1.The association between household poverty rates and tuberculosis case notification rates in Cambodia, 2010
Wong Man Kai ; Yadav Rajendra-Prasad ; Nishikiori Nobuyuku ; Eang Mao Tan
Western Pacific Surveillance and Response 2013;4(1):25-33
Introduction: Poverty is a risk factor for tuberculosis (TB); it increases the risk of infection and active disease but limits diagnostic opportunities. The role of poverty in the stagnant case detection in Cambodia is unclear. This study aims to assess the relationship between district household poverty rates and sputum-positive TB case notification rates (CNRs) in Cambodia in 2010.
Methods: Poisson regression models were used to calculate the relative risk of new sputum-positive TB CNR for Operational Districts (ODs) with different poverty rates using data from the National Centre for Tuberculosis and Leprosy Control and the National Committee for SubNational Democratic Development. Models were adjusted for other major covariates and a geographical information system was used to examine the spatial distribution of these covariates in the country.
Results: The univariate model showed a positive association between household poverty rates and sputum-positive TB CNRs. However, in multivariate models, after adjusting for major covariates, household poverty rates showed a significantly negative association with sputum-positive TB CNRs (relative risk [RR] = 0.95 per 5% increase in poverty rate). The negative association was stronger among males than females (RR = 0.93 versus 0.96 per 5% increase in poverty rate). Similar spatial patterns were observed between household poverty rates and other covariates, particularly OD population density.
Conclusion: Household poverty rate is associated with a decrease in sputum-positive TB CNR in Cambodia, particularly in men. The potential of combining surveillance data and socioeconomic variables should be explored further to provide more insights for TB control programme planning.
2.Features of ciguatera fish poisoning cases in Hong Kong 2004-2007.
Chun-Kwan WONG ; Patricia HUNG ; Kellie L H LEE ; Tina MOK ; Thomas CHUNG ; Kai-Man KAM
Biomedical and Environmental Sciences 2008;21(6):521-527
OBJECTIVETo review the clinical features and laboratory investigations of ciguatera patients in Hong Kong between 2004 and 2007 in order to show the timely sampling of implicated fish from ciguatera victims and application of validated mouse bioassay for confirming suspected clinical cases of ciguatera.
METHODSDiagnosis of the ciguatera victims was based on history of coral fish consumption and clinical presentations stated in official guidelines for clinical diagnosis of ciguatera fish poisoning in Hong Kong. Food remnants of coral fish samples were collected swiftly from ciguatera victims between 2004 and 2007 for ciguatoxins (CTXs) analysis.
RESULTSMajor clinical symptoms in ciguatera patients included gastrointestinal and neurological effects including limb numbness and diarrhoea, which developed at 0.5 to 15 hours after consumption of fish. In most cases, neurological symptoms were more common than gastrointestinal symptoms. A broad range of attack rate (10%-100%) was observed in each ciguatera outbreak. Validated mouse bioassay on ether extracts of the food remnant samples confirmed that all were CTXs-positive (<0.5 - 4.3 MU/20 mg ether extract) and directly linked to the corresponding ciguatera cases.
CONCLUSIONConsistency between clinical and laboratory analysis for ciguatera poisoning illustrates the application of laboratory mouse bioassay in a timely fashion for confirming ciguatera poisoning cases and implementing effective public health measures. With further improvement in laboratory techniques, features of ciguatera fish poisoning cases can be better defined. Further studies are needed to determine the risk of each class of CTXs (Pacific-, Indian- and Caribbean-CTXs) in Hong Kong.
Animals ; Biological Assay ; Ciguatera Poisoning ; blood ; diagnosis ; epidemiology ; Ciguatoxins ; analysis ; Disease Outbreaks ; Fishes ; Gastrointestinal Diseases ; blood ; diagnosis ; epidemiology ; Hong Kong ; epidemiology ; Humans ; Mice ; Nervous System Diseases ; blood ; diagnosis ; epidemiology ; Prevalence ; Public Health ; Risk Factors ; Time Factors
3.Development of an ICR mouse bioassay for toxicity evaluation in neurotoxic poisoning toxins-contaminated shellfish.
Chun Kwan WONG ; Patricia HUNG ; Kai Man KAM
Biomedical and Environmental Sciences 2013;26(5):346-364
OBJECTIVETo develop an ICR (female) mouse bioassay (MBA) for toxicity confirmation and evaluation of neurotoxins (brevetoxins)-contaminated shellfish.
METHODSBrevetoxins (BTX-B) as a causative agent of neurotoxic shellfish poisoning (NSP) under different shellfish matrices were intraperitoneally injected at different doses into mice to study their toxic effects and to differentiate the range of lethal and sublethal dosages. Their sensitivity and specificity were analyzed with 2 competitive ELISA kits for quantitative determination of standard BTX-B and dihydroBTX-B under different shellfish matrix-diluent combinations. Detection rates of MBA and two antibody-based assays for BTX-B from field NSP-positive shellfish samples were compared.
RESULTSBTX-B could be detected in shellfish tissues at concentration of 50-400 μg/100 g under shellfish matrix-Tween-saline media, which were appropriate to identify toxic shellfish at or above the regulatory limit (80 μg/100 g shellfish tissues). The LD50 identified was 455 mg/kg for BTX-B under general shellfish matrices (excluding oyster matrices) dissolved in Tween-saline. The presence of shellfish matrices, of oyster matrices in particular, retarded the occurrence of death and toxicity presentation in mice. Two antibody-based assays, even in the presence of different shellfish matrix-diluent combinations, showed acceptable results in quantifying BTX-B and dihydroBTX-B well below the regulatory limit.
CONCLUSIONThe two ELISA analyses agree favorably (correlation coefficient, r³⋝0.96; Student's t-tests, P>0.05) with the developed bioassay.
Animals ; Biological Assay ; Calibration ; Female ; Marine Toxins ; toxicity ; Mice ; Mice, Inbred ICR ; Oxocins ; toxicity ; Shellfish ; analysis
4.Evaluation of the relationship between cardiac calcification and cardiovascular disease using the echocardiographic calcium score in patients undergoing peritoneal dialysis: a cross-sectional study.
Ho-Kwan SIN ; Ping-Nam WONG ; Kin-Yee LO ; Man-Wai LO ; Shuk-Fan CHAN ; Kwok-Chi LO ; Yuk-Yi WONG ; Lo-Yi HO ; Wing-Tung KWOK ; Kai-Chun CHAN ; Andrew Kui-Man WONG ; Siu-Ka MAK
Singapore medical journal 2023;64(6):379-384
INTRODUCTION:
An echocardiographic calcium score (ECS) predicts cardiovascular disease (CVD) in the general population. Its utility in peritoneal dialysis (PD) patients is unknown.
METHODS:
This cross-sectional study assessed 125 patients on PD. The ECS (range 0-8) was compared between subjects with CVD and those without.
RESULTS:
Among the subjects, 54 had CVD and 71 did not. Subjects with CVD were older (69 years vs. 56 years, P < 0.001) and had a higher prevalence of diabetes mellitus (DM) (81.5% vs. 45.1%, P < 0.001). They had lower diastolic blood pressure (72 mmHg vs. 81 mmHg, P < 0.001), lower phosphate (1.6 mmol/L vs. 1.9 mmol/L, P = 0.002), albumin (30 g/L vs. 32 g/L, P = 0.001), parathyroid hormone (34.4 pmol/L vs. 55.8 pmol/L, P = 0.002), total cholesterol (4.5 vs. 4.9, P = 0.047), LDL cholesterol (2.4 mmol/L vs. 2.8 mmol/L, P = 0.019) and HDL cholesterol (0.8 mmol/L vs. 1.1 mmol/L, P = 0.002). The ECS was found to be higher in subjects with CVD than in those without (2 vs. 1, P = 0.001). On multivariate analysis, only DM and age were independently associated with CVD.
CONCLUSION
The ECS was significantly higher in PD patients with CVD than in those without, reflecting a higher vascular calcification burden in the former. It is a potentially useful tool to quantify vascular calcification in PD patients.
Humans
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Cardiovascular Diseases/diagnostic imaging*
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Cross-Sectional Studies
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Calcium
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Peritoneal Dialysis/adverse effects*
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Vascular Calcification/epidemiology*
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Echocardiography