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Successful pregnancy outcome following gamete intra-Fallopian transfer in a patient with Müllerian dysgenesis

Lee CS, Lie AT

Reprod Biomed Online, 2012 May;24(5):547-9.
PMID: 22410277 DOI: 10.1016/j.rbmo.2012.01.021

A 29-year-old lady with Müllerian dysgenesis was keen to have a baby. Clinically, she was medium built with well-developed secondary female sexual characteristics. There was a short and blind vagina. She had undergone surgery for an imperforated hymen. Her FSH and LH concentrations were normal. Laparoscopy revealed a patent right Fallopian tube, a rudimentary right uterus and extensive pelvic endometriosis. She subsequently underwent gamete intra-Fallopian transfer (GIFT). Oocyte retrieval was carried out laparoscopically and a total of nine oocytes were retrieved. Four of the oocytes were transferred together with motile spermatozoa into the right Fallopian tube and the remaining five oocytes were inseminated with spermatozoa for IVF. Three embryos resulted and were frozen. She subsequently developed moderate ovarian hyperstimulation syndrome. Serum β-human chorionic gonadotrophin concentration 14 days after GIFT was 1612 IU/l. Her antenatal care was relatively uneventful until 31 weeks of gestation when she was diagnosed to have intrauterine growth retardation and oligohydramnios. She then underwent an emergency Caesarean section at 32 weeks of pregnancy delivering a normal baby. This case study describes a successful pregnancy outcome following gamete intra-Fallopian transfer (GIFT) in a woman with malformation of the vagina (Müllerian dysgenesis). A 29-year-old lady with Müllerian dysgenesis diagnosed at 16 years of age was keen to become pregnant. Upon examination, a decision was made for a William's vulvovaginoplasty but as the patient was indecisive the surgery was deferred. Clinically, she is a medium-built lady with well-developed secondary female sexual characteristics. There was a short and blind vagina. Her serum FSH and LH concentrations were normal. Laparoscopy revealed a patent right Fallopian tube, a rudimentary right uterus and extensive pelvic endometriosis. She subsequently underwent GIFT. Nine oocytes were retrieved through laparoscopy. Four of the oocytes were transferred together with motile sperm into the right Fallopian tube and the remaining five oocytes were inseminated with sperm for IVF. Three embryos resulted and were frozen. Serum β human chorionic gonadotrophin concentration measured 14 days after GIFT was 1612 IU/l. An abdominal ultrasonography performed at 5 weeks showed one intrauterine gestational sac. Her antenatal care was uneventful until 31 weeks of gestation when she developed a deficiency of amniotic fluid in the amniotic sac. She then underwent an emergency Caesarean section at 32 weeks of pregnancy. She delivered a healthy, normal 1.24 kg baby boy. Her post-natal care was uneventful.
Shyness, Loneliness Avoidance, and Internet Addiction: What are the Relationships?

Ang CS, Chan NN, Lee CS

J Psychol, 2018 Jan 02;152(1):25-35.
PMID: 29236584 DOI: 10.1080/00223980.2017.1399854

Given that shyness has been consistently linked to Internet addiction in youth, an examination into the mediating effect of a desire to avoid loneliness on the shyness-Internet addiction link could offer potential insights into a possible explanatory mechanism as well as directions for Internet addiction prevention and intervention in young adulthood. Thus, the aim of this study is to investigate the mediating role of loneliness avoidance in the relationship between shyness and Internet addiction among 286 youth Internet users. Shyness was significantly and positively correlated with loneliness avoidance and Internet addiction. In addition, loneliness avoidance was significantly and positively correlated with Internet addiction. Most importantly, loneliness avoidance may predispose shy youth to become addicted to the Internet. Theoretical and practical implications of the research findings for youth wellness are addressed in this study.
Fulltext Lectins: an effective tool for screening of potential cancer biomarkers

Hashim OH, Jayapalan JJ, Lee CS

PeerJ, 2017;5:e3784.
PMID: 28894650 DOI: 10.7717/peerj.3784

In recent years, the use of lectins for screening of potential biomarkers has gained increased importance in cancer research, given the development in glycobiology that highlights altered structural changes of glycans in cancer associated processes. Lectins, having the properties of recognizing specific carbohydrate moieties of glycoconjugates, have become an effective tool for detection of new cancer biomarkers in complex bodily fluids and tissues. The specificity of lectins provides an added advantage of selecting peptides that are differently glycosylated and aberrantly expressed in cancer patients, many of which are not possibly detected using conventional methods because of their low abundance in bodily fluids. When coupled with mass spectrometry, research utilizing lectins, which are mainly from plants and fungi, has led to identification of numerous potential cancer biomarkers that may be used in the future. This article reviews lectin-based methods that are commonly adopted in cancer biomarker discovery research.
Controller Design and Stability Analysis of Intensification Process using Analytical Exact Gain-Phase Margin approach

Lee CS, Abd Shukor SR

Environ Sci Pollut Res Int, 2023 Dec;30(60):124790-124805.
PMID: 36961637 DOI: 10.1007/s11356-023-26358-x

The controllable intensified process has received immense attention from researchers in order to deliver the benefit of process intensification to be operated in a desired way to provide a more sustainable process toward reduction of environmental impact and improvement of intrinsic safety and process efficiency. Despite numerous studies on gain and phase margin approach on conventional process systems, it is yet to be tested on intensified systems as evidenced by the lack of available literature, to improve the controller performance and robustness. Thus, this paper proposed the exact gain and phase margin (EGPM) through analytical method to develop suitable controller design for intensified system using Proportional-Integral-Derivative (PID) controller formulation, and it was compared to conventional Direct Synthesis methods (DS), Internal Model Control (IMC), and Industrial IMC method in terms of the performance and stability analysis. Simulation results showed that EGPM method provides good setpoint tracking and disturbance rejection as compared to DS, IMC, and Industrial IMC while retaining overall performance stability as time delay increases. The Bode Stability Criterion was used to determine the stability of the open-loop transfer function of each method and the result demonstrated decrease in stability as time delay increases for controllers designed using DS, IMC, and Industrial IMC, and hence control performance degrades. However, the proposed EGPM controller maintains the overall robustness and control performance throughout the increase of time delay and outperform other controller design methods at higher time delay with [Formula: see text] uncertainty test. Additionally, the proposed EGPM controller design method provides overall superior control performance with lower overshoot and shorter rise time compared to other controllers when process time constant is smaller in magnitude ([Formula: see text]) than the instrumentation element, which is one of the major concerns during the design of intensified controllers, resulting overall system with a higher order. The desired selection of gain margin and phase margin were suggested at 2.5 to 4 and 60 °-70 [Formula: see text], respectively, for a wide range of control conditions for intensified processes where higher instrumentation dynamic would be possible to achieve robust control as well. The proposed EGPM method controller is thought to be a more reliable design strategy for maintaining the overall robustness and performance of higher order and complex systems that are highly affected by time delay and high dynamic response of intensified processes.
Optimisation of extraction and sludge dewatering efficiencies of bio-flocculants extracted from Abelmoschus esculentus (okra)

Lee CS, Chong MF, Robinson J, Binner E

J Environ Manage, 2015 Jul 1;157:320-5.
PMID: 25929197 DOI: 10.1016/j.jenvman.2015.04.028

The production of natural biopolymers as flocculants for water treatment is highly desirable due to their inherent low toxicity and low environmental footprint. In this study, bio-flocculants were extracted from Hibiscus/Abelmoschus esculentus (okra) by using a water extraction method, and the extract yield and its performance in sludge dewatering were evaluated. Single factor experimental design was employed to obtain the optimum conditions for extraction temperature (25-90 °C), time (0.25-5 h), solvent loading (0.5-5 w/w) and agitation speed (0-225 rpm). Results showed that extraction yield was affected non-linearly by all experimental variables, whilst the sludge dewatering ability was only influenced by the temperature of the extraction process. The optimum extraction conditions were obtained at 70 °C, 2 h, solvent loading of 2.5 w/w and agitation at 200 rpm. Under the optimal conditions, the extract yield was 2.38%, which is comparable to the extraction of other polysaccharides (0.69-3.66%). The bio-flocculants displayed >98% removal of suspended solids and 68% water recovery during sludge dewatering, and were shown to be comparable with commercial polyacrylamide flocculants. This work shows that bio-flocculants could offer a feasible alternative to synthetic flocculants for water treatment and sludge dewatering applications, and can be extracted using only water as a solvent, minimising the environmental footprint of the extraction process.
Fulltext Differential expression of senescence tumour markers and its implications on survival outcomes of breast cancer patients

Pare R, Soon PS, Shah A, Lee CS

PLoS One, 2019;14(4):e0214604.
PMID: 30998679 DOI: 10.1371/journal.pone.0214604

Breast cancer is a heterogeneous disease displaying different histopathological characteristics, molecular profiling and clinical behavior. This study describes the expression patterns of senescence markers P53, DEC1 and DCR2 and assesses their significance on patient survival as a single or combined marker with P16 or P14 using breast cancer progression series. One thousand and eighty (1080) patients with primary invasive ductal carcinoma, no special type, were recruited through an 11-year retrospective study period. We constructed tissue microarrays of normal, benign hyperplasia, ductal carcinoma in situ and invasive ductal carcinoma from each patient and performed immunohistochemical staining to study the protein expression. Statistical analysis includes Pearson chi-square, Kaplan-Meier log ran test and Cox proportional hazard regression were undertaken to determine the associations and predict the survival outcomes. P53, DEC1 and DCR2 expression correlated significantly with normal, benign, premalignant and malignant tissues with (p<0.05). The expression profile of these genes increases from normal to benign to premalignant and plateaued from premalignant to malignant phenotype. There is a significant association between P53 protein expression and age, grade, staging, lymphovascular invasion, estrogen receptor, progesterone receptor and HER2 whereas DCR2 protein expression significantly correlated with tumour grade, hormone receptors status and HER2 (p<0.05 respectively). P53 overexpression correlated with increased risk of relapse (p = 0.002) specifically in patients who did not receive hormone therapy (p = 0.005) or chemotherapy (p<0.0001). The combination of P53+/P16+ is significantly correlated with poor overall and disease-free survival, whereas a combination of P53+/P14+ is associated with worse outcome in disease-free survival (p<0.05 respectively). P53 overexpression appears to be a univariate predictor of poor disease-free survival. The expression profiles of DEC1 and DCR2 do not appear to correlate with patient survival outcomes. The combination of P53 with P16, rather P53 expression alone, appears to provide more useful clinical information on patient survival outcomes in breast cancer.
Optimisation of Reactive Black 5 dye removal by electrocoagulation process using response surface methodology

Mook WT, Aroua MK, Szlachta M, Lee CS

Water Sci Technol, 2017 02;75(3-4):952-962.
PMID: 28234295 DOI: 10.2166/wst.2016.563

In this work, a regression model obtained from response surface methodology (RSM) was proposed for the electrocoagulation (EC) treatment of textile wastewater. The Reactive Black 5 dye (RB5) was used as a model dye to evaluate the performance of the model design. The effect of initial solution pH, applied current and treatment time on RB5 removal was investigated. The total number of experiments designed by RSM amounted to 27 runs, including three repeated experimental runs at the central point. The accuracy of the model was evaluated by the F-test, coefficient of determination (R(2)), adjusted R(2) and standard deviation. The optimum conditions for RB5 removal were as follows: initial pH of 6.63, current of 0.075 A, electrolyte dose of 0.11 g/L and EC time of 50.3 min. The predicted RB5 removal was 83.3% and the percentage error between experimental and predicted results was only 3-5%. The obtained data confirm that the proposed model can be used for accurate prediction of RB5 removal. The value of the zeta potential increased with treatment time, and the X-ray diffraction pattern shows that iron complexes were found in the sludge.
Distribution of Microplastics and Nanoplastics in Aquatic Ecosystems and Their Impacts on Aquatic Organisms, with Emphasis on Microalgae

Wan JK, Chu WL, Kok YY, Lee CS

Rev Environ Contam Toxicol, 2018 Jun 06.
PMID: 29872923 DOI: 10.1007/398_2018_14

Plastics, with their many useful physical and chemical properties, are widely used in various industries and activities of daily living. Yet, the insidious effects of plastics, particularly long-term effects on aquatic organisms, are not properly understood. Plastics have been shown to degrade to micro- and nanosize particles known as microplastics and nanoplastics, respectively. These minute particles have been shown to cause various adverse effects on aquatic organisms, ranging from growth inhibition, developmental delay and altered feeding behaviour in aquatic animals to decrease of photosynthetic efficiency and induction of oxidative stress in microalgae. This review paper covers the distribution of microplastics and nanoplastics in aquatic ecosystems, focusing on their effects on microalgae as well as co-toxicity of microplastics and nanoplastics with other pollutants. Besides that, this review paper also discusses future research directions which could be taken to gain a better understanding of the impacts of microplastics and nanoplastics on aquatic ecosystems.
Influence of polystyrene microplastic and nanoplastic on copper toxicity in two freshwater microalgae

Wan JK, Chu WL, Kok YY, Lee CS

Environ Sci Pollut Res Int, 2021 Mar 01.
PMID: 33646549 DOI: 10.1007/s11356-021-12983-x

There has been increasing concern over the toxic effects of microplastics (MP), nanoplastics (NP), and copper (Cu) on microalgae. However, the combined toxicity of the metal in the presence of polystyrene (PS) MP/NP on microalgae has not been well studied, particularly after long-term exposure (i.e., longer than 4 days). The primary aim of the present study was to investigate the effect of PS MP and NP on Cu toxicity on two freshwater microalgae, namely Chlorella sp. TJ6-5 and Pseudokirchneriella subcapitata NIES-35 after acute exposure for 4 days and up to 16 days. The results showed that both microalgae were sensitive to Cu, but tolerant to MP/NP. However, MP/NP increased the toxicity of Cu at EC50 in both microalgae, which was only noticeable in chronic exposure. Single and combined treatment of MP/NP and Cu induced higher oxidative stress and caused morphological and ultrastructural changes in both microalgae. The adsorption of Cu to MP and NP was low (0.23-14.9%), with most of the Cu present in free ionic form (81.6-105.8%). The findings on different sensitivity of microalgae to Cu in the presence of MP/NP may have significant implication as microalgae are likely to be exposed to a mixture of both MP/NP and Cu in the environment. For example, in air-blasting technology, MP and NP are used as abrasive medium to remove Cu-containing antifouling paints on hulls of ship and submerged surfaces. Wastewater treatment plants receive household wastes containing MP and NP, as well as stormwater runoffs and industrial wastes contaminated with heavy metals.
An improved lectin-based method for the detection of mucin-type O-glycans in biological samples

Lee CS, Muthusamy A, Abdul-Rahman PS, Bhavanandan VP, Hashim OH

Analyst, 2013 Jun 21;138(12):3522-9.
PMID: 23665615 DOI: 10.1039/c3an36258b

Mucins and mucin-type glycoproteins, collectively referred to as mucin-type O-glycans, are implicated in many important biological functions and pathological conditions, including malignancy. Presently, there is no reliable method to measure the total mucin-type O-glycans of a sample, which may contain one or more of these macromolecules of unknown structures. We report the development of an improved microassay that is based on the binding of lectins to the unique and constant GalNAc-Ser/Thr structural feature of mucin-type O-glycans. Since the sugar-amino acid linkage in the mucin-type O-glycans is invariably cryptic, we first chemically removed the heterogeneous peripheral and core saccharides of model glycoconjugates before examining for their interactions using an enzyme-linked lectin assay (ELLA). Desialylation of the model glycoconjugates led to maximal binding of the lectins but additional treatments such as Smith degradation did not result in increased binding. Of the lectins tested for their ability to probe the desialylated O-glycans, jacalin showed the highest sensitivity followed by champedak galactose binding (CGB) lectin and Vicia villosa agglutinin. Further improvement in the sensitivity of ELLA was achieved by using microtiter plates that were pre-coated with the CGB lectin, which increased the specificity of the assay to mucin-type O-glycans. Finally, the applicability of the developed sandwich ELLA to crude samples was demonstrated by estimating trace quantities of the mucin-type O-glycans in the human serum.
Genetic diversity of enterovirus 71 isolated from cases of hand, foot and mouth disease in the 1997, 2000 and 2005 outbreaks, Peninsular Malaysia

Chua KB, Chua BH, Lee CS, Chem YK, Ismail N, Kiyu A, et al.

Malays J Pathol, 2007 Dec;29(2):69-78.
PMID: 19108398

All known field isolates of enterovirus 71 (EV71) can be divided into three distinct genogroups (A, B, C) and 10 subgenogroups (A, B1-5, C1-4) based on VP1 gene sequences. We examined VP1 gene sequences of 10, 12 and 11 EV71 strains isolated in peninsular Malaysia during the outbreaks of hand, foot and mouth disease in 1997, 2000 and 2005 respectively. Four EV71 strains isolated in the hand, foot and mouth disease outbreak of 2006 in Sarawak (Malaysian Borneo) were included to describe their genetic relationship. Four subgenogroups (C1, C2, B3 and B4) of EV71 co-circulated and caused the outbreak of hand, foot and mouth disease in peninsular Malaysia in 1997. Two subgenogroups (C1 and B4) were noted to cause the outbreak in 2000. In the 2005 outbreak, besides EV71 strains of subgenogroup C1, EV71 strains belonged to subgenogroup B5 were isolated but formed a cluster which was distinct from EV71 strains of the subgenogroup B5 isolated in 2003. The four EV71 strains isolated from clinical specimens of patients with hand, foot and mouth disease in the Sarawak outbreak in early 2006 also belonged to subgenogroup B5. Phylogenetic analysis of the VP1 gene sequences showed that the four Sarawak EV71 isolates belonged to the same cluster as the EV71 strains that were isolated in peninsular Malaysia as early as May 2005. The data suggested that the EV71 strains causing the outbreak in Sarawak could have originated from peninsular Malaysia.
Fulltext Post-operative health related quality of life assessment in scoliosis patients

Chan CYW, Kwan MK, Saw LB, Deepak AS, Chong CS, Liew TM, et al.

Med J Malaysia, 2008 Jun;63(2):137-9.
PMID: 18942300

Adolescent Idiopathic Scoliosis is a spinal deformity which affects patients' self image and confidence. Surgery is offered when the curve is more than 50 degrees based on its likelihood of progression. Studies on the radiological outcome of scoliosis correction are abundant. Therefore, it is the objective of this study to evaluate the health related quality of life in scoliosis patients who had undergone surgical correction in University Malaya Medical Center, Kuala Lumpur, Malaysia using Scoliosis Research Society-22 (SRS-22) patient questionnaire. This is a prospective evaluation of SRS-22 scores of thirty eight patients operated in our center over the past five years with a minimum follow up of one year. There were thirty two females and six males. Twenty six (68.4%) were Chinese, eight (21.1%) Malay and four (10.5%) Indian patients. The age of the patients ranged from twelve to twenty eight years, with a mean age of 18.4 +/- 3.5. Based on the King and Moe's classification, sixteen patients had King's 3 curve. The mean pre-operative Cobb angle was 68.6 degree and post-operative Cobb angle was 35.8 degree. The average curve correction was 48.5%. The overall score for SRS-22 was 4.2. The SRS-22 scores were highest for the pain domains and lowest for the functional domains. Satisfaction domain scored 4.3. The function domain scored significantly higher in those who have twenty four months or less follow up duration. Curve magnitude and the amount of correction did not significantly alter the SRS scores. In conclusion, patients were satisfied with the outcome of their operation. Although pain was common, the intensity of the pain was minimal. The amount of curve correction did not correlate with the quality of life after operation.
Fulltext Relationship between cold pressor pain-sensitivity and sleep quality in opioid-dependent males on methadone treatment

Zahari Z, Lee CS, Tan SC, Mohamad N, Lee YY, Ismail R

PeerJ, 2015;3:e839.
PMID: 25870765 DOI: 10.7717/peerj.839

Aim. Poor sleep quality due to pain has been reported among opioid-dependent male patients on methadone maintenance therapy (MMT) but objective pain data are lacking. This study aimed to investigate the rate of pain-sensitivity using cold pressor test (CPT) and the relationship between pain-sensitivity and sleep quality in this population.
Methods. A total of 168 male participants were included into the study. Objective pain-tolerance was evaluated at 0 h and at 24 h after the first CPT. Malay version of the Pittsburgh Sleep Quality Index (PSQI) and the subjective opiate withdrawal scale (SOWS) questionnaires were administered to evaluate the quality of sleep and withdrawal symptoms, respectively.
Results. The mean age of study participants was 37.22 (SD 6.20) years old. Mean daily methadone dose was 76.64 (SD 37.63) mg/day, mean global PSQI score was 5.47 (SD 2.74) and mean averaged SOWS score was 5.43 (SD 6.91). The averaged pain-tolerance time ranged from 7 to 300 s with a mean time of 32.16 (SE 2.72) s, slightly below the cut-off score of 37.53 s. More specifically, 78.6% (n = 132) of participants were identified as pain-sensitive (averaged pain-tolerance time ≤37.53 s), and 36 (21.4%) participants were pain-tolerant (averaged pain-tolerance time >37.53 s). The pain-sensitive group reported poorer sleep quality with mean (SD) PSQI of 5.78 (2.80) compared with the pain-tolerant group with mean (SD) PSQI of 4.31 (2.18) (p = 0.005). With analysis of covariance, pain-sensitive group was found to have higher global PSQI scores (adjusted mean 5.76, 95% CI 5.29; 6.22) than pain-tolerant participants (adjusted mean 4.42, 95% CI 3.52; 5.32) (p = 0.010).
Conclusions. Majority of opioid-dependent male patients on methadone treatment are pain-sensitive with CPT. Poor sleep quality is associated with cold pressor pain-sensitivity. Pain and sleep complaints in this male population should not be overlooked.
Study site: Hospital Universiti Sains Malaysia (HUSM) and other MMT clinics (Kota Bharu, Pasir Mas, Pasir Puteh and Bachok), Kelantan, Malaysia
Molecular epidemiology of enterovirus 71 in peninsular Malaysia, 1997-2000

Herrero LJ, Lee CS, Hurrelbrink RJ, Chua BH, Chua KB, McMinn PC

Arch Virol, 2003 Jul;148(7):1369-85.
PMID: 12827466

Human enterovirus 71 (EV71) (genus Enterovirus, family Picornaviridae) has been responsible for sporadic cases and outbreaks of hand-foot-and-mouth disease (HFMD), aseptic meningitis, encephalitis and poliomyelitis-like disease in Europe, the U.S.A., Australia and Asia. Recently, there has been an increase in EV71 activity in the Asia-Pacific region, with many outbreaks of HFMD associated with brainstem encephalitis manifesting as neurogenic pulmonary oedema with a high case fatality rate. In 1997, and again in 2000, EV71 outbreaks occurred in peninsular Malaysia. Variations in VP1 gene sequences have been shown to divide all known EV71 field isolates into three distinct genogroups (A, B and C). Consequently we examined the VP1 gene sequences of 43 EV71 strains isolated in peninsular Malaysia between 1997 and 2000 in order to determine the genogroup prevalence over the period. In this study we show that four subgenogroups (B3, B4, C1 and C2) of EV71 circulated in peninsular Malaysia between 1997 and 2000. Subgenogroups B3, B4 and C1 have been identified as the primary cause of the outbreaks of EV71 in peninsular Malaysia. Subgenogroup C1 also displayed endemic circulation from 1997 to 2000 and subgenogroup C2 was present at a low level during the 1997 outbreak.
Fulltext Production of Biodegradable Palm Oil-Based Polyurethane as Potential Biomaterial for Biomedical Applications

Yeoh FH, Lee CS, Kang YB, Wong SF, Cheng SF, Ng WS

Polymers (Basel), 2020 Aug 17;12(8).
PMID: 32824514 DOI: 10.3390/polym12081842

Being biodegradable and biocompatible are crucial characteristics for biomaterial used for medical and biomedical applications. Vegetable oil-based polyols are known to contribute both the biodegradability and biocompatibility of polyurethanes; however, petrochemical-based polyols were often incorporated to improve the thermal and mechanical properties of polyurethane. In this work, palm oil-based polyester polyol (PPP) derived from epoxidized palm olein and glutaric acid was reacted with isophorone diisocyanate to produce an aliphatic polyurethane, without the incorporation of any commercial petrochemical-based polyol. The effects of water content and isocyanate index were investigated. The polyurethanes produced consisted of > 90% porosity with interconnected micropores and macropores (37-1700 µm) and PU 1.0 possessed tensile strength and compression stress of 111 kPa and 64 kPa. The polyurethanes with comparable thermal stability, yet susceptible to enzymatic degradation with 7-59% of mass loss after 4 weeks of treatment. The polyurethanes demonstrated superior water uptake (up to 450%) and did not induce significant changes in pH of the medium. The chemical changes of the polyurethanes after enzymatic degradation were evaluated by FTIR and TGA analyses. The polyurethanes showed cell viability of 53.43% and 80.37% after 1 and 10 day(s) of cytotoxicity test; and cell adhesion and proliferation in cell adhesion test. The polyurethanes produced demonstrated its potential as biomaterial for soft tissue engineering applications.
A review of recent developments on kinetics parameters for glycerol electrochemical conversion - A by-product of biodiesel

Rahim SANM, Lee CS, Abnisa F, Aroua MK, Daud WAW, Cognet P, et al.

Sci Total Environ, 2020 Feb 25;705:135137.
PMID: 31846815 DOI: 10.1016/j.scitotenv.2019.135137

Glycerol is a by-product produced from biodiesel, fatty acid, soap and bioethanol industries. Today, the value of glycerol is decreasing in the global market due to glycerol surplus, which primarily resulted from the speedy expansion of biodiesel producers around the world. Numerous studies have proposed ways of managing and treating glycerol, as well as converting it into value-added compounds. The electrochemical conversion method is preferred for this transformation due to its simplicity and hence, it is discussed in detail. Additionally, the factors that could affect the process mechanisms and products distribution in the electrochemical process, including electrodes materials, pH of electrolyte, applied potential, current density, temperature and additives are also thoroughly explained. Value-added compounds that can be produced from the electrochemical conversion of glycerol include glyceraldehyde, dihydroxyacetone, glycolic acid, glyceric acid, lactic acid, 1,2-propanediol, 1,3-propanediol, tartronic acid and mesoxalic acid. These compounds are found to have broad applications in cosmetics, pharmaceutical, food and polymer industries are also described. This review will be devoted to a comprehensive overview of the current scenario in the glycerol electrochemical conversion, the factors affecting the mechanism pathways, reaction rates, product selectivity and yield. Possible outcomes obtained from the process and their benefits to the industries are discussed. The utilization of solid acid catalysts as additives for future studies is also suggested.
Fulltext Selective Electrochemical Conversion of Glycerol to Glycolic Acid and Lactic Acid on a Mixed Carbon-Black Activated Carbon Electrode in a Single Compartment Electrochemical Cell

Lee CS, Aroua MK, Wan Daud WA, Cognet P, Pérès Y, Ajeel MA

Front Chem, 2019;7:110.
PMID: 30931294 DOI: 10.3389/fchem.2019.00110

In recent years, the rapid swift increase in world biodiesel production has caused an oversupply of its by-product, glycerol. Therefore, extensive research is done worldwide to convert glycerol into numerous high added-value chemicals i.e., glyceric acid, 1,2-propanediol, acrolein, glycerol carbonate, dihydroxyacetone, etc. Hydroxyl acids, glycolic acid and lactic acid, which comprise of carboxyl and alcohol functional groups, are the focus of this study. They are chemicals that are commonly found in the cosmetic industry as an antioxidant or exfoliator and a chemical source of emulsifier in the food industry, respectively. The aim of this study is to selectively convert glycerol into these acids in a single compartment electrochemical cell. For the first time, electrochemical conversion was performed on the mixed carbon-black activated carbon composite (CBAC) with Amberlyst-15 as acid catalyst. To the best of our knowledge, conversion of glycerol to glycolic and lactic acids via electrochemical studies using this electrode has not been reported yet. Two operating parameters i.e., catalyst dosage (6.4-12.8% w/v) and reaction temperature [room temperature (300 K) to 353 K] were tested. At 353 K, the selectivity of glycolic acid can reach up to 72% (with a yield of 66%), using 9.6% w/v catalyst. Under the same temperature, lactic acid achieved its highest selectivity (20.7%) and yield (18.6%) at low catalyst dosage, 6.4% w/v.
iTRAQ analysis of urinary proteins: Potential use of gelsolin and osteopontin to distinguish benign thyroid goiter from papillary thyroid carcinoma

Jayapalan JJ, Lee CS, Lee CC, Ng KL, Junit SM, Hashim OH

Clin Biochem, 2018 Mar;53:127-131.
PMID: 29355489 DOI: 10.1016/j.clinbiochem.2018.01.008

BACKGROUND: Benign thyroid goiter (BTG) and papillary thyroid carcinoma (PTC) are often interchangeably misdiagnosed.
METHODS: Pooled urine samples of patients with BTG (n=10), patients with PTC (n=9) and healthy controls (n=10) were subjected to iTRAQ analysis and immunoblotting.
RESULTS: The ITRAQ analysis of the urine samples detected 646 proteins, 18 of which showed significant altered levels (p<0.01; fold-change>1.5) between patients and controls. Whilst four urinary proteins were commonly altered in both BTG and PTC patients, 14 were unique to either BTG or PTC. Amongst these, four proteins were further chosen for validation using immunoblotting, and the enhanced levels of osteopontin in BTG patients and increased levels of a truncated gelsolin fragment in PTC patients, relative to controls, appeared to corroborate the findings of the iTRAQ analysis.
CONCLUSION: The data of the present study is suggestive of the potential application of urinary osteopontin and gelsolin to discriminate patients with BTG from those with PTC non-invasively. However, this needs to be further validated in studies of individual urine samples.
Proteomics analysis of blood plasma in HIV-infected patients with chronic kidney disease

Lavinya AA, Lee CS, Hashim OH, Azwa I, Rajasuriar R, Lim SK, et al.

Clin Biochem, 2019 Nov;73:90-97.
PMID: 31401122 DOI: 10.1016/j.clinbiochem.2019.08.006

BACKGROUND: Patients treated for human immunodeficiency virus (HIV) infection are prone to developing chronic kidney disease (CKD). Current methods used in assessing kidney function suffer inaccuracy in HIV-infected patients. This study aims to identify biomarkers that could complement existing methods of kidney assessment among HIV-infected subjects.
METHODS: Plasma protein profiling was performed for HIV patients with CKD presented with negative/trace proteinuria (non-proteinuric) (n = 8) and their matched non-CKD controls, using two-dimensional gel electrophoresis (2DE); selected protein candidates were identified using mass spectrometry. Subsequently, altered plasma abundance of protein candidates were verified using Western blotting in HIV-infected subjects with non-proteinuric CKD (n = 8), proteinuric CKD (n = 5), and their matched non-CKD controls, as well as in HIV-uninfected subjects with impaired kidney function (n = 3) and their matched controls.
RESULTS: Analysis of 2DE found significantly altered abundance of five protein candidates between HIV-infected patients with non-proteinuric CKD and without CKD: alpha-1-microglobulin (A1M), serum albumin (ALB), zinc-alpha-2-glycoprotein (AZGP1), haptoglobin (HP), and retinol binding protein (RBP4). Western blotting showed an increased abundance of A1M and HP in HIV-infected patients with non-proteinuric CKD compared to their non-CKD controls, whereas A1M, AZGP1, and RBP4 were significantly increased in HIV-infected patients with proteinuric CKD compared to their non-CKD controls. Such pattern was not found in HIV-uninfected subjects with impaired kidney function.
CONCLUSION: The data suggests four proteins that may be used as biomarkers of CKD in HIV-infected patients. Further validation in a larger cohort of HIV-infected patients is necessary for assessing the clinical use of these proposed biomarkers for CKD.
Fulltext Alteration of foot temperature in diabetic neuropathy: is it another piece of puzzle?

Naicker AS, Roohi SA, Lee CS, Chan WH, Tay LS, Din XJ, et al.

Med J Malaysia, 2006 Feb;61 Suppl A:10-3.
PMID: 17042221

Poor glycaemic control and the duration of diabetes mellitus are known to accelerate development and progression of neuropathy. Diabetic co-morbidities: hypertension and hyperlipidaemia, have been postulated to associate with development of neuropathy. A diabetic foot with low temperature and frequent exposure to low temperature environment has recently been hypothesized to be at higher risk to develop early neuropathy. This cross-sectional study is undertaken to identify risk factors for diabetic neuropathy and the association between foot temperature and development of diabetic neuropathy by using simple clinical examination in the outpatient setting. From April 18, to April 30, 2005, universal sampling method was used to select 134 diabetic patients (type 1 or type 2 for >1 year) with peripheral neuropathy. Excluded are those with chronic alcoholism, drug-induced neuropathy, dietary history of vitamin B deficiency and family history of porphyria and hereditary sensorimotor neuropathy. The patient's duration of diabetes, glycaemic control status and the presence of co-morbids: hypertension and hyperlipidemia, were recorded. The temperature of the foot was measured by using thermo buddy. Of 134 patients representing Malaysian ethnic distribution with an equal number of males and females, 20.1% were in the age group of 61 to 65 years and, 85.1% and 67.9% belonged to lower socioeconomic and educational groups respectively. Associations between diabetic neuropathy and glycaemic control (p = 0.018) and duration of diabetes (p < 0.05) were significant. However, hypertension, hyperlipidaemia and low foot temperature were not significantly associated with development of diabetic neuropathy. Poor glycaemic control is significantly associated with diabetic neuropathy. Foot temperature alteration is merely an effect of autonomic neuropathy with a cold foot is attributed to co-existing peripheral arterial disease.

Study site: Pusat Perubatan Primer Bandar Tasik Selatan, Kuala Lumpur, Malaysia

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