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Modulatory effects of mesenchymal stem cells on leucocytes and leukemic cells: A double-edged sword?

Low JH, Ramdas P, Radhakrishnan AK

Blood Cells Mol. Dis., 2015 Dec;55(4):351-7.
PMID: 26460259 DOI: 10.1016/j.bcmd.2015.07.017

Mesenchymal stem cells (MSCs) have drawn much attention amongst stem cell researchers in the past few decades. The ability of the MSC to differentiate into cells of mesodermal and non-mesodermal origins has made them an attractive approach for cell-based therapy and regenerative medicine. The MSCs have immunosuppressive activities that may have considerable therapeutic values in autoimmune diseases. However, despite the many beneficial effects reported, there is a growing body of evidence, which suggests that MSCs could be a culprit of enhanced tumour growth, metastasis and drug resistance in leukaemia, via some modulatory effects. Many controversies regarding the interactions between MSCs and leukaemia still exist. Furthermore, the role of MSCs in leukemogenesis and its progression remain largely unknown. Hence it is important to understand how the MSCs modulate leukaemia before these cells could be safely used in the treatment of leukaemia patients.
Fulltext Weak and strong ties and its connection to experts' problem-solving styles in scaffolding students' PBL activities on social media

Abdullah AH, Neo TK, Low JH

F1000Res, 2021;10:1076.
PMID: 35035894 DOI: 10.12688/f1000research.73210.2

Background: Studies have acknowledged that social media enables students to connect with and learn from experts from different ties available in the students' personal learning environment (PLE). Incorporating experts into formal learning activities such as scaffolding problem-solving tasks through social media, allows students to understand how experts solve real-world problems. However, studies that evaluate experts' problem-solving styles on social media in relation to the tie strength of the experts with the students are scarce in the extant literature. This study aimed to explore the problem-solving styles that the experts portrayed based on their ties with the students in problem-based learning (PBL) on Facebook. Methods: This study employed a simultaneous within-subject experimental design which was conducted in three closed Facebook groups with 12 final year management students, six business experts, and one instructor as the participants. The experts were invited by the students from the weak and strong ties in their PLE. Hinging on the Strength of Weak Ties Theory (Granovetter, 1973) and problem-solving styles (Selby et al., 2004), this study employed thematic analysis using the ATLAS.ti qualitative data analysis software to map the experts' comments on Facebook. Results: The experts from strong and weak ties who had a prior relationship with the students showed people preference style by being more sensitive to the students' learning needs and demonstrating firmer scaffolding compared to the weak ties' experts who had no prior relationship with the students. Regardless of the types of ties, all experts applied all manner of processing information and orientation to change but the degree of its applications are correlated with the working experience of the experts. Conclusion: The use of weak or strong ties benefited the students as it expedited their problem-solving tasks since the experts have unique expertise to offer depending on the problem-solving styles that they exhibited.
Seizures among young adults consuming kratom beverages in Malaysia: A case series

Halim SA, Low JH, Chee YC, Alias MR

Epilepsy Behav, 2021 08;121(Pt A):108057.
PMID: 34052638 DOI: 10.1016/j.yebeh.2021.108057

We report a case series of young adults who were admitted to hospital with seizures after regular kratom beverage consumption. This study aimed to determine kratom consumption habits and seizure characteristics and to explore whether chronic kratom ingestion without concomitant drug abuse leads to recurrent seizure or epilepsy. All patients underwent blood investigations, a brain computed tomography (CT) scan, electroencephalography, and urine testing for mitragynine and drug toxicology. Eleven participants who had a positive urine mitragynine test were included in the study. The longest duration of kratom consumption was 84 months: - most drank more than eight times per month (>200 mL/drink). Seizure developed within 10 minutes or up to 72 hours post-ingestion. Seizure occurred one to three times per year in most cases. Four patients had a focal to bilateral tonic-clonic seizure whereas the remaining participants had a generalized tonic-clonic seizure. Four patients mixed kratom with diphenhydramine syrup, and one patient took methamphetamine. Two patients had positive urine results for recreational drugs (opioid and amphetamine). This study provided indirect evidence that chronic kratom use with or without concomitant drug abuse can cause recurrent seizures in susceptible individuals, which may progress to epilepsy or require antiepileptic medication.
Fulltext Compact organic liquid dielectric resonator antenna for air pressure sensing using soft material

Low JH, Chee PS, Lim EH, Lee KY

Sci Rep, 2020 Sep 10;10(1):14907.
PMID: 32913321 DOI: 10.1038/s41598-020-72021-7

For the first time, a flexible and deformable liquid dielectric resonator antenna (LDRA) is proposed for air pressure sensing. The proposed LDRA can be made very compact as it has employed liquidized organic dielectric with high dielectric constant (~ 33) with low loss tangent (~ 0.05). Here, a soft elastomer container has been fabricated using soft-lithography method for holding the liquid, and an air cavity is tactfully embedded into the central part of a cylindrical DRA to form an annular structure that can be used for sensing air pressure. It will be shown that the inclusion of the air cavity is essential for making the antenna structure sensitive to pressure changes. Simulations and experiments have been conducted to verify the functionalities of the proposed organic LDRA as microwave radiator and as air pressure sensor. It has been proven to have higher antenna gain than the water LDRA in the frequency range of 1.8-2.8 GHz, while achieving a good air pressure sensitivity of 270 MHz/bar.
WiFi-Powered Sensor Integrated into a Smart Glove with a Fully Fabric Antenna for the Human-Machine Interface

Lee KT, Lim EH, Tan CH, Low JH, Wong KL, Guan C, et al.

ACS Appl Mater Interfaces, 2024 Nov 13;16(45):62914-62924.
PMID: 39497522 DOI: 10.1021/acsami.4c12371

The integration of flexible sensors into human-machine interfaces (HMIs) is in increasing demand for intuitive and effective manipulation. Traditional glove-based HMIs, constrained by nonconformal rigid structures or the need for bulky batteries, face limitations in continuous operation. Addressing this, we introduce yarn-based bend sensors in our smart glove, which are wirelessly powered and harvest energy from a fully textile 5.8 GHz WiFi-band antenna receiver. These sensors exhibit a gauge factor (GF) of 5.60 for strains ranging from 0 to 10%. They show a consistent performance regardless of the straining frequency when being stretched and released at frequencies between 0.1 and 0.7 Hz. This reliability ensures that the sensor output is solely dependent on the yarn's elongation. Accurately detecting finger-bending movements from 0° to 90° in a virtual environment, the sensors enable enhanced degrees of freedom for human finger interaction. When integrated with advanced machine-learning techniques, the system achieves a classification accuracy of 98.75% for object recognition, demonstrating its potential for precise and accurate HMI. Unlike conventional near-field energy transfer methods that rely on magnetic flux and are limited by power loss over distance, our fully textile design effectively harvests microwave energy, showing no voltage deterioration up to 1 m away. This minimalist microwave-powered smart glove represents a significant advancement, offering a viable and practical solution for developing intuitive and reliable HMIs.
Roxithromycin potentiates the effects of chloroquine and mefloquine on multidrug-resistant Plasmodium falciparum in vitro

Min TH, Khairul MF, Low JH, Che Nasriyyah CH, A'shikin AN, Norazmi MN, et al.

Exp Parasitol, 2007 Apr;115(4):387-92.
PMID: 17118354

Chloroquine (CQ) and mefloquine (MQ) are no longer potent antimalarial drugs due to the emergence of resistant Plasmodium falciparum. Combination therapy has become the standard for many regimes in overcoming drug resistance. Roxithromycin (ROM), a known p-glycoprotein inhibitor, is reported to have antimalarial activity and it is hoped it will potentiate the effects of both CQ/MQ and reverse CQ/MQ-resistance. We assayed the effects of CQ and MQ individually and in combination with ROM on synchronized P. falciparum (Dd2 strain) cultures. The IC(50) values of CQ and MQ were 60.0+/-5.0 and 16.0+/-3.0 ng/ml; these were decreased substantially when combined with ROM. Isobolograms indicate that CQ-ROM combinations were relatively more synergistic (mean FICI 0.70) than MQ-ROM (mean FICI 0.85) with their synergistic effect at par with CQ-verapamil (VRP) (mean FICI 0.64) and MQ-VRP (mean FICI 0.60) combinations. We conclude that ROM potentiates the CQ/MQ response on multidrug-resistant P. falciparum.
Tailoring the field and indication of adjuvant pelvic radiation for patients with FIGO stage Ib lymph nodes-negative cervical carcinoma following radical surgery based on the GOG score--a pilot study

Rushdan MN, Tay EH, Khoo-Tan HS, Lee KM, Low JH, Ho TH, et al.

Ann Acad Med Singap, 2004 Jul;33(4):467-72.
PMID: 15329758

INTRODUCTION: The traditional indications for adjuvant pelvic radiotherapy (RT) for International Federation of Obstetrics and Gynecology (FIGO) stage Ib1 lymph nodes-negative cervix carcinoma following radical surgery based on histopathological factors, such as deep stromal invasion and lymphovascular space invasion (LVSI), were often inconsistently applied. The perceived risk of relapse was subjectively determined. This pilot study attempts to determine if the treatment outcome will be affected when the indication for RT is based on the Gynecologic Oncology Group (GOG) Risk Score (RS) and the field of adjuvant RT is tailored to the RS.
MATERIALS AND METHODS: From 1997 to 1999, 55 patients with FIGO stage Ib1 lymph nodes-negative cervical carcinoma limited to the cervix were prescribed RT following radical surgery, based on their RS, as follows: RS <40, RT is omitted; RS >40 to <120, modified (smaller) field RT; and RS >120, standard field pelvic RT. Their incidence and site of recurrence were compared with a similar cohort of 40 patients who were treated prior to 1997.
RESULTS: Prior to 1997, of the 40 patients, 10 patients were given standard field RT. There were 2 (5%) recurrent diseases. The mean duration of follow-up was 61.6 months (range, 1 to 103 months). The RS of 23 of the 30 patients who were not given RT were available. The mean RS was 22 with 5 patients having a score of >40. From 1997 onwards, of the 55 patients, 28 (51%) did not require RT, 13 (23%) were treated with modified (smaller) field RT and 14 (26%) were given standard field RT. There were 2 (3.6%) cases of relapse. The mean duration of follow-up was 36.4 months (range, 5 to 60 months). All patients with a RS of <40 did not suffer any relapse. Their survival outcomes were better when compared to patients who did not have any RT in the GOG Study.
CONCLUSIONS: The results of this study indicated that postoperative adjuvant RT given to patients with a high GOG RS of >120, significantly improved their 5-year recurrence rate and disease-free survival, as compared with the similar group of patients who were without adjuvant therapy in the GOG study. Patients with a GOG risk-score of <40 may be safely spared from adjuvant pelvic RT. The current treatment protocol did not compromise the outcome in patients, compared with the use of a less precise treatment protocol in the past.
Fluoxetine potentiates chloroquine and mefloquine effect on multidrug-resistant Plasmodium falciparum in vitro

Khairul MF, Min TH, Low JH, Nasriyyah CH, A'shikin AN, Norazmi MN, et al.

Jpn J Infect Dis, 2006 Oct;59(5):329-31.
PMID: 17060702

Fluoxetine (FLX), a P-glycoprotein inhibitor with antimalarial activity, is promising candidate for reversing chloroquine/mefloquine (CQ/MQ) resistance. The Dd2 strain of CQ- and MQ-resistant Plasmodium falciparum was synchronized and assayed with various concentrations of CQ/MQ individually and in combination with FLX or verapamil (VPL). Our results indicated the 50% inhibitory concentration values of CQ and MQ were greatly lowered when FLX was used simultaneously. Isobolograms indicated that CQ-FLX combinations are more synergistic (mean fractional inhibitory concentration [FIC] index 0.55) than MQ-FLX (mean FIC index 0.64), and their synergistic effect was better than or at par with CQ-VPL (mean FIC index 0.88) and MQ-VPL (mean FIC index 0.60) combinations. We conclude that the FLX potentiates the CQ and MQ response on multidrug-resistant P. falciparum at clinically achievable concentrations.
Willingness to Pay for National Health Insurance: A Contingent Valuation Study Among Patients Visiting Public Hospitals in Melaka, Malaysia

Tan RTH, Abdul Rasid SZ, Wan Ismail WK, Tobechan J, Tan ETY, Yusof AN, et al.

Appl Health Econ Health Policy, 2022 Mar;20(2):255-267.
PMID: 34927225 DOI: 10.1007/s40258-021-00691-z

BACKGROUND: The Malaysian public healthcare system is tax funded, with healthcare costs highly subsidized by the Government. The current health financing is not sustainable to cover all the healthcare resources. Introducing a national health insurance (NHI), a prepayment method, would protect the population from financial hardship by reducing out-of-pocket payment, minimizing the barrier to accessing health and achieving equitable healthcare. Studies on the willingness to pay (WTP) for NHI are available in different contexts; however, little was found in Malaysia. In addition, factors affecting the WTP for NHI have been less researched in the Malaysian context.
OBJECTIVE: This study investigates the WTP for NHI and factors influencing it in Melaka, Malaysia.
METHOD: Using the contingent valuation method, the researchers distributed a pre-tested self-administered questionnaire to 489 respondents in three leading public hospitals from 1 to 9 November 2019. Multi-stage sampling forms the selection of respondents. Respondents were presented with a hypothetical scenario on NHI and asked whether they would be willing to pay for NHI. Chi-square was used to examine the association between categorical independent variables and WTP for NHI, and binary logistic regression was applied to determine the variables with the most predictive effect towards WTP for NHI.
RESULTS: Out of 462 usable responses, 344 respondents (74.5%) were willing to pay for NHI. The majority (51.3%) of the respondents were willing to pay 15 Malaysian Ringgit (3.70 US dollars) or more for the NHI scheme. Chi-square analysis revealed that age, marital status, education level, employment status, chronic diseases, and perception towards NHI were significantly associated with WTP for NHI. Binary regression analysis found that marital status and perception towards NHI have the most predictive effect on respondents' WTP for NHI.
CONCLUSION: This study revealed that the majority of the respondents are willing to pay for NHI if implemented in Malaysia. The findings lay a foundation for implementing a future NHI framework in Malaysia and reference future health financing research.
Fulltext Clinical and Histopathological Effects of Intracameral Ranibizumab in Experimental Trabeculectomy

Azhany Y, Rahman WFWA, Jaafar H, Low JH, Yusuf WNW, Liza-Sharmini AT, et al.

Int J Mol Sci, 2023 Apr 17;24(8).
PMID: 37108535 DOI: 10.3390/ijms24087372

Post-surgical scarring is a known cause of trabeculectomy failure. The aim of this study was to investigate the effectiveness of ranibizumab as an adjuvant anti-scarring agent in experimental trabeculectomy. Forty New Zealand white rabbits were randomised into four eye treatment groups: groups A (control), B (ranibizumab 0.5 mg/mL), C (mitomycin C [MMC] 0.4 mg/mL), and D (ranibizumab 0.5 mg/mL and MMC 0.4 mg/mL). Modified trabeculectomy was performed. Clinical parameters were assessed on post-operative days 1, 2, 3, 7, 14, and 21. Twenty rabbits were euthanised on day 7, and the other twenty were euthanised on day 21. Eye tissue samples were obtained from the rabbits and stained with haematoxylin and eosin (H&E). All treatment groups showed a significant difference in IOP reduction compared with group A (p < 0.05). Groups C and D showed a significant difference in bleb status on days 7 (p = 0.001) and 21 (p = 0.002) relative to group A. H&E staining showed significantly low fibrotic activity (p < 0.001) in group C on both days and inflammatory cell grade in group B on day 7 (p < 0.001). The grade for new vessel formation was significantly low in groups B and D on day 7 (p < 0.001) and in group D on day 21 (p = 0.007). Ranibizumab plays a role in reducing scarring, and a single application of the ranibizumab-MMC combination showed a moderate wound-modulating effect in the early post-operative phase.

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