122 results on '"Ong KC"'
Search Results
2. Is It Acid or Is It Fire?
- Author
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Aubel, Amaury, primary and Ong, KC, additional
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- 2020
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3. Treatment of signs and symptoms of the common cold using EPs 7630 - results of a meta-analysis
- Author
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Schapowal, A, Dobos, G, Cramer, H, Ong, KC, Adler, M, Zimmermann, A, Brandes-Schramm, J, Lehmacher, W, Schapowal, A, Dobos, G, Cramer, H, Ong, KC, Adler, M, Zimmermann, A, Brandes-Schramm, J, and Lehmacher, W
- Abstract
© 2019 The Author(s) The efficacy of Pelargonium sidoides preparation EPs 7630 in the common cold (CC) was assessed by performing meta-analyses of randomized, double-blind, placebo-controlled trials. Mean differences (MD) and risk ratios (RR) with their 95% confidence intervals (CI) were computed. Five trials with a total of 833 patients were included. All trials had a treatment period of ten days with visits at days 3, 5, and 10 after baseline and used a ten-symptom Cold Intensity Score (CIS) as the primary outcome. Significant differences favoring EPs 7630 were observed for total CIS reduction (day 5: MD = -2·30; 95%CI = -4·12,-0·49; day 10: MD = -1·16; 95%CI = -2·22,-0·10), proportion of patients with substantial improvement (day 5: RR = 1·73; day 10: RR = 1·06) and complete remission (day 5: RR = 2·52; day 10: RR = 2·13). Subjects treated with EPs 7630 missed fewer days at work, used less paracetamol and had an improved sleep quality. No serious adverse reactions to EPs 7630 were reported. The results support the efficacy of EPs 7630 in adults with CC.
- Published
- 2019
4. The role of heat shock proteins and glucose regulated proteins in cancer
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J S J, Tan, K C, Ong Kc, and A, Rhodes
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Carcinogenesis ,Neoplasms ,Animals ,Humans ,Membrane Proteins ,HSP70 Heat-Shock Proteins ,Heat-Shock Proteins - Abstract
Heat shock proteins (HSPs) are a family of evolutionary conserved proteins that work as molecular chaperones for cellular proteins essential for cell viability and growth as well as having numerous cyto-protective roles. They are sub-categorised based on their molecular weights; amongst which some of the most extensively studied are the HSP90 and HSP70 families. Important members of these two families; Heat shock proteins 70 and heat shock proteins 90 (Hsp70/90), are the glucose regulated proteins (GRP). These stress-inducible chaperones possess distinct roles from that of the other HSPs, residing mostly in the endoplasmic reticulum and mitochondria, but they can also be translocated to other cellular locations. Their ability in adapting to stress conditions in the tumour microenvironment suggests novel functions in cancer. GRPs have been implicated in many crucial steps of carcinogenesis to include stabilization of oncogenic proteins, induction of tumour angiogenesis, inhibition of apoptosis and replicative senescence, and promotion of invasion and metastasis.
- Published
- 2016
5. Viral neuronotropism is important in the pathogenesis of Murray Valley encephalitis
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Fu, TL, Ong, KC, Tran, YD, McLean, CA, Wong, KT, Fu, TL, Ong, KC, Tran, YD, McLean, CA, and Wong, KT
- Published
- 2016
6. Protection against henipavirus infection by use of recombinant adeno-associated virus-vector vaccines.
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Ploquin A, Szécsi J, Mathieu C, Guillaume V, Barateau V, Ong KC, Wong KT, Cosset FL, Horvat B, Salvetti A, Ploquin, Aurélie, Szécsi, Judit, Mathieu, Cyrille, Guillaume, Vanessa, Barateau, Véronique, Ong, Kien Chai, Wong, Kum Thong, Cosset, François-Loïc, Horvat, Branka, and Salvetti, Anna
- Abstract
Nipah virus (NiV) and Hendra virus (HeV) are closely related, recently emerged paramyxoviruses that are capable of causing considerable morbidity and mortality in several mammalian species, including humans. Henipavirus-specific vaccines are still commercially unavailable, and development of novel antiviral strategies to prevent lethal infections due to henipaviruses is highly desirable. Here we describe the development of adeno-associated virus (AAV) vaccines expressing the NiV G protein. Characterization of these vaccines in mice demonstrated that a single intramuscular AAV injection was sufficient to induce a potent and long-lasting antibody response. Translational studies in hamsters further demonstrated that all vaccinated animals were protected against lethal challenge with NiV. In addition, this vaccine induced a cross-protective immune response that was able to protect 50% of the animals against a challenge by HeV. This study presents a new efficient vaccination strategy against henipaviruses and opens novel perspectives on the use of AAV vectors as vaccines against emergent diseases. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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7. Depressive symptoms and chronic obstructive pulmonary disease: effect on mortality, hospital readmission, symptom burden, functional status, and quality of life.
- Author
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Ng TP, Niti M, Tan WC, Cao Z, Ong KC, and Eng P
- Published
- 2007
8. Antiviral activity of povidone-iodine gargle and mouthwash solution against Enterovirus A71, Coxsackieviruses A16, A10 and A6.
- Author
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Ang WX, Tan SH, Wong KT, Perera D, Kuppusamy UR, and Ong KC
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- Humans, Vero Cells, Animals, Chlorocebus aethiops, Hand, Foot and Mouth Disease virology, Hand, Foot and Mouth Disease prevention & control, Enterovirus A, Human drug effects, Povidone-Iodine pharmacology, Antiviral Agents pharmacology, Enterovirus drug effects, Mouthwashes pharmacology
- Abstract
Hand, Foot and Mouth Disease (HFMD), a highly contagious viral disease common among infants and young children, is primarily caused by Enterovirus A71 (EV-A71) and Coxsackievirus A16 (CVA16). Nonetheless, emerging enteroviruses, such as CV-A10 and CV-A6, have also caused widespread outbreaks globally, in part due to the absence of effective antiviral therapies, and the high personto-person transmission rate. Person-to-person transmission is usually through fecal-oral or oral-oral routes, and sometimes via droplets. As the oral cavity is a primary site for early virus infection and replication, controlling oral viral shedding can mitigate the risk of transmission through this route. Povidone-iodine (PVP-I), a widely used antiseptic, has shown broad-spectrum antimicrobial properties but antiviral studies against HFMD-causing enteroviruses are limited, especially for CV-A10 and CVA6. Our study demonstrated that a 1% PVP-I solution (final concentration of 0.5%) exhibited virucidal activity against EV-A71, CV-A16, CV-A10, and CV-A6. All seven EV-A71 isolates and five CV-A16 isolates showed a significant virus titer reduction after a 1-minute incubation, while five CV-A10 isolates and two CV-A6 isolates required a 5-minute incubation to achieve this. The virucidal activity was confirmed through the EN14476:2013+A2:2019 virucidal quantitative suspension test, wherein all four viruses were completely inactivated after a 30-minute incubation with PVP-I at 37°C under both clean and dirty conditions. Western blot analysis suggested that PVP-I could affect the VP1 structural proteins of EV-A71. Our results suggest that PVP-I could serve as a potential virucidal agent to reduce the risk of person-to-person transmission of HFMD.
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- 2024
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9. A systematic review on Nipah virus: global molecular epidemiology and medical countermeasures development.
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Tan FH, Sukri A, Idris N, Ong KC, Schee JP, Tan CT, Tan SH, Wong KT, Wong LP, Tee KK, and Chang LY
- Abstract
Nipah virus (NiV) is an emerging pathogen that causes encephalitis and a high mortality rate in infected subjects. This systematic review aimed to comprehensively analyze the global epidemiology and research advancements of NiV to identify the key knowledge gaps in the literature. Articles searched using literature databases, namely PubMed, Scopus, Web of Science, and Science Direct yielded 5,596 articles. After article screening, 97 articles were included in this systematic review, comprising 41 epidemiological studies and 56 research developments on NiV. The majority of the NiV epidemiological studies were conducted in Bangladesh, reflecting the country's significant burden of NiV outbreaks. The initial NiV outbreak was identified in Malaysia in 1998, with subsequent outbreaks reported in Bangladesh, India, and the Philippines. Transmission routes vary by country, primarily through pigs in Malaysia, consumption of date palm juice in Bangladesh, and human-to-human in India. However, the availability of NiV genome sequences remains limited, particularly from Malaysia and India. Mortality rates also vary according to the country, exceeding 70% in Bangladesh, India, and the Philippines, and less than 40% in Malaysia. Understanding these differences in mortality rate among countries is crucial for informing NiV epidemiology and enhancing outbreak prevention and management strategies. In terms of research developments, the majority of studies focused on vaccine development, followed by phylogenetic analysis and antiviral research. While many vaccines and antivirals have demonstrated complete protection in animal models, only two vaccines have progressed to clinical trials. Phylogenetic analyses have revealed distinct clades between NiV Malaysia, NiV Bangladesh, and NiV India, with proposals to classify NiV India as a separate strain from NiV Bangladesh. Taken together, comprehensive OneHealth approaches integrating disease surveillance and research are imperative for future NiV studies. Expanding the dataset of NiV genome sequences, particularly from Malaysia, Bangladesh, and India will be pivotal. These research efforts are essential for advancing our understanding of NiV pathogenicity and for developing robust diagnostic assays, vaccines and therapeutics necessary for effective preparedness and response to future NiV outbreaks., Competing Interests: None declared., (© The Author(s) 2024. Published by Oxford University Press.)
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- 2024
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10. Revisiting the gene mutations and protein profile of WT 9-12: An autosomal dominant polycystic kidney disease cell line.
- Author
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Chai HC, Mahendran R, Ong KC, and Chua KH
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- Humans, Cell Line, Polymorphism, Single Nucleotide, DNA Copy Number Variations, Polycystic Kidney, Autosomal Dominant genetics, Polycystic Kidney, Autosomal Dominant metabolism, Polycystic Kidney, Autosomal Dominant pathology, Mutation, TRPP Cation Channels genetics, TRPP Cation Channels metabolism
- Abstract
WT 9-12 is one of the cell lines commonly used for autosomal dominant polycystic kidney disease (ADPKD) studies. Previous studies had described the PKD gene mutations and polycystin expression in WT 9-12. Nonetheless, the mutations occurring in other ADPKD-associated genes have not been investigated. This study aims to revisit these mutations and protein profile of WT 9-12. Whole genome sequencing verified the presence of truncation mutation at amino acid 2556 (Q2556X) in PKD1 gene of WT 9-12. Besides, those variations with high impacts included single nucleotide polymorphisms (rs8054182, rs117006360, and rs12925771) and insertions and deletions (InDels) (rs145602984 and rs55980345) in PKD1L2; InDel (rs1296698195) in PKD1L3; and copy number variations in GANAB. Protein profiles generated from the total proteins of WT 9-12 and HK-2 cells were compared using isobaric tags for relative and absolute quantitation (iTRAQ) analysis. Polycystin-1 was absent in WT 9-12. The gene ontology enrichment and reactome pathway analyses revealed that the upregulated and downregulated proteins of WT 9-12 relative to HK-2 cell line leaded to signaling pathways related to immune response and amino acid metabolism, respectively. The ADPKD-related mutations and signaling pathways associated with differentially expressed proteins in WT 9-12 may help researchers in cell line selection for their studies., (© 2024 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.)
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- 2024
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11. Obstruction in Hypertrophic Cardiomyopathy: Many Faces.
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Abbasi M, Ong KC, Newman DB, Dearani JA, Schaff HV, and Geske JB
- Subjects
- Humans, Echocardiography, Doppler methods, Echocardiography methods, Heart Ventricles diagnostic imaging, Heart Ventricles physiopathology, Cardiomyopathy, Hypertrophic complications, Cardiomyopathy, Hypertrophic diagnosis, Cardiomyopathy, Hypertrophic physiopathology, Cardiomyopathy, Hypertrophic therapy, Ventricular Outflow Obstruction etiology, Ventricular Outflow Obstruction physiopathology, Ventricular Outflow Obstruction diagnosis
- Abstract
Hypertrophic cardiomyopathy (HCM), the most common inherited cardiomyopathy, exhibits left ventricular hypertrophy not secondary to other causes, with varied phenotypic expression. Enhanced actin-myosin interaction underlies excessive myocardial contraction, frequently resulting in dynamic obstruction within the left ventricle. Left ventricular outflow tract obstruction, occurring at rest or with provocation in 75% of HCM patients, portends adverse prognosis, contributes to symptoms, and is frequently a therapeutic target. Transthoracic echocardiography plays a crucial role in the screening, initial diagnosis, management, and risk stratification of HCM. Herein, we explore echocardiographic evaluation of HCM, emphasizing Doppler assessment for obstruction. Echocardiography informs management strategies through noninvasive hemodynamic assessment, which is frequently obtained with various provocative maneuvers. Recognition of obstructive HCM phenotypes and associated anatomical abnormalities guides therapeutic decision-making. Doppler echocardiography allows monitoring of therapeutic responses, whether it be medical therapies (including cardiac myosin inhibitor therapy) or septal reduction therapies, including surgical myectomy and alcohol septal ablation. This article discusses the hemodynamics of obstruction and practical application of Doppler assessment in HCM. In addition, it provides a visual atlas of obstruction in HCM, including high-quality figures and complementary videos that illustrate the many facets of dynamic obstruction., Competing Interests: Conflicts of Interest None., (Copyright © 2024 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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12. Immunogenicity of trivalent DNA vaccine candidate encapsulated in Chitosan-TPP nanoparticles against EV-A71 and CV-A16.
- Author
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Yew JS, Ong SK, Lim HX, Tan SH, Ong KC, Wong KT, and Poh CL
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- Animals, Mice, Mice, Inbred BALB C, Female, Viral Vaccines immunology, Viral Vaccines administration & dosage, Humans, Plasmids, Interferon-gamma metabolism, Capsid Proteins immunology, Capsid Proteins chemistry, Polyphosphates, Vaccines, DNA immunology, Vaccines, DNA administration & dosage, Chitosan chemistry, Nanoparticles chemistry, Enterovirus A, Human immunology, Hand, Foot and Mouth Disease prevention & control, Hand, Foot and Mouth Disease immunology
- Abstract
Aim: To develop a trivalent DNA vaccine candidate encapsulated in Chitosan-TPP nanoparticles against hand foot and mouth disease (HFMD) and assess its immunogenicity in mice. Materials & methods: Trivalent plasmid carrying the VP1 and VP2 genes of EV-A71, VP1 gene of CV-A16 was encapsulated in Chitosan-TPP nanoparticles through ionic gelation. In vitro characterization and in vivo immunization studies of the CS-TPP-NPs (pIRES-VP121) were performed. Results: Mice administered with CS-TPP NPs (pIRES-VP121) intramuscularly were observed to have the highest IFN-γ response. Sera from mice immunized with the naked pDNA and CS-TPP-NPs (pIRES-VP121) demonstrated good viral clearance against wild-type EV-A71 and CV-A16 in RD cells. Conclusion: CS-TPP-NPs (pIRES-VP121) could serve as a prototype for future development of multivalent HFMD DNA vaccine candidates.
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- 2024
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13. Large-bore suction thrombectomy for sub-massive pulmonary embolism during second trimester of pregnancy: a case report.
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Kojodjojo P, Ng CH, Ong KC, Zuzarte-Ng R, and Chan WX
- Abstract
Background: Pregnancy-associated pulmonary embolism (PAPE) remains a significant cause of maternal mortality. Anticoagulation remains the mainstay of therapy for most pulmonary embolism (PE)-related pregnancies. However, in patients with haemodynamic compromise or those refractory to anticoagulation, management is challenging. Systemic thrombolysis is associated with a substantial risk of maternal bleeding and fetal loss. In non-pregnant PE patients, large bore catheter-directed suction thrombectomy is a proven and important technique to manage intermediate or high-risk PE, allowing for normalization of pulmonary pressures, avoidance of haemodynamic deterioration, without the need for thrombolytics, major surgery, significant blood loss, or prolonged hospitalization., Case Summary: A primigravid patient in her second trimester of pregnancy, initially diagnosed with a deep vein thrombosis refractory to heparin, presents with near-syncope due to sub-massive pulmonary embolism. The various management options including thrombolysis and surgical embolectomy etc. were discussed in detail by a multi-disciplinary PE team. She underwent large bore suction thrombectomy with complete thrombi removal, normalization of right heart strain, without the need for thrombolytics or surgery, minimal blood loss and was discharged after a short length of stay. She gave birth at term to a healthy infant., Conclusion: Suction thrombectomy is an important consideration for physicians managing high-risk PAPE and is likely to be associated with much a lower risk of maternal and fetal mortality compared to thrombolysis or surgery., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)
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- 2023
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14. Myricetin derivative-rich fraction from Syzygium malaccense prevents high-fat diet-induced obesity, glucose intolerance and oxidative stress in C57BL/6J mice.
- Author
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Nallappan D, Ong KC, Palanisamy UD, Chua KH, and Kuppusamy UR
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- Mice, Animals, Antioxidants metabolism, Diet, High-Fat adverse effects, Mice, Inbred C57BL, Obesity etiology, Obesity prevention & control, Obesity drug therapy, Oxidative Stress, Lipids, Glucose Intolerance etiology, Glucose Intolerance prevention & control, Syzygium metabolism, Insulin Resistance
- Abstract
Aim: A high-fat diet (HFD) can lead to obesity and related metabolic disorders. This study evaluated the preventive efficacy of myricetin derivative-rich fraction (MD) from Syzygium malaccense leaf extract against HFD-induced obesity, hyperglycaemia, and oxidative stress in C57BL/6J mice., Methods: HFD-fed mice were administered MD (50 mg/kg, 100 mg/kg, and 150 mg/kg) or 2 mg/kg metformin (positive control) orally for 16 weeks. Normal diet and HFD-fed control groups received normal saline., Results: MD dose of 50 mg/kg was better than 100 mg/kg and 150 mg/kg in significantly reducing weight-gain, glucose intolerance, insulin resistance, lipid accumulation in liver and kidney, and improving the serum lipid profile. Lowered protein carbonyls and lipid hydroperoxides in urine and tissue homogenates and elevated reduced glutathione, ferric reducing antioxidant power (FRAP), and Trolox equivalent antioxidant capacity (TEAC) levels in tissue homogenates indicated amelioration of oxidative stress., Conclusion: MD has therapeutic value in the prevention and management of obesity, hyperglycaemia, and oxidative stress.
- Published
- 2023
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15. The Medicinal Mushroom Ganoderma neo-japonicum (Agaricomycetes) Polysaccharide Extract Prevents Obesity-Induced Diabetes in C57BL/6J Mice.
- Author
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Subramaniam S, Ong KC, Sabaratnam V, Chua KH, and Kuppusamy UR
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- Animals, Mice, Mice, Inbred C57BL, Blood Glucose metabolism, Obesity complications, Obesity prevention & control, Insulin metabolism, Polysaccharides, Diet, High-Fat adverse effects, Lipids, Insulin Resistance, Diabetes Mellitus, Type 2 prevention & control, Agaricales metabolism, Metformin therapeutic use, Basidiomycota metabolism
- Abstract
Ganoderma neo-japonicum Imazeki is a medicinal mushroom consumed by the indigenous people in Malaysia as a remedy for diabetes. This study aims to validate the efficacy of G. neo-japonicum polysaccharides (GNJP) on obesity-induced type 2 diabetes mellitus (T2DM) in C57BL/6J mice. Mice were divided into seven groups; normal diet (ND)-control, high-fat-diet (HFD)-control, HFDGNJP-treated (50, 100, 200 mg/kg b.w.), HFDMET (metformin 50 mg/kg; positive-control) and ND-GNJP (200 mg/kg b.w.). Mice were administered GNJP or metformin orally for 10 weeks (thrice/week) and sacrificed after an oral glucose tolerance test. Body weight, serum biochemicals, liver histology, adipocyte gene expressions, glucose and insulin levels were measured. HFD caused obesity, dyslipidemia, and diabetes in the untreated groups. GNJP (50 mg/kg b.w.) supplementation prevented weight gain and liver steatosis, improved serum lipid profile and glucose tolerance and attenuated hyperglycemia and hyperinsulinemia more effectively when compared with the other treatment groups. The prevention of obesity and lipid dysregulation is plausibly attributed to the increased hormone-sensitive lipase and reduced Akt-1 and Ppary gene expressions while the up-regulation of AdipoQ (adiponectin), Prkag2 and Slc2a4 genes served to sensitize insulin and improve glucose uptake. Thus, supplementation with an appropriate dose of GNJP has promising efficacies in preventing HFD aka obesity-induced T2DM and associated metabolic abnormalities.
- Published
- 2023
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16. Neuronal infection is a major pathogenetic mechanism and cause of fatalities in human acute Nipah virus encephalitis.
- Author
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Ong KC, Ng KY, Ng CW, Tan SH, Teo WL, Karim N, Kumar S, and Wong KT
- Subjects
- Humans, Immunohistochemistry, Neurons pathology, Encephalitis pathology, Henipavirus Infections pathology
- Abstract
Objectives: Acute Nipah (NiV) encephalitis is characterised by a dual pathogenetic mechanism of neuroglial infection and ischaemia-microinfarction associated with vasculitis-induced thrombotic occlusion. We investigated the contributions of these two mechanisms in fatal cases., Materials and Methods: We analysed brain tissues (cerebrum, brainstem and cerebellum) from 15 autopsies using light microscopy, immunohistochemistry (IHC), in situ hybridisation and quantitative methods., Results: Three types of discrete plaque-like parenchymal lesions were identified: Type 1 with neuroglial IHC positivity for viral antigens and minimal or no necrosis; Type 2 with neuroglial immunopositivity and necrosis; and Type 3 with necrosis but no viral antigens. Most viral antigen/RNA-positive cells were neurons. Cerebral glial immunopositivity was rare, suggesting that microinfarction played a more important role in white matter injury. Type 1 lesions were also detected in the brainstem and cerebellum, but the differences between cerebral cortex and these two regions were not statistically significant. In the cerebral cortex, Type 1 lesions overwhelmingly predominated, and only 14% Type 1 vs 69% Type 2 lesions were associated with thrombosis. This suggests that neuronal infection as a mechanism of pathogenesis was more important than microinfarction, both in general and in Type 1 lesions in particular. Between the 'early' group (<8-day fever) and the 'late' group (≥8-day fever), there was a decrease of Type 1 and Type 2 lesions with a concomitant increase of Type 3 lesions, suggesting the latter possibly represented late-stage microinfarction and/or neuronal infection., Conclusion: Neuronal infection appears to play a more important role than vasculopathy-induced microinfarction in acute NiV encephalitis., (© 2022 British Neuropathological Society.)
- Published
- 2022
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17. Abrogating the inhibitory effects of volatile fatty acids and ammonia in overloaded food waste anaerobic digesters via the supplementation of nano-zero valent iron modified biochar.
- Author
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Lim EY, Lee JTE, Zhang L, Tian H, Ong KC, Tio ZK, Zhang J, and Tong YW
- Subjects
- Ammonia, Anaerobiosis, Bioreactors, Charcoal, Dietary Supplements, Fatty Acids, Volatile, Methane, Sewage, Iron, Refuse Disposal
- Abstract
The effects of different recovery strategies on inhibited anaerobic digestion (AD) of food waste (FW) was examined in this study, with the finding that dosing pine woodchip biochar could reverse the effect of volatile fatty acids (VFA) inhibition (mainly propionic acid) and yielded 105.55% more methane than the control. The addition of nano-zerovalent iron (nZVI) promoted the generation of VFA while causing a slight inhibition of the methanogens initially. In due time, the nZVI digester was able to recover and eventually produced 192.22% more methane compared to the control. Finally, nZVI-modified biochar was proved to be able to avoid the inhibitory effects brought about by the nanoparticles. The results indicated reduced dosage requirements as compared to using pristine pine woodchip biochar and accumulated 204.84% more methane than the control. The introduction of nZVI-biochar also promoted the growth of Methanosarcina species methanogens, which can perform direct-interspecies electron transfer. While all the recovery strategies using the additives were feasible, the results suggested that the use of modified biochar holds great potential as a significantly lower amount of amendment is required for the recovery of the inhibited AD system., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)
- Published
- 2022
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18. Immunomodulatory Effect and an Intervention of TNF Signalling Leading to Apoptotic and Cell Cycle Arrest on ORL-204 Oral Cancer Cells by Tiger Milk Mushroom, Lignosus rhinocerus .
- Author
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Yap HYY, Kong BH, Yap CSA, Ong KC, Zain RB, Tan SH, Zaini ZM, Ng ST, Tan CS, and Fung SY
- Abstract
Research Background: Tiger milk mushroom ( Lignosus rhinocerus ) is a medicinal mushroom that is geographically distributed in the region of South China, Thailand, Malaysia, Indonesia, Philippines and Papua New Guinea. Consumption of its sclerotium has been reported to treat various ailments. However, its anticancer potential towards oral cancer cell lines is yet to be determined considering the traditional method of its consumption by biting/chewing of the sclerotium., Experimental Approach: Mushroom sclerotial powder of cultivar TM02® was extracted and fractionated in a chromatographic column prior to cytotoxicity testing against a panel of human oral cancer cell lines. The capability of the identified bioactive fraction in regulating several molecules associated with its tumour necrosis factor (TNF) pathway was investigated., Results and Conclusions: 2,5-Diphenyl-2H-tetrazolium bromide (MTT) proliferation assay indicated that cell lines ORL-48 (derived from gingiva), ORL-188 (derived from the tongue) and ORL-204 (derived from buccal mucosa) were inhibited by cold water extract of L. rhinocerus sclerotia and its high-molecular-mass fraction (HMM) in varying degrees with ORL-204 being most affected. Hence, the treatment of ORL-204 with HMM mushroom extract was further investigated. HMM mushroom extract induced apoptosis and G
0 /G1 phase cell cycle arrest through caspase-3/7 cleavage. Activities of MIP2 and COX-2 were downregulated by 0.2- and 4.6-fold respectively in the HMM mushroom extract-treated ORL-204 cells., Novelty and Scientific Contribution: Using ORL-204, we showed that HMM mushroom extract may act via the TNF pathway at various network sites as a potential dietary compound for cancer prevention and natural adjunct therapeutic to conventional cancer treatment., Competing Interests: CONFLICT OF INTEREST S.T. Ng and C.S. Tan are affiliated with LiGNO Biotech Sdn. Bhd., an industry that commercialises tiger milk mushroom. The authors declare they have no financial interests.- Published
- 2022
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19. Molecular mechanism of L-SP40 peptide and in vivo efficacy against EV-A71 in neonatal mice.
- Author
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Lalani S, Tan SH, Tan KO, Lim HX, Ong KC, Wong KT, and Poh CL
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- Animals, Animals, Newborn, Mice, Mice, Inbred ICR, Peptide Fragments administration & dosage, Protein Binding physiology, Treatment Outcome, Nucleolin, Enterovirus A, Human drug effects, Enterovirus A, Human metabolism, Enterovirus Infections drug therapy, Enterovirus Infections metabolism, Peptide Fragments metabolism, Phosphoproteins metabolism, RNA-Binding Proteins metabolism
- Abstract
Aims: Enterovirus A71 (EV-A71) is an etiological agent of hand foot and mouth disease (HFMD) and has the potential to cause severe neurological infections in children. L-SP40 peptide was previously known to inhibit EV-A71 by prophylactic action. This study aimed to identify the mechanism of inhibition in Rhabdomyosarcoma (RD) cells and in vivo therapeutic potential of L-SP40 peptide in a murine model., Main Methods: A pull-down assay was performed to identify the binding partner of the L-SP40 peptide. Co-immunoprecipitation and co-localization assays with the L-SP40 peptide were employed to confirm the receptor partner in RD cells. The outcomes were validated using receptor knockdown and antibody blocking assays. The L-SP40 peptide was further evaluated for the protection of neonatal mice against lethal challenge by mouse-adapted EV-A71., Key Findings: The L-SP40 peptide was found to interact and co-localize with nucleolin, the key attachment receptor of Enteroviruses A species, as demonstrated in the pull-down, co-immunoprecipitation and co-localization assays. Knockdown of nucleolin from RD cells led to a significant reduction of 3.5 logs of viral titer of EV-A71. The L-SP40 peptide demonstrated 80% protection of neonatal mice against lethal challenge by the mouse-adapted virus with a drastic reduction in the viral loads in the blood (~4.5 logs), skeletal muscles (1.5 logs) and brain stem (1.5 logs)., Significance: L-SP40 peptide prevented severe hind limb paralysis and death in suckling mice and could serve as a potential broad-spectrum antiviral candidate to be further evaluated for safety and potency in future clinical trials against EV-A71., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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20. Natural-derived compounds and their mechanisms in potential autosomal dominant polycystic kidney disease (ADPKD) treatment.
- Author
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Mahendran R, Lim SK, Ong KC, Chua KH, and Chai HC
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- Antioxidants pharmacology, Curcumin pharmacology, Diterpenes pharmacology, Diterpenes, Kaurane pharmacology, Emodin pharmacology, Epoxy Compounds pharmacology, Estrogen Antagonists pharmacology, Humans, Hypoglycemic Agents pharmacology, Phenanthrenes pharmacology, Plant Extracts therapeutic use, Protein Kinase Inhibitors pharmacology, Resveratrol pharmacology, Chalcones pharmacology, Flavanones pharmacology, Metformin pharmacology, Plant Extracts pharmacology, Polycystic Kidney, Autosomal Dominant drug therapy, Quercetin pharmacology
- Abstract
Background: Autosomal dominant polycystic kidney disease (ADPKD) is a monogenic kidney disorder that impairs renal functions progressively leading to kidney failure. The disease affects between 1:400 and 1:1000 ratio of the people worldwide. It is caused by the mutated PKD1 and PKD2 genes which encode for the defective polycystins. Polycystins mimic the receptor protein or protein channel and mediate aberrant cell signaling that causes cystic development in the renal parenchyma. The cystic development is driven by the increased cyclic AMP stimulating fluid secretion and infinite cell growth. In recent years, natural product-derived small molecules or drugs targeting specific signaling pathways have caught attention in the drug discovery discipline. The advantages of natural products over synthetic drugs enthusiast researchers to utilize the medicinal benefits in various diseases including ADPKD., Conclusion: Overall, this review discusses some of the previously studied and reported natural products and their mechanisms of action which may potentially be redirected into ADPKD., (© 2021. Japanese Society of Nephrology.)
- Published
- 2021
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21. In vitro antiviral activity of medicinal mushroom Ganoderma neo-japonicum Imazeki against enteroviruses that caused hand, foot and mouth disease.
- Author
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Ang WX, Sarasvathy S, Kuppusamy UR, Sabaratnam V, Tan SH, Wong KT, Perera D, and Ong KC
- Subjects
- Cells, Cultured, China, Enterovirus Infections, Fibroblasts virology, Hand, Foot and Mouth Disease, Humans, Antiviral Agents pharmacology, Biological Products pharmacology, Enterovirus A, Human drug effects, Ganoderma chemistry
- Abstract
Hand, foot and mouth disease (HFMD) is a highly contagious viral disease that predominantly affects children younger than 5 years old. HFMD is primarily caused by enterovirus A71 (EVA71) and coxsackievirus A16 (CV-A16). However, coxsackievirus A10 (CV-A10) and coxsackievirus A6 (CV-A6) are being increasingly reported as the predominant causative of HFMD outbreaks worldwide since the past decade. To date, there are still no licensed multivalent vaccines or antiviral drugs targeting enteroviruses that cause HFMD, despite HFMD outbreaks are still being frequently reported, especially in Asia-Pacific countries. The high rate of transmission, morbidity and potential neurological complications of HFMD is indeed making the development of broad-spectrum antiviral drugs/agents against these enteroviruses a compelling need. In this study, we have investigated the in vitro antiviral effect of 4 Ganoderma neo-japonicum Imazeki (GNJI) crude extracts (S1-S4) against EV-A71, CV-A16, CV-A10 and CV-A6. GNJI is a medicinal mushroom that can be found growing saprophytically on decaying bamboo clumps in Malaysian forests. The antiviral effects of this medicinal mushroom were determined using cytopathic inhibition and virus titration assays. The S2 (1.25 mg/ml) hot aqueous extract demonstrated the highest broad-spectrum antiviral activity against all tested enteroviruses in human primary oral fibroblast cells. Replication of EV-A71, CV-A16 and CVA10 were effectively inhibited at 2 hours post-infection (hpi) to 72 hpi, except for CV-A6 which was only at 2 hpi. S2 also has virucidal activity against EV-A71. Polysaccharides isolated and purified from crude hot aqueous extract demonstrated similar antiviral activity as S2, suggesting that polysaccharides could be one of the active compounds responsible for the antiviral activity shown by S2. To our knowledge, this study demonstrates for the first time the ability of GNJI to inhibit enterovirus infection and replication. Thus, GNJI is potential to be further developed as an antiviral agent against enteroviruses that caused HFMD.
- Published
- 2021
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22. Amelioration of high-fat diet-induced obesity and its associated complications by a myricetin derivative-rich fraction from Syzygium malaccense in C57BL/6J mice.
- Author
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Nallappan D, Chua KH, Ong KC, Chong CW, Teh CSJ, Palanisamy UD, and Kuppusamy UR
- Subjects
- Animals, Antioxidants, Blood Glucose, Dyslipidemias, Energy Intake, Flavonoids chemistry, Gastrointestinal Microbiome drug effects, Glutathione metabolism, Insulin blood, Insulin Resistance, Male, Metabolic Diseases, Mice, Mice, Inbred C57BL, Obesity chemically induced, Thermogenesis, Diet, High-Fat adverse effects, Flavonoids pharmacology, Obesity metabolism, Syzygium chemistry
- Abstract
Obesity is a driving factor in the onset of metabolic disorders. This study aims to investigate the effects of the myricetin derivative-rich fraction (MD) from Syzygium malaccense leaf extract on high-fat diet (HFD)-induced obesity and its associated complications and its influence on uncoupling protein-1 (UCP-1) and gut microbiota in C57BL/6J mice. Mice were randomly assigned into four groups (n = 6) and given a normal diet (ND) or high-fat diet (HFD) for 10 weeks to induce obesity. The HFD groups (continued with HFD) were administered 50 mg kg-1 MD (treatment), 50 mg kg-1 metformin (positive control) and normal saline (HFD and ND controls) daily for four weeks via oral gavage. The ten-week HFD-feeding resulted in hyperglycemia and elevated urinary oxidative indices. The subsequent MD administration caused significant weight reduction without appetite suppression and amelioration of insulin resistance, steatosis and dyslipidemia. Besides, MD significantly reduced lipid hydroperoxides and protein carbonyls in tissue homogenates and urine and elevated Trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP) and reduced glutathione (GSH) and thus, alleviated oxidative stress. The weight reduction was correlated with downregulation of inflammatory markers and the increased UCP-1 level, suggesting weight loss plausibly through thermogenesis. The Akkermansia genus (reflects improved metabolic status) in the HFD50 group was more abundant than that in the HFD group while the non-enzymatic antioxidant markers were strongly associated with UCP-1. In conclusion, MD ameliorates obesity and its related complications possibly via the upregulation of UCP-1 and increased abundance of Akkermansia genus and is promising as a therapeutic agent in the treatment of obesity and its associated metabolic disorders.
- Published
- 2021
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23. Vaccine candidates generated by codon and codon pair deoptimization of enterovirus A71 protect against lethal challenge in mice.
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Lee MHP, Tan CW, Tee HK, Ong KC, Sam IC, and Chan YF
- Subjects
- Animals, Codon, Mice, Mice, Inbred ICR, Enterovirus, Enterovirus A, Human genetics, Enterovirus Infections prevention & control, Hand, Foot and Mouth Disease prevention & control, Viral Vaccines genetics
- Abstract
Enterovirus A71 (EV-A71) causes hand, foot and mouth disease (HFMD) in young children. It is associated with severe neurological complications and death. This study aims to develop a live-attenuated vaccine by codon deoptimization (CD) and codon-pair deoptimization (CPD) of EV-A71. CD is generated by introducing the least preferred codons for amino acids while CPD increases the presence of underrepresented codon pairs in the specific genes. CD and CPD chimeras were generated by synonymous mutations at the VP2, VP3, VP1 and 2A gene regions, designated as XYZ. All twelve deoptimized viruses were viable with similar replication kinetics, but the plaque sizes were inversely proportional to the level of deoptimization. All the deoptimized viruses showed attenuated growth in vitro with reduced viral protein expression at 48 h and lower viral RNA at 39 °C. Six-week-old ICR mice were immunized intraperitoneally with selected CD and CPD X and XY vaccine candidates covering the VP2-VP3 and VP2-VP3-VP1 genes, respectively. All vaccine candidates elicited high anti-EV-A71 IgG levels similar to wild-type (WT) EV-A71. The CD X and CPD X vaccines produced robust neutralizing antibodies but not the CD XY and CPD XY. On lethal challenge, offspring of mice immunized with WT, CD X and CPD X were fully protected, but the CD XY- and CPD XY-vaccinated mice had delayed symptoms and eventually died. Similarly, active immunization of 1-day-old suckling mice with CD X, CPD X and CD XY vaccine candidates provided complete immune protection but CPD XY only protected 40% of the challenged mice. Histology of the muscles from CD X- and CPD X-vaccinated mice showed minimal pathology compared to extensive inflammation in the post-challenged mock-vaccinated mice. Overall, we demonstrated that the CD X and CPD X elicited good neutralizing antibodies, conferred immune protection and are promising live-attenuated vaccine candidates for EV-A71., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2021
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24. A novel orally infected hamster model for Coxsackievirus A16 hand-foot-and-mouth disease and encephalomyelitis.
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Hooi YT, Ong KC, Tan SH, Perera D, and Wong KT
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- Animals, Antigens, Viral metabolism, Child, Encephalomyelitis diagnosis, Enterovirus A, Human genetics, Enterovirus A, Human metabolism, Feces virology, Hand, Foot and Mouth Disease diagnosis, Humans, Immunohistochemistry, In Situ Hybridization, Mouth pathology, Mouth Mucosa pathology, Mouth Mucosa virology, RNA, Viral genetics, Sensitivity and Specificity, Cricetinae virology, Disease Models, Animal, Encephalomyelitis virology, Enterovirus A, Human physiology, Hand, Foot and Mouth Disease virology, Mouth virology
- Abstract
Coxsackievirus A16 (CV-A16) is one of the major causes of mild and self-limiting hand-foot-and-mouth disease (HFMD) in young children, which may occasionally leads to serious neurological complications. In this study, we had developed a novel, consistent, orally infected CV-A16 HFMD hamster model with encephalomyelitis. Four groups of 7-day-old hamsters in a kinetic study were orally infected with mouse-adapted CV-A16 strains and sacrificed at 1-4 days post infection (dpi), respectively. Tissues were studied by light microscopy, immunohistochemistry to detect viral antigens, in situ hybridization to detect viral RNA, and by viral titration. In a separate transmission experiment, orally infected index hamsters were housed together with contact hamsters to investigate oral and fecal viral shedding by virus culture and reverse transcription polymerase chain reaction (RT-PCR). At severe infection/death endpoints, index and contact hamster infection were also histopathologically analyzed. In the kinetic study, infected hamsters developed signs of infection at 4 dpi. Viral antigens/RNA were localized to brainstem (medulla/pons; reticular formation and motor trigeminal nucleus) and spinal cord anterior horn neurons, oral squamous epithelia and epidermis from 3 to 4 dpi. Salivary and lacrimal glands, myocardium, brown adipose tissue, intestinal smooth muscle, and skeletal muscle infection was also demonstrated. Viremia at 1 dpi and increasing viral titers in various tissues were observed from 2 dpi. In the transmission study, all contact hamsters developed disease 3-5 days later than index hamsters, but demonstrated similar histopathological findings at endpoint. Viral culture and RT-PCR positive oral washes and feces confirmed viral shedding. Our hamster model, orally infected by the natural route for human infection, confirmed CV-A16 neurotropism and demonstrated squamous epitheliotropism reminiscent of HFMD, attributes not found in other animal models. It should be useful to investigate neuropathogenesis, model person-to-person transmission, and for testing antiviral drugs and vaccines.
- Published
- 2020
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25. Coxsackievirus A16 in a 1-Day-Old Mouse Model of Central Nervous System Infection Shows Lower Neurovirulence than Enterovirus A71.
- Author
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Hooi YT, Ong KC, Tan SH, Perera D, and Wong KT
- Subjects
- Animals, Animals, Newborn, Disease Models, Animal, Mice, Virulence, Central Nervous System Infections virology, Coxsackievirus Infections virology, Enterovirus A, Human pathogenicity
- Abstract
Coxsackievirus A16 (CV-A16) and enterovirus A71 (EV-A71) are the major causes of hand, foot and mouth disease in young children. Although less so with CV-A16, both viruses are associated with serious neurological syndromes, but the differences between their central nervous system infections remain unclear. We conducted a comparative infection study using clinically-isolated CV-A16 and EV-A71 strains in a 1-day-old mouse model to better understand the neuropathology and neurovirulence of the viruses. New serotype-specific probes for in situ hybridization were developed and validated to detect CV-A16 and EV-A71 RNA in infected tissues. Demonstration of CV-A16 virus antigens/RNA, mainly in the brainstem and spinal cord neurons, confirmed neurovirulence, but showed lower densities than in EV-A71 infected animals. A higher lethal dose
50 for CV-A16 suggested that CV-A16 is less neurovirulent. Focal virus antigens/RNA in the anterior horn white matter and adjacent efferent motor nerves suggested that neuroinvasion is possibly via retrograde axonal transport in peripheral motor nerves., (Copyright © 2020 Elsevier Ltd. All rights reserved.)- Published
- 2020
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26. Diabetic foot infection and surgical treatment in a secondary health care centre in Malaysia.
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Ng BW, Muhammad Firdaus A, Mohd Syafiqq Al Hakim HR, Nur Sa'idah MS, Loi KW, Ong KC, and Abdul Muttalib AW
- Subjects
- Adolescent, Adult, Aged, Child, Female, Humans, Length of Stay trends, Malaysia, Male, Middle Aged, Reoperation trends, Retrospective Studies, Surgical Procedures, Operative trends, Young Adult, Diabetic Foot microbiology, Diabetic Foot surgery, Tertiary Care Centers
- Abstract
Introduction: Diabetic foot infection is often associated with high morbidity, disability and poor quality of life. This study focuses on the demography, the number of repetitive surgery and length of stay in hospital of patients with diabetic foot infection., Method: This is a retrospective observational study. Patients who were admitted to the Orthopaedic ward of Hospital Segamat (HS), Johor, Malaysia from January 2016 to December 2018 and required surgical intervention were included in the study. Data was collected from the computer system of HS and medical notes of patients., Results: 35.6% of the total orthopaedic emergency surgeries performed were for patients with diabetic foot infection, 25% of the surgical procedures performed were major amputations of lower limb and 40% of the patients with diabetic foot infection required more than one surgical operation., Discussion: The demographics of the patients is consistent with the demographics of Malaysia where majority of them are Malays followed by Chinese, Indians and others. Despite being only 10% of total admission to the department, this group of patients contributed to 35.6% of the total emergency surgeries performed. The amputation rate in the centre is comparable to the other local studies. The average length of stay in hospital was found to be shorter compared to overseas due to different rehabilitation protocols.
- Published
- 2020
27. Japanese Encephalitis Virus Infects the Thalamus Early Followed by Sensory-Associated Cortex and Other Parts of the Central and Peripheral Nervous Systems.
- Author
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Fu TL, Ong KC, Tan SH, and Wong KT
- Subjects
- Animals, Brain pathology, Cells, Cultured, Central Nervous System Infections pathology, Central Nervous System Infections virology, Disease Models, Animal, Encephalitis Virus, Japanese isolation & purification, Mice, Inbred ICR, Neurons pathology, Peripheral Nervous System pathology, Piriform Cortex pathology, Piriform Cortex virology, Somatosensory Cortex pathology, Somatosensory Cortex virology, Thalamus pathology, Brain virology, Encephalitis Virus, Japanese physiology, Neurons virology, Peripheral Nervous System virology, Thalamus virology
- Abstract
Japanese encephalitis (JE) is a known CNS viral infection that often involves the thalamus early. To investigate the possible role of sensory peripheral nervous system (PNS) in early neuroinvasion, we developed a left hindlimb footpad-inoculation mouse model to recapitulate human infection by a mosquito bite. A 1-5 days postinfection (dpi) study, demonstrated focal viral antigens/RNA in contralateral thalamic neurons at 3 dpi in 50% of the animals. From 4 to 5 dpi, gradual increase in viral antigens/RNA was observed in bilateral thalami, somatosensory, and piriform cortices, and then the entire CNS. Infection of neuronal bodies and adjacent nerves in dorsal root ganglia (DRGs), trigeminal ganglia, and autonomic ganglia (intestine, etc.) was also observed from 5 dpi. Infection of explant organotypic whole brain slice cultures demonstrated no viral predilection for the thalamus, while DRG and intestinal ganglia organotypic cultures confirmed sensory and autonomic ganglia susceptibility to infection, respectively. Early thalamus and sensory-associated cortex involvement suggest an important role for sensory pathways in neuroinvasion. Our results suggest that JE virus neuronotropism is much more extensive than previously known, and that the sensory PNS and autonomic system are susceptible to infection., (© 2019 American Association of Neuropathologists, Inc. All rights reserved.)
- Published
- 2019
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28. Polymorphisms in the androgen receptor CAG repeat sequence are related to tumour stage but not to ERG or androgen receptor expression in Malaysian men with prostate cancer.
- Author
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Tan JSJ, Ong KC, Ong DBL, Wu YS, Razack A, Kuppusamy S, Lim J, and Rhodes A
- Subjects
- Aged, Aged, 80 and over, Androgens metabolism, Gene Expression genetics, Humans, Male, Middle Aged, Prostatic Hyperplasia genetics, Transcriptional Regulator ERG genetics, Trinucleotide Repeats genetics, Prostatic Neoplasms genetics, Receptors, Androgen genetics
- Abstract
Introduction: Polymorphic expression of a CAG repeat sequence in the androgen receptor (AR) gene may influence the activity of the AR and the occurrence of prostate cancer and the TMPRSS2-ERG fusion event. Furthermore, this polymorphism may be responsible for the ethnic variation observed in prostate cancer occurrence and expression of the ERG oncogene. We investigate the expression of AR and ERG in the biopsies of Malaysian men with prostate cancer and in the same patients relate this to the length of the CAG repeat sequence in their AR gene., Materials and Methods: From a PSA screening initiative, 161 men were shown to have elevated PSA levels in their blood and underwent prostatic tissue biopsy. DNA was extracted from the blood, and exon 1 of the AR gene amplified by PCR and sequenced. The number of CAG repeat sequences were counted and compared to the immunohistochemical expression of ERG and AR in the matched tumour biopsies., Results: Of men with elevated PSA, 89 were diagnosed with prostate cancer, and 72 with benign prostatic hyperplasia (BPH). There was no significant difference in the length of the CAG repeat in men with prostate cancer and BPH. The CAG repeat length was not associated with; age, PSA or tumour grade, though a longer CAG repeat was associated with tumour stage. ERG and AR were expressed in 36% and 86% of the cancers, respectively. There was no significant association between CAG repeat length and ERG or AR expression. However, there was a significant inverse relationship between ERG and AR expression. In addition, a significantly great proportion of Indian men had ERG positive tumours, compared to men of Malay or Chinese descent., Conclusions: CAG repeat length is not associated with prostate cancer or expression of ERG or AR. However, ERG appears to be more common in the prostate cancers of Malaysian Indian men than in the prostate cancers of other Malaysian ethnicities and its expression in this study was inversely related to AR expression.
- Published
- 2019
29. Necrotising fasciitis caused by aeromonas sobria: Not just a simple catfish sting.
- Author
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Ng BW, Ong KC, Ahmad-Azraf A, and Abdul-Muttalib AW
- Subjects
- Animals, Catfishes, Diagnosis, Differential, Fasciitis, Necrotizing diagnosis, Fasciitis, Necrotizing surgery, Gram-Negative Bacterial Infections diagnosis, Gram-Negative Bacterial Infections surgery, Humans, Male, Middle Aged, Rare Diseases, Aeromonas isolation & purification, Fasciitis, Necrotizing microbiology, Gram-Negative Bacterial Infections microbiology
- Abstract
Necrotising fasciitis is a life-threatening infection of the soft tissue which can be caused by different microorganisms, but infection caused by Aeromonas spp. or Vibrio spp. is frequently associated with higher mortality rate. Necrotising fasciitis progresses rapidly and often need aggressive surgical intervention. We present a rare case of necrotising fasciitis cause by Aeromonas sobria which mortality was successfully prevented by swift diagnosis and aggressive surgery.
- Published
- 2019
30. Treatment of signs and symptoms of the common cold using EPs 7630 - results of a meta-analysis.
- Author
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Schapowal A, Dobos G, Cramer H, Ong KC, Adler M, Zimmermann A, Brandes-Schramm J, and Lehmacher W
- Abstract
The efficacy of Pelargonium sidoides preparation EPs 7630 in the common cold (CC) was assessed by performing meta-analyses of randomized, double-blind, placebo-controlled trials. Mean differences (MD) and risk ratios (RR) with their 95% confidence intervals (CI) were computed. Five trials with a total of 833 patients were included. All trials had a treatment period of ten days with visits at days 3, 5, and 10 after baseline and used a ten-symptom Cold Intensity Score (CIS) as the primary outcome. Significant differences favoring EPs 7630 were observed for total CIS reduction (day 5: MD = -2·30; 95%CI = -4·12,-0·49; day 10: MD = -1·16; 95%CI = -2·22,-0·10), proportion of patients with substantial improvement (day 5: RR = 1·73; day 10: RR = 1·06) and complete remission (day 5: RR = 2·52; day 10: RR = 2·13). Subjects treated with EPs 7630 missed fewer days at work, used less paracetamol and had an improved sleep quality. No serious adverse reactions to EPs 7630 were reported. The results support the efficacy of EPs 7630 in adults with CC., (© 2019 The Author(s).)
- Published
- 2019
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31. Electrostatic interactions at the five-fold axis alter heparin-binding phenotype and drive enterovirus A71 virulence in mice.
- Author
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Tee HK, Tan CW, Yogarajah T, Lee MHP, Chai HJ, Hanapi NA, Yusof SR, Ong KC, Lee VS, Sam IC, and Chan YF
- Subjects
- Animals, Brain metabolism, Brain pathology, Capsid Proteins chemistry, Capsid Proteins genetics, Enterovirus chemistry, Enterovirus Infections epidemiology, Enterovirus Infections metabolism, Heparin chemistry, Host-Pathogen Interactions, Humans, Mice, Mice, Inbred ICR, Mutation, Phenotype, Static Electricity, Tumor Cells, Cultured, Virulence, Virulence Factors chemistry, Virulence Factors genetics, Virus Replication, Brain virology, Capsid Proteins metabolism, Enterovirus genetics, Enterovirus A, Human genetics, Enterovirus Infections virology, Heparin metabolism, Virulence Factors metabolism
- Abstract
Enterovirus A71 (EV-A71) causes hand, foot and mouth disease epidemics with neurological complications and fatalities. However, the neuropathogenesis of EV-A71 remains poorly understood. In mice, adaptation and virulence determinants have been mapped to mutations at VP2-149, VP1-145 and VP1-244. We investigate how these amino acids alter heparin-binding phenotype and shapes EV-A71 virulence in one-day old mice. We constructed six viruses with varying residues at VP1-98, VP1-145 (which are both heparin-binding determinants) and VP2-149 (based on the wild type 149K/98E/145Q, termed KEQ) to generate KKQ, KKE, KEE, IEE and IEQ variants. We demonstrated that the weak heparin-binder IEE was highly lethal in mice. The initially strong heparin-binding IEQ variant acquired an additional mutation VP1-K244E, which confers weak heparin-binding phenotype resulting in elevated viremia and increased virus antigens in mice brain, with subsequent high virulence. IEE and IEQ-244E variants inoculated into mice disseminated efficiently and displayed high viremia. Increasing polymerase fidelity and impairing recombination of IEQ attenuated the virulence, suggesting the importance of population diversity in EV-A71 pathogenesis in vivo. Combining in silico docking and deep sequencing approaches, we inferred that virus population diversity is shaped by electrostatic interactions at the five-fold axis of the virus surface. Electrostatic surface charges facilitate virus adaptation by generating poor heparin-binding variants for better in vivo dissemination in mice, likely due to reduced adsorption to heparin-rich peripheral tissues, which ultimately results in increased neurovirulence. The dynamic switching between heparin-binding and weak heparin-binding phenotype in vivo explained the neurovirulence of EV-A71., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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32. Development of live attenuated Enterovirus 71 vaccine strains that confer protection against lethal challenge in mice.
- Author
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Yee PTI, Tan SH, Ong KC, Tan KO, Wong KT, Hassan SS, and Poh CL
- Subjects
- Animals, Antigens, Viral analysis, Antigens, Viral immunology, Cell Line, Tumor, Disease Models, Animal, Enterovirus A, Human genetics, Enterovirus A, Human isolation & purification, Genome, Viral genetics, Hand, Foot and Mouth Disease diagnosis, Hand, Foot and Mouth Disease immunology, Hand, Foot and Mouth Disease virology, Humans, Immunity, Cellular, Immunity, Humoral, Immunogenicity, Vaccine, Mice, MicroRNAs genetics, Mutation, RNA, Viral isolation & purification, Vaccines, Attenuated administration & dosage, Vaccines, Attenuated genetics, Vaccines, Attenuated immunology, Viral Load, Viral Vaccines genetics, Viral Vaccines immunology, Virus Replication immunology, Enterovirus A, Human immunology, Hand, Foot and Mouth Disease prevention & control, Viral Vaccines administration & dosage, Virulence genetics
- Abstract
Besides causing mild hand, foot and mouth infections, Enterovirus A71 (EV-A71) is associated with neurological complications and fatality. With concerns about rising EV-A71 virulence, there is an urgency for more effective vaccines. The live attenuated vaccine (LAV) is a more valuable vaccine as it can elicit both humoral and cellular immune responses. A miRNA-based vaccine strain (pIY) carrying let-7a and miR-124a target genes in the EV-A71 genome which has a partial deletion in the 5'NTR (∆11 bp) and G64R mutation (3D
p °l ) was designed. The viral RNA copy number and viral titers of the pIY strain were significantly lower in SHSY-5Y cells that expressed both let-7a and miR-124a. Inhibition of the cognate miRNAs expressed in RD and SHSY-5Y cells demonstrated de-repression of viral mRNA translation. A previously constructed multiply mutated strain, MMS and the pIY vaccine strain were assessed in their ability to protect 4-week old mice from hind limb paralysis. The MMS showed higher amounts of IFN-γ ex vivo than the pIY vaccine strain. There was absence of EV-A71 antigen in the skeletal muscles and spinal cord micrographs of mice vaccinated with the MMS and pIY strains. The MMS and pIY strains are promising LAV candidates developed against severe EV-A71 infections.- Published
- 2019
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33. Neuronal transcriptomic responses to Japanese encephalitis virus infection with a special focus on chemokine CXCL11 and pattern recognition receptors RIG-1 and MDA5.
- Author
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Yu SP, Ong KC, Perera D, and Wong KT
- Subjects
- Antigens, Viral metabolism, Cell Line, Chemokine CXCL11 metabolism, Encephalitis Virus, Japanese immunology, Gene Expression Profiling, Humans, Oligonucleotide Array Sequence Analysis, Receptors, Immunologic, Up-Regulation, Chemokine CXCL11 genetics, DEAD Box Protein 58 genetics, Encephalitis Virus, Japanese physiology, Encephalitis, Japanese virology, Interferon-Induced Helicase, IFIH1 genetics, Neurons virology
- Abstract
Japanese encephalitis virus (JEV) causes central nervous system neuronal injury and inflammation. A clear understanding of neuronal responses to JEV infection remains elusive. Using the Affymetrix array to investigate the transcriptome of infected SK-N-MC cells, 1316 and 2737 dysregulated genes (≥ 2/-2 fold change, P < 0.05) were found at 48 hours post-infection (hpi) and 60 hpi, respectively. The genes were mainly involved in anti-microbial responses, cell signalling, cellular function and maintenance, and cell death and survival. Among the most highly upregulated genes (≥ 10 folds, P < 0.05) were chemokines CCL5, CXCL11, IL8 and CXCL10. The upregulation and expression of CXCL11 were confirmed by qRT-PCR and immunofluorescence. Pathogen recognition receptors retinoic acid-inducible gene-1 (RIG-1) and melanoma differentiation-associated protein 5 (MDA5) were also upregulated. Our results strongly suggest that neuronal cells play a significant role in immunity against JEV. CXCL11, RIG-1 and MDA5 and other cytokines may be important in neuropathogenesis., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2019
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34. Heterogenous expression of ERG oncoprotein in Malaysian men with adenocarcinoma of the prostate.
- Author
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Tan JSJ, Ong KC, Ong DBL, Razack A, Lim J, Yunus R, Sundram M, and Rhodes A
- Subjects
- Aged, Humans, Malaysia, Male, Middle Aged, Transcriptional Regulator ERG analysis, Transcriptional Regulator ERG biosynthesis, Adenocarcinoma pathology, Biomarkers, Tumor analysis, Prostatic Neoplasms pathology
- Abstract
Introduction: Prostate cancer is a heterogenous disease and the mechanisms that drive it to behave differently are not well understood. Tumour expression of the ERG oncogene occurs in the majority of patients with prostate cancer in Western studies. This is considered to be oncogenic as ERG acts as a transcription factor to regulate genes involved in tumour proliferation and invasion. In this study we investigated expression of ERG in Malaysian men with prostate cancer., Methods: Tissues were collected from 80 patients with clinically detected prostate cancer and treated with radical prostatectomy. Cases were tested for ERG by immunohistochemistry using the mouse monoclonal antibody EP111. All blocks on 48 cases were tested in order to determine the extent of heterogeneity of ERG expression within individual cases. ERG expression was analysed in relation to patient age, ethnicity and tumour stage and grade., Results: Forty-six percent of cases were ERG positive. There was no significant association between ERG and tumour grade or stage. Sixty-nine percent of Indian patients had ERG positive tumours; this was significantly higher (p=0.031) than for Chinese (40%) and Malay (44%) patients. Heterogeneity of ERG expression, in which both positive and negative clones were present, was seen in 35% of evaluated cases. Evaluation by tumour foci showed younger patients had more ERG positive tumour foci than older patients (p=0.01). Indian patients were more likely to have the majority of tumour foci with ERG staining positively, compared to either Chinese or Malay patients (P <0.01)., Conclusion: In this study, tumour expression of ERG was more likely to occur in patients of Indian ethnicity.
- Published
- 2018
35. Identification and characterization of neutralization epitopes at VP2 and VP1 of enterovirus A71.
- Author
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NikNadia N, Tan CW, Ong KC, Sam IC, and Chan YF
- Subjects
- Adult, Animals, Capsid Proteins genetics, Epitope Mapping, Epitopes genetics, Humans, Immunodominant Epitopes immunology, Mice, Mutation, Missense, Antibodies, Neutralizing immunology, Antibodies, Viral immunology, Capsid Proteins immunology, Enterovirus A, Human immunology, Epitopes immunology
- Abstract
Enterovirus A71 (EV-A71) neutralization escape mutants were generated with monoclonal antibody MAB979 (Millipore). The VP2-T141I and VP1-D14N substitutions were identified. Using reverse genetics, infectious clones with these substitutions were constructed and tested by neutralization assay with immune sera from mice and humans. The N-terminus VP1-14 is more important than EF loop VP2-141 in acute human infection, mainly because it recognised IgM present in acute infection. The N-terminus VP1 could be a useful target for diagnostics and therapeutic antibodies in acute infection., (© 2018 Wiley Periodicals, Inc.)
- Published
- 2018
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36. RSAD2 and AIM2 Modulate Coxsackievirus A16 and Enterovirus A71 Replication in Neuronal Cells in Different Ways That May Be Associated with Their 5' Nontranslated Regions.
- Author
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Yogarajah T, Ong KC, Perera D, and Wong KT
- Subjects
- Cell Line, Tumor, DNA-Binding Proteins genetics, Gene Knockdown Techniques, Humans, Neurons pathology, Neurons virology, Oxidoreductases Acting on CH-CH Group Donors, Proteins genetics, 5' Untranslated Regions, DNA-Binding Proteins metabolism, Enterovirus A, Human physiology, Enterovirus C, Human physiology, Neurons metabolism, Proteins metabolism, Virus Replication physiology
- Abstract
Coxsackievirus A16 (CV-A16) and enterovirus A71 (EV-A71) are closely related enteroviruses that cause the same hand, foot, and mouth disease (HFMD), but neurological complications occur only very rarely in CV-A16 compared to EV-A71 infections. To elucidate host responses that may be able to explain these differences, we performed transcriptomic analysis and real-time quantitative PCR (RT-qPCR) in CV-A16-infected neuroblastoma cells (SK-N-SH), and the results showed that the radical S -adenosylmethionine domain containing 2 (RSAD2) was the highest upregulated gene in the antimicrobial pathway. Increased RSAD2 expression was correlated with reduced viral replication, while RSAD2 knockdown cells were correlated with increased replication. EV-A71 replication showed no apparent correlation to RSAD2 expressions. Absent in melanoma 2 (AIM2), which is associated with pyroptotic cell death, was upregulated in EV-A71-infected neurons but not in CV-A16 infection, suggesting that the AIM2 inflammasome played a significant role in suppressing EV-A71 replication. Chimeric viruses derived from CV-A16 and EV-A71 but containing swapped 5' nontranslated regions (5' NTRs) showed that RSAD2 expression/viral replication and AIM2 expression/viral replication patterns may be linked to the 5' NTRs of parental viruses. Differences in secondary structure of internal ribosomal entry sites within the 5' NTR may be responsible for these findings. Overall, our results suggest that CV-A16 and EV-A71 elicit different host responses to infection, which may help explain the apparent lower incidence of CV-A16-associated neurovirulence in HFMD outbreaks compared to EV-A71 infection. IMPORTANCE Although coxsackievirus A16 (CV-A16) and enterovirus A17 (EV-A71) both cause hand, foot, and mouth disease, EV-A71 has emerged as a leading cause of nonpolio, enteroviral fatal encephalomyelitis among young children. The significance of our research is in the identification of the possible differing and novel mechanisms of CV-A16 and EV-A71 inhibition in neuronal cells that may impact viral neuropathogenesis. We further showed that viral 5' NTRs may play significant roles in eliciting different host response mechanisms., (Copyright © 2018 American Society for Microbiology.)
- Published
- 2018
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37. Effect of Body Mass Index on Exercise Capacity in Patients With Hypertrophic Cardiomyopathy.
- Author
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Larsen CM, Ball CA, Hebl VB, Ong KC, Siontis KC, Olson TP, Ackerman MJ, Ommen SR, Allison TG, and Geske JB
- Subjects
- Adult, Aged, Cardiac Output, Cardiomyopathy, Hypertrophic complications, Echocardiography, Exercise Test, Female, Heart Rate, Humans, Male, Middle Aged, Retrospective Studies, Body Mass Index, Cardiomyopathy, Hypertrophic physiopathology, Exercise Tolerance physiology
- Abstract
The objective of this study was to evaluate the relation between body mass index (BMI), exercise capacity, and symptoms in patients with hypertrophic cardiomyopathy (HC) and to utilize results of cardiopulmonary exercise tests (CPX) and transthoracic echocardiograms to understand the mechanism(s) of reduced exercise capacity across body mass index groups. Over a 6-year period, 510 consecutive patients with HC seen at a tertiary referral center underwent (CPX) and a transthoracic echocardiogram. Increasing BMI was associated with decreased exercise capacity as assessed by peak VO
2 (ml/kg/min). However, the prevalence of cardiac impairment did not vary by BMI group. In conclusion, these findings suggest that in some patients with hypertrophic cardiomyopathy, cardiac impairment is not the primary cause of exercise limitation and weight loss may result in improved exercise capacity., (Copyright © 2017 Elsevier Inc. All rights reserved.)- Published
- 2018
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38. Women with hypertrophic cardiomyopathy have worse survival.
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Geske JB, Ong KC, Siontis KC, Hebl VB, Ackerman MJ, Hodge DO, Miller VM, Nishimura RA, Oh JK, Schaff HV, Gersh BJ, and Ommen SR
- Subjects
- Ablation Techniques mortality, Ablation Techniques statistics & numerical data, Cardiomyopathy, Hypertrophic therapy, Echocardiography, Female, Humans, Kaplan-Meier Estimate, Middle Aged, Minnesota epidemiology, Proportional Hazards Models, Sex Distribution, Cardiomyopathy, Hypertrophic mortality
- Abstract
Aims: Sex differences in hypertrophic cardiomyopathy (HCM) remain unclear. We sought to characterize sex differences in a large HCM referral centre population., Methods and Results: Three thousand six hundred and seventy-three adult patients with HCM underwent evaluation between January 1975 and September 2012 with 1661 (45.2%) female. Kaplan-Meier survival curves were assessed via log-rank test. Cox proportional hazard regression analyses evaluated the relation of sex with survival. At index visit, women were older (59 ± 16 vs. 52 ± 15 years, P < 0.0001) had more symptoms [New York Heart Association (NYHA) Class III-IV 45.0% vs. 35.3%, P < 0.0001], more obstructive physiology (77.4% vs. 71.8%, P = 0.0001), more mitral regurgitation (moderate or greater in 56.1% vs. 43.9%, P < 0.0001), higher E/e' ratio (n = 1649, 20.6 vs. 15.6, P < 0.0001), higher estimated pulmonary artery systolic pressure (n = 1783, 40.8 ± 15.4 vs. 34.8 ± 10.8 mmHg, P < 0.0001), worse cardiopulmonary exercise performance (n = 1267; percent VO2 predicted 62.8 ± 20% vs. 65.8 ± 19.2%, P = 0.007), and underwent more frequent alcohol septal ablation (4.9% vs. 3.0%, P = 0.004) but similar frequency of myectomy (28% vs. 30%, P = 0.24). Median follow-up was 10.9 (IQR 7.4-16.2) years. Kaplan-Meier analysis demonstrated lower survival in women compared with men (P < 0.0001). In multivariable modelling, female sex remained independently associated with mortality (HR 1.13 [1.03-1.22], P = 0.01) when adjusted for age, NYHA Class III-IV symptoms, and cardiovascular comorbidities., Conclusion: Women with HCM present at more advanced age, with more symptoms, worse cardiopulmonary exercise tolerance, and different haemodynamics than men. Sex is an important determinant in HCM management as women with HCM have worse survival. Women may require more aggressive diagnostic and therapeutic approaches., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2017
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39. Mechanisms of action and in vivo antibacterial efficacy assessment of five novel hybrid peptides derived from Indolicidin and Ranalexin against Streptococcus pneumoniae .
- Author
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Jindal HM, Zandi K, Ong KC, Velayuthan RD, Rasid SM, Samudi Raju C, and Sekaran SD
- Abstract
Background: Antimicrobial peptides (AMPs) are of great potential as novel antibiotics for the treatment of broad spectrum of pathogenic microorganisms including resistant bacteria. In this study, the mechanisms of action and the therapeutic efficacy of the hybrid peptides were examined., Methods: TEM, SEM and ATP efflux assay were used to evaluate the effect of hybrid peptides on the integrity of the pneumococcal cell wall/membrane. DNA retardation assay was assessed to measure the impact of hybrid peptides on the migration of genomic DNA through the agarose gel. In vitro synergistic effect was checked using the chequerboard assay. ICR male mice were used to evaluate the in vivo toxicity and antibacterial activity of the hybrid peptides in a standalone form and in combination with ceftriaxone., Results: The results obtained from TEM and SEM indicated that the hybrid peptides caused significant morphological alterations in Streptococcus pneumoniae and disrupting the integrity of the cell wall/membrane. The rapid release of ATP from pneumococcal cells after one hour of incubation proposing that the antibacterial action for the hybrid peptides is based on membrane permeabilization and damage. The DNA retardation assay revealed that at 62.5 µg/ml all the hybrid peptides were capable of binding and preventing the pneumococcal genomic DNA from migrating through the agarose gel. In vitro synergy was observed when pneumococcal cells treated with combinations of hybrid peptides with each other and with conventional drugs erythromycin and ceftriaxone. The in vivo therapeutic efficacy results revealed that the hybrid peptide RN7-IN8 at 20 mg/kg could improve the survival rate of pneumococcal bacteremia infected mice, as 50% of the infected mice survived up to seven days post-infection. In vivo antibacterial efficacy of the hybrid peptide RN7-IN8 was signficantly improved when combined with the standard antibiotic ceftriaxone at (20 mg/kg + 20 mg/kg) as 100% of the infected mice survived up to seven days post-infection., Discussion: Our results suggest that attacking and breaching the cell wall/membrane is most probably the principal mechanism for the hybrid peptides. In addition, the hybrid peptides could possess another mechanism of action by inhibiting intracellular functions such as DNA synthesis. AMPs could play a great role in combating antibiotic resistance as they can reduce the therapeutic concentrations of standard drugs., Competing Interests: The authors declare there are no competing interests.
- Published
- 2017
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40. AIM2 Inflammasome-Mediated Pyroptosis in Enterovirus A71-Infected Neuronal Cells Restricts Viral Replication.
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Yogarajah T, Ong KC, Perera D, and Wong KT
- Subjects
- Antigens metabolism, Caspase 1 metabolism, Cell Line, Tumor, Encephalomyelitis pathology, Encephalomyelitis virology, Gene Expression Profiling, Humans, Interleukin-1beta metabolism, Neurons metabolism, Up-Regulation genetics, DNA-Binding Proteins metabolism, Enterovirus physiology, Inflammasomes metabolism, Neurons virology, Pyroptosis, Virus Replication
- Abstract
Encephalomyelitis is a well-known complication of hand, foot, and mouth disease (HFMD) due to Enterovirus 71 (EV71) infection. Viral RNA/antigens could be detected in the central nervous system (CNS) neurons in fatal encephalomyelitis but the mechanisms of neuronal cell death is not clearly understood. We investigated the role of absent in melanoma 2 (AIM2) inflammasome in neuronal cell death, and its relationship to viral replication. Our transcriptomic analysis, RT-qPCR, Western blot, immunofluorescence and flow cytometry studies consistently showed AIM2 gene up-regulation and protein expression in EV-A71-infected SK-N-SH cells. Downstream AIM2-induced genes, CARD16, caspase-1 and IL-1β were also up-regulated and caspase-1 was activated to form cleaved caspase-1 p20 subunits. As evidenced by 7-AAD positivity, pyroptosis was confirmed in infected cells. Overall, these findings have a strong correlation with decreases in viral titers, copy numbers and proteins, and reduced proportions of infected cells. AIM2 and viral antigens were detected by immunohistochemistry in infected neurons in inflamed areas of the CNS in EV-A71 encephalomyelitis. In infected AIM2-knockdown cells, AIM2 and related downstream gene expressions, and pyroptosis were suppressed, resulting in significantly increased virus infection. These results support the notion that AIM2 inflammasome-mediated pyroptosis is an important mechanism of neuronal cell death and it could play an important role in limiting EV-A71 replication.
- Published
- 2017
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41. Modelling person-to-person transmission in an Enterovirus A71 orally infected hamster model of hand-foot-and-mouth disease and encephalomyelitis.
- Author
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Phyu WK, Ong KC, and Wong KT
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- Animals, Asymptomatic Infections, Central Nervous System Infections virology, Cricetinae, Enterovirus Infections virology, Epithelial Cells virology, Feces virology, Hand, Foot and Mouth Disease complications, Hand, Foot and Mouth Disease virology, Humans, Immunohistochemistry, In Situ Hybridization, Inflammation pathology, Mothers, Mouth virology, Mouth Mucosa virology, Muscles virology, Salivary Glands virology, Skin virology, Virus Shedding, Disease Models, Animal, Encephalomyelitis virology, Enterovirus Infections transmission, Hand, Foot and Mouth Disease physiopathology, Hand, Foot and Mouth Disease transmission
- Abstract
Enterovirus A71 (EV-A71) causes hand-foot-and-mouth disease (HFMD), which may be complicated by fatal encephalomyelitis. Although fecal-oral or oral-oral routes are important in person-to-person transmission, how viral shedding and exposure may predispose individuals to infection remains unknown. We investigated person-to-person transmission by using a model of HFMD and encephalomyelitis based on EV-A71 oral infection of 2-week-old hamsters. Animals (index animals) infected with 10
4 50% cell culture infective doses of virus uniformly developed severe disease four days post-infection (dpi), whereas littermate contacts developed severe disease after six to seven days of exposure to index animals. Virus was detected in oral washes and feces at 3-4 dpi in index animals and at three to eight days after exposure to index animals in littermate contact animals. In a second experiment, non-littermate contact animals exposed for 8 or 12 h to index animals developed the disease six and four days post-exposure, respectively. Tissues from killed index and contact animals, studied by light microscopy, immunohistochemistry and in situ hybridization, exhibited mild inflammatory lesions and/or viral antigens/RNA in the squamous epithelia of the oral cavity, tongue, paws, skin, esophagus, gastric epithelium, salivary glands, lacrimal glands, central nervous system neurons, muscles (skeletal, cardiac and smooth muscles) and liver. Orally shed viruses were probably derived from infected oral mucosa and salivary glands, whereas fecal viruses may have derived from these sites as well as from esophageal and gastric epithelia. Asymptomatic seroconversion in exposed mother hamsters was demonstrated. Our hamster model should be useful in studying person-to-person EV-A71 transmission and how drugs and vaccines may interrupt transmission.- Published
- 2017
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42. Squamous epitheliotropism of Enterovirus A71 in human epidermis and oral mucosa.
- Author
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Phyu WK, Ong KC, Kong CK, Alizan AK, Ramanujam TM, and Wong KT
- Subjects
- Animals, Cell Proliferation, Chlorocebus aethiops, Enterovirus Infections pathology, Epidermis pathology, Humans, Immunohistochemistry, In Situ Hybridization, Keratinocytes metabolism, Keratinocytes virology, Mouth Mucosa pathology, Organ Culture Techniques, Vero Cells, Virus Replication, Enterovirus A, Human physiology, Enterovirus Infections virology, Epidermis virology, Mouth Mucosa virology, Viral Tropism
- Abstract
Hand-foot-and-mouth disease is a self-limiting paediatric infectious disease commonly caused by Enterovirus A71 (Genus: Enterovirus, Family: Picornaviridae). Typical lesions in and around the hands, feet, oral cavity and other places may rarely be complicated by acute flaccid paralysis and acute encephalomyelitis. Although virus is readily cultured from skin vesicles and oral secretions, the cellular target/s of Enterovirus A71 in human skin and oral mucosa are unknown. In Enterovirus A71-infected human skin and oral mucosa organotypic cultures derived from the prepuce and lip biopsies, focal viral antigens and viral RNA were localized to cytoplasm of epidermal and mucosal squamous cells as early as 2 days post-infection. Viral antigens/RNA were associated with cytoplasmic vacuolation and cellular necrosis. Infected primary prepuce epidermal keratinocyte cultures showed cytopathic effects with concomitant detection of viral antigens from 2 days post-infection. Supernatant and/or tissue homogenates from prepuce skin organotypic cultures and primary prepuce keratinocyte cultures showed viral titres consistent with active viral replication. Our data strongly support Enterovirus A71 squamous epitheliotropism in the human epidermis and oral mucosa, and suggest that these organs are important primary and/or secondary viral replication sites that contribute significantly to oral and cutaneous viral shedding resulting in person-to-person transmission, and viraemia, which could lead to neuroinvasion.
- Published
- 2017
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43. Enterovirus A71 and coxsackievirus A16 show different replication kinetics in human neuronal and non-neuronal cell lines.
- Author
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Yogarajah T, Ong KC, Perera D, and Wong KT
- Subjects
- Cell Line, DNA Replication, Enterovirus, Enterovirus A, Human chemistry, Enterovirus A, Human classification, Enterovirus A, Human growth & development, Humans, Kinetics, RNA, Viral genetics, RNA, Viral metabolism, Virus Replication, Enterovirus A, Human physiology, Hand, Foot and Mouth Disease virology, Neurons virology
- Abstract
Enterovirus A71 (EV-A71) and coxsackievirus A16 (CV-A16) are closely related enteroviruses that cause hand, foot and mouth disease (HFMD) in children. Serious neurological complications almost always occur in EV-A71 infection, but are rare in CV-A16 infection. Based on the hypothesis that this may be because EV-A71 infects neuronal cells more easily than CV-A16, we compared virus infection, replication and spread of EV-A71 and CV-A16 in SK-N-SH cells. We found that CV-A16 invariably showed significantly lower replication and caused less necrotic cell death in SK-N-SH cells, compared with EV-A71. This was not due to a lower proportion of CV-A16-infected cells, since both viruses showed similar proportions of infected cells at all time points analyzed. Furthermore, reduced replication of CV-A16 in SK-N-SH cells does not appear to be due to limited viral receptor availability, which might limit viral entry, because experiments with viral RNA-transfected cells showed the same results as for live virus infections. On the other hand, no differences were observed between EV-A71 and CV-A16 in RD cells and results were generally similar in RD cells for both viruses. Taken together, our findings suggest that the poor growth of CV-A16 and EV-A71in SK-N-SH cells, compared with RD cells, may be due to cell type-specific restrictions on viral replication and spread. Furthermore, the lower viral replication and necrotic cell death in CV-A16-infected SK-N-SH cells, compared with EV-A71-infected SK-N-SH cells, is consistent with the lower prevalence of neurotropism observed in CV-A16-associated HFMD outbreaks. Nonetheless, in vivo data and more extensive comparisons of different viral strains are essential to confirm our findings.
- Published
- 2017
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44. Pathogenesis of Plasmodium berghei ANKA infection in the gerbil (Meriones unguiculatus) as an experimental model for severe malaria.
- Author
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Junaid QO, Khaw LT, Mahmud R, Ong KC, Lau YL, Borade PU, Liew JWK, Sivanandam S, Wong KT, and Vythilingam I
- Subjects
- Animals, Body Temperature, Body Weight, Brain immunology, Brain pathology, Cytokines analysis, Cytokines genetics, DNA, Complementary genetics, Erythrocyte Count, Hemoglobins analysis, In Situ Hybridization, Liver pathology, Malaria mortality, Malaria parasitology, Parasitemia etiology, Parasitemia mortality, Parasitemia parasitology, RNA genetics, RNA isolation & purification, Real-Time Polymerase Chain Reaction, Spleen metabolism, Spleen pathology, Survival Rate, Disease Models, Animal, Gerbillinae parasitology, Malaria etiology, Plasmodium berghei physiology
- Abstract
Background: As the quest to eradicate malaria continues, there remains a need to gain further understanding of the disease, particularly with regard to pathogenesis. This is facilitated, apart from in vitro and clinical studies, mainly via in vivo mouse model studies. However, there are few studies that have used gerbils (Meriones unguiculatus) as animal models. Thus, this study is aimed at characterizing the effects of Plasmodium berghei ANKA (PbA) infection in gerbils, as well as the underlying pathogenesis., Methods: Gerbils, 5-7 weeks old were infected by PbA via intraperitoneal injection of 1 × 10
6 (0.2 mL) infected red blood cells. Parasitemia, weight gain/loss, hemoglobin concentration, red blood cell count and body temperature changes in both control and infected groups were monitored over a duration of 13 days. RNA was extracted from the brain, spleen and whole blood to assess the immune response to PbA infection. Organs including the brain, spleen, heart, liver, kidneys and lungs were removed aseptically for histopathology., Results: Gerbils were susceptible to PbA infection, showing significant decreases in the hemoglobin concentration, RBC counts, body weights and body temperature, over the course of the infection. There were no neurological signs observed. Both pro-inflammatory (IFNγ and TNF) and anti-inflammatory (IL-10) cytokines were significantly elevated. Splenomegaly and hepatomegaly were also observed. PbA parasitized RBCs were observed in the organs, using routine light microscopy and in situ hybridization., Conclusion: Gerbils may serve as a good model for severe malaria to further understand its pathogenesis., (© Q.O. Junaid et al., published by EDP Sciences, 2017.)- Published
- 2017
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45. The role of heat shock proteins and glucose regulated proteins in cancer.
- Author
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Tan JS, Ong Kc KC, and Rhodes A
- Subjects
- Animals, Humans, Carcinogenesis metabolism, HSP70 Heat-Shock Proteins metabolism, Heat-Shock Proteins metabolism, Membrane Proteins metabolism, Neoplasms metabolism
- Abstract
Heat shock proteins (HSPs) are a family of evolutionary conserved proteins that work as molecular chaperones for cellular proteins essential for cell viability and growth as well as having numerous cyto-protective roles. They are sub-categorised based on their molecular weights; amongst which some of the most extensively studied are the HSP90 and HSP70 families. Important members of these two families; Heat shock proteins 70 and heat shock proteins 90 (Hsp70/90), are the glucose regulated proteins (GRP). These stress-inducible chaperones possess distinct roles from that of the other HSPs, residing mostly in the endoplasmic reticulum and mitochondria, but they can also be translocated to other cellular locations. Their ability in adapting to stress conditions in the tumour microenvironment suggests novel functions in cancer. GRPs have been implicated in many crucial steps of carcinogenesis to include stabilization of oncogenic proteins, induction of tumour angiogenesis, inhibition of apoptosis and replicative senescence, and promotion of invasion and metastasis.
- Published
- 2016
46. A monoclonal antibody to ameliorate central nervous system infection and improve survival in a murine model of human Enterovirus-A71 encephalomyelitis.
- Author
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Tan SH, Ong KC, Perera D, and Wong KT
- Subjects
- Animals, Antibodies, Monoclonal immunology, Antibodies, Neutralizing immunology, Cell Line, Disease Models, Animal, Encephalomyelitis drug therapy, Encephalomyelitis immunology, Encephalomyelitis mortality, Enterovirus A, Human classification, Enterovirus A, Human immunology, Enterovirus Infections drug therapy, Enterovirus Infections immunology, Enterovirus Infections mortality, Humans, Mice, Neutralization Tests, Viral Load, Antibodies, Monoclonal pharmacology, Antibodies, Neutralizing pharmacology, Antiviral Agents pharmacology, Encephalomyelitis virology, Enterovirus A, Human drug effects, Enterovirus Infections virology
- Abstract
Background: Enterovirus A71 (EV-A71) encephalomyelitis is an often fatal disease for which there is no specific treatment available. Passive immunization with a specific monoclonal antibody to EV-A71 was used on a murine model of EV-A71 encephalomyelitis to evaluate its therapeutic effectiveness before and after established central nervous system (CNS) infection., Methods: Mice were intraperitoneally-infected with a mouse-adapted EV-A71 strain and treated with a dose of monoclonal antibody (MAb) daily for 3 days on day 1, 2 and 3 post-infection or for 3 days on 3, 4 and 5 post-infection. Treatment effectiveness was evaluated by signs of infection and survival rate. Histopathology and qPCR analyses were performed on mice sacrificed a day after completing treatment., Results: In mock-treated mice, CNS infection was established from day 3 post-infection. All mice treated before established CNS infection, survived and recovered completely without CNS infection. All mice treated after established CNS infection survived with mild paralysis, and viral load and antigens/RNA at day 6 post-infection were significantly reduced., Conclusions: Passive immunization with our MAb could prevent CNS infection in mice if given early before the establishment of CNS infection. It could also ameliorate established CNS infection if optimal and repeated doses were given., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2016
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47. Pulmonary hypertension is associated with worse survival in hypertrophic cardiomyopathy.
- Author
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Ong KC, Geske JB, Hebl VB, Nishimura RA, Schaff HV, Ackerman MJ, Klarich KW, Siontis KC, Coutinho T, Dearani JA, Ommen SR, and Gersh BJ
- Subjects
- Adult, Aged, Cardiac Surgical Procedures methods, Cardiomyopathy, Hypertrophic surgery, Cause of Death, Cohort Studies, Comorbidity, Female, Humans, Hypertension, Pulmonary surgery, Kaplan-Meier Estimate, Male, Middle Aged, Prognosis, Proportional Hazards Models, Pulmonary Wedge Pressure, Retrospective Studies, Risk Assessment, Severity of Illness Index, Survival Analysis, Cardiomyopathy, Hypertrophic diagnostic imaging, Cardiomyopathy, Hypertrophic epidemiology, Echocardiography, Hypertension, Pulmonary diagnostic imaging, Hypertension, Pulmonary epidemiology
- Abstract
Aims: Pulmonary hypertension (PH) is associated with increased mortality in various forms of left-sided heart disease. However, the implications of PH in hypertrophic cardiomyopathy (HCM) have not been elucidated. The objective of this study was to determine the prevalence and prognostic implications of PH in HCM., Methods and Results: The study cohort consisted of 1570 (54 ± 15 years; 53% male) adults with HCM followed for a median of 3.3 years. PH [pulmonary artery systolic pressure (PASP) >36 mmHg] was identified in 38% of patients who were older (57 ± 15 vs. 52 ± 15 years, P < 0.0001), more likely to be female (59 vs. 40%, P < 0.0001), and were characterized by a higher prevalence of New York Heart Association (NYHA) class 3 or 4 symptoms (61 vs. 45%, P < 0.0001) and atrial fibrillation (29 vs. 15%, P < 0.0001) vs. those without PH. Only 12% had moderate or severe PH (PASP >50 mmHg). In multivariate Cox regression analyses adjusted for age, sex, NYHA class 3 or 4 symptoms, and atrial fibrillation, PASP was an independent predictor of all-cause mortality in patients with non-obstructive HCM (HR 1.59 per 10 mmHg PASP increase, 95% CI 1.28-1.96, P < 0.0001) and in those with obstructive physiology who did not undergo septal reduction therapy (SRT) (HR 1.15 per 10 mmHg PASP, 95% CI 1.01-1.31, P = 0.035). However, PH was not predictive of outcomes in patients with obstructive HCM who underwent SRT., Conclusions: Over one-third of adults evaluated in our referral HCM clinic demonstrated concomitant PH, and this was associated with increased mortality except in those with obstructive HCM who underwent SRT., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)
- Published
- 2016
- Full Text
- View/download PDF
48. Abnormal stress echocardiography findings in cardiac amyloidosis.
- Author
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Ong KC, Askew JW, Dispenzieri A, Maleszewski JJ, Klarich KW, Anavekar NS, Mulvagh SL, and Grogan M
- Subjects
- Aged, Amyloid ultrastructure, Amyloidosis complications, Amyloidosis metabolism, Amyloidosis mortality, Blood Pressure, Cardiomyopathies complications, Cardiomyopathies metabolism, Cardiomyopathies mortality, Chest Pain physiopathology, Coronary Angiography, Dyspnea physiopathology, Echocardiography methods, Exercise Test, Female, Humans, Immunoglobulin Light Chains chemistry, Immunoglobulin Light Chains ultrastructure, Male, Middle Aged, Myocardium metabolism, Myocardium pathology, Retrospective Studies, Survival Analysis, Amyloid chemistry, Amyloidosis diagnostic imaging, Cardiomyopathies diagnostic imaging, Myocardium chemistry
- Abstract
Background: Cardiac involvement in immunoglobulin light chain (amyloid light chain, AL) amyloidosis is characterized by myocardial interstitial deposition but can also cause obstructive deposits in the coronary microvasculature., Methods: We retrospectively identified 20 patients who underwent stress echocardiography within 1 year prior to the histologic diagnosis of AL amyloidosis. Only patients with cardiac amyloidosis and no known obstructive coronary disease were included., Results: Stress echocardiograms (13 exercise; 7 dobutamine) were performed for evaluation of dyspnea and/or chest pain. Stress-induced wall motion abnormalities (WMAs) occurred in 11 patients (55%), 4 of whom had normal left ventricular wall thickness. Coronary angiogram was performed in 9 of 11 patients and demonstrated no or mild epicardial coronary artery disease. Seven (54%) patients had an abnormal exercise blood pressure which occurred with similar likelihood between those with and without stress-induced WMAs., Conclusions: Stress-induced WMAs and abnormal exercise blood pressure may occur in patients with cardiac AL amyloidosis despite the absence of significant epicardial coronary artery disease. This finding should raise the possibility of cardiac amyloidosis even in the absence of significant myocardial thickening.
- Published
- 2016
- Full Text
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49. Viral neuronotropism is important in the pathogenesis of Murray Valley encephalitis.
- Author
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Fu TL, Ong KC, Tran YD, McLean CA, and Wong KT
- Subjects
- Brain pathology, Encephalitis Virus, Murray Valley, Humans, Immunohistochemistry, Infant, Male, Neurons pathology, Brain virology, Encephalitis, Arbovirus pathology, Neurons virology
- Published
- 2016
- Full Text
- View/download PDF
50. The Natural History of Nonobstructive Hypertrophic Cardiomyopathy.
- Author
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Hebl VB, Miranda WR, Ong KC, Hodge DO, Bos JM, Gentile F, Klarich KW, Nishimura RA, Ackerman MJ, Gersh BJ, Ommen SR, and Geske JB
- Subjects
- Adult, Age Factors, Aged, Cohort Studies, Female, Follow-Up Studies, Humans, Male, Middle Aged, Retrospective Studies, Risk Factors, Sex Factors, Survival Rate, United States, Cardiomyopathy, Hypertrophic mortality, Heart Failure mortality, White People statistics & numerical data
- Abstract
Objective: To describe the survival of a large nonobstructive hypertrophic cardiomyopathy (NO-HCM) cohort and to identify risk factors for increased mortality in this population., Patients and Methods: Patients were identified from the Mayo Clinic HCM database from January 1, 1975, through November 30, 2006, for this retrospective observational study. Patients with resting or provocable left ventricular outflow tract gradients were excluded. Echocardiographic, clinical, and genetic data were compared between subgroups, and survival data were compared with expected population rates., Results: A total of 706 patients with NO-HCM were identified. During median follow-up of 5 years (mean, 7 years), there were 208 deaths. Overall survival was no different than expected compared with age- and sex-matched white US population mortality rates (P=.77). Independent predictors of death were age at diagnosis, "burned out" HCM, and history of transient ischemic attack or stroke; use of an implantable cardioverter defibrillator (ICD) was inversely related to death. After exclusion of patients with an ICD, there was no difference in survival compared with age- and sex- matched individuals (P=.39); age, previous transient ischemic attack/stroke, and burned out HCM were predictors of death., Conclusion: In this cohort, patients with NO-HCM had similar survival rates as age- and sex-matched white US population mortality rates. Although use of an ICD was inversely related to death, no differences in overall survival were seen after those patients were excluded. Burned out HCM was independently associated with an increased risk of death, identifying a subset of patients who may benefit from more aggressive therapies., (Copyright © 2016 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
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