8 results on '"Lu, Chan"'
Search Results
2. Prevalence, risk factors, impact and management of pneumonia among preschool children in Chinese seven cities: a cross-sectional study with interrupted time series analysis
- Author
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Shi, Haonan, Wang, Tingting, Zhao, Zhuohui, Norback, Dan, Wang, Xiaowei, Li, Yongsheng, Deng, Qihong, Lu, Chan, Zhang, Xin, Zheng, Xiaohong, Qian, Hua, Zhang, Ling, Yu, Wei, Shi, Yuqing, Chen, Tianyi, Yu, Huaijiang, Qi, Huizhen, Yang, Ye, Jiang, Lan, Lin, Yuting, Yao, Jian, Lu, Junwen, and Yan, Qi
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- 2023
- Full Text
- View/download PDF
3. Preconceptional and prenatal exposure to diurnal temperature variation increases the risk of childhood pneumonia
- Author
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Zheng, Xiangrong, Kuang, Jian, Lu, Chan, Deng, Qihong, Wu, Haiyu, Murithi, Rachael Gakii, Johnson, McSherry Brownel, Peng, Wang, and Wu, Maolan
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- 2021
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- View/download PDF
4. Laboratory markers of disease severity in Plasmodium knowlesi infection: a case control study
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Sanjeev Krishna, Atique Ahmed, Janet Cox-Singh, Matthias Willmann, Balbir Singh, Angela Siner, Lu Chan Woon, Ing Tien Wong, University of St Andrews. School of Medicine, University of St Andrews. Infection Group, and University of St Andrews. Biomedical Sciences Research Complex
- Subjects
Male ,Platelet count ,Neutrophils ,Parasitemia ,Parasite load ,Severity of Illness Index ,Parasite Load ,Leukocyte Count ,0302 clinical medicine ,Borneo ,030212 general & internal medicine ,Children ,Parasitaemia ,Containing Leukocytes ,Middle Aged ,Thailand ,3. Good health ,Infectious Diseases ,Plasmodium knowlesi ,Female ,Malaria pigment ,Adult ,Hemeproteins ,medicine.medical_specialty ,lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 ,030231 tropical medicine ,Biology ,R Medicine ,Models, Biological ,lcsh:Infectious and parasitic diseases ,Association ,Haemozoin ,03 medical and health sciences ,SDG 3 - Good Health and Well-being ,Internal medicine ,Severity of illness ,parasitic diseases ,medicine ,Humans ,lcsh:RC109-216 ,Receiver operating characteristic ,Research ,Odds ratio ,Pigments, Biological ,medicine.disease ,biology.organism_classification ,Severity markers ,Confidence interval ,Malaria ,Case-Control Studies ,Immunology ,Parasitology ,Biomarkers - Abstract
Background Plasmodium knowlesi malaria causes severe disease in up to 10% of cases in Malaysian Borneo and has a mortality rate of 1 - 2%. However, laboratory markers with the ability to identify patients at risk of developing complications have not yet been assessed as they have for other species of Plasmodium. Methods A case control study was undertaken in two hospitals in Sarikei and Sibu, Malaysian Borneo. One hundred and ten patients with uncomplicated (n = 93) and severe (n = 17) P. knowlesi malaria were studied. Standardized pigment-containing neutrophil (PCN) count, parasite density and platelet counts were determined and analysed by logistic regression and receiver operating characteristic (ROC) analysis. Results The PCN count was strongly associated with risk of disease severity. Patients with high parasite density (≥ 35,000/μl) or with thrombocytopaenia (≤ 45,000/μl) were also more likely to develop complications (odds ratio (OR) = 9.93 and OR = 5.27, respectively). The PCN count yielded the highest area under the ROC curve (AUC) estimate among all markers of severity (AUC = 0.8561, 95% confidence interval: 0.7328, 0.9794). However, the difference between all parameter AUC estimates was not statistically significant (Wald test, p = 0.73). Conclusion Counting PCN is labour-intensive and not superior in predicting severity over parasitaemia and platelet counts. Parasite and platelet counts are simpler tests with an acceptable degree of precision. Any adult patient diagnosed with P. knowlesi malaria and having a parasite count ≥35,000/μl or ≥1% or a platelet count ≤45,000/μl can be regarded at risk of developing complications and should be managed according to current WHO guidelines for the treatment of severe malaria.
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- 2012
5. Susceptibility of human Plasmodium knowlesi infections to anti-malarials.
- Author
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Fatih, Farrah A., Staines, Henry M., Siner, Angela, Ahmed, Mohammed Atique, Lu Chan Woon, Pasini, Erica M., Kocken, Clemens H. M., Singh, Balbir, Cox-Singh, Janet, and Krishna, Sanjeev
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PLASMODIUM falciparum ,ANTIMALARIALS ,MALARIA treatment ,ZOONOSES - Abstract
Background Evidence suggests that Plasmodium knowlesi malaria in Sarawak, Malaysian Borneo remains zoonotic, meaning anti-malarial drug resistance is unlikely to have developed in the absence of drug selection pressure. Therefore, adequate response to available anti-malarial treatments is assumed. Methods Here the ex vivo sensitivity of human P. knowlesi isolates in Malaysian Borneo were studied, using a WHO schizont maturation assay modified to accommodate the quotidian life cycle of this parasite. The in vitro sensitivities of P. knowlesi H strain adapted from a primate infection to in vitro culture (by measuring the production of Plasmodium lactate dehydrogenase) were also examined together with some assays using Plasmodium falciparum and Plasmodium vivax. Results Plasmodium knowlesi is uniformly highly sensitive to artemisinins, variably and moderately sensitive to chloroquine, and less sensitive to mefloquine. Conclusions Taken together with reports of clinical failures when P. knowlesi is treated with mefloquine, the data suggest that caution is required if using mefloquine in prevention or treatment of P. knowlesi infections, until further studies are undertaken. [ABSTRACT FROM AUTHOR]
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- 2013
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6. Laboratory markers of disease severity in Plasmodium knowlesi infection: a case control study.
- Author
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Willmann, Matthias, Ahmed, Atique, Siner, Angela, Ing Tien Wong, Lu Chan Woon, Singh, Balbir, Krishna, Sanjeev, and Cox-Singh, Janet
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BIOMARKERS ,PLASMODIUM ,MALARIA ,MORTALITY ,SOCIAL indicators - Abstract
Background: Plasmodium knowlesi malaria causes severe disease in up to 10% of cases in Malaysian Borneo and has a mortality rate of 1 - 2%. However, laboratory markers with the ability to identify patients at risk of developing complications have not yet been assessed as they have for other species of Plasmodium. Methods: A case control study was undertaken in two hospitals in Sarikei and Sibu, Malaysian Borneo. One hundred and ten patients with uncomplicated (n = 93) and severe (n = 17) P. knowlesi malaria were studied. Standardized pigment-containing neutrophil (PCN) count, parasite density and platelet counts were determined and analysed by logistic regression and receiver operating characteristic (ROC) analysis. Results: The PCN count was strongly associated with risk of disease severity. Patients with high parasite density (≥ 35,000/μl) or with thrombocytopaenia (≤ 45,000/μl) were also more likely to develop complications (odds ratio (OR) = 9.93 and OR = 5.27, respectively). The PCN count yielded the highest area under the ROC curve (AUC) estimate among all markers of severity (AUC = 0.8561, 95% confidence interval: 0.7328, 0.9794). However, the difference between all parameter AUC estimates was not statistically significant (Wald test, p = 0.73). Conclusion: Counting PCN is labour-intensive and not superior in predicting severity over parasitaemia and platelet counts. Parasite and platelet counts are simpler tests with an acceptable degree of precision. Any adult patient diagnosed with P. knowlesi malaria and having a parasite count ≥35,000/μl or ≥1% or a platelet count ≤45,000/μl can be regarded at risk of developing complications and should be managed according to current WHO guidelines for the treatment of severe malaria. [ABSTRACT FROM AUTHOR]
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- 2012
- Full Text
- View/download PDF
7. Adaptation of in vitro cytoadherence assay to Plasmodium knowlesi field isolates.
- Author
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Fatih, Farrah A., Siner, Angela, Ahmed, Atique, Lu Chan Woon, Craig, Alister, Staines, Henry M., Singh, Balbir, Krishna, Sanjeev, and Cox-Singh, Janet
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MALARIA ,PLASMODIUM - Abstract
An abstract of the article "Adaptation of in vitro cytoadherence assay to Plasmodium knowlesi field isolates" that was presented at a conference titled "From Parasite to Prevention: Advances in the understanding of malaria" held in Edinburgh, Great Britain on October 20-22, 2010, is presented.
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- 2010
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8. Cytoadherence and virulence - the case of Plasmodium knowlesi malaria.
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Fatih FA, Siner A, Ahmed A, Woon LC, Craig AG, Singh B, Krishna S, and Cox-Singh J
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- Adolescent, Adult, CD36 Antigens metabolism, Cell Adhesion, Cells, Cultured, Endothelium, Vascular parasitology, Endothelium, Vascular physiopathology, Erythrocyte Count, Erythrocytes metabolism, Female, Humans, Malaria physiopathology, Male, Middle Aged, Plasmodium knowlesi physiology, Protein Binding, Recombinant Proteins metabolism, Schizonts physiology, Trophozoites physiology, Virulence, Erythrocytes parasitology, Intercellular Adhesion Molecule-1 metabolism, Malaria parasitology, Plasmodium knowlesi pathogenicity, Vascular Cell Adhesion Molecule-1 metabolism
- Abstract
Background: Cytoadherence of infected red blood cells to brain endothelium is causally implicated in malarial coma, one of the severe manifestations of falciparum malaria. Cytoadherence is mediated by specific binding of variant parasite antigens, expressed on the surface of infected erythrocytes, to endothelial receptors including, ICAM-1, VCAM and CD36. In fatal cases of severe falciparum malaria with coma, blood vessels in the brain are characteristically congested with infected erythrocytes. Brain sections from a fatal case of knowlesi malaria, but without coma, were similarly congested with infected erythrocytes. The objective of this study was to determine the binding phenotype of Plasmodium knowlesi infected human erythrocytes to recombinant human ICAM-1, VCAM and CD36., Methods: Five patients with PCR-confirmed P. knowlesi malaria were recruited into the study with consent between April and August 2010. Pre-treatment venous blood was washed and cultured ex vivo to increase the proportion of schizont-infected erythrocytes. Cultured blood was seeded into Petri dishes with triplicate areas coated with ICAM-1, VCAM and CD36. Following incubation at 37°C for one hour the dishes were washed and the number of infected erythrocytes bound/mm2 to PBS control areas and to recombinant human ICAM-1 VCAM and CD36 coated areas were recorded. Each assay was performed in duplicate. Assay performance was monitored with the Plasmodium falciparum clone HB3., Results: Blood samples were cultured ex vivo for up to 14.5 h (mean 11.3 ± 1.9 h) to increase the relative proportion of mature trophozoite and schizont-infected red blood cells to at least 50% (mean 65.8 ± 17.51%). Three (60%) isolates bound significantly to ICAM-1 and VCAM, one (20%) isolate bound to VCAM and none of the five bound significantly to CD36., Conclusions: Plasmodium knowlesi infected erythrocytes from human subjects bind in a specific but variable manner to the inducible endothelial receptors ICAM-1 and VCAM. Binding to the constitutively-expressed endothelial receptor CD36 was not detected. Further work will be required to define the pathological consequences of these interactions.
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- 2012
- Full Text
- View/download PDF
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