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Dengue maculopathy: a case report

Tan SY, Kumar G, Surrun SK, Ong YY

Travel Med Infect Dis, 2007 Jan;5(1):62-3.
PMID: 17161325

Dengue fever is endemic in many countries of South East Asia. In spite of the occasional epidemics, dengue maculopathy remains a rare entity.
Isolation and identification of lactic acid bacteria from fermented red dragon fruit juices

Ong YY, Tan WS, Rosfarizan M, Chan ES, Tey BT

J Food Sci, 2012 Oct;77(10):M560-4.
PMID: 22924854 DOI: 10.1111/j.1750-3841.2012.02894.x

Red dragon fruit or red pitaya is rich in potassium, fiber, and antioxidants. Its nutritional properties and unique flesh color have made it an attractive raw material of various types of food products and beverages including fermented beverages or enzyme drinks. In this study, phenotypic and genotypic methods were used to confirm the identity of lactic acid bacteria (LAB) appeared in fermented red dragon fruit (Hylocereus polyrhizus) beverages. A total of 21 isolates of LAB were isolated and characterized. They belonged to the genus of Enterococcus based on their biochemical characteristics. The isolates can be clustered into two groups by using the randomly amplified polymorphic DNA method. Nucleotide sequencing and restriction fragment length polymorphism of the 16S rRNA region suggested that they were either Enterococcus faecalis or Enterococcus durans.
Fulltext Study on bioaccessibility of betacyanins from red dragon fruit (Hylocereus polyrhizus)

Choo KY, Ong YY, Lim RLH, Tan CP, Ho CW

Food Sci Biotechnol, 2019 Aug;28(4):1163-1169.
PMID: 31275716 DOI: 10.1007/s10068-018-00550-z

Betacyanins are bioactive dietary phytochemicals which can be found in red dragon fruit (RDF). Therefore, the bioaccessibility of betacyanins that present in fermented red dragon fruit drink (RDFD) and pressed red dragon fruit juice (RDFJ) was accessed in simulated gastric and intestinal digestion. Results disclosed that betacyanins from RDFD and RDFJ suffered minor loss (
Fulltext Studies on the storage stability of fermented red dragon fruit (Hylocereus polyrhizus) drink

Choo KY, Kho C, Ong YY, Thoo YY, Lim RLH, Tan CP, et al.

Food Sci Biotechnol, 2018 Oct;27(5):1411-1417.
PMID: 30319851 DOI: 10.1007/s10068-018-0367-4

The objective of this work was to study the effect of storage temperatures and duration on the stability of fermented red dragon fruit drink (FRDFD) on its betacyanins content, physicochemical and microbiological qualities (BPM) and determining sensory acceptability. Results showed that both storage temperatures and duration have a significant effect on betacyanins content and physicochemical properties of FRDFD. Aerobic mesophilic and yeast and mold counts were lower than 1 × 103 CFU/mL for FRDFD stored at both temperatures. The loss of betanin (16.53-13.93 g/L) at 4 °C was 15.73% with no significant changes in physicochemical properties from week two onwards compared to 56.32% (16.53-7.22 g/L) of betanin loss at 25 °C. At week eight, FRDFD stored at 4 °C still contained 13.93 g/L betanin with a pH value of 3.46, suggested its potential as a functional drink which is sensory acceptable (mean score > 80% using hedonic test) among consumers.
Fulltext Effect of lipopolysaccharide on cell proliferation and vascular endothelial growth factor secretion of periodontal ligament stem cells

Keong JY, Low LW, Chong JM, Ong YY, Pulikkotil SJ, Singh G, et al.

Saudi Dent J, 2020 Mar;32(3):148-154.
PMID: 32180672 DOI: 10.1016/j.sdentj.2019.08.001

PURPOSE: Periodontal ligament stem cells (PDLSCs) have considerable potential for use as a means of achieving periodontal regeneration due to their noteworthy proliferative properties and secretory functions. In particular, PDLSCs secrete vascular endothelial growth factor (VEGF) which enhances angiogenesis and osteogenesis. The resulting repair and development of blood vessels and hard tissues which would occur in the presence of these cells could be central to an effective periodontal regeneration procedure.The bacterial biofilm of tooth surface related to the periodontium might provide either an inhibition or a stimulus to different factors involved in a regenerative process. Cell culture experiments have been investigated in vitro by adding lipopolysaccharide (LPS) to the culture medium but the effect of various concentration of LPS in these circumstances has not been investigated. Therefore, this study aimed to investigate the effect of LPS concentrations on proliferation of PDLSCs in vitro and on their secretion of VEGF.
MATERIALS AND METHODS: PDLSCs were treated with 0, 5, 10 and 20 µg/mL of Escherichia coli LPS. At 48 and 96 h, total cell numbers of control and LPS treated PDLSCs were counted by haemocytometer under a microscope. The VEGF concentration in the conditioned media of the PDLSCs was measured by ELISA.
RESULTS: Rate of cell proliferation of PDLSCs decreased significantly in all LPS treated groups at both 48 h and 96 h except for the group treated with 5 µg/mL of LPS at 48 h. At both 48 and 96 h, VEGF secretion from PDLSCs was reduced significantly at all three LPS concentrations. There was no statistically significant difference in cell proliferation and the amount of VEGF secretion of PDLSCs among the groups treated with different LPS concentrations. No statistically significant change was found in cell proliferation of LPS treated PDLSCs over time, whereas VEGF secretion of PDLSCs was found to have increased significantly with time despite the LPS treatment.
CONCLUSIONS: LPS reduced cell proliferation and VEGF secretion of PDLSCs, suggesting that periodontal pathogens might reduce the capability of PDLSCs in periodontal regeneration. Yet, LPS treated PDLSCs remained viable and VEGF secretion increased significantly over time. Further research is needed to study the potential use of PDLSCs in periodontal regeneration and the relationship of biofilm LPS accumulations.
Ethnicity, obstructive sleep apnoea and ischaemic heart disease

Tan YK, Khoo KL, Low JA, Wong ZW, Theng CT, Ong TH, et al.

Ann Acad Med Singap, 1999 Mar;28(2):214-6.
PMID: 10497669

We studied the relationship between different ethnic groups, obstructive sleep apnoea (OSA) and ischaemic heart disease. Four hundred and thirty-two inpatients from the medical wards were interviewed. Limited overnight sleep studies were done in 129 of those who had habitual snoring, daytime sleepiness based on an Epworth sleepiness scale of 8 or more, or a large neck size of 40 cm or more. There were 315 Chinese (72.9%), 67 Malays (15.5%), 43 Indians (10%) and 3 from other races (1.4%). The prevalence of OSA was 19.7%, 30% and 12% among the Chinese, Malays and Indians, respectively. The prevalence ratio for OSA was 1.52 in Malays using Chinese patients as the baseline (P = 0.07). The median neck circumference was 37 cm in both racial groups. The median body mass index was 22.7 kg/m2 in Chinese compared to 23.6 kg/m2 in Malays. The median apnoea-hypopnoea index was 22.7, 19.0 and 26.9 events/hour among the Chinese, Malays and Indians, respectively. OSA was independently associated with the prevalence of IHD (adjusted prevalence ratio 1.68; 95% CI: 1.15, 2.46; P = 0.009). The prevalence of ischaemic heart disease (IHD) was 31%, 24% and 28% in Chinese, Malays and Indians, respectively. The prevalence ratio for IHD in Malays compared to Chinese was 0.77. After adjusting for OSA, there was an even greater reduction in the risk of IHD (adjusted prevalence ratio 0.70). This suggests that OSA is a confounder in the relationship between race and ischaemic heart disease.