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Fua’di MT, Er B, Lee S, Chan PP, Khoo J, Tan D, Li H, Muhammad IR, Raj P, Kurupatham L, Lee V, Tan LK, Chan JSH, Li A, Aung KT. Characteristics of Gastroenteritis Outbreaks Investigated in Singapore: 2018-2021. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2024; 21:64. [PMID: 38248529 PMCID: PMC10815581 DOI: 10.3390/ijerph21010064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/30/2023] [Accepted: 01/04/2024] [Indexed: 01/23/2024]
Abstract
There is a need to study the characteristics of outbreaks via Singapore's outbreak surveillance system to understand and identify the gaps in food safety for targeted policy interventions due to the increasing trend in gastroenteritis outbreaks and consequential increase in foodborne-related deaths and economic burden on public health systems worldwide. A total of 171 gastroenteritis outbreaks were investigated in Singapore from January 2018 to December 2021. This study analyzed the annual trend of investigated gastroenteritis outbreaks, the proportion of outbreaks by implicated sources of food, and the proportion of the type of pathogens identified from human cases, food samples, and environmental swabs collected from outbreak investigations. Among the foodborne gastroenteritis outbreaks (n = 121) investigated in Singapore, approximately 42.1% of the outbreaks had food prepared by caterers, 14.9% by restaurants, and 12.4% had food prepared by in-house kitchens. Clostridium perfringens and Salmonella were the most common causative pathogens in foodborne outbreaks throughout the analysis period. The food samples and environmental swabs collected were mostly detected for Bacillus cereus. Norovirus was the most common causative pathogen in non-foodborne outbreaks and was mainly attributable to preschools. This highlights the importance of monitoring and educating the catering industry and preschools to prevent future outbreaks.
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Wang Y, Teo E, Lin KJ, Wu Y, Chan JSH, Tan LK. Quantification of Pork, Chicken, Beef, and Sheep Contents in Meat Products Using Duplex Real-Time PCR. Foods 2023; 12:2971. [PMID: 37569240 PMCID: PMC10418471 DOI: 10.3390/foods12152971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/28/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023] Open
Abstract
Accurate methods for meat speciation and quantification are essential for ensuring the supply of safe and wholesome meat and composite products with animal origins to negate the potential associated hazards, aid classification of consignments at the import control system, and thwart food fraud committed for financial gain. To better enhance meat safety control and combat food fraud, this study developed two duplex real-time polymerase chain reaction (real-time PCR) systems specifically designed for chicken, pork, sheep, and beef, using single-copy, chromosomally encoded, species-specific gene sequences to accurately measure the content of each meat type in meat products. DNA extracted from the raw and boiled reference materials prepared in varying proportions (ranging from 1% to 75%) were used in the development of the duplex assay to derive calibration factors to determine the meat content in different meat products. The method was further validated using proficiency test samples and market monitoring samples. Our findings showed that this method exhibits high specificity and sensitivity, with a significant accuracy range of 0.14% to 24.07% in quantifying the four meat types in both raw and processed meat products. Validation results further confirmed the effectiveness of our method in accurately quantifying meat content. Thus, we have demonstrated the duplex qPCR assays as promising approaches for implementation in routine analysis to strengthen meat safety control systems and combat meat fraud, thereby safeguarding consumer health and trust in the meat industry.
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Chan SH, Liau SH, Low YJ, Chng KR, Wu Y, Chan JSH, Tan LK. A Real-Time PCR Approach for Rapid Detection of Viable Salmonella Enteritidis in Shell Eggs. Microorganisms 2023; 11:microorganisms11040844. [PMID: 37110268 PMCID: PMC10143610 DOI: 10.3390/microorganisms11040844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 03/29/2023] Open
Abstract
Rapid and robust detection assays for Salmonella Enteritidis (SE) in shell eggs are essential to enable a quick testing turnaround time (TAT) at the earliest checkpoint and to ensure effective food safety control. Real-time polymerase chain reaction (qPCR) assays provide a workaround for the protracted lead times associated with conventional Salmonella diagnostic testing. However, DNA-based analysis cannot reliably discriminate between signals from viable and dead bacteria. We developed a strategy based on an SE qPCR assay that can be integrated into system testing to accelerate the detection of viable SE in egg-enriched cultures and verify the yielded SE isolates. The specificity of the assay was evaluated against 89 Salmonella strains, and SE was accurately identified in every instance. To define the indicator for a viable bacteria readout, viable or heat-inactivated SE were spiked into shell egg contents to generate post-enriched, artificially contaminated cultures to establish the quantification cycle (Cq) for viable SE. Our study has demonstrated that this technique could potentially be applied to accurately identify viable SE during the screening stage of naturally contaminated shell eggs following enrichment to provide an early alert, and that it consistently identified the serotypes of SE isolates in a shorter time than conventional testing.
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Low SL, Leo YS, Lai YL, Lam S, Tan HH, Wong JCC, Tan LK, Ng LC. Evaluation of eight commercial Zika virus IgM and IgG serology assays for diagnostics and research. PLoS One 2021; 16:e0244601. [PMID: 33497414 PMCID: PMC7837473 DOI: 10.1371/journal.pone.0244601] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 12/11/2020] [Indexed: 11/18/2022] Open
Abstract
Several commercial Zika virus (ZIKV) serology assays have been developed since the recognition of ZIKV outbreaks as a Public Health Emergency of International Concern in 2016. However, test interpretation for ZIKV serology can be challenging due to antibody cross-reactivity with other flaviviruses like dengue virus (DENV). Therefore, we sought to evaluate the performance of eight commercially available ZIKV IgM and IgG assays across three testing platforms, namely, immunochromatographic tests (ICT), ELISAs and immunofluorescence tests (IIFT). The test panel comprised of 278 samples, including acute and convalescent sera or plasma from ZIKV-confirmed, DENV-confirmed, non-ZIKV and non-DENV patients, and residual sera from healthy blood donors. The ZIKV IgM and IgG serology assays yielded higher test sensitivities of 23.5% - 97.1% among ZIKV convalescent samples as compared to 5.6% - 27.8% among ZIKV acute samples; the test specificities were 63.3% - 100% among acute and convalescent DENV, non-DENV samples. Among the ELISAs and IIFTs, the Diapro ZIKV IgM ELISA demonstrated high test sensitivity (96%) and specificity (80%) when tested on early convalescent samples, while the Euroimmun ZIKV IgG ELISA yielded the highest test specificity of 97% - 100% on samples from non-ZIKV patients and healthy blood donors. For rapid ICTs, the LumiQuick IgM rapid ICT yielded low test sensitivity, suggesting its limited utility. We showed that commercial ZIKV IgM and IgG serology assays have differing test performances, with some having moderate to high test sensitivities and specificities when used in a dengue endemic setting, although there were limitations in IgG serology.
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Sangkaew S, Tan LK, Ng LC, Ferguson NM, Dorigatti I. Using cluster analysis to reconstruct dengue exposure patterns from cross-sectional serological studies in Singapore. Parasit Vectors 2020; 13:32. [PMID: 31952539 PMCID: PMC6969465 DOI: 10.1186/s13071-020-3898-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 01/07/2020] [Indexed: 12/20/2022] Open
Abstract
Background Dengue is a mosquito-borne viral disease caused by one of four serotypes (DENV1-4). Infection provides long-term homologous immunity against reinfection with the same serotype. Plaque reduction neutralization test (PRNT) is the gold standard to assess serotype-specific antibody levels. We analysed serotype-specific antibody levels obtained by PRNT in two serological surveys conducted in Singapore in 2009 and 2013 using cluster analysis, a machine learning technique that was used to identify the most common histories of DENV exposure. Methods We explored the use of five distinct clustering methods (i.e. agglomerative hierarchical, divisive hierarchical, K-means, K-medoids and model-based clustering) with varying number (from 4 to 10) of clusters for each method. Weighted rank aggregation, an evaluating technique for a set of internal validity metrics, was adopted to determine the optimal algorithm, comprising the optimal clustering method and the optimal number of clusters. Results The K-means algorithm with six clusters was selected as the algorithm with the highest weighted rank aggregation. The six clusters were characterised by (i) dominant DENV2 PRNT titres; (ii) co-dominant DENV1 and DENV2 titres with average DENV2 titre > average DENV1 titre; (iii) co-dominant DENV1 and DENV2 titres with average DENV1 titre > average DENV2 titre; (iv) low PRNT titres against DENV1-4; (v) intermediate PRNT titres against DENV1-4; and (vi) dominant DENV1-3 titres. Analyses of the relative size and age-stratification of the clusters by year of sample collection and the application of cluster analysis to the 2009 and 2013 datasets considered separately revealed the epidemic circulation of DENV2 and DENV3 between 2009 and 2013. Conclusion Cluster analysis is an unsupervised machine learning technique that can be applied to analyse PRNT antibody titres (without pre-established cut-off thresholds to indicate protection) to explore common patterns of DENV infection and infer the likely history of dengue exposure in a population.
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Iqbal Penwala T, Bin Mohamed Yusof AK, Tan LK. P884 Rare case of primary cardiac lymphoma in immunocompetent patient. Eur Heart J Cardiovasc Imaging 2020. [DOI: 10.1093/ehjci/jez319.524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Primary cardiac lymphoma is a rare tumour especially in immunocompetent person. It is invariably fatal unless diagnosed and treated early. Our patient was a 76 year old Chinese gentlemen, known case diabetes mellitus and hypertension, who presented with 3 months history of failure symptoms. He also had loss of appetite.
His vital signs were stable. There was bibasal crepitation, raised JVP with normal heart sounds and bilateral pedal edema. Chest X-ray showed bilateral pleural effusion.He was admitted for stabilization of heart failure and started on diuretics.
Echocardiography showed the LV ejection fraction was 50% with grade 1 diastolic dysfunction. There was a global pericardial effusion with effusion size 2.52cm maximum at posterior to LV. There was partial RA collapse .Patient was otherwise hemodynamically stable. Patient was observed closely and diuretics continued. Echocardiography on the third day of admission showed a suspicious looking mass in the right atrial (RA) and right ventricular (RV) wall near the AV groove. It become apparent after pericardial effusion became less. Patient was counselled and agreed for pericardial tapping but procedure had to be abandoned as effusion has reduced compared to before (<20mm).
MRI cardiac showed an infiltrating mass around the right atrio-ventricular groove extending to the right ventricular free wall and around the pericardial lining around the ascending aorta and pulmonary trunks. There is inhomogenous signal in STIR with iso-intensity on T1 weighted images. First pass metabolism revealed some vascularity. There was a patchy myocardial enhancement on late gadolinium enhancement. pericardium was thickened with global pericardial effusion- 16mm. Large right pleural effusion seen and minimal left pleural effusion. Mediastinal lymphadenopathy was seen. The finding were suggestive of cardiac lymphoma with differential sarcoma.
Subsequent day, patient develop acute ischemic stroke which was complicated by aspiration pneumonia and septic shock. Fortunately he recovered after 1 week of antibiotics and non-invasive ventilatory support.
FDG PET- CT scan showed FDG-avid primary cardiac lymphoma with pericardial involvement and conglomerate of multiple group of mediastinal and supra clavicular lymph nodes . Bilateral hypermetabolic adrenal nodule were seen but unable to determine its relevance to the primary pathology(lymphoma). No marrow or other organ involvement. Stage is likely IIE.
We were unable to harvest the lymph node because they were too deep. Patient"s family was counselled for cardiac biopsy but family did not want to take the risk as patient was bedridden and fragile. They were also not keen for any chemotherapy or invasive procedure. Once patient was out of infection, they requested to bring back patient to home. He was sent to nursing home for full time care but succumbed to another bout of aspiration pneumonia one week after discharge.
Abstract P884 Figure. Echo, MRI, Pet CT scan
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Iqbal Penwala T, Sanusi AR, Yahaya SA, E Samonte PE, Tan LK. P1342 Secondary cardiac tumour -a metastasis from renal cell carcinoma via transvenous extension. Eur Heart J Cardiovasc Imaging 2020. [DOI: 10.1093/ehjci/jez319.780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Secondary cardiac tumour is 20-40 times more common than primary cardiac tumour. Most common tumour that metastasize to the heart are lung cancer, breast cancer and hematologic malignancy. Melanoma and pleural mesothelioma has high inclination to metastasize. Other cancer with high rate of cardiac metastasis include gastric, ovarian, renal and pancreatic cancer. The presentation of cardiac metastasis is usually non-specific and sometimes mimic other cardiac condition. We would like to present one such case where we used multimodality approach for proper evaluation.
A 57 year old lady presented with intermittent chest discomfort for one month which worsen on day of admission. Otherwise she had good effort tolerance. Electrocardiogram had no acute ischemic changes and Troponin T was not elevated. Bedside echocardiography revealed a large cardiac mass in right atrium around 66mm x 29mm, protruding to right ventricle. Apart from that noted aneurysm of interatrial septum towards LA.
MRI cardiac showed an inhomogenous mass extending from the right renal vein and inferior vena cava(IVC) into the right atrium(RA). The tumour mass in the right atrium a highly mobile and flops across the tricuspid valve into the right ventricle during ventricular diastole causing right ventricular outflow tract obstruction. The mass was hyperintense on T2- and isointense on T1-weighted images. There was vascularity within the mass with inhomogenous gadolinium enhancement. There was also 2 masses in right kidney , a larger inhomogenous encapsulated mass at the right lower pole and smaller at lower pole. The findings were suggestive of a primary renal cell carcinoma with tumour mass extension into right renal vein, inferior vena cava and into the right atrium.
A staging CT scan thorax , abdomen and pelvis did not show any other possible primary source of cancer and reconfirm the extracardiac finding of the MRI. No evidence of tumour extension into hepatic veins and left renal vein. There was however small nodular opacities in both right and left lung suggesting lung metastasis.
A combined operation was done with our cardiothoracic surgeon and urologist from nearby tertiery hospital. Nephrectomy and removal of tumour thrombus from IVC and RA was done with 18 degree Celcius circulatory arrest with cardiopulmonary bypass.
Section of renal mass showed a poorly circumscribed lobulated tumour with areas of hemorrhage and necrosis. The tumour was close to capsule but has not breached it. The tumour was mainly clear cell carcinoma variant, nuclear grade III. Section from IVC that extend to RA appeared elongated sausage-like measuring 150mm in length and 30mm in diameter had tumour embolus. Pulmonary artery and perirenal blood vessel also had tumour emboli. The hilar nodes however were free from tumour.
Patient recovered well and was discharged home day 9 post operation. Follow-up echocardiogram 3weeks post-op showed no recurrence of the mass and good LV function.
Abstract P1342 Figure. Echo, CTscan, MRI and Pathology images
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Tan LK, Low SL, Sun H, Shi Y, Liu L, Lam S, Tan HH, Ang LW, Wong WY, Chua R, Teo D, Ng LC, Cook AR. Force of Infection and True Infection Rate of Dengue in Singapore: Implications for Dengue Control and Management. Am J Epidemiol 2019; 188:1529-1538. [PMID: 31062837 PMCID: PMC6670050 DOI: 10.1093/aje/kwz110] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 04/24/2019] [Accepted: 04/26/2019] [Indexed: 12/23/2022] Open
Abstract
National data on dengue notifications do not capture all dengue infections and do not reflect the true intensity of disease transmission. To assess the true dengue infection rate and disease control efforts in Singapore, we conducted age-stratified serosurveys among residents after a 2013 outbreak that was the largest dengue outbreak on record. The age-weighted prevalence of dengue immunoglobulin G among residents was 49.8% (95% confidence interval: 48.4, 51.1) in 2013 and 48.6% (95% confidence interval: 47.0, 50.0) in 2017; prevalence increased with age. Combining these data with those from previous serosurveys, the year-on-year estimates of the dengue force of infection from 1930 to 2017 revealed a significant decrease from the late 1960s to the mid-1990s, after which the force of infection remained stable at approximately 10 per 1,000 persons per year. The reproduction number (R0) had also declined since the 1960s. The reduction in dengue transmission may be attributed to the sustained national vector program and partly to a change in the age structure of the population. The improved estimated ratio of notified cases to true infections, from 1:14 in 2005–2009 to 1:6 in 2014–2017, signifies that the national notification system, which relies on diagnosed cases, has improved over time. The data also suggest that the magnitudes of dengue epidemics cannot be fairly compared across calendar years and that the current disease control program remains applicable.
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Roslan A, Kamsani SH, Nay TW, Tan KL, Hakim N, Tan AM, Megat Samsudim WN, Tan KL, Jauhari AT, Krishnan M, Leong D, Supramaniam T, Tan LK, Nuruddin AA. Echocardiographic and electrocardiographic presentations of patients with endomyocardial biopsy-proven cardiac amyloidosis. THE MEDICAL JOURNAL OF MALAYSIA 2018; 73:388-392. [PMID: 30647209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
OBJECTIVE Cardiac amyloidosis is under diagnosed and its prevalence is unknown. This is a retrospective, nonrandomised, single centre study of patients with endomyocardial biopsy-proven cardiac amyloidosis focusing on their echocardiographic and electrocardiogram (ECG) presentations. This is the first case series in Malaysia on this subject. METHODS We identified all of our endomyocardial biopsyproven cardiac amyloidosis patients from January 2010 to January 2018 and reviewed their medical records. All patients echocardiographic and ECG findings reviewed and analysed comparing to basic mean population value. RESULTS In total there are 13 biopsy-proven cardiac amyloidosis patients. All of the biopsies shows light chain (AL) amyloid. Majority of the patients (8, 61.5%) is male, and most of our patients (8, 61.5%) is Chinese. All seven patients on whom we performed deformation imaging have apical sparing pattern on longitudinal strain echocardiogram. Mean ejection fraction is 49.3%, (SD=7.9). All patients have concentric left ventricular hypertrophy and right ventricular hypertrophy. Diastolic dysfunction was present in all of our patients with nine out of 13 patients (69.2%) having restrictive filling patterns (E/A ≥2.0 E/e' ≥15). On electrocardiogram, 12 (92%) patients have prolonged PR interval (median 200ms, IQR 76.50ms) and 9 (69.2%) patients have pseudoinfarct pattern. CONCLUSION Echocardiography plays an important role in diagnosing cardiac amyloidosis. The findings of concentric left ventricular hypertrophy with preserved ejection fraction without increased in loading condition should alert the clinician towards its possibility. This is further supported by right ventricular hypertrophy and particularly longitudinal strain imaging showing apical sparing pattern.
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Tan HK, Tan BK, Tan LK, Olofsson JI, Dahm-Kähler P, Brännström M. Authors' reply re: Starting a Uterus transplantation service: Notes from a small island. BJOG 2017; 125:516. [PMID: 29226565 DOI: 10.1111/1471-0528.15019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2017] [Indexed: 11/29/2022]
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Bakhtiar MF, Too CL, Tan LK, Sulaiman S, Tang MM, Fauzi NAA, Nagum AR, Joseph CT, Kwok FY, Rayappa GC. P11: NON-STEROIDAL ANTI-INFLAMMATORY DRUG INDUCED URTICARIA/ANGIOEDEMA ASSOCIATIONS WITH THE HUMAN LEUKOCYTE ANTIGEN (HLA) GENES IN A MALAY POPULATION. Intern Med J 2017. [DOI: 10.1111/imj.11_13578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Liu JY, Tan WK, Tan EL, Tan JL, Tan LK. A case of successfully managed pregnancy in a patient with complex cyanotic congenital heart disease. Obstet Med 2017; 10:88-92. [PMID: 28680470 PMCID: PMC5480644 DOI: 10.1177/1753495x16678487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 10/17/2016] [Indexed: 03/27/2024] Open
Abstract
Medical advances have increased survival of patients with congenital heart disease. However, cardiac disease in pregnancy carries significant maternal and fetal risks, posing enormous challenges to obstetricians. Cyanotic congenital heart disease is associated with maternal complications such as arrhythmias, thromboembolic events and death. Fetal complications include small for gestational age, miscarriage and prematurity. Cyanotic congenital heart disease patients who continue their pregnancies require holistic multidisciplinary team care with early and coordinated planning for delivery. Management of such patients include early counseling regarding pregnancy-associated risks, close monitoring of their cardiac function and regular scanning for fetal assessment. Choice of anesthesia for these patients requires meticulous planning to achieve a favorable balance between systemic and pulmonary vascular resistance, ensuring minimal change in right-to-left shunting. We report a case of a successfully managed pregnancy in a patient with complex congenital heart disease and a single ventricle of left ventricle morphology.
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Hui CYY, Tan WC, Tan EL, Tan LK. Repeated failed non-invasive prenatal testing in a woman with immune thrombocytopenia and antiphospholipid syndrome: lessons learnt. BMJ Case Rep 2016; 2016:bcr-2016-216593. [PMID: 27920020 DOI: 10.1136/bcr-2016-216593] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
We present a case of a 37-year-old Chinese woman (gravida 4 para 0) with a history of immune thrombocytopenia and type IIb antiphospholipid syndrome. She was started on 100 mg of aspirin, 20 mg of prednisolone and 20 mg of subcutaneous low-molecular-weight heparin daily for her fourth pregnancy. She opted for non-invasive prenatal testing for aneuploidy screening but had failed results three times consecutively from insufficient fetal cfDNA initially or high variance in cfDNA counts on redraws. She declined invasive karyotyping. Her pregnancy was complicated by severe pre-eclampsia and fetal growth restriction at 19+6 weeks of gestation and was terminated. Subsequent fetal karyotyping revealed a normal karyotype of 46XY with no apparent abnormalities.
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Chay J, Koh M, Tan HH, Ng J, Ng HJ, Chia N, Kuperan P, Tan J, Lew E, Tan LK, Koh PL, Desouza KA, Bin Mohd Fathil S, Kyaw PM, Ang AL. A national common massive transfusion protocol (MTP) is a feasible and advantageous option for centralized blood services and hospitals. Vox Sang 2015; 110:36-50. [PMID: 26178308 DOI: 10.1111/vox.12311] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 05/29/2015] [Accepted: 06/08/2015] [Indexed: 12/12/2022]
Abstract
BACKGROUND A common national MTP was jointly implemented in 2011 by the national blood service (Blood Services Group) and seven participating acute hospitals to provide rapid access to transfusion support for massively haemorrhaging patients treated in all acute care hospitals. METHODS Through a systematic clinical workflow, blood components are transfused in a ratio of 1:1:1 (pRBC: whole blood-derived platelets: FFP), together with cryoprecipitate for fibrinogen replacement. The composition of components for the MTP is fixed, although operational aspects of the MTP can be adapted by individual hospitals to suit local hospital workflow. The MTP could be activated in support of any patient with critical bleeding and at risk of massive transfusion, including trauma and non-trauma general medical, surgical and obstetric patients. RESULTS There were 434 activations of the MTP from October 2011 to October 2013. Thirty-nine per cent were for trauma patients, and 30% were for surgical patients with heavy intra-operative bleeding, with 25% and 6% for patients with gastrointestinal bleeding and peri-partum haemorrhage, respectively. Several hospitals reported reduction in mean time between request and arrival of blood. Mean transfusion ratio achieved was one red cell unit: 0·8 FFP units: 0·8 whole blood-derived platelet units: 0·4 units of cryoprecipitate. Although cryoprecipitate usage more than doubled after introduction of MTP, there was no significant rise in overall red cells, platelet and FFP usage following implementation. CONCLUSION This successful collaboration shows that shared transfusion protocols are feasible and potentially advantageous for hospitals sharing a central blood provider.
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Liew YM, McLaughlin RA, Chan BT, Aziz YFA, Chee KH, Ung NM, Tan LK, Lai KW, Ng S, Lim E. Motion corrected LV quantification based on 3D modelling for improved functional assessment in cardiac MRI. Phys Med Biol 2015; 60:2715-33. [DOI: 10.1088/0031-9155/60/7/2715] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Sidek S, Ramli N, Rahmat K, Ramli NM, Abdulrahman F, Tan LK. Glaucoma severity affects diffusion tensor imaging (DTI) parameters of the optic nerve and optic radiation. Eur J Radiol 2014; 83:1437-41. [PMID: 24908588 DOI: 10.1016/j.ejrad.2014.05.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 04/23/2014] [Accepted: 05/06/2014] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To evaluate whether MR diffusion tensor imaging (DTI) of the optic nerve and optic radiation in glaucoma patients provides parameters to discriminate between mild and severe glaucoma and to determine whether DTI derived indices correlate with retinal nerve fibre layer (RNFL) thickness. METHODS 3-Tesla DTI was performed on 90 subjects (30 normal, 30 mild glaucoma and 30 severe glaucoma subjects) and the FA and MD of the optic nerve and optic radiation were measured. The categorisation into mild and severe glaucoma was done using the Hodapp-Parrish-Anderson (HPA) classification. RNFL thickness was also assessed on all subjects using OCT. Receiver operating characteristic (ROC) analysis and Spearman's correlation coefficient was carried out. RESULTS FA and MD values in the optic nerve and optic radiation decreased and increased respectively as the disease progressed. FA at the optic nerve had the highest sensitivity (87%) and specificity (80%). FA values displayed the strongest correlation with RNFL thickness in the optic nerve (r=0.684, p ≤ 0.001) while MD at the optic radiation showed the weakest correlation with RNFL thickness (r=-0.360, p ≤ 0.001). CONCLUSIONS The high sensitivity and specificity of DTI-derived FA values in the optic nerve and the strong correlation between DTI-FA and RNFL thickness suggest that these parameters could serve as indicators of disease severity.
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Conlon N, Gallagher M, Catalano J, Howard J, Tan LK. Abstract P1-02-09: Positive predictive value (PPV) of the diagnosis of atypia in breast core biopsies: An audit of MSKCC breast pathology service. Cancer Res 2013. [DOI: 10.1158/0008-5472.sabcs13-p1-02-09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Percutaneous needle core biopsy is the standard of care in the assessment of suspicious breast lesions. The diagnostic term “Atypia” is used in breast biopsy reporting when histologic appearances are suspicious but not diagnostic of malignancy. Multiple histopathological appearances are encompassed by the umbrella term “atypia”, including atypical ductal hyperplasia (ADH), columnar cell change with atypia (CCCWA), which is also known as flat epithelial atypia (FEA), and a miscellaneous group of diagnoses, known as atypia NOS.
A pathologic diagnosis of “atypia” in breast core biopsies usually leads to a recommendation to surgically excise the lesion. Many studies have correlated the diagnosis of “atypia” in core biopsies with the subsequent finding of carcinoma in the surgical excisions, and the percentage of carcinoma found represents the positive predictive value (PPV) of the diagnosis. To date, there is no agreed target PPV for the diagnosis of breast atypia on biopsy, but the most studies have demonstrated a PPV of 20- 40%. Individual “atypia” diagnoses such as CCCWA have an even lower PPV of 10-15%.
One method of performance review is an audit of the average breast-atypia PPV within individual pathology departments, which then can be monitored and studied over time, to detect trends and “diagnostic drift” at an early stage. In addition, assessment of the individual PPV of each breast pathologist allows for analysis of the consistency of the diagnostic practice of each individual with their colleagues. Surprisingly, there have been no major studies assessing the intradepartmental range of PPVs for breast atypia diagnoses to date. In contrast, the American College of Radiology has designed the BIRADS classification system in order to audit and monitor the PPV of breast imaging in diagnosing malignancy.
We undertook to measure the departmental PPV for malignancy following a biopsy diagnosis of breast atypia, and performed an anonymized subanalysis in order to establish the range of PPVs of atypia diagnoses between the sub-specialized breast pathologists within the department.
This study established that the baseline PPV in our department is comparable to previously reported studies at 24%, while the range of PPV for an atypia diagnosis between pathologists is between 22.8 and 25% for 5 of 6 pathologists, with one pathologist demonstrating a higher PPV of 36.8%. ADH was the most common diagnosis of the atypia subtypes, and the PPV for ADH alone was 29.9%. 15% of ADH diagnoses were described as “ADH bordering on low grade DCIS”; within this subgroup the PPV was 48.5%. The PPV for a diagnosis of CCCWA alone was 10%.
This study demonstrates that the PPV for breast atypia in a major tertiary cancer center is approximately 24%. We have demonstrated very reproducible use of this diagnostic term within the department. We plan to use the findings of this study to identify subgroups of patients with a sufficiently low PPV to justify a decision not to proceed to surgical intervention. We aim to develop an algorithm for use in the clinical setting in order to direct further patient management. The ultimate aim of this research is to reduce the number of patients undergoing unnecessary surgical interventions.
Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-02-09.
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Tan LK, Lam S, Ling Low S, Hui Tan F, Ching Ng L, Teo D. Evaluation of Pathogen Reduction Systems to Inactivate Dengue and Chikungunya Viruses in Apheresis Platelets Suspended in Plasma. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/aid.2013.31001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Loh KB, Ramli N, Tan LK, Roziah M, Rahmat K, Ariffin H. Quantification of diffusion tensor imaging in normal white matter maturation of early childhood using an automated processing pipeline. Eur Radiol 2012; 22:1413-26. [PMID: 22434420 DOI: 10.1007/s00330-012-2396-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Revised: 11/29/2011] [Accepted: 12/18/2011] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The degree and status of white matter myelination can be sensitively monitored using diffusion tensor imaging (DTI). This study looks at the measurement of fractional anistropy (FA) and mean diffusivity (MD) using an automated ROI with an existing DTI atlas. METHODS Anatomical MRI and structural DTI were performed cross-sectionally on 26 normal children (newborn to 48 months old), using 1.5-T MRI. The automated processing pipeline was implemented to convert diffusion-weighted images into the NIfTI format. DTI-TK software was used to register the processed images to the ICBM DTI-81 atlas, while AFNI software was used for automated atlas-based volumes of interest (VOIs) and statistical value extraction. RESULTS DTI exhibited consistent grey-white matter contrast. Triphasic temporal variation of the FA and MD values was noted, with FA increasing and MD decreasing rapidly early in the first 12 months. The second phase lasted 12-24 months during which the rate of FA and MD changes was reduced. After 24 months, the FA and MD values plateaued. CONCLUSION DTI is a superior technique to conventional MR imaging in depicting WM maturation. The use of the automated processing pipeline provides a reliable environment for quantitative analysis of high-throughput DTI data. KEY POINTS Diffusion tensor imaging outperforms conventional MRI in depicting white matter maturation. • DTI will become an important clinical tool for diagnosing paediatric neurological diseases. • DTI appears especially helpful for developmental abnormalities, tumours and white matter disease. • An automated processing pipeline assists quantitative analysis of high throughput DTI data.
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Low JGH, Ong A, Tan LK, Chaterji S, Chow A, Lim WY, Lee KW, Chua R, Chua CR, Tan SWS, Cheung YB, Hibberd ML, Vasudevan SG, Ng LC, Leo YS, Ooi EE. The early clinical features of dengue in adults: challenges for early clinical diagnosis. PLoS Negl Trop Dis 2011; 5:e1191. [PMID: 21655307 PMCID: PMC3104968 DOI: 10.1371/journal.pntd.0001191] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 04/21/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The emergence of dengue throughout the tropical world is affecting an increasing proportion of adult cases. The clinical features of dengue in different age groups have not been well examined, especially in the context of early clinical diagnosis. METHODOLOGY/PRINCIPAL FINDINGS We structured a prospective study of adults (≥ 18 years of age) presenting with acute febrile illness within 72 hours from illness onset upon informed consent. Patients were followed up over a 3-4 week period to determine the clinical outcome. A total of 2,129 adults were enrolled in the study, of which 250 (11.7%) had dengue. Differences in the rates of dengue-associated symptoms resulted in high sensitivities when the WHO 1997 or 2009 classification schemes for probable dengue fever were applied to the cohort. However, when the cases were stratified into age groups, fewer older adults reported symptoms such as myalgia, arthralgia, retro-orbital pain and mucosal bleeding, resulting in reduced sensitivity of the WHO classification schemes. On the other hand, the risks of severe dengue and hospitalization were not diminished in older adults, indicating that this group of patients can benefit from early diagnosis, especially when an antiviral drug becomes available. Our data also suggests that older adults who present with fever and leukopenia should be tested for dengue, even in the absence of other symptoms. CONCLUSION Early clinical diagnosis based on previously defined symptoms that are associated with dengue, even when used in the schematics of both the WHO 1997 and 2009 classifications, is difficult in older adults.
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Koh BCM, Chong LL, Goh LG, Iau P, Kuperan P, Lee LH, Lim LC, Ng HJ, Sia A, Tan HH, Tan LK, Tay KH, Teo LTD, Ting WC, Yong TT. Ministry of health clinical practice guidelines: clinical blood transfusion. Singapore Med J 2011; 52:209-219. [PMID: 21451931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The Health Sciences Authority (HSA) and the Ministry of Health (MOH) publish clinical practice guidelines on Clinical Blood Transfusion to provide doctors and patients in Singapore with evidence-based guidance for blood transfusion. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the HSA-MOH clinical practice guidelines on Clinical Blood Transfusion, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov.sg/mohcorp/publications.aspx?id=25700). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.
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Yang LY, Thia EWH, Tan LK. Obstetric outcomes in women with end-stage renal disease on chronic dialysis: a review. Obstet Med 2010; 3:48-53. [PMID: 27582842 DOI: 10.1258/om.2010.100001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2010] [Indexed: 11/18/2022] Open
Abstract
Pregnancies in women on chronic dialysis for end-stage renal disease are high risk, but outcomes appear to have improved with increasing experience and advances in dialysis care. This paper reviews the existing data on outcomes in such pregnancies to enable evidence-based preconception counselling and anticipation of antenatal complications.
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Pang YP, Rajesh H, Tan LK. Molar pregnancy with false negative urine hCG: the hook effect. Singapore Med J 2010; 51:e58-e61. [PMID: 20428735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Urine pregnancy tests are widely used in emergency departments as the first screening test for patients of reproductive age presenting with gynaecological problems in order to rule out pregnancy. Conditions such as complete molar pregnancy, which produces large amounts of beta human chorionic gonadotropin (beta-hCG), may cause a false negative result due to an oversaturation of the assay system, known as the "hook effect". We report a case where the exclusion of pregnancy by urine testing led to the initial misdiagnosis of a molar pregnancy as a degenerative fibroid. Physicians need to be reminded of the possibility of false negative results with this commonly used test. Negative or inconclusive results in patients with a high suspicion of pregnancy should be further evaluated by serum quantification of beta-hCG and appropriate sample dilution.
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Koh E, Devendra K, Tan LK. B-Lynch suture for the treatment of uterine atony. Singapore Med J 2009; 50:693-697. [PMID: 19644624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
INTRODUCTION Over 125,000 women die of postpartum haemorrhage (PPH) each year, with the commonest cause being uterine atony (75-90 percent). Failing conservative management, hysterectomy is usually the final resort. In 1997, Christopher B-Lynch devised an innovative technique to treat uterine atony, and it has been widely used around the world since its original report. However, there are hardly any reports of this technique being utilised in East Asian countries, including Singapore. Our study reviews the cases in which the B-Lynch suture was used to treat uterine atony, and the clinical outcomes of these cases. METHODS A retrospective study of data of all women who delivered between May 2004 and June 2007 was collected from the department's database, to identify patients who had undergone the B-Lynch procedure. Primary PPH is defined as a blood loss of more than 500 ml at or within 24 hours of delivery. RESULTS There were a total of 5,470 deliveries during this period, with primary PPH occurring in 100 cases. The B-Lynch procedure was performed in seven women, avoiding the need for a hysterectomy in five cases. CONCLUSION Our series of cases treated with the B-Lynch procedure showed that it is an effective method of containing PPH. It has the advantage of being applied easily and rapidly, and should be taught to all trainees and registrars in obstetrics. It should be attempted when conservative management of PPH fails and before any radical surgery is considered.
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