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Fulltext Bacterial constituents of indoor air in a high throughput building in the tropics

Li TC, Ambu S, Mohandas K, Wah MJ, Sulaiman LH, Murgaiyah M

Trop Biomed, 2014 Sep;31(3):540-56.
PMID: 25382482 MyJurnal

Airborne bacteria are significant biotic constituents of bioaerosol. Bacteria at high concentrations in the air can compromise indoor air quality (IAQ) and result in many diseases. In tropical environments like Malaysia that extensively utilize air-conditioning systems, this is particularly significant due to continuous recirculation of indoor air and the potential implications for human health. Currently, there is a lack of knowledge regarding the impact of airborne bacteria on IAQ in Malaysia. This study was prompted by a need for reliable baseline data on airborne bacteria in the indoor environment of tropical equatorial Malaysia, that may be used as a reference for further investigations on the potential role played by airborne bacteria as an agent of disease in this region. It was further necessitated due to the threat of bioterrorism with the potentiality of release of exotic pathogenic microorganisms into indoor or outdoor air. Before scientists can detect the latter, a gauge of the common microorganisms in indoor (as well as outdoor) air needs to be ascertained, hence the expediency of this study. Bacterial counts from the broad-based and targeted study were generally in the order of 10(2) colony-forming units (CFU) per m(3) of air. The most prevalent airborne bacteria found in the broad-based study that encompassed all five levels of the building were Gram-positive cocci (67.73%), followed by Gram-positive rods (24.26%) and Gram-negative rods (7.10%). Gram-negative cocci were rarely detected (0.71%). Amongst the genera identified, Kytococcus sp., Micrococcus sp., Staphylococcus sp., Leifsonia sp., Bacillus sp. and Corynebacterium sp. predominated in indoor air. The most dominant bacterial species were Kytococcus sedentarius, Staphylococcus epidermidis and Micrococcus luteus. The opportunistic and nosocomial pathogen, Stenotrophomonas maltophilia was also discovered at a high percentage in the cafeteria. The bacteria isolated in this study have been increasingly documented to cause opportunistic infections in immuno-compromised patients, sometimes with fatal outcomes. Furthermore, some of them are becoming increasingly resistant to antibiotics. Hence, we propose that indoor reservoirs of these bacteria and their associated clinical and more subtle health effects, if any, be investigated further.
Fulltext Neglected Intestinal Parasites, Malnutrition and Associated Key Factors: A Population Based Cross-Sectional Study among Indigenous Communities in Sarawak, Malaysia

Rajoo Y, Ambu S, Lim YA, Rajoo K, Tey SC, Lu CW, et al.

PLoS One, 2017;12(1):e0170174.
PMID: 28095446 DOI: 10.1371/journal.pone.0170174

Intestinal parasitic infections (IPIs) have been recognized as one of the most significant causes of illness among disadvantaged communities. Many studies have been conducted on the prevalence of IPIs in Malaysia. However, these studies mostly focused on the indigenous groups in Peninsular Malaysia. The present study was conducted to provide the current baseline data on prevalence of IPIs, anaemia, malnutrition and associated risk factors among the indigenous communities in Sarawak, situation at northwest Borneo island of Malaysia. A cross sectional study was conducted among the longhouses communities. Stool samples were obtained and examined for the presence of IPIs using microscopy technique. Haemoglobin measurement was done using a portable haemoglobin analyzer. Malnutrition (i.e., stunting, underweight and wasting) was assessed using the WHO Anthro software. Statistical analysis was carried out using SPSS software. A total of 341participants took part in this study. The overall prevalence of IPIs was 57.5%. Multivariate analysis indicated that the absence of toilets (OR = 1.6; 95% CI = 1.1-2.7; p = 0.002) and close contact with animals (OR = 1.8; 95% CI = 1.3-2.9; p = 0.027) as significant predictors for IPIs. The incidence of anaemia was 36.4%. The incidence of underweight, wasting and stunting were 22.2%, 5.6% and 35.4%, respectively. Multivariate analysis demonstrated that low level of parental education attainment (OR = 1.9; 95% CI = 1.2-3.0; p = 0.006) was identified as significant predictor for anaemia. The incidence of wasting was significantly associated with mild anaemia (OR = 1.2; 95% CI = 0.9-1.7; p = 0.024). Low household income was identified as significant predictor for stunting (OR = 2.1; 95% CI = 9.8-22.2; p = 0.001) and underweight (OR = 1.9; 95% CI = 5.6-18.7; p = 0.037), respectively. Essentially, the present study highlighted that intestinal parasitic infections, anaemia and malnutrition are still prevalent among rural indigenous community in Sarawak. Improvement of socioeconomic status, periodic mass deworming, iron supplementation and health education program should be included in the control and prevention of public health strategies.
Fulltext Risk factors for human leptospirosis following flooding: A meta-analysis of observational studies

Naing C, Reid SA, Aye SN, Htet NH, Ambu S

PLoS One, 2019;14(5):e0217643.
PMID: 31141558 DOI: 10.1371/journal.pone.0217643

Leptospirosis is probably the most widespread zoonotic disease in the world especially in tropical countries. There has been an increase in individual studies, which assessed the frequency of leptospirosis in flood conditions. Some studies showed contact with floods was significantly associated with the occurrence of leptospirosis while other studies reported differently. The objective of this meta-analysis was to synthesize the evidence on the risk factors which are associated with human leptospirosis following flooding. We set up the inclusion criteria and searched for the original studies, addressing leptospirosis in human with related to flood in health-related electronic databases including PubMed, Embase, Ovid Medline, google scholar and Scopus sources. We used the terms 'leptospirosis', 'flood', 'risk factor' and terms from the categories were connected with "OR" within each category and by "AND" between categories. The initial search yielded 557 citations. After the title and abstract screening, 49 full-text papers were reviewed and a final of 18 observational studies met the pre-specified inclusion criteria. Overall, the pooled estimates of 14 studies showed that the contact with flooding was a significant factor for the occurrence of leptospirosis (pooled OR: 2.19, 95%CI: 1.48-3.24, I2:86%). On stratification, the strength of association was greater in the case-control studies (pooled OR: 4.01, 95%CI: 1.26-12.72, I2:82%) than other designs (pooled OR:1.77,95%CI:1.18-2.65, I2:87%). Three factors such as 'being male'(pooled OR:2.06, 95%CI:1.29-2.83), the exposure to livestock animals (pooled OR: 1.95, 95%CI:1.26-2.64), the lacerated wound (pooled OR:4.35, 95%CI:3.07-5.64) were the risk factors significantly associated with the incidence of leptospirosis following flooding in the absence of within-study heterogeneity (I2: 0%). We acknowledge study limitations such as publication bias and type 2 statistical errors. We recommended flood control and other environmental modifications that are expected to reduce the risk of leptospiral infection, and a multi-sectoral effort to this aspect would have long-term benefits.
Fulltext Association between dietary patterns and overweight risk among Malaysian adults: evidence from nationally representative surveys

Shyam S, Khor GL, Ambak R, Mahadir B, Hasnan M, Ambu S, et al.

Public Health Nutr, 2020 Feb;23(2):319-328.
PMID: 31397262 DOI: 10.1017/S1368980019001861

OBJECTIVE: To investigate the association between dietary patterns (DP) and overweight risk in the Malaysian Adult Nutrition Surveys (MANS) of 2003 and 2014.
DESIGN: DP were derived from the MANS FFQ using principal component analysis. The cross-sectional association of the derived DP with prevalence of overweight was analysed.
SETTING: Malaysia.
PARTICIPANTS: Nationally representative sample of Malaysian adults from MANS (2003, n 6928; 2014, n 3000).
RESULTS: Three major DP were identified for both years. These were 'Traditional' (fish, eggs, local cakes), 'Western' (fast foods, meat, carbonated beverages) and 'Mixed' (ready-to-eat cereals, bread, vegetables). A fourth DP was generated in 2003, 'Flatbread & Beverages' (flatbread, creamer, malted beverages), and 2014, 'Noodles & Meat' (noodles, meat, eggs). These DP accounted for 25·6 and 26·6 % of DP variations in 2003 and 2014, respectively. For both years, Traditional DP was significantly associated with rural households, lower income, men and Malay ethnicity, while Western DP was associated with younger age and higher income. Mixed DP was positively associated with women and higher income. None of the DP showed positive association with overweight risk, except for reduced adjusted odds of overweight with adherence to Traditional DP in 2003.
CONCLUSIONS: Overweight could not be attributed to adherence to a single dietary pattern among Malaysian adults. This may be due to the constantly morphing dietary landscape in Malaysia, especially in urban areas, given the ease of availability and relative affordability of multi-ethnic and international foods. Timely surveys are recommended to monitor implications of these changes.
Fulltext Epidemiology and control of malaria in Malaysia

Mak JW, Jegathesan M, Lim PK, Hakim SL, Rain AN, Ambu S, et al.

Southeast Asian J Trop Med Public Health, 1992 Dec;23(4):572-7.
PMID: 1298064

In spite of more than 30 years of control activities, malaria continues to be the most important parasitic infection in Malaysia, accounting for 39,189 confirmed cases in 1991, giving an annual parasite incidence rate of 2.2 per 1,000 population. Some factors contributing to the continued transmission of malaria are the development of drug resistant Plasmodium falciparum, changes in vector behavior, and ecological changes due to socio-economic reasons. Malaria parasite rates are higher among the Aborigines, land scheme settlers and those in intimate contact with the jungle, like loggers. There has been no substantial change in the proportion of the three common malaria species responsible for infections, P. falciparum, P. vivax, P. malariae and mixed infections accounting for about 70%, 28%, 1% and 1%, respectively of all infections. Drug resistant P. falciparum is unevenly distributed in Malaysia, but based on clinical experience and in vitro drug sensitivity studies, chloroquine resistance is frequently encountered. There has been clinical and laboratory evidence of resistance to sulfadoxine/pyrimethamine combination as well as quinine, but all these have so far been successfully treated with a combination of quinine and tetracycline. The eradication of the disease is impossible in the near future but there is confidence that with better surveillance techniques and the use of alternative control measures like permethrin impregnated bed-nets to complement existing ones, the target of bringing down the annual parasite incidence to 2 per 1,000 population during the Sixth Malaysian Plan period (1991-1995) can be achieved.
Epidemiological Characteristics of Strongyloidiasis in Inhabitants of Indigenous Communities in Borneo Island, Malaysia

Ngui R, Halim NA, Rajoo Y, Lim YA, Ambu S, Rajoo K, et al.

Korean J Parasitol, 2016 Oct;54(5):673-678.
PMID: 27853126

Epidemiological study on strongyloidiasis in humans is currently lacking in Malaysia. Thus, a cross-sectional study was carried out to determine the prevalence of Strongyloides stercoralis infection among the inhabitants of longhouse indigenous communities in Sarawak. A single stool and blood sample were collected from each participant and subjected to microscopy, serological and molecular techniques. Five species of intestinal parasites were identified by stool microscopy. None of the stool samples were positive for S. stercoralis. However, 11% of 236 serum samples were seropositive for strongyloidiasis. Further confirmation using molecular technique on stool samples of the seropositive individuals successfully amplified 5 samples, suggesting current active infections. The prevalence was significantly higher in adult males and tended to increase with age. S. stercoralis should no longer be neglected in any intestinal parasitic survey. Combination of more than 1 diagnostic technique is necessary to increase the likelihood of estimating the 'true' prevalence of S. stercoralis.
Fulltext Inhibition of breast cancer xenografts in a mouse model and the induction of apoptosis in multiple breast cancer cell lines by lactoferricin B peptide

Rahman R, Fonseka AD, Sua SC, Ahmad M, Rajendran R, Ambu S, et al.

J Cell Mol Med, 2021 08;25(15):7181-7189.
PMID: 34236134 DOI: 10.1111/jcmm.16748

Breast cancer has a diverse aetiology characterized by the heterogeneous expression of hormone receptors and signalling molecules, resulting in varied sensitivity to chemotherapy. The adverse side effects of chemotherapy coupled with the development of drug resistance have prompted the exploration of natural products to combat cancer. Lactoferricin B (LfcinB) is a natural peptide derived from bovine lactoferrin that exhibits anticancer properties. LfcinB was evaluated in vitro for its inhibitory effects on cell lines representing different categories of breast cancer and in vivo for its suppressive effects on tumour xenografts in NOD-SCID mice. The different breast cancer cell lines exhibited varied levels of sensitivity to apoptosis induced by LfcinB in the order of SKBR3>MDA-MB-231>MDA-MB-468>MCF7, while the normal breast epithelial cells MCF-10A were not sensitive to LfcinB. The peptide also inhibited the invasion of the MDA-MB-231 and MDA-MB-468 cell lines. In the mouse xenograft model, intratumoural injections of LfcinB significantly reduced tumour growth rate and tumour size, as depicted by live imaging of the mice using in vivo imaging systems (IVIS). Harvested tumour volume and weight were significantly reduced by LfcinB treatment. LfcinB, therefore, is a promising and safe candidate that can be considered for the treatment of breast cancer.
Effect of madecassoside in reducing oxidative stress and blood glucose in streptozotocin-nicotinamide-induced diabetes in rats

Tan SC, Rajendran R, Bhattamisra SK, Krishnappa P, Davamani F, Chitra E, et al.

J Pharm Pharmacol, 2023 Aug 01;75(8):1034-1045.
PMID: 37402616 DOI: 10.1093/jpp/rgad063

OBJECTIVES: Madecassoside (MAD) is a triterpenoid constituent of Centella asiatica (L.) Urb., an ethnomedical tropical plant, extracts of which were shown to reduce blood glucose in experimental diabetes. This study examines MAD for its anti-hyperglycaemic effects and tests the hypothesis that it reduces the blood glucose in experimentally induced diabetic rats by protecting the β-cells.
METHODS: Diabetes was induced using streptozotocin (60 mg/kg, i.v.) followed by nicotinamide (210 mg/kg, intraperitoneal (i.p.)). MAD (50 mg/kg) was administered orally for 4 weeks, commencing 15 days after induction of diabetes; resveratrol (10 mg/kg) was used as a positive control. Fasting blood glucose, plasma insulin, HbA1c, liver and lipid parameters were measured, along with antioxidant enzymes and malondialdehyde as an index of lipid peroxidation; histological and immunohistochemical studies were also undertaken.
KEY FINDINGS: MAD normalized the elevated fasting blood glucose levels. This was associated with increased plasma insulin concentrations. MAD alleviated oxidative stress by improving enzymatic antioxidants and reducing lipid peroxidation. Histopathological examination showed significant recovery of islet structural degeneration and an increased area of islets. Immunohistochemical staining showed increased insulin content in islets of MAD-treated rats.
CONCLUSIONS: The results demonstrate an antidiabetic effect of MAD associated with preservation of β-cell structure and function.
Fulltext Association between long-term exposure to ambient air pollution and prevalence of diabetes mellitus among Malaysian adults

Wong SF, Yap PS, Mak JW, Chan WLE, Khor GL, Ambu S, et al.

Environ Health, 2020 04 03;19(1):37.
PMID: 32245482 DOI: 10.1186/s12940-020-00579-w

BACKGROUND: Malaysia has the highest rate of diabetes mellitus (DM) in the Southeast Asian region, and has ongoing air pollution and periodic haze exposure.
METHODS: Diabetes data were derived from the Malaysian National Health and Morbidity Surveys conducted in 2006, 2011 and 2015. The air pollution data (NOx, NO2, SO2, O3 and PM10) were obtained from the Department of Environment Malaysia. Using multiple logistic and linear regression models, the association between long-term exposure to these pollutants and prevalence of diabetes among Malaysian adults was evaluated.
RESULTS: The PM10 concentration decreased from 2006 to 2014, followed by an increase in 2015. Levels of NOx decreased while O3 increased annually. The air pollutant levels based on individual modelled air pollution exposure as measured by the nearest monitoring station were higher than the annual averages of the five pollutants present in the ambient air. The prevalence of overall diabetes increased from 11.4% in 2006 to 21.2% in 2015. The prevalence of known diabetes, underdiagnosed diabetes, overweight and obesity also increased over these years. There were significant positive effect estimates of known diabetes at 1.125 (95% CI, 1.042, 1.213) for PM10, 1.553 (95% CI, 1.328, 1.816) for O3, 1.271 (95% CI, 1.088, 1.486) for SO2, 1.124 (95% CI, 1.048, 1.207) for NO2, and 1.087 (95% CI, 1.024, 1.153) for NOx for NHMS 2006. The adjusted annual average levels of PM10 [1.187 (95% CI, 1.088, 1.294)], O3 [1.701 (95% CI, 1.387, 2.086)], NO2 [1.120 (95% CI, 1.026, 1.222)] and NOx [1.110 (95% CI, 1.028, 1.199)] increased significantly from NHMS 2006 to NHMS 2011 for overall diabetes. This was followed by a significant decreasing trend from NHMS 2011 to 2015 [0.911 for NO2, and 0.910 for NOx].
CONCLUSION: The findings of this study suggest that long-term exposure to O3 is an important associated factor of underdiagnosed DM risk in Malaysia. PM10, NO2 and NOx may have mixed effect estimates towards the risk of DM, and their roles should be further investigated with other interaction models. Policy and intervention measures should be taken to reduce air pollution in Malaysia.