode, respectively. Through PCA,
    it was identified that the main pollutants of LPS, MPS and SHPS came from industrial and vehicle emissions, agricultural
    systems, residential factors and natural emission sources. Among the three models yielded from the MLR analysis, it was
    found that SHPS is the most suitable model to be used for the prediction of Air Pollution Index. This study concluded that
    a clearer review and practical design of air quality monitoring network would be beneficial for better management of
    air pollution. The study also suggested that chemometric techniques have the ability to show significant information on
    spatial variability for large and complex air quality data.
    Matched MeSH terms: Carbon Monoxide
  20. Fulltext The mobile-phone-based iCOTM Smokerlyzer®: Comparison with the piCO+ Smokerlyzer® among smokers undergoing methadone-maintained therapy
    Wong HY, Subramaniyan M, Bullen C, Amer Siddiq AN, Danaee M, Yee A
    Tob Induc Dis, 2019;17:65.
    PMID: 31582954 DOI: 10.18332/tid/111355
    INTRODUCTION: The mobile-phone-based Bedfont iCOTM Smokerlyzer® is of unknown validity and reproducibility compared to the widely-used piCO+ Smokerlyzer®. We aimed to compare the validity and reproducibility of the iCOTM Smokerlyzer® with the piCO+ Smokerlyzer® among patients reducing or quitting tobacco smoking.

    METHODS: Methadone-maintained therapy (MMT) users from three centers in Malaysia had their exhaled carbon monoxide (eCO) levels recorded via the piCO+ and iCOTM Smokerlyzers®, their nicotine dependence assessed with the Malay version of the Fagerström Test for Nicotine Dependence (FTND-M), and daily tobacco intake measured via the Opiate Treatment Index (OTI) Tobacco Q-score. Pearson partial correlations were used to compare the eCO results of both devices, as well as the corresponding FTND-M scores.

    RESULTS: Among the 146 participants (mean age 47.9 years, 92.5% male, and 73.3% Malay ethnic group) most (55.5%) were moderate smokers (6-19 cigarettes/day). Mean eCO categories were significantly correlated between both devices (r=0.861, p<0.001), and the first and second readings were significantly correlated for each device (r=0.94 for the piCO+ Smokerlyzer®, p<0.001; r=0.91 for the iCOTM Smokerlyzer®, p<0.001). Exhaled CO correlated positively with FTND-M scores for both devices. The post hoc analysis revealed a significantly lower iCOTM Smokerlyzer® reading of 0.82 (95% CI: 0.69-0.94, p<0.001) compared to that of the piCO+ Smokerlyzer®, and a significant intercept of -0.34 (95% CI: -0.61 - -0.07, p=0.016) on linear regression analysis, suggesting that there may be a calibration error in one or more of the iCOTM Smokerlyzer® devices.

    CONCLUSIONS: The iCOTM Smokerlyzer® readings are highly reproducible compared to those of the piCO+ Smokerlyzer®, but calibration guidelines are required for the mobile-phone-based device. Further research is required to assess interchangeability.

    Matched MeSH terms: Carbon Monoxide
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