Steven Tien Guan Thng
National Skin Centre
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Publication
Featured researches published by Steven Tien Guan Thng.
Australasian Journal of Dermatology | 2005
Patricia Pei-Lin Ng; Steven Tien Guan Thng; Khatija Mohamed; Suat Hoon Tan
A prospective study was performed to assess the usefulness of desmoglein enzyme‐linked immunosorbent assay testing compared with indirect immunofluorescence in the diagnosis of new cases of pemphigus, as well as to compare the relative sensitivities of monkey oesophagus and normal human skin as substrates for indirect immunofluorescence. These tests were performed on the sera of 29 consecutive new cases of pemphigus diagnosed over a 2‐year period based on clinical, histological and direct immunofluorescence findings. Desmoglein enzyme‐linked immunosorbent assay was positive in all patients whereas indirect immunofluorescence was positive in only 25 of 29 patients. All four patients with negative indirect immunofluorescence had positive antinuclear antibodies or cytoplasmic fluorescence that could have masked the anti‐intercellular antibodies. Desmoglein enzyme‐linked immunosorbent assay appeared to reflect the disease activity better than indirect immunofluorescence in a few patients who had active disease of recent onset. Monkey oesophagus was found to be superior or equal to human skin as a substrate for indirect immunofluorescence in both pemphigus vulgaris and foliaceus.
Dermatologic Surgery | 2011
Harneet Ranu; Steven Tien Guan Thng; Boon Kee Goh; Allan Burger; Chee-Leok Goh
BACKGROUND Periorbital hyperpigmentation (POH) presents with a dark area surrounding the eyelids. It is an ill‐defined condition, and the pathogenesis can be multifactorial. OBJECTIVE This epidemiologic study was conducted to assess the prevalence of periorbital hyperpigmentation in Singapore in an attempt to propose a classification. MATERIALS AND METHODS One thousand consecutive patients attending the general dermatology clinic at the National Skin Center were enrolled in the study to assess for POH, of whom 200 with POH were examined and investigated to define the cause of POH. The possible causes were determined according to a detailed history, clinical examination, and assessment by three dermatologists. The extent of the POH was measured using a mexameter. RESULTS The commonest form of POH was the vascular type (41.8%), followed by constitutional (38.6%), postinflammatory hyperpigmentation (12%), and shadow effects (11.4%). The vascular type was seen predominantly in Chinese, whereas as the constitutional type was most common in Indians and Malays. CONCLUSION The vascular form of POH was the predominant type. We propose a comprehensive classification for POH that we hope will influence the choice of treatment modalities used in managing POH in the future. Unilever R&D Trumbul, USA provided funding for this study.
Dermatology | 2005
Patricia Pei-Lin Ng; Steven Tien Guan Thng
We report 3 cases of pemphigus vulgaris (PV) confirmed by histology and direct and indirect immunofluorescence that showed transition to pemphigus foliaceus (PF) 2–4 years from the time of disease onset. Desmoglein (Dsg) ELISA testing of the sera from these 3 patients in the later stages of their disease showed the presence of anti-Dsg1 antibodies and the absence of anti-Dsg3 antibodies. These patients were on prednisolone and immunosuppressives at the time the sera were tested, and it is unclear if the transition from PV to PF is a permanent one or whether it is due to preferential suppression of Dsg3 antibodies below a certain threshold. Previously reported cases of transition from PV to PF and PF to PV are summarized.
Pigment Cell & Melanoma Research | 2017
Emily Yiping Gan; Viktoria Eleftheriadou; Samia Esmat; Iltefat Hamzavi; T. Passeron; Markus Böhm; Tag S. Anbar; Boon Kee Goh; Cheng‐Che Eric Lan; Harvey Lui; M. Ramam; Noufal Raboobee; Ichiro Katayama; Tamio Suzuki; Davinder Parsad; Vaneeta Seth; Henry W. Lim; Nanja van Geel; Sanjeev V. Mulekar; John E. Harris; Richard A. Wittal; Laila Benzekri; Yvon Gauthier; Prasad Kumarasinghe; Steven Tien Guan Thng; Caio Cesar Silva de Castro; Marwa Abdallah; Charlotte Vrijman; Marcel Bekkenk; Julien Seneschal
The Vitiligo Global Issues Consensus Conference (VGICC), through an international e‐Delphi consensus, concluded that ‘repigmentation’ and ‘maintenance of gained repigmentation’ are essential core outcome measures in future vitiligo trials. This VGICC position paper addresses these core topics in two sections and includes an atlas depicting vitiligo repigmentation patterns and color match. The first section delineates mechanisms and characteristics of vitiligo repigmentation, and the second section summarizes the outcomes of international meeting discussions and two e‐surveys on vitiligo repigmentation, which had been carried out over 3 yr. Treatment is defined as successful if repigmentation exceeds 80% and at least 80% of the gained repigmentation is maintained for over 6 months. No agreement was found on the best outcome measure for assessing target or global repigmentation, therefore highlighting the limitations of e‐surveys in addressing clinical measurements. Until there is a clear consensus, existing tools should be selected according to the specific needs of each study. A workshop will be conducted to address the remaining issues so as to achieve a consensus.
Photoacoustics | 2017
Amalina Binte Ebrahim Attia; Sai Yee Chuah; Daniel Razansky; Chris Jun Hui Ho; Pinky Malempati; U. S. Dinish; Renzhe Bi; Chit Yaw Fu; Steven J. Ford; Joyce Siong-See Lee; Melissa Wee Ping Tan; Malini Olivo; Steven Tien Guan Thng
Currently, imaging technologies that enable dermsurgeons to visualize non-melanoma skin cancers (NMSC) in vivo preoperatively are lacking, resulting in excessive or incomplete removal. Multispectral optoacoustic tomography (MSOT) is a volumetric imaging tool to differentiate tissue chromophores and exogenous contrast agents, based on differences in their spectral signatures and used for high-resolution imaging of functional and molecular contrast at centimeter scale depth. We performed MSOT imaging with two- and three-dimensional handheld scanners on 21 Asian patients with NMSC. The tumors and their oxygenation parameters could be distinguished from normal skin endogenously. The lesion dimensions and depths were extracted from the spectral melanin component with three-dimensional spatial resolution up to 80 μm. The intraclass correlation coefficient correlating tumor dimension measurements between MSOT and ex vivo histology of excised tumors, showed good correlation. Real-time 3D imaging was found to provide information on lesion morphology and its underlying neovasculature, indicators of the tumor’s aggressiveness.
Skin Research and Technology | 2017
Sai Yee Chuah; Amalina Binte Ebrahim Attia; V. Long; Chris Jun Hui Ho; P. Malempati; Chit Yaw Fu; S. J. Ford; Joyce Siong-See Lee; W. P. Tan; Daniel Razansky; Malini Olivo; Steven Tien Guan Thng
Recent advances in technology have enabled the development of various non‐invasive skin imaging tools to aid real‐time diagnosis of both benign and malignant skin tumours, minimizing the need for invasive skin biopsy. Multispectral optoacoustic tomography (MSOT) is a recently developed non‐invasive imaging tool, which offers the unique capacity for high resolution three dimensional (3D) optical mapping of tissue by further delivering highly specific optical contrast from a depth of several millimetres to centimetres in living tissues. MSOT enables volumetric, spectroscopic differentiation of tissue, both in vivo and in real time, with and without the application of biomarker‐specific probes, and is further able of providing spatial maps of skin chromophores, as well as underlying blood vasculature.
Journal of Pigmentary Disorders | 2015
Wan Lin Teo; Emily Yiping Gan; Anjali Jinghan; Sai Yee Chuah; Khaiat Alain; Chee-Leok Goh; Steven Tien Guan Thng
Objectives: To evaluate the efficacy of an oral supplement containing carotenoids as an adjunct to a topical cosmetic lightening cream for the treatment of melasma. Methods: 44 subjects with melasma were recruited into a double-blinded, randomized, placebo controlled trial over 84 days at the Singapore National Skin Centre, to receive either an oral dietary supplement containing carotenoids or a placebo. All were prescribed a commercially available cream. Patients were assessed at onset, day 54 and day 84 by the Modified Melasma area and Severity Index (mMASI), photographic documentation, melanin and erythema indexes using a Mexameter®. Results: 44 patients completed the study. The median mMASI score fell significantly in both groups (both p<0.001). There was a greater decrease seen in those who received the oral supplement group (-2.1 vs -1.8, p <0.379). The erythema score showed significant improvements in both groups, with greater improvement in the group on the oral supplement, compared to placebo (median difference = -30, p =0.018, vs median difference = -20, p =0.020). Conclusion: Oral supplements containing carotenoids are potential adjuncts in melasma treatment. 1.5 Limitations: Small sample size and short study duration limit the observations noted in this study. Further larger-scale studies are required.
international conference on control, automation, robotics and vision | 2016
Xu Zhang; Yunfeng Liang; Dongyun Lin; Zhiping Lin; Steven Tien Guan Thng; Emily Yiping Gan; Evelyn Yuxin Tay
This paper proposes a new method for melasma pigmentary area segmentation utilizing re action-diffusion based level set model (RDLSM) together with local entropy thresholding. In the adopted level set model, a diffusion term is used to regularize the level set function while a reaction term with anticipated sign property is used to force the zero level set towards desired locations. Then local entropy thresholding is applied to address the over-segmentation issue of RDLSM and to extract desired boundaries with higher overall local entropy. As a result, the melasma pigmentary areas and the normal skin areas can be better identified. Experimental results show that the proposed method performs well for melasma image segmentation, especially for cases with severe non-uniform illumination distribution.
Acta Dermato-venereologica | 2014
Abdul Wali; Lu Liu; Takuya Takeichi; Musharraf Jelani; Obaid Ur Rahman; Yee Kiat Heng; Steven Tien Guan Thng; Joyce Siong-See Lee; Masashi Akiyama; John A. McGrath; Regina C. Betz
© 2015 The Authors. doi: 10.2340/00015555-2104 Journal Compilation
international conference on digital signal processing | 2017
Yunfeng Liang; Zhiping Lin; Lei Sun; Wee Ser; Feng Lin; Steven Tien Guan Thng
Melasma is a widely spread skin pigmentation disease and accurate assessments of the disease severity is crucial during its treatment. Recently, several computerized methods have been developed to overcome the shortcomings of the conventional clinical assessment method. As a key step in algorithm, image segmentation has extensive impacts on the accuracy of the assessment. Currently, the optimal hybrid thresholding (oHybrid) segmentation method that adaptively combines both local and global thresholding methods has obtained reasonable results in solving the melasma assessment problem. Nevertheless, the distance measure adopted in the oHybrid method is empirically selected and its influence is not well discussed. In this paper, a generalized distance measure is introduced and applied to improve the hybrid thresholding image segmentation method. The proposed method is tested on a data set of melasma patients to determine the lesion severity and it shows the best overall performance among the methods compared.