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Sim CSL, Asharani PV, Subramaniam M, Yi H. Roles and Dynamics within Community Mental Health Systems During the COVID-19 Pandemic: A Qualitative Systematic Review and Meta-Ethnography. Health Syst Reform 2024; 10:2314525. [PMID: 38598726 DOI: 10.1080/23288604.2024.2314525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 02/01/2024] [Indexed: 04/12/2024] Open
Abstract
Globally, COVID-19 had an immense impact on mental health systems, but research on how community mental health (CMH) systems and services contributed to the pandemic mental health response is limited. We conducted a systematic review and meta-ethnography to understand the roles of CMH services, determinants of the quality of CMH care, and dynamics within CMH systems during COVID-19. We searched and screened across five databases and appraised study quality using the CASP tool, which yielded 27 qualitative studies. Our meta-ethnographic process used Noblit and Hare's approach for synthesizing findings and applying interpretive analysis to original research. This identified several key themes. Firstly, CMH systems played the valuable pandemic role of safety nets and networks for the broader mental health ecosystem, while CMH service providers offered a continuous relationship of trust to service users amidst pandemic disruptions. Secondly, we found that the determinants of quality CMH care during COVID-19 included resourcing and capacity, connections across service providers, customized care options, ease of access, and human connection. Finally, we observed that power dynamics across the CMH landscape disproportionately excluded marginalized groups from mainstream CMH systems and services. Our findings suggest that while the pandemic role of CMH was clear, effectiveness was driven by the efforts of individual service providers to meet demand and service users' needs. To reprise its pandemic role in the future, a concerted effort is needed to make CMH systems a valuable part of countries' disaster mental health response and to invest in quality care, particularly for marginalized groups.
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Affiliation(s)
- Cheryl Su Ling Sim
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - P V Asharani
- Department of Research Division, Institute of Mental Health, Singapore, Singapore
| | - Mythily Subramaniam
- Department of Research Division, Institute of Mental Health, Singapore, Singapore
| | - Huso Yi
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
- National University Health System, Singapore, Singapore
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Asharani PV, Seet V, Devi F, Wang P, Roystonn K, Subramaniam M. Electronic nicotine delivery systems: prevalence and perception of risk/harm in individuals with mental illness. Singapore Med J 2024; 65:51-56. [PMID: 35851648 PMCID: PMC10863740 DOI: 10.11622/smedj.2022091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 08/09/2021] [Indexed: 11/18/2022]
Affiliation(s)
- PV Asharani
- Research Division, Institute of Mental Health, Singapore
| | - Vanessa Seet
- Research Division, Institute of Mental Health, Singapore
| | - Fiona Devi
- Research Division, Institute of Mental Health, Singapore
| | - Peizhi Wang
- Research Division, Institute of Mental Health, Singapore
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Subramaniam M, Lau JH, Asharani PV, Abdin E, Roystonn K, Wang P, Devi F, Vaingankar JA, Car LT, Sum CF, Lee ES, van Dam RM, Chong SA. Sources of information on diabetes and its demographic correlates: a nationwide survey among Singapore residents. Health Promot Int 2022; 37:6774997. [PMID: 36287520 PMCID: PMC9600454 DOI: 10.1093/heapro/daac107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Diabetes is a major public health concern in Singapore, and the Singapore Government declared a ‘War on Diabetes’, which included a nationwide public health campaign. It is important to identify what sources of diabetes information reach the general population, whether this differs by socio-demographic characteristics and if the sources of information influence knowledge of diabetes to aid the successful dissemination of health information. Two thousand eight hundred ninety-five respondents were part of a population-based cross-sectional study conducted from February 2019 to September 2020. Respondents rated on a five-point scale whether they had obtained information on diabetes from eight different information sources, and responses were dichotomized into ‘endorsed receiving information’ or ‘not endorsed receiving information’. Poisson regression models were conducted with the ‘endorsement of receiving information’ from each source as the outcome and socio-demographic variables as predictors. 95.9% of the study population had received information on diabetes from at least one source, and the mean number of sources was 4.2 ± 2.0. The leading source was media articles (82.1%), followed by health promotion videos/advertisements (77.9%), online websites (58.5%), books (56.5%), healthcare professionals (55.0%), radio (54.4%), public forums (27.7%) and support groups (15.5%). Endorsing a greater number of informational sources was associated with being younger, belonging to Malay or Indian instead of Chinese ethnicity, and having diabetes. An intensive nationwide diabetes awareness campaign successfully reached the public in Singapore with specific sources of information depending on socio-demographic characteristics. Findings suggest that diabetes information campaigns should utilize multiple channels for dissemination considering the different socio-demographic subgroups.
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Affiliation(s)
| | | | - P V Asharani
- Research Division, Institute of Mental Health, 10 Buangkok View, Singapore 539747, Singapore
| | - Edimansyah Abdin
- Research Division, Institute of Mental Health, 10 Buangkok View, Singapore 539747, Singapore
| | - Kumarasan Roystonn
- Research Division, Institute of Mental Health, 10 Buangkok View, Singapore 539747, Singapore
| | - Peizhi Wang
- Research Division, Institute of Mental Health, 10 Buangkok View, Singapore 539747, Singapore
| | - Fiona Devi
- Research Division, Institute of Mental Health, 10 Buangkok View, Singapore 539747, Singapore
| | - Janhavi Ajit Vaingankar
- Research Division, Institute of Mental Health, 10 Buangkok View, Singapore 539747, Singapore
| | - Lorainne Tudor Car
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Avenue, Singapore
| | - Chee Fang Sum
- Admiralty Medical Centre, Khoo Teck Puat Hospital, 676 Woodlands Drive 71, Singapore
| | - Eng Sing Lee
- National Healthcare Group Polyclinics, 3 Fusionopolis Link, Nexus@One-North, Singapore
| | - Rob M van Dam
- Saw Swee Hock School of Public Health, National University Hospital, Singapore,Department of Exercise and Nutrition Sciences, Milken Institute of Public Health, The George Washington University, Washington, DC, USA
| | - Siow Ann Chong
- Research Division, Institute of Mental Health, 10 Buangkok View, Singapore 539747, Singapore
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Mahabaleshwar H, Asharani PV, Loo TY, Koh SY, Pitman MR, Kwok S, Ma J, Hu B, Lin F, Li Lok X, Pitson SM, Saunders TE, Carney TJ. Slit‐Robo signalling establishes a Sphingosine‐1‐phosphate gradient to polarise fin mesenchyme. EMBO Rep 2022; 23:e54464. [DOI: 10.15252/embr.202154464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 05/12/2022] [Accepted: 05/18/2022] [Indexed: 11/09/2022] Open
Affiliation(s)
- Harsha Mahabaleshwar
- Lee Kong Chian School of Medicine Experimental Medicine Building Nanyang Technological University Singapore City Singapore
| | - PV Asharani
- Institute of Molecular and Cell Biology (IMCB) A*STAR (Agency for Science, Technology and Research) Singapore City Singapore
| | - Tricia Yi Loo
- Mechanobiology Institute National University of Singapore Singapore City Singapore
| | - Shze Yung Koh
- Lee Kong Chian School of Medicine Experimental Medicine Building Nanyang Technological University Singapore City Singapore
| | - Melissa R Pitman
- Centre for Cancer Biology University of South Australia, and SA Pathology North Tce Adelaide SA Australia
- School of Biological Sciences University of Adelaide Adelaide South Australia Australia
| | - Samuel Kwok
- Lee Kong Chian School of Medicine Experimental Medicine Building Nanyang Technological University Singapore City Singapore
| | - Jiajia Ma
- Lee Kong Chian School of Medicine Experimental Medicine Building Nanyang Technological University Singapore City Singapore
| | - Bo Hu
- Department of Anatomy & Cell Biology Carver College of Medicine The University of Iowa Iowa City IA USA
| | - Fang Lin
- Department of Anatomy & Cell Biology Carver College of Medicine The University of Iowa Iowa City IA USA
| | - Xue Li Lok
- Institute of Molecular and Cell Biology (IMCB) A*STAR (Agency for Science, Technology and Research) Singapore City Singapore
| | - Stuart M Pitson
- Centre for Cancer Biology University of South Australia, and SA Pathology North Tce Adelaide SA Australia
| | - Timothy E Saunders
- Institute of Molecular and Cell Biology (IMCB) A*STAR (Agency for Science, Technology and Research) Singapore City Singapore
- Mechanobiology Institute National University of Singapore Singapore City Singapore
- Warwick Medical School University of Warwick Coventry UK
| | - Tom J Carney
- Lee Kong Chian School of Medicine Experimental Medicine Building Nanyang Technological University Singapore City Singapore
- Institute of Molecular and Cell Biology (IMCB) A*STAR (Agency for Science, Technology and Research) Singapore City Singapore
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Koh YS, Asharani PV, Devi F, Roystonn K, Wang P, Vaingankar JA, Abdin E, Sum CF, Lee ES, Müller-Riemenschneider F, Chong SA, Subramaniam M. A cross-sectional study on the perceived barriers to physical activity and their associations with domain-specific physical activity and sedentary behaviour. BMC Public Health 2022; 22:1051. [PMID: 35614402 PMCID: PMC9132675 DOI: 10.1186/s12889-022-13431-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/13/2022] [Indexed: 11/10/2022] Open
Abstract
Background Physical inactivity and sedentary behaviour have detrimental consequences to the individual and the economy. Our study examined the prevalence of perceived barriers to physical activity in Singapore’s adult population and their associations with physical activity and sedentary behaviour. Methods This cross-sectional analysis utilised data from a nationwide survey in Singapore. Participants (n = 2867) were recruited from February 2019 to March 2020. The independent variables were internal (e.g. fatigue, age) and external (e.g. weather, cost) perceived barriers to physical activity. The outcomes were domain-specific physical activity (work, transport and leisure) and sedentary behaviour, all of which were assessed using the Global Physical Activity Questionnaire. The associations were examined using zero-inflated negative binomial regressions for physical activity and linear regression for sedentary behaviour. Results The median (Interquartile range) for work-related, transport-related and leisure-related physical activity were 0 (0 – 1440), 600 (160 – 1120) and 360 (0 – 1080) MET (metabolic equivalent)-minutes per week. The median sedentary behaviour (IQR) was 360 (240 – 540) minutes per day. The top three barriers were lack of time (65.3%), fatigue (64.7%) and pollution (56.1%). After adjustment, the level of transport-related physical activity was lower for respondents who cited lacking pavement or parks as a barrier, but higher for those who indicated cost and safety concerns. Respondents who reported pollution as a barrier were more likely to engage in transport-related physical activity. The level of leisure-related physical activity was lower for respondents indicating weather, lack of time and age as barriers, but higher for those reporting safety concerns. The odds of engaging in leisure-related physical activity was lower for those citing age, cost and fatigue as barriers, but higher for those indicating the weather. Sedentary behaviour was positively associated with work and limited accessibility to exercise facilities, but negatively with safety concerns. Conclusion Individuals can be motivated to overcome internal barriers (fatigue, lack of time, cost and age) through social support and emphasis on exercise benefits. External barriers (weather and lack of pavements or parks) can be reduced by raising awareness of existing infrastructure. Sedentary behaviour can be improved by implementing workplace measures, such as reducing the time spent sitting. Supplementary information The online version contains supplementary material available at 10.1186/s12889-022-13431-2.
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Affiliation(s)
- Yen Sin Koh
- Research Division, Institute of Mental Health, Singapore, Singapore.
| | - P V Asharani
- Research Division, Institute of Mental Health, Singapore, Singapore
| | - Fiona Devi
- Research Division, Institute of Mental Health, Singapore, Singapore
| | | | - Peizhi Wang
- Research Division, Institute of Mental Health, Singapore, Singapore
| | | | - Edimansyah Abdin
- Research Division, Institute of Mental Health, Singapore, Singapore
| | - Chee Fang Sum
- Admiralty Medical Centre, Khoo Teck Puat Hospital, Singapore, Singapore
| | - Eng Sing Lee
- Clinical Research Unit, National Healthcare Group Polyclinics, Singapore, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Falk Müller-Riemenschneider
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore.,Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Siow Ann Chong
- Research Division, Institute of Mental Health, Singapore, Singapore
| | - Mythily Subramaniam
- Research Division, Institute of Mental Health, Singapore, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
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Asharani PV, Lau JH, Roystonn K, Devi F, Peizhi W, Shafie S, Chang S, Jeyagurunathan A, Yiang CB, Abdin E, Vaingankar JA, Sum CF, Lee ES, Dam RV, Chong SA, Subramaniam M. Health Literacy and Diabetes Knowledge: A Nationwide Survey in a Multi-Ethnic Population. Int J Environ Res Public Health 2021; 18:9316. [PMID: 34501905 PMCID: PMC8431510 DOI: 10.3390/ijerph18179316] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/27/2021] [Accepted: 08/31/2021] [Indexed: 11/16/2022]
Abstract
Health literacy is a key determinant of the public health and health climate of the nation. This study examined the functional health literacy of the nation, factors associated with health literacy, and its relationship with diabetes recognition. This cross-sectional survey recruited participants (N = 2895) who were 18 years and above from a population registry through disproportionate stratified sampling. The Brief Health Literacy Screen and other questionnaires were administered through face-to-face interviews, in one of the four national languages (English, Chinese, Malay or Tamil). The majority (80.5%) had adequate functional health literacy and were able to recognise symptoms of diabetes correctly (83.5% overall; 83.7% and 82.2% in those with adequate and inadequate health literacy, respectively). Those with inadequate health literacy had a higher incidence of chronic conditions (p < 0.001) compared to those with adequate health literacy in bivariate analysis. The majority of the sample had sufficient levels of physical activity (83.3%), and more than half reported an unhealthy lifestyle (57.4%). Older age, Chinese ethnicity, those who were employed, with lower education (secondary or below), and were married had significantly higher odds of inadequate health literacy. Health literacy was not associated with lifestyle, physical activity, chronic conditions and diabetes recognition. Health literacy interventions should focus on the disadvantaged social groups for improving their health literacy.
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Affiliation(s)
- P. V. Asharani
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Jue Hua Lau
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Kumarasan Roystonn
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Fiona Devi
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Wang Peizhi
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Saleha Shafie
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Sherilyn Chang
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Anitha Jeyagurunathan
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Chua Boon Yiang
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Edimansyah Abdin
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Janhavi Ajit Vaingankar
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Chee Fang Sum
- Admiralty Medical Centre, Khoo Teck Puat Hospital, Singapore 730676, Singapore;
| | - Eng Sing Lee
- Clinical Research Unit, National Healthcare Group Polyclinics 3 Fusionopolis Link, Singapore 138543, Singapore;
| | - Rob Van Dam
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore 117549, Singapore;
| | - Siow Ann Chong
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
| | - Mythily Subramaniam
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (K.R.); (F.D.); (W.P.); (S.S.); (S.C.); (A.J.); (C.B.Y.); (E.A.); (J.A.V.); (S.A.C.); (M.S.)
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore 117549, Singapore;
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Lee YY, Lau JH, Seet V, Whitton C, Asharani PV, Siva Kumar FD, Wang P, Roystonn K, Cetty L, The WL, Verma S, Mok YM, Subramaniam M. Dietary intake of persons with depressive and psychotic disorders in Singapore. Ann Acad Med Singap 2021; 50:379-389. [PMID: 34100515 DOI: 10.47102/annals-acadmedsg.2020585] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
INTRODUCTION Nutritional psychiatry is an emerging field of study that investigates the role of diet and nutrition in mental health. Studies conducted in the general population have linked depressive symptoms with poor dietary patterns. The aim of this study was to characterise the dietary intake and analyse the dietary pattern using the Dietary Approach to Stop Hypertension (DASH) in a sample of psychiatric patients in a multiethnic Asian nation. METHODS Participants were recruited from an outpatient clinic and an inpatient unit at the Institute of Mental Health in Singapore. Self-reported dietary habits of a sample of psychiatric patients (N=380) were analysed using DASH. To examine the variables associated with DASH scores, a linear regression was conducted with the full sample and sociodemographic variables. RESULTS Persons with depressive disorders had a mean DASH score of 21.3 (±4.2), while persons with psychotic disorders had a mean DASH score of 21.2 (±4.9). Respondents who were older (B=1.94, 95% confidence interval [CI] 0.91-2.96, P<0.001), female (B=1.09, 95% CI 0.07-2.11, P=0.04) and economically inactive (B=1.98, 95% CI 0.006-3.96, P=0.049) were more likely to report a higher diet quality compared with their respective counterparts, while smokers (B= -1.39, 95% CI -2.45 to -0.34, P=0.009) tended to report a lower diet quality compared with their non-smoking counterparts. CONCLUSION Dietary patterns of persons with mental disorders were characterised. A host of sociodemographic factors, and not diagnosis of mental disorders, influenced the dietary quality of people with depressive and psychotic disorders. Clinicians treating psychiatric patients need to be aware of the nuanced reasons behind poor dietary choices and provide targeted psychoeducation to specific subgroups within the patient population.
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Affiliation(s)
- Ying Ying Lee
- Research Division, Institute of Mental Health, Singapore
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Seet V, Abdin E, Asharani PV, Lee YY, Roystonn K, Wang P, Devi F, Cetty L, Teh WL, Verma S, Mok YM, Subramaniam M. Physical activity, sedentary behaviour and smoking status among psychiatric patients in Singapore - a cross-sectional study. BMC Psychiatry 2021; 21:110. [PMID: 33602151 PMCID: PMC7893878 DOI: 10.1186/s12888-021-03103-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 01/27/2021] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Unhealthy behaviours such as physical inactivity, sedentary behaviour and smoking have been found to be more prevalent in people with psychiatric disorders than in the general population, leading to increased mortality risk. The present study seeks to identify correlates of physical activity and sedentary behaviour among psychiatric patients in Singapore, as well as investigate differences in their physical activity patterns by smoking status. METHODS Participants (n = 380) were recruited from a tertiary psychiatric hospital in Singapore as part of a study on the prevalence and correlates of smoking among psychiatric patients. Physical activity levels and sedentary behaviour were measured using the Global Physical Activity Questionnaire (GPAQ) and analysed based on GPAQ guidelines. Chi-square analyses were conducted to examine differences in physical activity by smoking status, and logistic regression analyses to yield sociodemographic correlates of meeting physical activity guidelines (as recommended by the World Health Organization) and sedentary behaviour. RESULTS Education was found to be significantly associated with meeting recommended physical activity levels, while age and marital status were significantly associated with excessive sedentary behaviour. Additionally, while no significant differences were found among current, former and non-smokers across all types of physical activity engagement levels, there was a high prevalence of inadequate physical activity (43.2%) and excessive sedentary behaviour (38.8%) among participants. CONCLUSION Given the high prevalence of inadequate physical activity and excessive sedentary behaviour among current, former and non-smokers with psychiatric disorders, programmes aimed at increasing physical activity and lowering sedentary behaviour levels should be integrated into targeted treatment plans to improve clinical outcomes.
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Affiliation(s)
- Vanessa Seet
- Research Division, Institute of Mental Health, Singapore, Singapore.
| | - Edimansyah Abdin
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Singapore, Singapore
| | - P. V. Asharani
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Singapore, Singapore
| | - Ying Ying Lee
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Singapore, Singapore
| | - Kumarasan Roystonn
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Singapore, Singapore
| | - Peizhi Wang
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Singapore, Singapore
| | - Fiona Devi
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Singapore, Singapore
| | - Laxman Cetty
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Singapore, Singapore
| | - Wen Lin Teh
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Singapore, Singapore
| | - Swapna Verma
- grid.414752.10000 0004 0469 9592Early Psychosis Intervention Programme, Institute of Mental health, Singapore, Singapore
| | - Yee Ming Mok
- grid.414752.10000 0004 0469 9592Department of Mood and Anxiety, Institute of Mental Health, Singapore, Singapore
| | - Mythily Subramaniam
- grid.414752.10000 0004 0469 9592Research Division, Institute of Mental Health, Singapore, Singapore
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Asharani PV, Lau JH, Ai Ling Seet V, Devi F, Wang P, Roystonn K, Lee YY, Cetty L, Teh WL, Verma S, Mok YM, Chong SA, Subramaniam M. Smoking-Related Health Beliefs in a Sample of Psychiatric Patients: Factors Associated with the Health Beliefs and Validation of the Health Belief Questionnaire. Int J Environ Res Public Health 2021; 18:ijerph18041571. [PMID: 33562257 PMCID: PMC7916053 DOI: 10.3390/ijerph18041571] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 12/12/2022]
Abstract
This study examined the (a) health beliefs and emotions (perception of risk, benefits, severity, and worry) about smoking among current and former smokers, (b) their awareness of health warnings, (c) factors associated with smoking-related health beliefs, and (d) the factor structure of the health belief questionnaire. Participants (n = 184) were recruited from a tertiary psychiatric care hospital. Current smokers showed a significantly higher risk perception and lower perceived benefits compared to former smokers. Younger age (<40 years), nicotine dependence (ND), a history of smoking-related diseases (SRD), and intention to quit were significantly associated with a higher risk perception in current smokers. Younger age, a history of SRDs, and motivation to quit were positively associated with health beliefs, while the latter two were associated with worry. Motivation and younger age were associated with a better perception of benefits and severity. Information on the cigarette packets was the major source of awareness for the sample, and 69% reported that existing campaigns were not effective in discouraging their smoking. Personalized risk communication and educational initiatives must focus on improving the knowledge of risk, benefits, and increase motivation to promote health cognition and thus smoking cessation.
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Affiliation(s)
- P. V. Asharani
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
- Correspondence: ; Tel.: +65-63892961
| | - Jue Hua Lau
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Vanessa Ai Ling Seet
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Fiona Devi
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Peizhi Wang
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Kumarasan Roystonn
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Ying Ying Lee
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Laxman Cetty
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Wen Lin Teh
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Swapna Verma
- Early Psychosis Intervention Programme, Institute of Mental Health, Singapore 539747, Singapore;
- Office of Education, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Yee Ming Mok
- Department of Mood and Anxiety, Institute of Mental Health, Singapore 539747, Singapore;
| | - Siow Ann Chong
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Mythily Subramaniam
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (J.H.L.); (V.A.L.S.); (F.D.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
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Asharani PV, Ling Seet VA, Abdin E, Siva Kumar FD, Wang P, Roystonn K, Lee YY, Cetty L, Teh WL, Verma S, Mok YM, Fung DSS, Chong SA, Subramaniam M. Smoking and Mental Illness: Prevalence, Patterns and Correlates of Smoking and Smoking Cessation among Psychiatric Patients. Int J Environ Res Public Health 2020; 17:ijerph17155571. [PMID: 32752263 PMCID: PMC7432787 DOI: 10.3390/ijerph17155571] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/22/2020] [Accepted: 07/29/2020] [Indexed: 12/16/2022]
Abstract
This study aims to understand (a) the prevalence and correlates of smoking in a psychiatric population, (b) factors that encourage smoking cessation, and (c) awareness towards cessation programmes. This study captured data (n = 380) through a modified version of the Global Adult Tobacco Survey (GATS). A descriptive analysis of the data was performed. The prevalence of smoking was 39.5% (n = 150) and 52.3% of the smokers were dependent on nicotine. More than half of the smokers had made at least one attempt to quit in the past 12 months and 56% reported no immediate plans to quit smoking. The awareness towards institutional smoking cessation programmes was fair (44%), with 49.7% of smokers having indicated that they were willing to use the service upon referral. Smokers endorsed that increasing the cost of cigarettes, restricting availability, and increasing knowledge of health harms could encourage smoking cessation. Past smokers reported that self-determination/willpower followed by substitution of smoking with other types of foods and drinks were factors that helped them achieve successful cessation. Given that the readiness to quit and awareness towards cessation programmes are low among the smokers, concerted efforts through educational programmes and policy changes are crucial to achieve successful cessation.
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Affiliation(s)
- P. V. Asharani
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
- Correspondence: ; Tel.: +65-63892961
| | - Vanessa Ai Ling Seet
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Edimansyah Abdin
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Fiona Devi Siva Kumar
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Peizhi Wang
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Kumarasan Roystonn
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Ying Ying Lee
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Laxman Cetty
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Wen Lin Teh
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Swapna Verma
- Early Psychosis Intervention Programme, Institute of Mental Health, Singapore 539747, Singapore;
| | - Yee Ming Mok
- Department of Mood and Anxiety, Institute of Mental Health, Singapore 539747, Singapore;
| | | | - Siow Ann Chong
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
| | - Mythily Subramaniam
- Research Division, Institute of Mental Health, Singapore 539747, Singapore; (V.A.L.S.); (E.A.); (F.D.S.K.); (P.W.); (K.R.); (Y.Y.L.); (L.C.); (W.L.T.); (S.A.C.); (M.S.)
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11
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Abstract
The epidermis of terrestrial vertebrates is a stratified epithelium and forms an essential protective barrier. It is continually renewed, with dead corneocytes shed from the surface and replaced from a basal keratinocyte stem cell population. Whilst mouse is the prime model system used for epidermal studies, there is increasing employment of the zebrafish to analyse epidermis development and homeostasis, however the architecture and ontogeny of the epidermis in this system are incompletely described. In particular, it is unclear if adult zebrafish epidermis is derived entirely from the basal epidermal stem cell layer, as in the mouse, or if the most superficial keratinocyte layer is a remnant of the embryonic periderm. Furthermore, a relative paucity of cellular markers and genetic reagents to label and manipulate the basal epidermal stem cell compartment has hampered research. Here we show that the type I keratin, krtt1c19e, is a suitable marker of the basal epidermal layer and identify a krtt1c19e promoter fragment able to drive strong and specific expression in this cell type. Use of this promoter to express an inducible Cre recombinase allowed permanent labelling of basal cells during embryogenesis, and demonstrated that these cells do indeed generate keratinocytes of all strata in the adult epidermis. Further deployment of the Cre-Lox system highlighted the transient nature of the embryonic periderm. We thus show that the epidermis of adult zebrafish, as in the mouse, derives from basal stem cells, further expanding the similarities of epidermal ontogeny across vertebrates. Future use of this promoter will assist genetic analysis of basal keratinocyte biology in zebrafish.
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Affiliation(s)
- Raymond T. H. Lee
- Discovery Research Division, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, Republic of Singapore
| | - P. V. Asharani
- Discovery Research Division, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, Republic of Singapore
| | - Thomas J. Carney
- Discovery Research Division, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, Republic of Singapore
- * E-mail:
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Lim HK, Asharani PV, Hande MP. Enhanced genotoxicity of silver nanoparticles in DNA repair deficient Mammalian cells. Front Genet 2012; 3:104. [PMID: 22707954 PMCID: PMC3374476 DOI: 10.3389/fgene.2012.00104] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 05/21/2012] [Indexed: 11/25/2022] Open
Abstract
Silver nanoparticles (Ag-np) have been used in medicine and commercially due to their anti-microbial properties. Therapeutic potentials of these nanoparticles are being explored extensively despite the lack of information on their mechanism of action at molecular and cellular level. Here, we have investigated the DNA damage response and repair following Ag-np treatment in mammalian cells. Studies have shown that Ag-np exerts genotoxicity through double-strand breaks (DSBs). DNA-PKcs, the catalytic subunit of DNA dependent protein kinase, is an important caretaker of the genome which is known to be the main player mediating Non-homologous End-Joining (NHEJ) repair pathway. We hypothesize that DNA-PKcs is responsible for the repair of Ag-np induced DNA damage. In vitro studies have been carried out to investigate both cytotoxicity and genotoxicity induced by Ag-np in normal human cells, DNA-PKcs proficient, and deficient mammalian cells. Chemical inhibition of DNA-PKcs activity with NU7026, an ATP-competitive inhibitor of DNA-PKcs, has been performed to further validate the role of DNA-PKcs in this model. Our results suggest that Ag-np induced more prominent dose-dependent decrease in cell viability in DNA-PKcs deficient or inhibited cells. The deficiency or inhibition of DNA-PKcs renders the cells with higher susceptibility to DNA damage and genome instability which in turn contributed to greater cell cycle arrest/cell death. These findings support the fact that DNA-PKcs is involved in the repair of Ag-np induced genotoxicity and NHEJ repair pathway and DNA-PKcs particularly is activated to safeguard the genome upon Ag-np exposure.
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Affiliation(s)
- Hui Kheng Lim
- Genome Stability Laboratory, Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore Singapore
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Asharani PV, Keupp K, Semler O, Wang W, Li Y, Thiele H, Yigit G, Pohl E, Becker J, Frommolt P, Sonntag C, Altmüller J, Zimmermann K, Greenspan DS, Akarsu NA, Netzer C, Schönau E, Wirth R, Hammerschmidt M, Nürnberg P, Wollnik B, Carney TJ. Attenuated BMP1 function compromises osteogenesis, leading to bone fragility in humans and zebrafish. Am J Hum Genet 2012; 90:661-74. [PMID: 22482805 DOI: 10.1016/j.ajhg.2012.02.026] [Citation(s) in RCA: 172] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 01/23/2012] [Accepted: 02/24/2012] [Indexed: 12/19/2022] Open
Abstract
Bone morphogenetic protein 1 (BMP1) is an astacin metalloprotease with important cellular functions and diverse substrates, including extracellular-matrix proteins and antagonists of some TGFβ superfamily members. Combining whole-exome sequencing and filtering for homozygous stretches of identified variants, we found a homozygous causative BMP1 mutation, c.34G>C, in a consanguineous family affected by increased bone mineral density and multiple recurrent fractures. The mutation is located within the BMP1 signal peptide and leads to impaired secretion and an alteration in posttranslational modification. We also characterize a zebrafish bone mutant harboring lesions in bmp1a, demonstrating conservation of BMP1 function in osteogenesis across species. Genetic, biochemical, and histological analyses of this mutant and a comparison to a second, similar locus reveal that Bmp1a is critically required for mature-collagen generation, downstream of osteoblast maturation, in bone. We thus define the molecular and cellular bases of BMP1-dependent osteogenesis and show the importance of this protein for bone formation and stability.
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Affiliation(s)
- P V Asharani
- Institute of Molecular and Cell Biology, Proteos, Singapore, Singapore
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Asharani PV, Lianwu Y, Gong Z, Valiyaveettil S. Comparison of the toxicity of silver, gold and platinum nanoparticles in developing zebrafish embryos. Nanotoxicology 2010; 5:43-54. [PMID: 21417687 DOI: 10.3109/17435390.2010.489207] [Citation(s) in RCA: 275] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Nanoparticles have diverse applications in electronics, medical devices, therapeutic agents and cosmetics. While the commercialization of nanoparticles is rapidly expanding, their health and environmental impact is not well understood. Toxicity assays of silver, gold, and platinum nanoparticles, using zebrafish embryos to study their developmental effects were carried out. Gold (Au-NP, 15-35 nm), silver (Ag-NP, 5-35 nm) and platinum nanoparticles (Pt-NP, 3-10 nm) were synthesized using polyvinyl alcohol (PVA) as a capping agent. Toxicity was recorded in terms of mortality, hatching delay, phenotypic defects and metal accumulation. The addition of Ag-NP resulted in a concentration-dependant increase in mortality rate. Both Ag-NP and Pt-NP induced hatching delays, as well as a concentration dependant drop in heart rate, touch response and axis curvatures. Ag-NP also induced other significant phenotypic changes including pericardial effusion, abnormal cardiac morphology, circulatory defects and absence or malformation of the eyes. In contrast, Au-NP did not show any indication of toxicity. Uptake and accumulation of nanoparticles in embryos was confirmed by inductively coupled plasma optical emission spectroscopy (ICP-OES), which revealed detectable levels in embryos within 72 hpf. Ag-NP and Au-NP were taken up by the embryos in relatively equal amounts whereas lower Pt concentrations were observed in embryos exposed to Pt-NP. This was probably due to the small size of the Pt nanoparticles compared to Ag-NP and Au-NP, thus resulting in fewer metal atoms being retained in the embryos. Among the nanoparticles studied, Ag-NPs were found to be the most toxic and Au-NPs the non-toxic. The toxic effects exhibited by the zebrafish embryos as a consequence of nanoparticle exposure, accompanied by the accumulation of metals inside the body calls for urgent further investigations in this field.
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Affiliation(s)
- P V Asharani
- Department of Chemistry, National University of Singapore, Singapore
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Asharani PV, Xinyi N, Hande MP, Valiyaveettil S. DNA damage and p53-mediated growth arrest in human cells treated with platinum nanoparticles. Nanomedicine (Lond) 2010; 5:51-64. [PMID: 20025464 DOI: 10.2217/nnm.09.85] [Citation(s) in RCA: 143] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM Platinum-based therapeutic agents are widely used in medicine. Thus, a thorough understanding of their mechanism of action in cells is warranted. This study investigates the uptake and bioactivity (e.g., cytotoxicity, genotoxicity and protein expression) of platinum nanoparticles (Pt-NPs, approximately 5-8 nm in size) in human cells. MATERIALS & METHODS Pt-NPs capped with polyvinyl alcohol were synthesized, characterized and incubated with human cells. Uptake and the biological properties were evaluated through metabolic activity, genome integrity, cell cycle and protein expression. RESULTS Pt-NPs entered the cells through diffusion, and localized inside the cytoplasm. Exposure to the Pt-NP increased DNA damage, accumulation of cells at the S-phase of the cell cycle and apoptosis. A significant number of cells recovered from the stress and formed colonies. Protein-expression levels uncovered upregulation of p53, phosphorylated p53, p21 and downregulation of proliferating cell nuclear antigen following Pt-NP treatment. Pro-caspase 3 and poly-ADP ribose polymerase and cyclin B levels were not altered in both the cell types after Pt-NP exposure. CONCLUSION The results suggest p53 activation in Pt-NP-treated cells due to genotoxic stress, with subsequent activation of p21 leading to a proliferating cell nuclear antigen-mediated growth arrest and apoptosis. This study recommends development of Pt-NP-based anticancer agents by appropriate surface modifications to augment its innate anticancer activity.
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Affiliation(s)
- P V Asharani
- Department of Chemistry, Faculty of Science, 3 Science Drive 3, National University of Singapore, Singapore.
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17
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Abstract
BACKGROUND Nanoparticles possess exceptional physical and chemical properties which led to rapid commercialisation. Silver nanoparticles (Ag-np) are among the most commercialized nanoparticles due to their antimicrobial potential. Ag-np based cosmetics, therapeutic agents and household products are in wide use, which raised a public concern regarding their safety associated with human and environmental use. No safety regulations are in practice for the use of these nanomaterials. The interactions of nanomaterials with cells, uptake mechanisms, distribution, excretion, toxicological endpoints and mechanism of action remain unanswered. RESULTS Normal human lung fibroblasts (IMR-90) and human glioblastoma cells (U251) were exposed to different doses of Ag-nps in vitro. Uptake of Ag-nps occurred mainly through endocytosis (clathrin mediated process and macropinocytosis), accompanied by a time dependent increase in exocytosis rate. The electron micrographs revealed a uniform intracellular distribution of Ag-np both in cytoplasm and nucleus. Ag-np treated cells exhibited chromosome instability and mitotic arrest in human cells. There was efficient recovery from arrest in normal human fibroblasts whereas the cancer cells ceased to proliferate. Toxicity of Ag-np is mediated through intracellular calcium (Ca2+) transients along with significant alterations in cell morphology and spreading and surface ruffling. Down regulation of major actin binding protein, filamin was observed after Ag-np exposure. Ag-np induced stress resulted in the up regulation of metallothionein and heme oxygenase -1 genes. CONCLUSION Here, we demonstrate that uptake of Ag-np occurs mainly through clathrin mediated endocytosis and macropinocytosis. Our results suggest that cancer cells are susceptible to damage with lack of recovery from Ag-np-induced stress. Ag-np is found to be acting through intracellular calcium transients and chromosomal aberrations, either directly or through activation of catabolic enzymes. The signalling cascades are believed to play key roles in cytoskeleton deformations and ultimately to inhibit cell proliferation.
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Affiliation(s)
- P V Asharani
- Department of Chemistry, Faculty of Science, 3 Science Drive 3, National University of Singapore, 117543 Singapore
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Asharani PV, Serina NGB, Nurmawati MH, Wu YL, Gong Z, Valiyaveettil S. Impact of multi-walled carbon nanotubes on aquatic species. J Nanosci Nanotechnol 2008; 8:3603-3609. [PMID: 19051917 DOI: 10.1166/jnn.2008.432] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
To understand the environmental impacts of carbon nanotubes (CNTs), the toxicity study was carried out with water-soluble multi-walled carbon nanotubes (MWCNTs) using zebrafish (Danio rerio) as a model system. Zebrafish embryos were treated with different concentrations of MWCNTs. Teratogenic effects were evaluated through changes in embryonic development after 24 hours post-fertilization (hpf), 48 hpf and 72 hpf. No observable effect concentration (NOEC) was at 40 microg/mL. Lowest effect concentration (LOEC) of MWCNTs which caused significant phenotypic defects in zebrafish embryo was 60 microg/mL. At concentration above 60 microg/mL, slimy mucus like coating was observed around the embryo. At high concentrations, MWCNTs was found to be involved in the apoptosis, delayed hatching and formation of abnormal spinal chords. Thus, the toxicity of multi-walled carbon nanotubes is concentration dependent.
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Affiliation(s)
- P V Asharani
- Department of Chemistry, Faculty of Science, 3 Science Drive 3, National University of Singapore, Singapore 117543
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Abstract
This study was initiated to enhance our insight on the health and environmental impact of silver nanoparticles (Ag-np). Using starch and bovine serum albumin (BSA) as capping agents, silver nanoparticles were synthesized to study their deleterious effects and distribution pattern in zebrafish embryos (Danio rerio). Toxicological endpoints like mortality, hatching, pericardial edema and heart rate were recorded. A concentration-dependent increase in mortality and hatching delay was observed in Ag-np treated embryos. Additionally, nanoparticle treatments resulted in concentration-dependent toxicity, typified by phenotypes that had abnormal body axes, twisted notochord, slow blood flow, pericardial edema and cardiac arrhythmia. Ag(+) ions and stabilizing agents showed no significant defects in developing embryos. Transmission electron microscopy (TEM) of the embryos demonstrated that nanoparticles were distributed in the brain, heart, yolk and blood of embryos as evident from the electron-dispersive x-ray analysis (EDS). Furthermore, the acridine orange staining showed an increased apoptosis in Ag-np treated embryos. These results suggest that silver nanoparticles induce a dose-dependent toxicity in embryos, which hinders normal development.
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Affiliation(s)
- P V Asharani
- Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, 117543, Singapore
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