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Risk factors for early death in acute ischemic stroke and intracerebral hemorrhage: A prospective hospital-based study in Asia. Asian Acute Stroke Advisory Panel

Wong KS

Stroke, 1999 Nov;30(11):2326-30.
PMID: 10548666

BACKGROUND AND PURPOSE: In Asia, there has been no international study to investigate the risk factors for early death in patients with ischemic stroke and intracerebral hemorrhage.
METHODS: We conducted a prospective study of consecutive patients with acute stroke who were admitted to 36 participating hospitals in China, India, Indonesia, Korea, Malaysia, the Philippines, Singapore, Taiwan, Thailand, and Vietnam. With the use of a simple identical data sheet, we recorded the demographics and cardiovascular risk factors of each patient. Early death was defined as death on discharge from the acute hospital.
RESULTS: We enrolled 2403 patients with ischemic stroke and 783 patients with intracerebral hemorrhage. Among patients with ischemic stroke, previous use of antiplatelet drugs (adjusted odds ratio [OR] 0.53; 95% confidence interval [CI] 0. 30 to 0.95) and relatively young age group 56 to 75 years (OR 0.65; 95% CI 0.42 to 1.00) were protective factors; atrial fibrillation (OR 2.23; 95% CI 1.40 to 3.57), ischemic heart disease (OR 2.03; 95% CI 1.37 to 3.05), diabetes (OR 1.52; 95% CI 1.04 to 2.22), and ex-smoker status (OR 2.18; 95% CI 1.18 to 4.05) were risk factors for early death. Among patients with intracerebral hemorrhage, hypertension (OR 0.56; 95% CI 0.38 to 0.82) and young age group 56 to 75 years old (OR 0.55; 95% CI 0.34 to 0.87) were associated with lower death rate, whereas diabetes (OR 1.74; 95% CI 1.01 to 2.98) was a risk factor for early death.
CONCLUSIONS: In Asian patients with stroke, previous use of antiplatelet drugs nearly halved the risk of early death in patients with ischemic stroke, whereas atrial fibrillation, ischemic heart disease, diabetes, and ex-smoker status were risk factors for early death. Among patients with intracerebral hemorrhage, diabetes was associated with early death, whereas young age group and hypertension were associated with lower death rates, though no clear explanation for the hypertension association could be discerned from the data available.
Fulltext A profile of hypertension among rural elderly Malaysians

Srinivas P, Wong KS, Chia YC, Poi PJ, Ebrahim S

Southeast Asian J. Trop. Med. Public Health, 1998 Dec;29(4):821-6.
PMID: 10772571

The main objective of this study was to survey the prevalence of hypertension in Malaysians aged 55 years and above who responded to a public health screening campaign in Kuala Langat district, Selangor, Malaysia. The relationship between the detection, treatment and control in the study population was also examined. An epidemiological survey of the elderly was conducted in Kuala Langat, a rural district in Malaysia for a consecutive period of six weeks. The survey was conducted using a standardized questionnaire and interview by trained research assistants. The medical students and nurses were trained on the correct protocol of measuring blood pressure based on the recommendations of the British Hypertension Society. Newly detected persons with blood pressure readings 160/95 mmHg and above, were given a green card to return to the nearest health center for a further 2 visits to check his/her blood pressure. A total of 1,392 people with a mean age of 65 years and comprising of 53.1% males and 46.9% females responded to the health survey. Based on the history 335 (24.1%) of the respondents were known hypertensives and 82.1% of this hypertensive group were on regular treatment. However good control of hypertension was achieved only in 161 (48.1%) of them. Newly detected hypertension was found in 204 (14.6%) of the respondents. The overall prevalence of hypertension in our sample of respondents was 25.6%. There was no significant difference between the sexes and the races in terms of their detection, treatment and control. However there was a significant difference between the persons aged less than 65 years of age and those older than 65 years. There was a large proportion of previously known hypertensives among the survey population. Of those detected, not all were on regular medications and the majority on medications were not well controlled. Education of the public through intensive public health campaigns is vital to improve their knowledge on hypertension and the need for effective control. More community studies are needed to formulate better methods in the detection, treatment and control of hypertension.
Fulltext Enhancing rate of water absorption in seeds via a miniature surface acoustic wave device

Wong KS, Lee L, Yeo LY, Tan MK

R Soc Open Sci, 2019 Mar;6(3):181560.
PMID: 31032012 DOI: 10.1098/rsos.181560

Seeds, which are high in protein and essential nutrients, must go through a hydration process before consumption. The ability to rapidly increase water absorption can significantly reduce the soaking time as well as the amount of energy needed for cooking seeds. Many studies in the literature employ high-power (102 W) low-frequency (104 Hz) ultrasound; although their results are very promising where more than 100% increase in water content can be obtained between the treated and untreated seeds, the high-power and low-frequency ultrasound often causes acoustic cavitation under high intensity, which can severely disrupt the cell walls and damage the seeds. In our study, however, we demonstrate that treating the seeds via a miniature surface acoustic wave device, which operates at low-power (100 W) and high-frequency (107 Hz) range, gives rise to a higher water absorption rate without the acoustic cavitations. By comparing the water content between the treated and untreated seeds, an increase of up to 2600% (for chickpeas) and 6350% (for mung bean) can be obtained after 60 min. A significantly higher water absorption in mung beans can be attributed to the larger pore size when compared with the acoustic wavelength in water, enabling an efficient transmission of acoustic wave inside the pores. Our results also indicate that the germination time can be reduced by half for treated seeds as compared to the untreated seeds.
Lamb to Rayleigh Wave Conversion on Superstrates as a Means to Facilitate Disposable Acoustomicrofluidic Applications

Wong KS, Lee L, Hung YM, Yeo LY, Tan MK

Anal Chem, 2019 10 01;91(19):12358-12368.
PMID: 31500406 DOI: 10.1021/acs.analchem.9b02850

Rayleigh surface acoustic waves (SAWs) have been demonstrated as a powerful and effective means for driving a wide range of microfluidic actuation processes. Traditionally, SAWs have been generated on piezoelectric substrates, although the cost of the material and the electrode deposition process makes them less amenable as low-cost and disposable components. As such, a "razor-and-blades" model that couples the acoustic energy of the SAW on the piezoelectric substrate through a fluid coupling layer and into a low-cost and, hence, disposable silicon superstrate on which various microfluidic processes can be conducted has been proposed. Nevertheless, it was shown that only bulk vibration in the form of Lamb waves can be excited in the superstrate, which is considerably less efficient and flexible in terms of microfluidic functionality compared to its surface counterpart, that is, the SAW. Here, we reveal an extremely simple way that quite unexpectedly and rather nonintuitively allows SAWs to be generated on the superstrate-by coating the superstrate with a thin gold layer. In addition to verifying the existence of the SAW on the coated superstrate, we carry out finite-difference time domain numerical simulations that not only confirm the experimental observations but also facilitate an understanding of the surprising difference that the coating makes. Finally, we elucidate the various power-dependent particle concentration phenomena that can be carried out in a sessile droplet atop the superstrate and show the possibility for simply carrying out rapid and effective microcentrifugation-a process that is considerably more difficult with Lamb wave excitation on the superstrate.
In situ generation of plasma-activated aerosols via surface acoustic wave nebulization for portable spray-based surface bacterial inactivation

Wong KS, Lim WTH, Ooi CW, Yeo LY, Tan MK

Lab Chip, 2020 05 19;20(10):1856-1868.
PMID: 32342089 DOI: 10.1039/d0lc00001a

The presence of reactive species in plasma-activated water is known to induce oxidative stresses in bacterial species, which can result in their inactivation. By integrating a microfludic chipscale nebulizer driven by surface acoustic waves (SAWs) with a low-temperature atmospheric plasma source, we demonstrate an efficient technique for in situ production and application of plasma-activated aerosols for surface disinfection. Unlike bulk conventional systems wherein the water is separately batch-treated within a container, we show in this work the first demonstration of continuous plasma-treatment of water as it is transported through a paper strip from a reservoir onto the chipscale SAW device. The significantly larger surface area to volume ratio of the water within the paper strip leads to a significant reduction in the duration of the plasma-treatment, while maintaining the concentration of the reactive species. The subsequent nebulization of the plasma-activated water by the SAW then allows the generation of plasma-activated aerosols, which can be directly sprayed onto the contaminated surface, therefore eliminating the storage of the plasma-activated water and hence circumventing the typical limitation in conventional systems wherein the concentration of the reactive species diminishes over time during storage, resulting in a reduction in the efficacy of bacterial inactivation. In particular, we show up to 96% reduction in Escherichia coli colonies through direct spraying with the plasma-activated aerosols. This novel, low-cost, portable and energy-efficient hybrid system necessitates only minimal maintenance as it only requires the supply of tap water and battery power for operation, and is thus suitable for decontamination in home environments.
Fulltext Diagnosing peripheral neuropathy in South-East Asia: A focus on diabetic neuropathy

Malik RA, Andag-Silva A, Dejthevaporn C, Hakim M, Koh JS, Pinzon R, et al.

J Diabetes Investig, 2020 Sep;11(5):1097-1103.
PMID: 32268012 DOI: 10.1111/jdi.13269

Burning and stabbing pain in the feet and lower limbs can have a significant impact on the activities of daily living, including walking, climbing stairs and sleeping. Peripheral neuropathy in particular is often misdiagnosed or underdiagnosed because of a lack of awareness amongst both patients and physicians. Furthermore, crude screening tools, such as the 10-g monofilament, only detect advanced neuropathy and a normal test will lead to false reassurance of those with small fiber mediated painful neuropathy. The underestimation of peripheral neuropathy is highly prevalent in the South-East Asia region due to a lack of consensus guidance on routine screening and diagnostic pathways. Although neuropathy as a result of diabetes is the most common cause in the region, other causes due to infections (human immunodeficiency virus, hepatitis B or C virus), chronic inflammatory demyelinating polyneuropathy, drug-induced neuropathy (cancer chemotherapy, antiretrovirals and antituberculous drugs) and vitamin deficiencies (vitamin B1 , B6 , B12 , D) should be actively excluded.
The changing pattern of primary glomerulonephritis in Singapore and other countries over the past 3 decades

Woo KT, Chan CM, Mooi CY, -L-Choong H, Tan HK, Foo M, et al.

Clin. Nephrol., 2010 Nov;74(5):372-83.
PMID: 20979946

This review of 2,586 renal biopsies over the past 3 decades in Singapore documents the changing pattern of glomerulonephritis (GN) from that of a third world country to that of a developed nation. In the 1st decade, mesangial proliferative glomerulonephritis was the most common form of primary GN, just as it was in the surrounding Asian countries. In the 2nd decade, the prevalence of mesangial proliferative GN decreased with a rise in membranous, GN which is also seen in China and Thailand. In the 3rd decade, there was a dramatic increase in focal sclerosing glomerulosclerosis. This increase reflects aging and obesity in keeping with more developed countries like Australia, India, Thailand and the United States of America. IgA nephritis remains the most common GN. Apart from the geographical influence, other socioeconomic factors play a significant role in the evolution of the renal biopsy pattern. Mesangial proliferative GN remains prevalent in many Asian countries, but in Singapore the prevalence is decreasing just as it is in Japan, Korea and Malaysia. Worldwide, the prevalence of focal sclerosing glomerulosclerosis continues to increase in many countries.
Changes in primary glomerulonephritis in Singapore over four decades 

Woo KT, Chan CM, Lim C, Choo J, Chin YM, Teng WL, et al.

Clin. Nephrol., 2019 Mar;91(3):155-161.
PMID: 30663975 DOI: 10.5414/CN109577

This review of 3,289 native kidney biopsies over the past four decades in Singapore documents the changing pattern of biopsy-proven glomerulonephritis (GN)from that of a third world country to that of a developed nation. In the 1st decade, mesangial proliferative GN was the most common form of primary GN, similar to the Asian region. In the 2nd decade, the percentage of mesangial proliferative GN decreased, but membranous GN became more common, as was seen in China and Thailand. In the 3rd decade, focal segmental glomerulosclerosis (FSGS) and membranous nephropathy continued to rise, but it was only recently, in the 4th decade, that FSGS prevalence increased dramatically, although membranous nephropathy continues to increase in some Asian countries. In the last decade in Singapore, Malaysia, and Japan, prevalence of IgA nephritis has decreased but remains the most common GN. The percentage of FSGS continues to increase in many countries like in Italy, United States of America, United Kingdom, China, and Malaysia. We surmise that socioeconomic factors play significant roles in the evolution of the renal biopsy pattern. .