54 results on '"Yap KH"'
Search Results
2. Multifocal multiview imaging and data compression based on angular-focal-spatial representation.
- Author
-
Wu K, Liu Q, Yap KH, and Yang Y
- Abstract
Multifocal multiview (MFMV) is an emerging high-dimensional optical data that allows to record richer scene information but yields huge volumes of data. To unveil its imaging mechanism, we present an angular-focal-spatial representation model, which decomposes high-dimensional MFMV data into angular, spatial, and focal dimensions. To construct a comprehensive MFMV dataset, we leverage representative imaging prototypes, including digital camera imaging, emerging plenoptic refocusing, and synthesized Blender 3D creation. It is believed to be the first-of-its-kind MFMV dataset in multiple acquisition ways. To efficiently compress MFMV data, we propose the first, to our knowledge, MFMV data compression scheme based on angular-focal-spatial representation. It exploits inter-view, inter-stack, and intra-frame predictions to eliminate data redundancy in angular, focal, and spatial dimensions, respectively. Experiments demonstrate the proposed scheme outperforms the standard HEVC and MV-HEVC coding methods. As high as 3.693 dB PSNR gains and 64.22% bitrate savings can be achieved.
- Published
- 2024
- Full Text
- View/download PDF
3. High dimensional optical data - varifocal multiview imaging, compression and evaluation.
- Author
-
Wu K, Liu Q, Yap KH, and Yang Y
- Abstract
Varifocal multiview (VFMV) is an emerging high-dimensional optical data in computational imaging and displays. It describes scenes in angular, spatial, and focal dimensions, whose complex imaging conditions involve dense viewpoints, high spatial resolutions, and variable focal planes, resulting in difficulties in data compression. In this paper, we propose an efficient VFMV compression scheme based on view mountain-shape rearrangement (VMSR) and all-directional prediction structure (ADPS). The VMSR rearranges the irregular VFMV to form a new regular VFMV with mountain-shape focusing distributions. This special rearrangement features prominently in enhancing inter-view correlations by smoothing focusing status changes and moderating view displacements. Then, the ADPS efficiently compresses the rearranged VFMV by exploiting the enhanced correlations. It conducts row-wise hierarchy divisions and creates prediction dependencies among views. The closest adjacent views from all directions serve as reference frames to improve the prediction efficiency. Extensive experiments demonstrate the proposed scheme outperforms comparison schemes by quantitative, qualitative, complexity, and forgery protection evaluations. As high as 3.17 dB gains of peak signal-to-noise ratio (PSNR) and 61.1% bitrate savings can be obtained, achieving the state-of-the-art compression performance. VFMV is also validated could serve as a novel secure imaging format protecting optical data against the forgery of large models.
- Published
- 2023
- Full Text
- View/download PDF
4. Obstructive sleep apnoea and glaucoma: a systematic review and meta-analysis.
- Author
-
Cheong AJY, Wang SKX, Woon CY, Yap KH, Ng KJY, Xu FWX, Alkan U, Ng ACW, See A, Loh SRH, Aung T, and Toh ST
- Subjects
- Humans, Cross-Sectional Studies, Data Collection, Sleep Apnea, Obstructive, Glaucoma complications, Glaucoma epidemiology, Cardiovascular Diseases
- Abstract
Introduction: Obstructive sleep apnoea (OSA) has been thought to be associated with glaucoma, however there are many conflicting studies on this topic. With many new studies having been published since the previous meta-analysis, we believe it is important to clarify this association. Hence, in this study we meta-analyse the recent literature regarding the association between OSA and glaucoma., Methods: Pubmed, Embase, Scopus and Cochrane Library were searched from inception till the 28th February 2022 for observational as well as cross-sectional studies examining the association between OSA and glaucoma. Two reviewers selected studies, extracted data, graded the quality of included non-randomized studies using the Newcastle-Ottawa scale. The overall quality of evidence was assessed using GRADE. Random-effects models were used to meta-analyse the maximally covariate- adjusted associations., Results: 48 studies were included in our systematic review, with 46 suitable for meta-analysis. Total study population was 4,566,984 patients. OSA was associated with a higher risk of glaucoma (OR 3.66, 95% CI 1.70 to 7.90, I
2 = 98%, p < 0.01). After adjustment for various important confounders including age, gender and patient comorbidities such as hyperlipidaemia, hypertension, cardiovascular diseases and diabetes, patients with OSA had up to 40% higher odds of glaucoma. Substantial heterogeneity was eliminated through subgroup and sensitivity analyses after consideration of glaucoma subtype, OSA severity and adjustment for confounders., Conclusions: In this meta-analysis, OSA was associated with higher risk of glaucoma, as well as more severe ocular findings characteristic of the glaucomatous disease process. We suggest more clinical studies looking into the effects of OSA treatment on the progression of glaucoma to help clinical decision making for patients., (© 2023. The Author(s), under exclusive licence to The Royal College of Ophthalmologists.)- Published
- 2023
- Full Text
- View/download PDF
5. Profiling neuroprotective potential of trehalose in animal models of neurodegenerative diseases: a systematic review.
- Author
-
Yap KH, Azmin S, Makpol S, Damanhuri HA, Mustapha M, Hamzah JC, and Ibrahim NM
- Abstract
Trehalose, a unique nonreducing crystalline disaccharide, is a potential disease-modifying treatment for neurodegenerative diseases associated with protein misfolding and aggregation due to aging, intrinsic mutations, or autophagy dysregulation. This systematic review summarizes the effects of trehalose on its underlying mechanisms in animal models of selected neurodegenerative disorders (tau pathology, synucleinopathy, polyglutamine tract, and motor neuron diseases). All animal studies on neurodegenerative diseases treated with trehalose published in Medline (accessed via EBSCOhost) and Scopus were considered. Of the 2259 studies screened, 29 met the eligibility criteria. According to the SYstematic Review Center for Laboratory Animal Experiment (SYRCLE) risk of bias tool, we reported 22 out of 29 studies with a high risk of bias. The present findings support the purported role of trehalose in autophagic flux and protein refolding. This review identified several other lesser-known pathways, including modifying amyloid precursor protein processing, inhibition of reactive gliosis, the integrity of the blood-brain barrier, activation of growth factors, upregulation of the downstream antioxidant signaling pathway, and protection against mitochondrial defects. The absence of adverse events and improvements in the outcome parameters were observed in some studies, which supports the transition to human clinical trials. It is possible to conclude that trehalose exerts its neuroprotective effects through both direct and indirect pathways. However, heterogeneous methodologies and outcome measures across the studies rendered it impossible to derive a definitive conclusion. Translational studies on trehalose would need to clarify three important questions: 1) bioavailability with oral administration, 2) optimal time window to confer neuroprotective benefits, and 3) optimal dosage to confer neuroprotection., Competing Interests: None
- Published
- 2023
- Full Text
- View/download PDF
6. Movement Disorders Resulting From Bilateral Basal Ganglia Lesions in End-Stage Kidney Disease: A Systematic Review.
- Author
-
Yap KH, Baharudin NH, Gafor AHA, Remli R, Lim SY, Zaidi WAW, Azmin S, Mukari SAM, Khalid RA, and Ibrahim NM
- Abstract
Objective: The basal ganglia (BG) are susceptible to fluctuations in blood urea levels, sometimes resulting in movement disorders. We described patients with end-stage kidney disease (ESKD) presenting with movement disorders associated with bilateral BG lesions on imaging., Methods: We report four patients and systematically reviewed all published cases of ESKD presenting with movement disorders and bilateral BG lesions (EBSCOhost and Ovid)., Results: Of the 72 patients identified, 55 (76.4%) were on regular dialysis. Parkinsonism was the most common movement disorder (n = 39; 54.2%), followed by chorea (n = 24; 33.3%). Diabetes mellitus (n = 51; 70.8%) and hypertension (n = 16; 22.2%) were the most common risk factors. Forty-three (59.7%) were of Asian ethnicity. Complete clinical resolution was reported in 17 (30.9%) patients, while 38 (69.1%) had incomplete clinical resolution with relapse. Complete radiological resolution occurred in 14 (34.1%) patients., Conclusion: Movement disorders associated with BG lesions should be recognized as a rare and potentially reversible metabolic movement disorder in patients with ESKD.
- Published
- 2022
- Full Text
- View/download PDF
7. Protocol for a feasibility evaluation of a Social and Emotional Learning (SEL) programme to improve resilience and academic achievement in refugee children from a community learning centre in Malaysia: PARSEL (Participatory Action Research on SEL).
- Author
-
Yap KH, Koh A, Kumar A, Lahpai M, Cheng KH, Ravindaran T, Vasu P, and Verghis S
- Subjects
- Child, Feasibility Studies, Health Services Research, Humans, Malaysia, Academic Success, Refugees
- Abstract
This paper describes a protocol for the feasibility evaluation of the Participatory Action Research on Social and Emotional Learning (PARSEL) programme. PARSEL aims to contribute towards the development of academic achievement and resilience among urban refugee students in a community learning centre in an upper middle-income country. The evaluation is a single arm pre-post design using a mixed methods approach, with the main focus on the feasibility of the programme. Measurements of impact are also included as the secondary outcomes of the study. The programme aims to enrol students from refugee background in a community learning centre. The programme is estimated to run for 18 months and the study is due to report in the end of fourth quarter of 2022., Competing Interests: Dr Verghis is on the Board of the organization, Health Equity Initiatives and Solutions Bhd (HEI) through which the main funding body has provided funds for this project. She is not paid by the organization and is not involved in the day-to-day operations. The appropriate conflict of interest form has been duly filled and approved at all levels in the university after establishing commitments of oversight by the supervisor and Head of School and criteria agreed for decision making on the project’s budget which removes her from participating in the decisions. S.V has been working in the area of refugee health at a wider community level for several years. Although the principal and teachers in the school are aware of her role in HEI and in this project, this was also briefed and disclosed during the initial meetings with the school. Other authors listed in this manuscript declare that they have neither financial nor competing interests. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
- Published
- 2022
- Full Text
- View/download PDF
8. Magnetic Resonance Imaging and Its Clinical Correlation in Spinocerebellar Ataxia Type 3: A Systematic Review.
- Author
-
Yap KH, Abdul Manan H, Yahya N, Azmin S, Mohamed Mukari SA, and Mohamed Ibrahim N
- Abstract
Background: Spinocerebellar ataxia type 3 (SCA3) is a complex cerebrocerebellar disease primarily characterized by ataxia symptoms alongside motor and cognitive impairments. The heterogeneous clinical presentation of SCA3 necessitates correlations between magnetic resonance imaging (MRI) and clinical findings in reflecting progressive disease changes. At present, an attempt to systematically examine the brain-behavior relationship in SCA3, specifically, the correlation between MRI and clinical findings, is lacking., Objective: We investigated the association strength between MRI abnormality and each clinical symptom to understand the brain-behavior relationship in SCA3., Methods: We conducted a systematic review on Medline and Scopus to review studies evaluating the brain MRI profile of SCA3 using structural MRI (volumetric, voxel-based morphometry, surface analysis), magnetic resonance spectroscopy, and diffusion tensor imaging, including their correlations with clinical outcomes., Results: Of 1,767 articles identified, 29 articles met the eligibility criteria. According to the National Institutes of Health quality assessment tool for case-control studies, all articles were of excellent quality. This systematic review found that SCA3 neuropathology contributes to widespread brain degeneration, affecting the cerebellum and brainstem. The disease gradually impedes the cerebral cortex and basal ganglia in the late stages of SCA3. Most findings reported moderate correlations ( r = 0.30-0.49) between MRI features in several regions and clinical findings. Regardless of the MRI techniques, most studies focused on the brainstem and cerebellum., Conclusions: Clinical findings suggest that rather than individual brain regions, the connectivity between different brain regions in distributed networks (i.e., cerebellar-cerebral network) may be responsible for motor and neurocognitive function in SCA3. This review highlights the importance of evaluating the progressive changes of the cerebellar-cerebral networks in SCA3 patients, specifically the functional connectivity. Given the relative lack of knowledge about functional connectivity on SCA3, future studies should investigate possible functional connectivity abnormalities in SCA3 using fMRI., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yap, Abdul Manan, Yahya, Azmin, Mohamed Mukari and Mohamed Ibrahim.)
- Published
- 2022
- Full Text
- View/download PDF
9. Pharmacological and non-pharmacological management of spinocerebellar ataxia: A systematic review.
- Author
-
Yap KH, Azmin S, Che Hamzah J, Ahmad N, van de Warrenburg B, and Mohamed Ibrahim N
- Subjects
- Ataxia diagnosis, Humans, Quality of Life, Cerebellar Ataxia, Spinocerebellar Ataxias drug therapy, Spinocerebellar Ataxias genetics, Transcranial Direct Current Stimulation
- Abstract
Spinocerebellar ataxias (SCA) comprise a rare, genetic subgroup within the degenerative ataxias and are dominantly inherited, with up to 48 recognized genetic subtypes. While an updated review on the management of degenerative ataxia is published recently, an evidence-based review focussed on the management of SCA is lacking. Here, we reviewed the pharmacological and non-pharmacological management of SCA by conducting a systematic review on Medline Ovid and Scopus. Of 29,284 studies identified, 47 studies (pharmacological: n = 25; non-pharmacological: n = 22) that predominantly involved SCA patients were included. Twenty studies had a high risk of bias based on the Cochrane's Collaboration risk of bias tool. As per the European Federation of Neurological Societies 2004 guideline for therapeutic intervention, the remaining 27 studies were of Class I (n = 4) and Class II (n = 23) evidence. Only two therapies had Level A recommendations for the management of ataxia symptoms: riluzole and immediate in-patient neurorehabilitation. Ten therapies had Level B recommendations for managing ataxia symptoms and require further investigations with better study design. These include high dose valproate acid, branched-chain amino acid, intravenous trehalose; restorative rehabilitation using cycling regimen and videogame; and cerebellar stimulations using transcranial direct current stimulation and transcranial magnetic stimulation. Lithium and coaching on psychological adjustment received Level B recommendation for depressive symptoms and quality of life, respectively. Heterogeneous study designs, different genotypes, and non-standardized clinical measures alongside short duration and small sample sizes may hamper meaningful clinical translation. Therefore, rating of recommendations only serve as points of reference., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)
- Published
- 2022
- Full Text
- View/download PDF
10. Neurocognitive Changes in Spinocerebellar Ataxia Type 3: A Systematic Review with a Narrative Design.
- Author
-
Yap KH, Kessels RPC, Azmin S, van de Warrenburg B, and Mohamed Ibrahim N
- Subjects
- Ataxia, Executive Function, Humans, Neuropsychological Tests, Quality of Life, Machado-Joseph Disease
- Abstract
Spinocerebellar ataxia type 3 (SCA3), the commonest dominantly inherited ataxia worldwide, is characterized by disruption in the cerebellar-cerebral and striatal-cortical networks. Findings on SCA3-associated cognitive impairments are mixed. The classification models, tests and scoring systems used, language, culture, ataxia severity, and depressive symptoms are all potential confounders in neuropsychological assessments and may have contributed to the heterogeneity of the neurocognitive profile of SCA3. We conducted a systematic review of studies evaluating neurocognitive function in SCA3 patients. Of 1304 articles identified, 15 articles met the eligibility criteria. All articles were of excellent quality according to the National Institutes of Health quality assessment tool for case-control studies. In line with the disrupted cerebellar-cerebral and striatal-cortical networks in SCA3, this systematic review found that the neurocognitive profile of SCA3 is characterized by a core impairment of executive function that affects processes such as nonverbal reasoning, executive aspects of language, and recall. Conversely, neurocognitive domains such as general intelligence, verbal reasoning, semantic aspect of language, attention/processing speed, recognition, and visuospatial perception and construction are relatively preserved. This review highlights the importance of evaluating neurocognitive function in SCA3 patients. Considering the negative impact of cognitive and affective impairment on quality of life, this review points to the profound impairments that existing or future treatments should prioritize., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2022
- Full Text
- View/download PDF
11. Protocol for a systematic review assessing the measurement of dietary sodium intake among adults with elevated blood pressure.
- Author
-
Soh YC, Yap KH, McGrattan A, Yasin S, Reidpath D, Siervo M, and Mohan D
- Subjects
- Adolescent, Adult, Antihypertensive Agents therapeutic use, Blood Pressure, Cross-Sectional Studies, Humans, Sodium Chloride, Dietary, Systematic Reviews as Topic, Hypertension drug therapy
- Abstract
Introduction: Accurate sodium intake estimates in adults with elevated blood pressure are essential for monitoring salt reduction progress and preventing cardiovascular diseases. However, sodium assessments are challenging in this high-risk population because many commonly used antihypertensive drugs alter urinary sodium excretion. Despite the high cost and substantial participant burden of gold-standard 24-hour urine collection, the relative performance of existing spot-urine based equations and dietary self-report instruments have not been well studied in this population, who will benefit from salt restriction. This systematic review aims to describe the current methods of assessing dietary sodium intake in adults with elevated blood pressure and determine what method can provide a valid and accurate estimate of sodium intake compared with the gold standard 24-hour urine collection., Methods and Analysis: Studies assessing sodium intake in adults aged 18 years and above with reported elevated blood pressure will be included. Five electronic databases (MEDLINE, Embase, Global Health, WoS and Cochrane CENTRAL) will be systematically searched from inception to March 2021. Also, a manual search of bibliographies and grey literature will be conducted. Two reviewers will screen the records independently for eligibility. One reviewer will extract all data, and two others will review the extracted data for accuracy. The methodological quality of included studies will be evaluated based on three scoring systems: (1) National Heart, Lung and Blood Institute for interventional studies; (2) Biomarker-based Cross-sectional Studies for biomarker-based observational studies and (3) European Micronutrient Recommendation Aligned Network of Excellence for validation studies of dietary self-report instruments., Ethics and Dissemination: As the proposed systematic review will collect and analyse secondary data associated with individuals, there will be no ethical approval requirement. Findings will be disseminated in a peer-reviewed journal or presented at a conference., Prospero Registration Number: CRD42020176137., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2022
- Full Text
- View/download PDF
12. Combination of slide tracheoplasty and side-to-side bronchoplasty for complex congenital tracheobronchial stenosis.
- Author
-
Chan JL, Yap KH, Teoh OH, and Nakao M
- Subjects
- Bronchi diagnostic imaging, Bronchi surgery, Constriction, Pathologic, Humans, Infant, Retrospective Studies, Trachea diagnostic imaging, Trachea surgery, Treatment Outcome, Bronchial Diseases diagnostic imaging, Bronchial Diseases surgery, Plastic Surgery Procedures, Tracheal Stenosis diagnostic imaging, Tracheal Stenosis surgery
- Abstract
Congenital tracheal stenosis is a rare but serious condition with high mortality and morbidity. We present a 6-month-old patient with complex congenital tracheal stenosis involving the trachea, carina and right bronchus intermedius, which was corrected with a combination of slide tracheoplasty and side-to-side bronchoplasty., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
13. Challenges for Diagnostic Clarity for Post-stroke Cognitive Impairment and Behavioural Issues in Middle-Income Countries: Case Studies From Malaysia.
- Author
-
Yap KH, Warren N, Allotey P, and Reidpath D
- Abstract
Following stroke, individuals require ongoing screening, diagnosis and monitoring for cognitive impairment. Services and policies around these vary widely between settings, and reports from many countries highlight persistent under-diagnosis of cognitive impairment in the months and years after stroke. Missed and delayed diagnosis of post-stroke cognitive impairment, including dementia, are important factors in shaping the experiences of people so affected and their family members, especially in low- and middle-income countries. Drawing upon ethnographic research conducted in Malaysia, this article draws upon three case studies to examine the continued health-seeking behaviour after the appearance of salient cognitive and behavioural symptoms that occurred after stroke. Findings highlight the challenges in getting formal diagnostic clarity for cognitive and behavioural symptoms in a rural setting within a middle-income country. No study participants sought help for memory or cognitive problems, partly due to limited lay awareness of cognitive impairment but more significantly due to health service factors. Despite their elevated risk for dementia, participants were not monitored for cognitive impairment during any follow-up care in various health facilities. Furthermore, caregivers' attempts to seek help when behavioural issues became untenable were met with multiple health system barriers. The journey was complicated by the meanings attached to the reactions towards cognitive symptoms at the community level. We suggest that strategies seek to increase the awareness of post-stroke cognitive and behavioural symptoms, and incorporate clear treatment pathways into the long-term care plans of community-dwelling stroke survivors., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Yap, Warren, Allotey and Reidpath.)
- Published
- 2021
- Full Text
- View/download PDF
14. The Unintended Consequences of the Pandemic: The New Normal for College Students in South Korea and Taiwan.
- Author
-
Chen WL, Song SY, and Yap KH
- Subjects
- Humans, Republic of Korea epidemiology, SARS-CoV-2, Students, Taiwan epidemiology, COVID-19, Pandemics
- Abstract
This study attempts to compare the impacts of the coronavirus (COVID-19) pandemic on college students' lifestyles and mental health conditions in South Korea and Taiwan. As the COVID-19 outbreak has spread across the globe, it has brought significant changes to college campuses worldwide. College students have been heavily affected by the closure, as online learning has become increasingly common in higher education institutions. Using data collected from college students in South Korea and Taiwan in the spring of 2020, this study examines the effects of pandemic-related lifestyle changes on mental health conditions for college students in the two countries. The results were 3-fold. First, compared to college students in Taiwan, college students in South Korea reported greater decreases in time spent traveling, being with friends, eating at restaurants, and engaging in part-time employment, and greater increases in online shopping and ordering food for delivery. Second, college students in South Korea reported a higher level of worry, a greater possibility of contact with a person with COVID-19, and a lower level of happiness than did college students in Taiwan. Third, our findings indicate that social activities, including spending time with friends, were positively correlated with mental health conditions in South Korea and Taiwan. Comparing Korean and Taiwanese students' lifestyle changes and mental health conditions amid the pandemic, the study argues that the decrease in socialization and interaction under these new circumstances may be a significant factor that explains an increase in mental health issues in Korean college students compared to Taiwanese students, given the increase in confirmed COVID-19 cases in South Korea and the corresponding greater use of online teaching platforms there than in Taiwan., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Chen, Song and Yap.)
- Published
- 2021
- Full Text
- View/download PDF
15. Modified ultrafiltration reduces postoperative blood loss and transfusions in adult cardiac surgery: a meta-analysis of randomized controlled trials.
- Author
-
Low ZK, Gao F, Sin KYK, and Yap KH
- Subjects
- Adult, Blood Transfusion, Cardiopulmonary Bypass adverse effects, Humans, Randomized Controlled Trials as Topic, Ultrafiltration, Cardiac Surgical Procedures adverse effects, Hemofiltration, Postoperative Hemorrhage etiology, Postoperative Hemorrhage prevention & control
- Abstract
Objectives: Cardiopulmonary bypass in cardiac surgery has been associated with several deleterious effects including haemodilution and systemic inflammation. Modified ultrafiltration (MUF) has been well established in paediatric cardiac surgery in counteracting postperfusion syndrome. However, MUF is less commonly used in adult cardiac surgery. In this meta-analysis, we compared clinical outcomes in adult patients who underwent cardiopulmonary bypass with and without MUF., Methods: Electronic searches were performed using Pubmed, Ovid Medline, EMBASE and the Cochrane Library until April 2020. Selection criteria were randomized studies of adult cardiac surgery patients comparing MUF versus no MUF. Primary outcomes were postoperative mortality, haematocrit, blood transfusion, chest tube drainage, duration of intensive care unit (ICU) stay and duration of mechanical ventilation., Results: Thirteen randomized controlled trials were included, comprising 626 patients in the MUF group, and 610 patients in the control (no-MUF) group. There was a significantly improved postoperative haematocrit [mean difference 2.70, 95% confidence interval (CI) 0.68-4.73, P = 0.009], lower chest tube drainage (mean difference -105 ml, 95% CI -202 to -7 ml, P = 0.032), lower postoperative blood transfusion rate (mean difference -0.73 units, 95% CI -0.98 to -0.47 units, P < 0.0001) and shorter duration of ICU stay (mean difference -0.13 days, 95% CI -0.27 to -0.00 days, P = 0.048) in the MUF group. There was no difference in ventilation time (mean difference -0.47 h, 95% CI -2.05 to 1.12 h, P = 0.56) or mortality rates (odds ratio 0.62, 95% CI 0.28-1.33, P = 0.22). There were no reported complications associated with MUF., Conclusions: MUF is a safe and feasible option in adult cardiac patients, with significant benefits including improved postoperative haematocrit, as well as reduced postoperative chest tube bleeding, transfusion requirements and duration of ICU stay., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
16. Congenital diaphragmatic hernia repair in patients requiring extracorporeal membrane oxygenation: are outcomes better with repair on ECMO or after decannulation?
- Author
-
Low ZK, Tan ASM, Nakao M, and Yap KH
- Subjects
- Herniorrhaphy adverse effects, Humans, Retrospective Studies, Survival Rate, Extracorporeal Membrane Oxygenation adverse effects, Hernias, Diaphragmatic, Congenital surgery
- Abstract
A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether congenital diaphragmatic hernia repair outcomes are better before or after decannulation in infants requiring extracorporeal membrane oxygenation (ECMO). A total of 884 papers were found using the reported search, of which 9 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that infants with congenital diaphragmatic hernia requiring ECMO should undergo a trial of weaning and aim for post-decannulation repair, as this has been associated with improved survival, shorter ECMO duration and fewer bleeding complications. However, if weaning of ECMO is unsuccessful, the patient should ideally undergo early on-ECMO repair (within 72 h of cannulation), which has been associated with improved survival, less bleeding, shorter ECMO duration and fewer circuit changes compared to late on-ECMO repair. Anticoagulation protocols including perioperative administration of aminocaproic acid or tranexamic acid, as well as close perioperative monitoring of coagulation parameters have been associated with reduced bleeding risk with on-ECMO repairs., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
17. Congenital left atrial appendage aneurysm with unexpected course of left anterior descending coronary artery.
- Author
-
Low ZK, Yap KH, Fortier MV, and Nakao M
- Subjects
- Atrial Appendage diagnostic imaging, Coronary Vessels diagnostic imaging, Heart Aneurysm diagnostic imaging, Heart Defects, Congenital diagnostic imaging, Humans, Infant, Newborn, Male, Retrospective Studies, Tomography, X-Ray Computed methods, Atrial Appendage surgery, Coronary Vessels surgery, Heart Aneurysm surgery, Heart Defects, Congenital surgery
- Abstract
The left atrial appendage (LAA) aneurysm is a rare condition that can produce local compressive effects and complications including supraventricular tachyarrhythmias, thromboembolic events and myocardial ischaemia. We present a rare case of a neonate with a congenital LAA aneurysm which resulted in local compressive effects on the left ventricle, severe mitral regurgitation and malposition of the left anterior descending (LAD) coronary artery. Intraoperatively, the LAD was found to be within the aneurysmal wall exterior to the left ventricular epicardium and was inadvertently injured during LAA aneurysm resection. Retrospective review of the preoperative computed tomography and echocardiography scans demonstrated the LAD lying within the wall of the LAA aneurysm, although this had not been well appreciated at that time. This highlights the importance of thorough multimodal preoperative imaging and intraoperative assessment for recognition of this rare association between the LAA aneurysm and LAD malposition, and prevention of inadvertent LAD injury during aneurysm resection., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
18. Understandings of stroke in rural Malaysia: ethnographic insights.
- Author
-
Yap KH, Warren N, Allotey P, and Reidpath DD
- Subjects
- Caregivers, Humans, Malaysia, Survivors, Stroke, Stroke Rehabilitation
- Abstract
Background: Stroke is a public health concern in Malaysia but local beliefs and lay understandings of stroke have not been examined before. Explanatory models provide a way for people to make sense of their illness and influence health seeking behaviors, in a locally relevant way., Methods: Drawing on ethnographic research from rural Malaysia, this descriptive article explores ethnic Malaysian-Chinese stroke survivors' lay understandings of stroke. Eighteen community-dwelling stroke survivors aged 50-83 took part in the study., Results: Causation of stroke was derived from cultural, biomedical and social sources. Participants also drew simultaneously from both biomedical and traditional explanations of stroke to develop their own understanding of etiology. Similarities with biomedical causation and other studies from different cultures were found. Participants' typically focused on the more immediate effects of stroke and often do not attribute causation and association with their comorbid conditions which are also risk factors of stroke., Conclusion: Lack of knowledge about stroke and its symptoms was evident in participants' account. Findings emphasize the importance of knowledge based health interventions, especially in health education strategies for stroke survivors to reduce delays to diagnosis and potentially improve health outcomes post-stroke. Implications for rehabilitation Stroke survivors often form explanatory models of stroke that draw from both biomedical and traditional explanations of stroke. Understanding how people derive lay understandings of stroke can contribute towards developing the goals and activities that facilitate recovery and rehabilitation in similar settings. Health practitioners in the community should strengthen communication regarding the identification, etiology and risk factors of stroke with stroke survivors and their carers to improve compliance to medication, exercise and diet for better recovery. Sustained health education which is culturally relevant is recommended. Communication should also include non-physical impact of stroke (such as cognitive deficits and emotional difficulties) as the stroke survivors were unlikely to relate such symptoms to stroke.
- Published
- 2021
- Full Text
- View/download PDF
19. Heterogeneity in brain functional changes of cognitive processing in ADHD across age: A systematic review of task-based fMRI studies.
- Author
-
Yap KH, Abdul Manan H, and Sharip S
- Subjects
- Adolescent, Adult, Attention Deficit Disorder with Hyperactivity diagnostic imaging, Cerebral Cortex diagnostic imaging, Cerebral Cortex growth & development, Child, Corpus Striatum diagnostic imaging, Corpus Striatum growth & development, Female, Humans, Male, Nerve Net diagnostic imaging, Nerve Net growth & development, Young Adult, Attention Deficit Disorder with Hyperactivity physiopathology, Cerebral Cortex physiopathology, Corpus Striatum physiopathology, Executive Function physiology, Human Development physiology, Magnetic Resonance Imaging, Memory, Short-Term physiology, Nerve Net physiopathology, Psychomotor Performance physiology
- Abstract
This review aims to establish the cognitive processing of patients with attention-deficit hyperactive disorder (ADHD) across age. Functional magnetic resonance imaging (fMRI) studies on children and adult populations were conducted, thus delineating deficits that could have been maintained and ameliorated across age. This allowed for the examination of the correlation between patterns of brain activation and the corresponding development of functional heterogeneity in ADHD. A systematic literature search of fMRI studies on ADHD was conducted using the PubMed and Scopus electronic databases based on PRISMA guidelines. References and citations were verified in Scopus database. The present study has identified 14 studies on children, 16 studies on adults, and one study on both populations of ADHD consisting of 1371 participants. Functional heterogeneity is present in ADHD across age, which can manifest either as different brain activation patterns, intra-subject variability, or both. This is shown in the increased role of the frontal regions and the specialized network in adults with ADHD from inefficient non-specific activation in childhood. Functional heterogeneity may manifest when delayed maturation is insufficient to normalize frontal lobe functions., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
20. Catalpol Ameliorates Insulin Sensitivity and Mitochondrial Respiration in Skeletal Muscle of Type-2 Diabetic Mice Through Insulin Signaling Pathway and AMPK/SIRT1/PGC-1α/PPAR-γ Activation.
- Author
-
Yap KH, Yee GS, Candasamy M, Tan SC, Md S, Abdul Majeed AB, and Bhattamisra SK
- Subjects
- AMP-Activated Protein Kinase Kinases, Animals, Diabetes Mellitus, Type 2 genetics, Diabetes Mellitus, Type 2 metabolism, Diabetes Mellitus, Type 2 pathology, Disease Models, Animal, Humans, Insulin genetics, Insulin metabolism, Insulin Resistance genetics, Mice, Inbred NOD genetics, Mitochondrial Diseases, Muscle, Skeletal drug effects, Muscle, Skeletal metabolism, Muscle, Skeletal pathology, Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha genetics, Signal Transduction drug effects, Diabetes Mellitus, Type 2 drug therapy, Iridoid Glucosides pharmacology, PPAR gamma genetics, Protein Kinases genetics, Sirtuin 1 genetics
- Abstract
Catalpol was tested for various disorders including diabetes mellitus. Numerous molecular mechanisms have emerged supporting its biological effects but with little information towards its insulin sensitizing effect. In this study, we have investigated its effect on skeletal muscle mitochondrial respiration and insulin signaling pathway. Type-2 diabetes (T2DM) was induced in male C57BL/6 by a high fat diet (60% Kcal) and streptozotocin (50 mg/kg, i.p.). Diabetic mice were orally administered with catalpol (100 and 200 mg/kg), metformin (200 mg/kg), and saline for four weeks. Fasting blood glucose (FBG), HbA1c, plasma insulin, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), oxygen consumption rate, gene (IRS-1, Akt, PI3k, AMPK, GLUT4, and PGC-1α) and protein (AMPK, GLUT4, and PPAR-γ) expression in muscle were measured. Catalpol (200 mg/kg) significantly ( p < 0.05) reduced the FBG, HbA1C, HOMA_IR index, and AUC of OGTT whereas, improved the ITT slope. Gene (IRS-1, Akt, PI3k, GLUT4, AMPK, and PGC-1α) and protein (AMPK, p-AMPK, PPAR-γ and GLUT4) expressions, as well as augmented state-3 respiration, oxygen consumption rate, and citrate synthase activity in muscle was observed in catalpol treated mice. The antidiabetic activity of catalpol is credited with a marked improvement in insulin sensitivity and mitochondrial respiration through the insulin signaling pathway and AMPK/SIRT1/PGC-1α/PPAR-γ activation in the skeletal muscle of T2DM mice.
- Published
- 2020
- Full Text
- View/download PDF
21. Black Pleural Effusion: When Lung White(out) Turns Black.
- Author
-
Ng Z, Tan GP, and Yap KH
- Subjects
- Black or African American, Humans, Lung diagnostic imaging, Lung Neoplasms, Pleural Effusion diagnostic imaging
- Published
- 2020
22. Chronic disease profiles of subjective memory complaints: a latent class analysis of older people in a rural Malaysian community.
- Author
-
Yap KH, Warren N, Allotey P, and Reidpath DD
- Subjects
- Aged, Chronic Disease, Cross-Sectional Studies, Humans, Latent Class Analysis, Memory, Multimorbidity
- Abstract
Background: Subjective memory complaints (SMC) are common in the elderly and have been suggested as the first subtle sign of decline which can predict dementia. Cognitive decline is thought to be related to inflammatory processes similarly found in other chronic diseases and conditions such as stroke, heart disease and arthritis. This study aimed to examine the association of SMC with chronic diseases and the profile of these health conditions reported by a group of older adults. Methods: Data from a cross-sectional survey conducted from August 2013 and March 2014 was drawn from 6179 individuals aged 56 years and above. Multivariable logistic regression analyses were used to examine SMC's relationship with individual chronic diseases (asthma, kidney disease, heart disease, stroke, arthritis, hypertension and diabetes) and multimorbidity. Latent class analysis (LCA) was used to identify the profile of health conditions. The effect of SMC was estimated in a multinomial logistic regression as part of the latent class model. Results: SMC was statistically significant in its association with asthma, stroke, heart disease, arthritis and multimorbidity in the fully controlled multivariable logistic regression models. Three health profiles were identified: low comorbidity ( n = 4136, low rates in all health conditions), arthritis group ( n = 860) and diabetes and hypertension group ( n = 1183). SMC was associated with arthritis group (OR = 2.04, 95% CI = 1.51-2.75) and diabetes and hypertension group (OR = 1.22, 95% CI = 1.03-1.46). Conclusion: Adapting a combination of analytical approaches allows a better understanding in the assessment of SMC's relationship with chronic diseases and the patterns of distribution of these health conditions.
- Published
- 2020
- Full Text
- View/download PDF
23. Does concurrent use of intra-aortic balloon pumps improve survival in patients with cardiogenic shock requiring venoarterial extracorporeal membrane oxygenation?
- Author
-
Wang D, Chao V, Yap KH, and Tan TE
- Subjects
- Global Health, Hospital Mortality, Humans, Incidence, Shock, Cardiogenic epidemiology, Survival Rate trends, Cardiac Surgical Procedures methods, Extracorporeal Membrane Oxygenation methods, Heart-Assist Devices, Intra-Aortic Balloon Pumping methods, Shock, Cardiogenic surgery
- Abstract
A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'Does concurrent use of intra-aortic balloon pump (IABP) improve survival in patients with cardiogenic shock requiring venoarterial extracorporeal membrane oxygenation (VA-ECMO)?'. Altogether 472 papers were found using the reported search, of which 3 level 2 systematic reviews represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The reported comparative outcomes were mortality, weaning off extracorporeal membrane oxygenation (ECMO), vascular complications and non-vascular complications. One systematic review demonstrated significantly lower in-hospital mortality with concurrent use of IABP and VA-ECMO, while the other 2 studies showed no difference in mortality. One paper reported on the weaning success from ECMO and demonstrated significantly higher weaning success with concurrent IABP usage. Another paper reported on the complications and showed no differences in vascular and non-vascular complications. We conclude that there was no significant improvement in survival with the concurrent use of IABP and VA-ECMO for a cardiogenic shock as compared to the use of VA-ECMO alone. However, the concurrent use of IABP with VA-ECMO improved weaning success from VA-ECMO. The incidence of vascular and non-vascular complications was similar with or without IABP usage., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
24. Assessing Neural Compensation With Visuospatial Working Memory Load Using Near-Infrared Imaging.
- Author
-
Ung WC, Yap KH, Ebenezer EGM, Chin PS, Nordin N, Chan SC, Yip HL, Lu CK, Kiguchi M, and Tang TB
- Subjects
- Aged, Aged, 80 and over, Algorithms, Alzheimer Disease diagnostic imaging, Alzheimer Disease psychology, Brain Mapping, Cognitive Dysfunction diagnostic imaging, Cost of Illness, Educational Status, Feasibility Studies, Female, Humans, Male, Mental Status and Dementia Tests, Middle Aged, Prefrontal Cortex diagnostic imaging, Psychomotor Performance, Spectroscopy, Near-Infrared, Dementia diagnostic imaging, Dementia psychology, Memory, Short-Term, Neuroimaging methods, Space Perception, Visual Perception
- Abstract
Alzheimer's disease is characterized by the progressive deterioration of cognitive abilities particularly working memory while mild cognitive impairment (MCI) represents its prodrome. It is generally believed that neural compensation is intact in MCI but absent in Alzheimer's disease. This study investigated the effects of increasing task load as a means to induce neural compensation through a novel visual working memory (VSWM) task using functional near-infrared spectroscopy (fNIRS). The bilateral prefrontal cortex (PFC) was explored due to its relevance in VSWM and neural compensation. A total of 31 healthy controls (HC), 12 patients with MCI and 18 patients with mild Alzheimer's disease (mAD) were recruited. Although all groups showed sensitivity in terms of behavioral performance (i.e. score) towards increasing task load (level 1 to 3), only in MCI load effect on cortical response (as measured by fNIRS) was significant. At lower task load, bilateral PFC activation did not differ between MCI and HC. Neural compensation in the form of hyperactivation was only noticeable in MCI with a moderate task load. Lack of hyperactivation in mAD, coupled with significantly poorer task performance across task loads, suggested the inability to compensate due to a greater degree of neurodegeneration. Our findings provided an insight into the interaction of cognitive load theory and neural compensatory mechanisms. The experiment results demonstrated the feasibility of inducing neural compensation with the proposed VSWM task at the right amount of cognitive load. This may provide a promising avenue to develop an effective cognitive training and rehabilitation for dementia population.
- Published
- 2020
- Full Text
- View/download PDF
25. Link Between Dietary Sodium Intake, Cognitive Function, and Dementia Risk in Middle-Aged and Older Adults: A Systematic Review.
- Author
-
Mohan D, Yap KH, Reidpath D, Soh YC, McGrattan A, Stephan BCM, Robinson L, Chaiyakunapruk N, and Siervo M
- Subjects
- Age Factors, Cardiovascular Diseases prevention & control, Cross-Sectional Studies, Humans, Nutritional Status, Sodium Chloride, Dietary metabolism, Cognition drug effects, Cognitive Dysfunction prevention & control, Dementia prevention & control, Hypertension prevention & control, Sodium Chloride, Dietary pharmacology
- Abstract
Background: A key focus for dementia risk-reduction is the prevention of socio-demographic, lifestyle, and nutritional risk factors. High sodium intake is associated with hypertension and cardiovascular disease (both are linked to dementia), generating numerous recommendations for salt reduction to improve cardiovascular health., Objective: This systematic review aimed to assess, in middle- and older-aged people, the relationship between dietary sodium intake and cognitive outcomes including cognitive function, risk of cognitive decline, or dementia., Methods: Six databases (PubMed, EMBASE, CINAHL, Psych info, Web of Science, and Cochrane Library) were searched from inception to 1 March 2020. Data extraction included information on study design, population characteristics, sodium reduction strategy (trials) or assessment of dietary sodium intake (observational studies), measurement of cognitive function or dementia, and summary of main results. Risk-of-bias assessments were performed using the National Heart, Lung, and Blood Institute (NHLBI) assessment tool., Results: Fifteen studies met the inclusion criteria including one clinical trial, six cohorts, and eight cross-sectional studies. Studies reported mixed associations between sodium levels and cognition. Results from the only clinical trial showed that a lower sodium intake was associated with improved cognition over six months. In analysis restricted to only high-quality studies, three out of four studies found that higher sodium intake was associated with impaired cognitive function., Conclusion: There is some evidence that high salt intake is associated with poor cognition. However, findings are mixed, likely due to poor methodological quality, and heterogeneous dietary, analytical, and cognitive assessment methods and design of the studies. Reduced sodium intake may be a potential target for intervention. High quality prospective studies and clinical trials are needed.
- Published
- 2020
- Full Text
- View/download PDF
26. Multiple Biological Effects of an Iridoid Glucoside, Catalpol and Its Underlying Molecular Mechanisms.
- Author
-
Bhattamisra SK, Yap KH, Rao V, and Choudhury H
- Subjects
- Animals, Humans, Anti-Infective Agents pharmacology, Anti-Inflammatory Agents pharmacology, Antioxidants pharmacology, Iridoid Glucosides pharmacology
- Abstract
Catalpol, an iridoid glucoside, is widely distributed in many plant families and is primarily obtained from the root of Rehmannia glutinosa Libosch. Rehmannia glutinosa is a plant very commonly used in Chinese and Korean traditional medicine for various disorders, including diabetes mellitus, neuronal disorders, and inflammation. Catalpol has been studied extensively for its biological properties both in vitro and in vivo. This review aims to appraise the biological effects of catalpol and their underlying mechanisms. An extensive literature search was conducted using the keyword "Catalpol" in the public domains of Google scholar, PubMed, and Scifinder. Catalpol exhibits anti-diabetic, cardiovascular protective, neuroprotective, anticancer, hepatoprotective, anti-inflammatory, and anti-oxidant effects in experimental studies. Anti-inflammatory and antioxidant properties are mostly related for its biological effect. However, some specific mechanisms are also elucidated. Elevated serotonin and BDNF level by catalpol significantly protect against depression and neurodegeneration. Catalpol demonstrated an increased mitochondrial biogenesis and activation of PI3K/Akt pathway for insulin sensitizing effect. Further, its cardiovascular protective effect was linked to PI3K/Akt, apelin/APJ and Jak-Stat pathway. Catalpol produced a significant reduction in cell proliferation and an increase in apoptosis in different cancer conditions. Overall, catalpol demonstrated multiple biological effects due to its numerous mechanisms including anti-inflammatory and antioxidant effects., Competing Interests: The authors declare no conflict of interest.
- Published
- 2019
- Full Text
- View/download PDF
27. Interpretations of self-rated health in stroke survivors from a semi-rural community in South East Asia.
- Author
-
Yap KH, Warren N, Reidpath DD, and Allotey P
- Subjects
- Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Self Report, Health Status, Rural Population, Stroke, Survivors psychology
- Abstract
Purpose : Stroke survivors report poorer self-rated health (SRH) compared to the general population but there is limited understanding on what contributes to SRH. This ethnographic study examined the individual and contextual factors that shape stroke survivors' SRH in a rural middle income country situated in South East Asia. Methods: Ethnographic methods which encompasses various data collection methods from different data sources were used in this study to describe the socio-cultural context of 16 stroke survivors living in a rural village. Within this context, the experiences of these participants were then interpreted in terms of what contributed to their perception of health and recovery, juxtaposed with objectively measure physical and cognitive states. Results : SRH reflected the post stroke adjustment of stroke survivors. Better SRH was influenced by good post-stroke adjustment that was achieved by a combination of physical functioning, cognitive functioning, emotional well-being and family support. Poorer SRH appear to reflect poor post-stroke adjustment regardless of the objective physical and cognitive states of the stroke survivors. It was also observed that cognitive deficits, though its presence was acknowledged by participants, were usually not taken into account when rating SRH. However, while physical functioning was perceived by participants to directly impact SRH, the presence of cognitive deficits (often in tandem with depressive symptoms) indirectly complicated the recovery of physical functions treasured by participants. Conclusion: Stroke survivors reporting poorer SRH warrant further attention and intervention from health practitioners supporting the longer-term needs of stroke survivors in similar settings.
- Published
- 2019
- Full Text
- View/download PDF
28. Homemade Candy Plug Using a Zenith Alpha Thoracic Stent-Graft for False Lumen Distal Occlusion in Acute-on-Chronic Type B Aortic Dissection.
- Author
-
Yap KH, Tham YC, Tay KH, Tze Tec C, Irani FG, Kian CJ, and Chao VTT
- Subjects
- Acute Disease, Aortic Dissection diagnostic imaging, Aortic Dissection physiopathology, Aortic Aneurysm diagnostic imaging, Aortic Aneurysm physiopathology, Chronic Disease, Humans, Male, Middle Aged, Treatment Outcome, Aortic Dissection surgery, Aortic Aneurysm surgery, Blood Vessel Prosthesis, Blood Vessel Prosthesis Implantation instrumentation, Endovascular Procedures instrumentation, Prosthesis Design, Stents
- Abstract
Purpose: To report a candy-plug technique using a Zenith Alpha stent-graft to occlude the distal false lumen in a patient with a complicated chronic type B aortic dissection. Case Report: A 50-year-old male smoker presented with chest pain due to rapidly growing complicated chronic type B aortic dissection. Computed tomography angiography (CTA) showed the dissection extending from distal to the origin of the left subclavian artery (LSA) down to the left femoral artery. There was fusiform aneurysmal dilatation of the proximal descending aorta measuring up to 5.8 cm in diameter. He underwent left carotid-subclavian artery bypass, thoracic endovascular aortic repair with a Zenith Alpha stent-graft, a left common carotid artery chimney, and embolization of the proximal LSA. Serial CTA showed persistent false lumen flow. A decision was made to occlude the distal large false lumen using the candy-plug technique. A 44×125-mm Zenith Alpha stent-graft was used to prepare the candy plug. A gutter leak and a type Ia endoleak were embolized via a left brachial artery approach. At 2.5 years, imaging showed the candy plug in position, no endoleak, and the thrombosed false lumen in the thoracic aorta reduced in size. Conclusion: The candy-plug technique is useful in facilitating complete occlusion of the false lumen in chronic aortic dissection, which avoids an open procedure and the risk of higher morbidity.
- Published
- 2019
- Full Text
- View/download PDF
29. Effects of Subjective Memory Complaints (SMCs) and Social Capital on Self-Rated Health (SRH) in a Semirural Malaysian Population.
- Author
-
Yap KH, Mohan D, Stephan BCM, Warren N, Allotey P, and Reidpath DD
- Abstract
Subjective memory complaints (SMCs) and social capital were known to be related to self-rated health (SRH). Despite this, no studies have examined the potential interaction of SMC and social capital on SRH. Using data from a cross-sectional health survey of men and women aged 56 years and above ( n = 6,421), we examined how SMCs and social capital explained SRH in a population of community-dwelling older adults in a semirural area in Malaysia. We also evaluated whether SRH's relationship with SMCs is moderated by social capital. The association of SMC and social capital with poor SRH was investigated using multivariable logistic regression. Social capital (OR = 0.86, 95% CI = 0.82-0.89), mild SMC (OR = 1.70, 95% CI = 1.50-1.94), and moderate SMC (OR = 1.90, 95% CI = 1.63-2.20) were found to be associated with poor SRH after adjustment for sociodemographic factors and depression in the initial regression model. SMC was found to have partial interaction effects with social capital which was included in the subsequent regression model. Unlike individuals with no SMC and mild SMC, those who reported moderate SMC did not show decreasing probabilities of poor SRH despite increasing levels of social capital. Nevertheless, this analysis suggests that social capital and SMC are independent predictors of poor SRH. Further research needs to be targeted at improving the understanding on how social capital and SMC moderate and interact with the perception of health in older adults.
- Published
- 2019
- Full Text
- View/download PDF
30. Large Thrombosed Right Coronary Artery Aneurysm Mimicking Right Atrial Mass.
- Author
-
Tham YC, Yap KH, and Ch'ng JK
- Abstract
Competing Interests: The authors have no financial conflicts of interest.
- Published
- 2019
- Full Text
- View/download PDF
31. The safe volume threshold for chest drain removal following pulmonary resection.
- Author
-
Yap KH, Soon JL, Ong BH, and Loh YJ
- Subjects
- Humans, Chest Tubes, Drainage methods, Pneumonectomy methods, Postoperative Care methods
- Abstract
A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was 'In patients undergoing pulmonary resection, is there a safe drainage volume threshold for chest drain removal?' Altogether 1054 papers were found, of which 5 papers represented the best evidence. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Chest drainage threshold, where used, ranged from 250 to 500 ml/day. Both randomized controlled trials showed no significant difference in reintervention rates with a higher chest drainage volume threshold. Four studies that performed analysis on other complications showed no statistical significant difference with a higher chest drainage volume threshold. Four studies evaluating length of hospital stay showed reduced or no difference in the length of stay with a higher chest drainage volume threshold. Two cohort studies reported the mortality rate of 0-0.01% with a higher chest drainage volume threshold. We conclude that early chest drain removal after pulmonary resection, accepting a higher chest drainage volume threshold of 250-500 ml/day is safe, and may result in shorter hospital stay without increasing reintervention, morbidity or mortality., (© The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
32. Visualizing Hyperactivation in Neurodegeneration Based on Prefrontal Oxygenation: A Comparative Study of Mild Alzheimer's Disease, Mild Cognitive Impairment, and Healthy Controls.
- Author
-
Yap KH, Ung WC, Ebenezer EGM, Nordin N, Chin PS, Sugathan S, Chan SC, Yip HL, Kiguchi M, and Tang TB
- Abstract
Background: Cognitive performance is relatively well preserved during early cognitive impairment owing to compensatory mechanisms. Methods: We explored functional near-infrared spectroscopy (fNIRS) alongside a semantic verbal fluency task (SVFT) to investigate any compensation exhibited by the prefrontal cortex (PFC) in Mild Cognitive Impairment (MCI) and mild Alzheimer's disease (AD). In addition, a group of healthy controls (HC) was studied. A total of 61 volunteers (31 HC, 12 patients with MCI and 18 patients with mild AD) took part in the present study. Results: Although not statistically significant, MCI exhibited a greater mean activation of both the right and left PFC, followed by HC and mild AD. Analysis showed that in the left PFC, the time taken for HC to achieve the activation level was shorter than MCI and mild AD ( p = 0.0047 and 0.0498, respectively); in the right PFC, mild AD took a longer time to achieve the activation level than HC and MCI ( p = 0.0469 and 0.0335, respectively); in the right PFC, HC, and MCI demonstrated a steeper slope compared to mild AD ( p = 0.0432 and 0. 0107, respectively). The results were, however, not significant when corrected by the Bonferroni-Holm method. There was also found to be a moderately positive correlation ( R = 0.5886) between the oxygenation levels in the left PFC and a clinical measure [Mini-Mental State Examination (MMSE) score] in MCI subjects uniquely. Discussion: The hyperactivation in MCI coupled with a better SVFT performance may suggest neural compensation, although it is not known to what degree hyperactivation manifests as a potential indicator of compensatory mechanisms. However, hypoactivation plus a poorer SVFT performance in mild AD might indicate an inability to compensate due to the degree of structural impairment. Conclusion: Consistent with the scaffolding theory of aging and cognition, the task-elicited hyperactivation in MCI might reflect the presence of compensatory mechanisms and hypoactivation in mild AD could reflect an inability to compensate. Future studies will investigate the fNIRS parameters with a larger sample size, and their validity as prognostic biomarkers of neurodegeneration.
- Published
- 2017
- Full Text
- View/download PDF
33. Does preoperative statin therapy prevent postoperative atrial fibrillation in patients undergoing cardiac surgery?
- Author
-
Goh SL, Yap KH, Chua KC, and Chao VT
- Subjects
- Humans, Atrial Fibrillation prevention & control, Cardiac Surgical Procedures, Cardiovascular Diseases surgery, Hydroxymethylglutaryl-CoA Reductase Inhibitors therapeutic use, Postoperative Complications prevention & control, Preoperative Care methods
- Abstract
A best evidence topic was written according to a structured protocol. The question addressed was: does preoperative statin therapy prevent postoperative atrial fibrillation (AF) in patients undergoing cardiac surgery? There were 445 papers found using the reported search. From these, 12 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. This paper includes three systematic reviews with meta-analysis, five randomized controlled trials and four retrospective studies. All the papers compared either all or some of the following postoperative complications: mortality, morbidity, AF, length of hospital stay (intensive care unit and hospital) and inflammatory markers. The largest study in this paper includes a systematic review of 91 491 patients that showed a reduction in postoperative AF with preoperative statin therapy (OR = 0.71, 95% CI 0.61-0.82, P <0.0001). However, the durations (3 days to 2 months preoperatively), doses and types of preoperative statin differed between these papers. Although the majority of studies (10 of 12) support the use of statins preoperatively, 2 studies found no association between preoperative statin therapy and the reduction of postoperative AF. In conclusion, the available evidence suggests that preoperative statin therapy in patients undergoing elective cardiac surgery is associated with the following: (1) a lower incidence and risk of developing postoperative AF, (2) reduced stroke, (3) a shorter hospital stay and (4) reduced levels of inflammatory markers postoperatively. However, while the evidence supports the use of statins preoperatively, the optimal duration, dose and type of statin cannot be concluded from this review., (© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
34. Is it possible to predict the risk of ischaemic bowel after cardiac surgery?
- Author
-
Yap KH, Chua KC, Lim SL, and Sin YK
- Subjects
- Adult, Age Factors, Aged, Benchmarking, Cardiac Surgical Procedures mortality, Cardiopulmonary Bypass adverse effects, Cardiovascular Agents therapeutic use, Comorbidity, Constriction, Evidence-Based Medicine, Hemodynamics, Humans, Intra-Aortic Balloon Pumping adverse effects, Mesenteric Ischemia diagnosis, Mesenteric Ischemia mortality, Mesenteric Ischemia physiopathology, Mesenteric Ischemia prevention & control, Middle Aged, Odds Ratio, Risk Assessment, Risk Factors, Time Factors, Treatment Outcome, Cardiac Surgical Procedures adverse effects, Mesenteric Ischemia etiology
- Abstract
A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'Is it possible to predict the risk of ischaemic bowel after cardiac surgery?' Altogether 80 papers were found as a result of the reported search, of which 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. This best evidence topic presents 68 214 cardiac surgical patients from seven major cardiothoracic centres dated from 1980 to 2011. The incidence and mortality rates of bowel ischaemia after cardiac surgery range from 0.07-0.5 and 59-64%, respectively. Advanced age and peripheral vascular disease are the common preoperative risk factors, which were reported by 3 papers each. The most common intraoperative risk factors were prolonged cross-clamp and cardiopulmonary bypass time, which were reported by 3 papers each. Five of 7 papers reported that the use of intra-aortic balloon pump was a significant risk factor. The use of inotropes, postoperative blood loss and postoperative renal failure were reported by 3 of 7 papers, each to be a significant risk factor for postoperative bowel ischaemia in cardiac surgery patients. We, therefore, conclude that these are probably the most significant and useful predictive risk factors for bowel ischaemia after cardiac surgery. Thus, careful intraoperative management to minimize cardiopulmonary bypass and cross-clamp time and optimal care of patients' postoperative haemodynamic status, particularly in elderly patients with severe atherosclerotic disease, are useful in preventing this rare but lethal postoperative complication. Besides that, a heightened clinical suspicion in patients with these risk factors may lead to prompt diagnosis of bowel ischaemia, allowing intervention to prevent mortality. The variability of the study design and risk factors studied in each paper impose limitation to summarize the predicting risk factors., (© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
35. Medical thoracoscopy: rigid thoracoscopy or flexi-rigid pleuroscopy?
- Author
-
Yap KH, Phillips MJ, and Lee YC
- Subjects
- Biopsy, Diagnosis, Differential, Equipment Design, Humans, Pleural Effusion pathology, Pleural Effusion diagnosis, Thoracoscopes, Thoracoscopy instrumentation, Thoracoscopy methods
- Abstract
Purpose of Review: In managing pleural diseases, medical thoracoscopy is often performed as a diagnostic and/or therapeutic procedure, particularly in undiagnosed pleural effusions. Flexi-rigid pleuroscopes are now widely available as an alternative to conventional rigid thoracoscopes. There is an ongoing debate on which is the better instrument. This review analyses the current literature that compared rigid and flexi-rigid approaches, and outlines the medical advances that may influence the future role of thoracoscopy., Recent Findings: Both rigid and flexi-rigid thoracoscopies are well tolerated. Although biopsies are smaller with flexi-rigid biopsy forceps, two small randomized trials reported similar diagnostic yield using either instrument. No studies have specifically examined patient comfort or the outcome of talc poudrage using the two devices. New techniques (e.g. insulated-tip knife and cryobiopsy) have been used as adjuncts with flexi-rigid pleuroscopy to overcome the difficulties in sampling thickened pleura., Summary: The rigid and flex-rigid instruments have different merits and limitations. Both approaches provide comparable diagnostic yields in the overall patient population undergoing diagnostic thoracoscopy, though their performances specifically in patients with fibrotic pleural thickening have not been examined. Operators using the flexi-rigid approach should have alternative strategies for sampling thickened pleura. Advances in cytopathology and imaging-guided biopsy will likely reduce the need of medical thoracoscopy in the future.
- Published
- 2014
- Full Text
- View/download PDF
36. Discriminative BoW framework for mobile landmark recognition.
- Author
-
Chen T and Yap KH
- Abstract
This paper proposes a new soft bag-of-words (BoW) method for mobile landmark recognition based on discriminative learning of image patches. Conventional BoW methods often consider the patches/regions in the images as equally important for learning. Amongst the few existing works that consider the discriminative information of the patches, they mainly focus on selecting the representative patches for training, and discard the others. This binary hard selection approach results in underutilization of the information available, as some discarded patches may still contain useful discriminative information. Further, not all the selected patches will contribute equally to the learning process. In view of this, this paper presents a new discriminative soft BoW approach for mobile landmark recognition. The main contribution of the method is that the representative and discriminative information of the landmark is learned at three levels: patches, images, and codewords. The patch discriminative information for each landmark is first learned and incorporated through vector quantization to generate soft BoW histograms. Coupled with the learned representative information of the images and codewords, these histograms are used to train an ensemble of classifiers using fuzzy support vector machine. Experimental results on two different datasets show that the proposed method is effective in mobile landmark recognition.
- Published
- 2014
- Full Text
- View/download PDF
37. Carney complex: fourth time excision of recurrent atrial myxoma via left thoracotomy.
- Author
-
Azzam R, Abdelbar A, Yap KH, and Abousteit A
- Subjects
- Cardiac Surgical Procedures adverse effects, Carney Complex complications, Echocardiography, Doppler methods, Follow-Up Studies, Heart Atria, Heart Neoplasms complications, Heart Neoplasms surgery, Humans, Male, Middle Aged, Myxoma complications, Myxoma diagnosis, Neoplasm Recurrence, Local surgery, Postoperative Complications physiopathology, Postoperative Complications therapy, Reoperation methods, Reoperation statistics & numerical data, Risk Assessment, Thoracotomy adverse effects, Thoracotomy methods, Time Factors, Tomography, X-Ray Computed methods, Cardiac Surgical Procedures methods, Carney Complex diagnosis, Heart Neoplasms diagnosis, Myxoma surgery, Neoplasm Recurrence, Local diagnosis
- Abstract
We report a case of a 51-year-old male patient with a known history of Carney complex, who was operated on for the fourth time due to recurrent left atrial myxomas. Despite surgical challenge, the operation was uneventful. The patient had a difficult postoperative period and needed further treatment for complications. After a prolonged recovery, he is currently well and remains myxoma-free up until now (36 months postsurgery) with regular follow-up using cardiac CT and transthoracic echocardiogram.
- Published
- 2014
- Full Text
- View/download PDF
38. Is cryoanalgesia effective for post-thoracotomy pain?
- Author
-
Khanbhai M, Yap KH, Mohamed S, and Dunning J
- Subjects
- Analgesia adverse effects, Benchmarking, Evidence-Based Medicine, Female, Humans, Male, Middle Aged, Pain Measurement, Pain, Postoperative diagnosis, Pain, Postoperative etiology, Treatment Outcome, Analgesia methods, Cold Temperature adverse effects, Cryotherapy adverse effects, Pain, Postoperative prevention & control, Thoracotomy adverse effects
- Abstract
A best evidence topic was written according to a structured protocol. The question addressed was whether cryoanalgesia improves post-thoracotomy pain and recovery. Twelve articles were identified that provided the best evidence to answer the question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Reported measures were pain scores, additional opiate requirements, incidence of hypoesthesia and change in lung function. Half of the articles reviewed failed to demonstrate superiority of cryoanalgesia over other pain relief methods; however, additional opiate requirements were reduced in patients receiving cryoanalgesia. Change in lung function postoperatively was equivocal. Cryoanalgesia potentiated the incidence of postoperative neuropathic pain. Further analysis of the source of cryoanalgesia, duration, temperature obtained and extent of blockade revealed numerous discrepancies. Three studies utilized CO2 as the source of cryoanalgesia and four used nitrous oxide, but at differing temperatures and duration. Five studies did not reveal the source of cyroanalgesia. The number of intercostal nerves anaesthetized in each study varied. Seven articles anaesthetized three intercostal nerves, three articles used five intercostal nerves, one article used four intercostal nerves and one used one intercostal nerve at the thoracotomy site. Thoracotomy closure and site of area of chest drain insertion may have a role in postoperative pain; but only one article explained method of closure, and two articles mentioned placement of chest drain through blocked dermatomes. No causal inferences can be made by the above results as they are not directly comparable due to confounding variables between studies. Currently, the evidence does not support the use of cryoanalgesia alone as an effective method for relieving post-thoracotomy pain.
- Published
- 2014
- Full Text
- View/download PDF
39. Dissection of the pulmonary ligament during upper lobectomy: is it necessary?
- Author
-
Khanbhai M, Dunning J, Yap KH, and Rammohan KS
- Subjects
- Benchmarking, Evidence-Based Medicine, Female, Humans, Male, Middle Aged, Pneumonectomy adverse effects, Pneumonectomy mortality, Postoperative Complications mortality, Postoperative Complications prevention & control, Risk Factors, Treatment Outcome, Dissection adverse effects, Dissection mortality, Ligaments surgery, Pneumonectomy methods
- Abstract
A best evidence topic was written according to a structured protocol. The question addressed was whether dissection of the pulmonary ligament during an upper lobectomy would result in improved outcomes. A total of 85 articles were found using the reported search, of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Reported measures were complications associated with dissection (atelectasis, bronchial stenosis, bronchial obstruction and bronchial deformation) and preservation (insufficient lung expansion, pooling of effusion and atelectasis) of the pulmonary ligament, ratio (%) of dead space in longitudinal axis (movement of nonoperated lobes), change in the angle (degrees) of main bronchus on the operated side, overall morbidity and mortality, overall survival and conversion rates. In a randomized control trial, the dissection of the pulmonary ligament revealed no significant difference in the dead space ratio or change in the angle of the main bronchus when compared with preservation. Dissection of the ligament, in theory, reduces the free space in the upper thorax by increasing the mobility of the residual lobes. Dissection of the ligament may lead to bronchial deformation, stenosis, obstruction or lobar torsion. Preservation of the ligament may prevent this complication by suppressing the upward movement of residual lobes. However, this may result in pleural effusion in the free thoracic space that may potentially become infected resulting in an empyema or bronchial fistula. Five large case series were analysed; three routinely dissected the pulmonary ligament and two did not. There was no observed difference in clinical outcomes between the two groups. There is no convincing evidence that dissection of the pulmonary ligament in an upper lobectomy significantly improves outcomes and reduces complications.
- Published
- 2013
- Full Text
- View/download PDF
40. Aortic valve replacement: is porcine or bovine valve better?
- Author
-
Yap KH, Murphy R, Devbhandari M, and Venkateswaran R
- Subjects
- Aged, Animals, Aortic Valve physiopathology, Aortic Valve Stenosis mortality, Aortic Valve Stenosis physiopathology, Benchmarking, Cattle, Evidence-Based Medicine, Female, Heart Valve Prosthesis Implantation adverse effects, Heart Valve Prosthesis Implantation mortality, Hemodynamics, Humans, Male, Prosthesis Design, Prosthesis Failure, Swine, Time Factors, Treatment Outcome, Aortic Valve surgery, Aortic Valve Stenosis surgery, Bioprosthesis, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation instrumentation
- Abstract
A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: 'Is porcine or bovine valve better for aortic valve replacement?' Altogether, 562 papers were found using the reported search, of which 15 represented the best evidence to answer the question. All papers represent either level 1 or 2 evidence. The authors, journal, date, country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. This best evidence paper includes 9880 patients from 1974-2006 to compare both valve types. All studies compared either all or some of the following outcomes: complication, durability, mortality, functional status and haemodynamic function. Ten of 15 papers assessed the complication profile due to aortic valve replacement in both valve types. Four papers concluded that bovine valves are superior, whereas only one favoured porcine valves. Five papers showed a similar complication profile between both valves. Six of 15 papers commented on valve durability. Both porcine and bovine valve groups have two papers each to support their superiority in valve durability. Two papers demonstrated similar durability in both valves. There are 11 papers comparing the postoperative mortality. We suggest that there is no difference in mortality profile as eight papers showed that both valves had similar mortality profiles. Two papers supported bovine valve and one paper supported porcine valve in this aspect. There were four papers assessing the postoperative functional status, with three papers suggesting that both valve types had similar clinical improvement postoperatively. Eleven papers compared the haemodynamic function. Nine papers were in favour of bovine valves. Two papers demonstrated similar haemodynamic profiles in both valves. In conclusion, the bovine valve is superior in its complication and haemodynamic profiles. Both bovine and porcine valves have comparable results with regard to the mortality, postoperative functional status and valve durability. Significant variability between the valve manufacturers, study designs, study period and patient population in the above studies impose limitations to the comparison of both valves.
- Published
- 2013
- Full Text
- View/download PDF
41. Late presentation of congenital diaphragmatic hernia after a diagnostic laparoscopic surgery (a case report).
- Author
-
Yap KH and Jones M
- Subjects
- Adolescent, Female, Hernia, Diaphragmatic diagnosis, Hernia, Diaphragmatic physiopathology, Hernia, Diaphragmatic surgery, Herniorrhaphy methods, Humans, Laparoscopy methods, Surgical Mesh, Hernias, Diaphragmatic, Congenital
- Abstract
The authors report a rare case of 17-year-old lady with late presentation of congenital diaphragmatic hernia. She presented with vague abdominal pain and was thought to have urinary tract infection, ruptured ovarian cyst, and appendicitis by different medical teams in the first few days. She eventually underwent a diagnostic laparoscopy with no significant findings. In the early postoperative recovery period, she suffered from severe cardiorespiratory distress and a large intestinal left diaphragmatic hernia was diagnosed subsequently. At further operation a strangulated loop of large bowel herniating through a left antero-lateral congenital diaphragmatic hernia was discovered, which was reduced and repaired with a prolene mesh through thoracotomy. She made an excellent recovery and was discharged a few days after the operation. The authors postulate a mechanism of positive pressure from laparoscopic surgery causing herniation of large bowel through a pre-existing diaphragmatic defect. This case highlights the diagnostic challenge of this disease due to its diverse clinical presentation, the importance of prompt diagnosis and intervention.
- Published
- 2013
- Full Text
- View/download PDF
42. Transcranial Doppler ultrasound: a review of the physical principles and major applications in critical care.
- Author
-
Naqvi J, Yap KH, Ahmad G, and Ghosh J
- Abstract
Transcranial Doppler (TCD) is a noninvasive ultrasound (US) study used to measure cerebral blood flow velocity (CBF-V) in the major intracranial arteries. It involves use of low-frequency (≤2 MHz) US waves to insonate the basal cerebral arteries through relatively thin bone windows. TCD allows dynamic monitoring of CBF-V and vessel pulsatility, with a high temporal resolution. It is relatively inexpensive, repeatable, and portable. However, the performance of TCD is highly operator dependent and can be difficult, with approximately 10-20% of patients having inadequate transtemporal acoustic windows. Current applications of TCD include vasospasm in sickle cell disease, subarachnoid haemorrhage (SAH), and intra- and extracranial arterial stenosis and occlusion. TCD is also used in brain stem death, head injury, raised intracranial pressure (ICP), intraoperative monitoring, cerebral microembolism, and autoregulatory testing.
- Published
- 2013
- Full Text
- View/download PDF
43. Intercostal artery aneurysm with coarctation of the aorta.
- Author
-
Lee PT, Yap KH, McBride K, Danton M, and Fairbairn I
- Subjects
- Adult, Aortic Aneurysm, Thoracic diagnosis, Aortic Aneurysm, Thoracic surgery, Aortic Coarctation diagnosis, Aortic Coarctation surgery, Diagnosis, Differential, Female, Humans, Treatment Outcome, Aortic Aneurysm, Thoracic complications, Aortic Coarctation complications, Vascular Surgical Procedures methods
- Published
- 2013
- Full Text
- View/download PDF
44. Isolated pulmonary infective endocarditis with septic pulmonary embolism complicating a right ventricular outflow tract obstruction: scarce and devious presentation.
- Author
-
Abdelbar A, Azzam R, Yap KH, and Abousteit A
- Abstract
We present a case of a fifty-three-year-old male who presented with severe sepsis. He had been treated as a pneumonia patient for five months before the admission. Investigations revealed isolated pulmonary valve endocarditis and septic pulmonary embolism in addition to undiagnosed right ventricular outflow tract (RVOT) obstruction. The patient underwent surgery for the relief of RVOT obstruction by substantial muscle resection of the RVOT, pulmonary artery embolectomy, pulmonary valve replacement, and reconstruction of RVOT and main pulmonary artery with two separate bovine pericardial patches. He was discharged from our hospital after 6 weeks of intravenous antibiotics. He recovered well on follow-up 16 weeks after discharge. A high-suspicion index is needed to diagnose right-side heart endocarditis. Blood cultures and transesophageal echocardiogram are the key diagnostic tools.
- Published
- 2013
- Full Text
- View/download PDF
45. Incidental Finding of a Left-over Guide-Wire on a Positron Emission Tomography.
- Author
-
Yap KH, Lee PT, Buch M, and Rammohan KS
- Published
- 2012
- Full Text
- View/download PDF
46. Pulmonary atelectasis from compression of the left main bronchus by an aortic aneurysm.
- Author
-
Yap KH and Sulaiman S
- Subjects
- Aged, Aortic Aneurysm, Thoracic diagnostic imaging, Female, Humans, Hypertension complications, Pleural Effusion diagnosis, Pleural Effusion diagnostic imaging, Pulmonary Atelectasis diagnosis, Pulmonary Atelectasis diagnostic imaging, Tomography, X-Ray Computed methods, Trachea pathology, Treatment Outcome, Aortic Aneurysm, Thoracic diagnosis, Bronchi physiopathology, Pulmonary Atelectasis complications
- Abstract
Pulmonary atelectasis may be caused by endobronchial lesions or by extrinsic compression of the bronchus. However, lung collapse due to compression from a thoracic aneurysm is uncommon. We report a 76-year-old hypertensive female patient who has pulmonary atelectasis due to an extrinsic compression from a descending thoracic aortic aneurysm, and discuss possible treatment options.
- Published
- 2009
47. A nonlinear least square technique for simultaneous image registration and super-resolution.
- Author
-
He Y, Yap KH, Chen L, and Chau LP
- Subjects
- Computer Simulation, Information Storage and Retrieval methods, Least-Squares Analysis, Models, Statistical, Nonlinear Dynamics, Reproducibility of Results, Sensitivity and Specificity, Algorithms, Artificial Intelligence, Data Interpretation, Statistical, Image Enhancement methods, Image Interpretation, Computer-Assisted methods, Pattern Recognition, Automated methods, Subtraction Technique
- Abstract
This paper proposes a new algorithm to integrate image registration into image super-resolution (SR). Image SR is a process to reconstruct a high-resolution (HR) image by fusing multiple low-resolution (LR) images. A critical step in image SR is accurate registration of the LR images or, in other words, effective estimation of motion parameters. Conventional SR algorithms assume either the estimated motion parameters by existing registration methods to be error-free or the motion parameters are known a priori. This assumption, however, is impractical in many applications, as most existing registration algorithms still experience various degrees of errors, and the motion parameters among the LR images are generally unknown a priori. In view of this, this paper presents a new framework that performs simultaneous image registration and HR image reconstruction. As opposed to other current methods that treat image registration and HR reconstruction as disjoint processes, the new framework enables image registration and HR reconstruction to be estimated simultaneously and improved progressively. Further, unlike most algorithms that focus on the translational motion model, the proposed method adopts a more generic motion model that includes both translation as well as rotation. An iterative scheme is developed to solve the arising nonlinear least squares problem. Experimental results show that the proposed method is effective in performing image registration and SR for simulated as well as real-life images.
- Published
- 2007
- Full Text
- View/download PDF
48. Identification and characterization of a novel allergen from Blomia tropicalis: Blo t 21.
- Author
-
Gao YF, Wang de Y, Ong TC, Tay SL, Yap KH, and Chew FT
- Subjects
- Adult, Allergens chemistry, Allergens genetics, Amino Acid Sequence, Animals, Child, Cross Reactions, Genome, Humans, Immunoglobulin E immunology, Mites genetics, Molecular Sequence Data, Protein Structure, Secondary, Sequence Alignment, Allergens immunology, Mites immunology
- Abstract
Background: Allergenic components from Blomia tropicalis are important triggers of allergies in the tropics., Objective: We sought to identify and characterize a novel allergen, Blo t 21, from B tropicalis., Methods: Blo t 21 was initially identified from an expressed sequence tag database generated from a B tropicalis cDNA library. Allergenicity of this antigen was examined by means of skin prick testing, ELISA, and IgE immuno-dot blotting. We evaluated whether Blo t 21 and Blo t 5 were cross-reactive by using IgE inhibition ELISAs., Results: Blo t 21, a 129-amino-acid protein sharing 39% identity with Blo t 5, is a product of a single-copy gene. It has an alpha-helical secondary structure and localizes to midgut and hindgut contents of B tropicalis, as well as fecal particles. Positive responses to Blo t 21 were shown in 93% (40/43) by means of ELISA and 95% (41/43) by means of skin prick testing when assayed in 43 adult patients with ongoing persistent allergic rhinitis. However, sera of 494 consecutive individuals attending outpatient allergy clinics over 1(1/2) years showed 57.9% (286/494) had positive responses to Blo t 21. Although the majority (>75%) of sensitized individuals were cosensitized to both Blo t 5 and Blo t 21, these 2 allergens had a low-to-moderate degree of cross-reactivity., Conclusion: Blo t 21 is a major allergen in B tropicalis that is not highly cross-reactive to Blo t 5, despite sharing some sequence and structural identity., Clinical Implications: Blo t 21, representing a new group of allergens, is an important B tropicalis allergen.
- Published
- 2007
- Full Text
- View/download PDF
49. A soft double regularization approach to parametric blind image deconvolution.
- Author
-
Chen L and Yap KH
- Subjects
- Artificial Intelligence, Computer Simulation, Models, Biological, Reproducibility of Results, Sensitivity and Specificity, Algorithms, Image Enhancement methods, Image Interpretation, Computer-Assisted methods, Information Storage and Retrieval methods, Models, Statistical
- Abstract
This paper proposes a blind image deconvolution scheme based on soft integration of parametric blur structures. Conventional blind image deconvolution methods encounter a difficult dilemma of either imposing stringent and inflexible preconditions on the problem formulation or experiencing poor restoration results due to lack of information. This paper attempts to address this issue by assessing the relevance of parametric blur information, and incorporating the knowledge into the parametric double regularization (PDR) scheme. The PDR method assumes that the actual blur satisfies up to a certain degree of parametric structure, as there are many well-known parametric blurs in practical applications. Further, it can be tailored flexibly to include other blur types if some prior parametric knowledge of the blur is available. A manifold soft parametric modeling technique is proposed to generate the blur manifolds, and estimate the fuzzy blur structure. The PDR scheme involves the development of the meaningful cost function, the estimation of blur support and structure, and the optimization of the cost function. Experimental results show that it is effective in restoring degraded images under different environments.
- Published
- 2005
- Full Text
- View/download PDF
50. Population genetic characteristics of the STR Loci D21S11 and FGA in eight diverse human populations.
- Author
-
Frégeau CJ, Tan-Siew WF, Yap KH, Carmody GR, Chow ST, and Fourney RM
- Subjects
- Canada, Ethnicity genetics, Fibrinogen genetics, Humans, Indians, North American genetics, Likelihood Functions, Singapore, White People genetics, Gene Frequency, Microsatellite Repeats, Polymorphism, Genetic genetics
- Abstract
A highly polymorphic multiplex short tandem repeat (STR) system composed of D21S11, FGA, and the sex-typing system amelogenin (AMG) has been used to investigate allele frequency distributions in two Canadian Caucasian samples (British Columbia and Alberta), three Canadian aboriginal populations (Coastal Salishans from British Columbia, Ojibwa from northern Ontario, and Cree from Saskatchewan), and three ethnic groups from Singapore (Chinese, Malays, and Asian Indians). Using the automated fluorescence detection approach on an ABD 373A DNA Sequencer, we distinguished 20 D21S11 and 22 FGA alleles with a nearly equal representation of two- and four-base variants. An overlap in allele sizes for both STR loci across populations was observed, but frequency differences were noted. Statistical analysis revealed that (1) both D21S11 and FGA loci conform to Hardy-Weinberg equilibrium in all eight surveyed populations based on five different tests and (2) both STR loci are in linkage equilibrium. Results from the 2 x N contingency table exact tests for population differentiation demonstrated that the Canadian samples from two different provinces were not distinguishable from one another at either STR locus and therefore could be combined to form one Caucasian group. Likewise, Chinese and Malays from Singapore did not show significant differences at either STR locus. In contrast, all other examined populations exhibited differences deemed statistically significant. As a complement to our study, we compared D21S11 allele frequency distributions in 21 worldwide populations and FGA allele frequency distributions in 14 populations. Many alleles never previously reported in worldwide populations were identified in Canadian aboriginal and Asian samples from this study. Twenty-four D21S11 and 29 FGA alleles were distinguished in worldwide groups. Interesting similarities in allele frequency distribution patterns across populations suggest that the STR polymorphism at these loci predates the geographic dispersal of ancestral human populations. This study further demonstrates the utility of highly informative STR loci such as D21S11 and FGA in human population evolutionary history and in forensic medicine.
- Published
- 1998
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.