1.Pathological findings in a mouse model for Coxsackievirus A16 infection
Yuan Teng Hooi ; Kien Chai Ong ; David Perera ; Kum Thong Wong
Neurology Asia 2015;20(4):343-347
Coxsackievirus A16 (CV-A16) is the leading cause of hand-foot-mouth disease (HFMD), which usually
presents as mild and self-limiting symptoms in young children. Rarely, CV-A16 has been reported
to cause severe and fatal neurological complications but little is known about these complications.
In the present study, 1-day and 7-day old mouse models of CV-A16 were developed using a clinical
strain via subcutaneous inoculation. All infected mice exhibited clinical signs of infection, including
reduced mobility, limb weakness and paralysis between 3 to 6 days post-infection. Pathologically,
the main organs involved were the central nervous system (CNS), skeletal muscles and brown fat. In
the CNS, viral antigens as demonstrated by immunohistochemistry, were localized mainly to neurons
in the brain stem and spinal cord, suggesting that CV-A16 is neurotropic although inflammation is
very mild. The skeletal muscles showed necrosis and myositis due to viral infection as evidenced by
the dense viral antigens. Focal viral antigens were also detected in the brown fat. These preliminary
pathological findings indicate that our mouse models can be further developed to be useful models
for pathogenesis studies, and vaccine and anti-viral drug evaluation.
Coxsackievirus Infections
2.Pathological findings in a mouse model for Coxsackievirus A16 infection
Yuan Teng Hooi ; Kien Chai Ong ; David Perera ; Kum Thong Wong
Neurology Asia 2015;20(3):343-347
Coxsackievirus A16 (CV-A16) is the leading cause of hand-foot-mouth disease (HFMD), which usually
presents as mild and self-limiting symptoms in young children. Rarely, CV-A16 has been reported
to cause severe and fatal neurological complications but little is known about these complications.
In the present study, 1-day and 7-day old mouse models of CV-A16 were developed using a clinical
strain via subcutaneous inoculation. All infected mice exhibited clinical signs of infection, including
reduced mobility, limb weakness and paralysis between 3 to 6 days post-infection. Pathologically,
the main organs involved were the central nervous system (CNS), skeletal muscles and brown fat. In
the CNS, viral antigens as demonstrated by immunohistochemistry, were localized mainly to neurons
in the brain stem and spinal cord, suggesting that CV-A16 is neurotropic although inflammation is
very mild. The skeletal muscles showed necrosis and myositis due to viral infection as evidenced by
the dense viral antigens. Focal viral antigens were also detected in the brown fat. These preliminary
pathological findings indicate that our mouse models can be further developed to be useful models
for pathogenesis studies, and vaccine and anti-viral drug evaluation.
3.Japanese encephalitis virus: Biological clones from a clinical isolate quasispecies show differing neurovirulence in vitro and in a mouse model
Shu Pin Yu ; Kien Chai Ong ; Soon Hao Tan ; David Perera ; Kum Thong Wong
Neurology Asia 2020;25(3):279-284
The Japanese encephalitis virus (JEV), a leading cause of encephalitis, exists as quasispecies in clinical
isolates. Using a limiting dilution method combined with immunohistochemistry to detect viral antigens,
10 biological clones were isolated and purified from a clinical JEV isolate (CNS138/9) derived from
an autopsy brain. These biological clones were tested for neurovirulence in SK-N-MC and NIE-115
neuronal cells, and a 2-week-old, footpad-infected, JE mouse model. Nine clones were found to be
neurovirulent; one clone neuroattenuated. Although further studies are needed to determine genotypic
differences, if any, in these clones, the limiting dilution purification and neurovirulence testing methods
described herein should be useful for phenotypic studies of quasispecies of neurotropic viruses in
general, and JEV and other flaviviruses in particular.
4.Pediatric to adult inflammatory bowel disease transition: the Asian experience
Intestinal Research 2020;18(1):11-17
Many tertiary inflammatory bowel disease (IBD) centers recognize that a structured transition program is fundamental for an IBD unit. However, the path to ensuring a seamless transition for all stakeholders is often fraught with challenges. In this review, we go through current evidence, identify the requirementsof a successful transition program, and the barriers to seamless transfer. We also aim to shed light on differences in needs between the Western and Asian adolescent IBD populations. Majority of healthcare providers viewed having a structured transition program to be very important. The lack of a standard protocol led us to come up with a list of requirements ofa successful program. These include: multidisciplinary team meetings, alternating visits between the adultand pediatric clinics, proper documentation of records, and determining the ideal timing for transfer. The difficulties forthe Asian adolescent IBD population may be attributed to the reliance on parental support to make decisions regarding medicaltreatment. Lastly, there are various physician, patient and disease factors which are barriers to seamless transition. These includethe lack of proper documentation, and lack of patient self-efficacy. We also propose a standardized template for documentation of medical records for IBD patients.
5.Magnetic resonance imaging of the fetal central nervous system in Singapore.
Phua Hwee TANG ; Chiou Li ONG ; David STRINGER ; June V K TAN ; George S H YEO
Annals of the Academy of Medicine, Singapore 2009;38(9):774-781
INTRODUCTIONFetal imaging has improved with the development of faster magnetic resonance imaging (MRI) sequences, obviating the requirement for sedation. It is useful in characterising abnormality of the central nervous system in fetuses with abnormal or equivocal antenatal ultrasound findings. We reviewed all cases of fetal brain and spine MRI performed in our institution.
MATERIALS AND METHODSAll cases of fetal central nervous system MRI imaging from May 2006 to December 2008 were retrospectively reviewed, including fetal MRI, postnatal MRI and autopsy findings.
RESULTSThirty-one fetuses were imaged with MRI for evaluation of the central nervous system of which 3 were specifically for spinal evaluation. On fetal MRI, there were 11 normal fetuses (2 with minor ventricular asymmetry), 4 fetuses with minor ventriculomegaly and 16 fetuses with significant abnormalities. Twenty-three fetuses were delivered and 8 were terminated. Fifteen of 23 babies underwent postnatal imaging, 21 had clinical follow-up and 2 were lost to clinical follow-up. Of the 11 fetuses reported as normal on fetal MRI, 3 had additional postnatal findings. A fetus with a megacisterna magna on fetal MRI was diagnosed with a posterior fossa arachnoid cyst on postnatal MRI. One, who had fetal MRI to assess suspected absent inferior cerebellar vermis, had intracranial calcifications from rubella infection. One was diagnosed with cerebro-occular-facio-skeletal (COFS) syndrome postnatally, 1 was lost to follow-up and the rest were discharged well. Seven out of 16 fetuses with significantly abnormal fetal MRI findings had confirmation of the findings on postnatal imaging. Postnatal MRI detected 2 cases of polymicrogyria which were not seen on fetal MRI. Autopsy was available in 1 abortus confirming intrauterine diagnosis of Dandy Walker malformation. A myelomeningocele was clinically obvious in 1 abortus.
CONCLUSIONFetal MRI is a good method of assessing brain and spine abnormalities in utero. However, disorders of neuronal migration remain a challenging diagnostic problem in fetal imaging.
Central Nervous System ; abnormalities ; Fetus ; Humans ; Infant, Newborn ; Magnetic Resonance Imaging ; Malformations of Cortical Development ; diagnosis ; epidemiology ; physiopathology ; Medical Audit ; Retrospective Studies ; Singapore ; epidemiology
6.Genomic and Molecular Characterization of Brain Tumors in Asian and Non-Asian Patients of Los Angeles: A Single Institution Analysis.
Courtney DUONG ; Thien NGUYEN ; John P SHEPPARD ; Vera ONG ; Lawrance K CHUNG ; Daniel T NAGASAWA ; Isaac YANG
Brain Tumor Research and Treatment 2017;5(2):64-69
BACKGROUND: Worldwide, approximately 2% of new cancers are of the brain. Five-year survival rates among brain cancer patients have been reported as a little over a third. Differences in clinical outcomes between brain tumor patients of different races remain poorly understood. METHODS: A retrospective chart review was performed on brain tumor resection patients≥18 years old. Demographics, treatment variables, and survival outcomes were collected. Primary outcomes were length of stay, recurrence rate, progression-free survival (PFS), and overall survival (OS). RESULTS: A total of 452 patients were included in analysis. Females and males had nearly a 1:1 ratio (n=242 and n=220, respectively). Mean age was 54.8 years (SD: 14.5 range: 18–90). Females composed 69% (n=48) of Asian patients; males constituted 31% (n=22). Mean age of the Asian patients was 55.9 years (SD: 14.6 range: 26–89). Asian-only cohort tumor pathologies included glioblastoma (GBM) (n=14), high-grade glioma (n=7), low-grade glioma (n=4), meningioma (n=38), and metastases (n=7). Of the 185 meningioma patients, non-Asian patients comprised 79% of the group (n=146). Of the 65 GBM patients in total, non-Asian patients made up 89% of the GBM cohort (n=58). There were no statistically significant differences between these groups of both cohorts in recurrence (p=0.1580 and p=0.6294, respectively), PFS (p=0.9662 and p=0.4048, respectively), or OS (p=0.3711 and p=0.8183, respectively). CONCLUSION: Studies evaluating the survival between patients of different racial backgrounds against several tumor varieties are rare. Patients of certain racial backgrounds may need additional consideration when being attended to despite the same mutational composition as their counterparts. Repeated studies using national databases may yield more conclusive results.
Asian Continental Ancestry Group*
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Biomarkers
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Brain Neoplasms*
;
Brain*
;
Cohort Studies
;
Continental Population Groups
;
Demography
;
Disease-Free Survival
;
Female
;
Glioblastoma
;
Glioma
;
Humans
;
Length of Stay
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Male
;
Meningioma
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Neoplasm Metastasis
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Pathology
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Recurrence
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Retrospective Studies
;
Survival Rate
7.Geographic-time distribution of ambulance calls in Singapore: utility of geographic information system in ambulance deployment (CARE 3).
Marcus E H ONG ; Faith S P NG ; Jerry OVERTON ; Susan YAP ; Derek ANDRESEN ; David K L YONG ; Swee Han LIM ; V ANANTHARAMAN
Annals of the Academy of Medicine, Singapore 2009;38(3):184-191
INTRODUCTIONPre-hospital ambulance calls are not random events, but occur in patterns and trends that are related to movement patterns of people, as well as the geographical epidemiology of the population. This study describes the geographic-time epidemiology of ambulance calls in a large urban city and conducts a time demand analysis. This will facilitate a Systems Status Plan for the deployment of ambulances based on the most cost effective deployment strategy.
MATERIALS AND METHODSAn observational prospective study looking at the geographic-time epidemiology of all ambulance calls in Singapore. Locations of ambulance calls were spot mapped using Geographic Information Systems (GIS) technology. Ambulance response times were mapped and a demand analysis conducted by postal districts.
RESULTSBetween 1 January 2006 and 31 May 2006, 31,896 patients were enrolled into the study. Mean age of patients was 51.6 years (S.D. 23.0) with 60.0% male. Race distribution was 62.5% Chinese, 19.4% Malay, 12.9% Indian and 5.2% others. Trauma consisted 31.2% of calls and medical 68.8%. 9.7% of cases were priority 1 (most severe) and 70.1% priority 2 (moderate severity). Mean call receipt to arrival at scene was 8.0 min (S.D. 4.8). Call volumes in the day were almost twice those at night, with the most calls on Mondays. We found a definite geographical distribution pattern with heavier call volumes in the suburban town centres in the Eastern and Southern part of the country. We characterised the top 35 districts with the highest call volumes by time periods, which will form the basis for ambulance deployment plans.
CONCLUSIONWe found a definite geographical distribution pattern of ambulance calls. This study demonstrates the utility of GIS with despatch demand analysis and has implications for maximising the effectiveness of ambulance deployment.
Ambulances ; utilization ; Geographic Information Systems ; Singapore
8.Effect of location of out-of-hospital cardiac arrest on survival outcomes.
E Shaun GOH ; Benjamin LIANG ; Stephanie FOOK-CHONG ; Nur SHAHIDAH ; Swee Sung SOON ; Susan YAP ; Benjamin LEONG ; Han Nee GAN ; David FOO ; Lai Peng THAM ; Rabind CHARLES ; Marcus E H ONG
Annals of the Academy of Medicine, Singapore 2013;42(9):437-444
INTRODUCTIONThis study aims to study how the effect of the location of patient collapses from cardiac arrest, in the residential and non-residential areas within Singapore, relates to certain survival outcomes.
MATERIALS AND METHODSA retrospective cohort study of data were done from the Cardiac Arrest and Resuscitation Epidemiology (CARE) project. Out-of- hospital cardiac arrest (OHCA) data from October 2001 to October 2004 (CARE) were used. All patients with OHCA as confirmed by the absence of a pulse, unresponsiveness and apnoea were included. All events had occurred in Singapore. Analysis was performed and expressed in terms of the odds ratio (OR) and the corresponding 95% confidence interval (CI).
RESULTSA total of 2375 cases were used for this analysis. Outcomes for OHCA in residential areas were poorer than in non-residential areas-1638 (68.9%) patients collapsed in residential areas, and 14 (0.9%) survived to discharge. This was significantly less than the 2.7% of patients who survived after collapsing in a non-residential area (OR 0.31 [0.16 - 0.62]). Multivariate logistic regression analysis showed that location alone had no independent effect on survival (adjusted OR 1.13 [0.32 - 4.05]); instead, underlying factors such as bystander CPR (OR 3.67 [1.13 - 11.97]) and initial shockable rhythms (OR 6.78 [1.95 - 23.53]) gave rise to better outcomes.
CONCLUSIONEfforts to improve survival from OHCA in residential areas should include increasing CPR by family members, and reducing ambulance response times.
Adult ; Aged ; Aged, 80 and over ; Ambulances ; Cardiopulmonary Resuscitation ; statistics & numerical data ; Cohort Studies ; Emergency Medical Services ; statistics & numerical data ; Female ; Geography ; Humans ; Logistic Models ; Male ; Middle Aged ; Multivariate Analysis ; Odds Ratio ; Out-of-Hospital Cardiac Arrest ; mortality ; Residence Characteristics ; statistics & numerical data ; Retrospective Studies ; Singapore ; epidemiology ; Time-to-Treatment ; statistics & numerical data ; Treatment Outcome
9.Double trouble: Establishing synchronous primary tumors of the urothelium and prostate by Immunohistomorphology: A report of two cases
David Jerome Ong ; Elizabeth Ann Alcazaren ; Jose Carnate Jr.
Philippine Journal of Pathology 2020;5(1):44-49
Synchronous primary tumors of the urothelium and prostate are a diagnostic challenge among
pathologists. Differentiating carcinomas of urothelial and prostatic origin requires careful assessment of histomorphology coupled with ancillary studies such as immunohistochemistry stains (IHC) to support the diagnosis. We report two cases of adult patients who underwent transurethral resection of the prostate (TURP), with two distinct morphologies noted on routine H&E sections. After a panel of immunohistochemical stains (HMWCK, CK5/6, CK7, CK20, GATA-3, p63, NKX3.1, and PSA), both cases were signed out as papillary urothelial carcinoma and prostatic acinar adenocarcinoma. Correlation of histomorphology with an IHC panel consisting of cytokeratins (CK5/6, CK7, CK20), a urothelial marker (GATA-3), and at least two prostatic markers (PSA, NKX3.1) is recommended in such cases.
10.99m Technetium Pertechnetate Thyroid Scan for remnant thyroid tissue detection among post-thyroidectomy patients at Jose R. Reyes Memorial Medical Center: A retrospective analysis
Athena Charisse S. Ong ; Marcelino A. Tanquilut ; Wenceslao S. Llauderes ; Emelito O. Valdez-Tan ; Ivan Ray F. David
The Philippine Journal of Nuclear Medicine 2022;17(2):36-42
This study aims to determine the diagnostic value of a 99mTc-pertechnetate (99m TcO-4) thyroid scan among
patients with DTC who underwent thyroidectomy to assess functioning thyroid remnants before radioactive
iodine therapy. A retrospective non-experimental cross-sectional design was done to compare the results of the
99m TcO-4 thyroid scan with the patient's post-RAI scan. A review of all our patients' charts was done for eight
years, and after excluding those that did not fit the criteria, 70 patients were included in the study. Data
collected was analyzed on a "per patient" basis– where patients either had a "positive scan" or "negative scan",
and on a "per lesion" basis – where every lesion's presence and size were compared on both modalities.
99m TcO-4 thyroid scan in the "per patient" analysis showed a sensitivity of 73.91%, specificity of 100%, positive
predictive value (PPV) or 100%, and accuracy of 74.29%, however, negative predictive value was determined to
be 5.26%. In the "per lesion" analysis, the scan had a less favorable performance with the computed sensitivity
of 61.69%, PPV of 94.93%, and accuracy at 59.41%. It was then concluded that 99mTc-pertechnetate scan may
be useful in determining functioning remnant thyroid tissue and subsequent management of DTC patients after
thyroidectomy, but must take note of its low negative predictive value.
Thyroid Neoplasms