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Fulltext Changing patterns in the treatment of early breast cancer: a historical perspective and a review of changing local trends

Sim E, Lim TC, Tan WT, Rauff A

Med J Malaysia, 1993 Jun;48(2):211-6.
PMID: 8350798

Over the past 50 years, a variety of surgical procedures have been advocated for the treatment of operable breast cancer, ranging from local excision to supraradical mastectomy. Today, the surgical treatment of breast cancer remains highly contentious. We review the historical development of breast cancer surgery and analyse the available evidence supporting conservative procedures. We also express our opinions on the treatment of early breast cancer and illustrate the changing patterns of surgery with our experience at National University Hospital.
Solubilities of trace copper and lead species and the complexing capacity of river water in the Linggi River Basin

Tan WT, Tan GS, Nather Khan IS

Environ Pollut, 1988;52(3):221-35.
PMID: 15092608

Chemical forms of copper and lead in river water of the Linggi River Basin have been fractionated into ASV labile, moderately labile, slowly labile, and inert metal species, based on a previously proposed scheme. Free (hydrated) metal ions were identified by a potentiometric method using an ion selective electrode. Speciation results showed that the soluble copper and lead species occurred mainly in the moderately labile and slowly labile fractions. The speciation results are primarily interpreted in terms of organic interaction due to agricultural based and light industries, and urban discharges. The measured metal complexing capacity (MCC) of the samples reveals consistency of the results with the nature of the discharge. MCC correlates reasonably well with the value from the permanganate test on the river water. In general, the speciation pattern was found to be consistent with the findings of other workers.
Emulsion liquid membrane modeling for chromium removal from electroplating wastewater using TOMAC as a carrier

Othman N, Noah NFM, Sulaiman RNR, Jusoh N, Tan WT

Water Environ Res, 2021 Sep;93(9):1669-1679.
PMID: 33704848 DOI: 10.1002/wer.1551

Hexavalent chromium, emanating primarily from the electroplating industries, can be reduced to the less toxic trivalent variety by several methods, including emulsion liquid membrane (ELM). In this work, studies on the continuous removal of chromium from authentic electroplating wastewater by ELM are reported. The effects of treat ratio, external feed phase, and stripping agent concentration were examined. A mathematical boundary breakage model was used to study the extraction efficiency of chromium through the ELM process. The model representing the prediction of ELM extraction performance for chromium was validated through the comparison between the simulation and experimental results. The result showed the simulation model is found to be in good agreement with the experimental result. Almost 100% of 40 ppm chromium in the external feed phase was extracted within 3 to 5 min using 0.022 M TOMAC as extractant, 1.0 M acidic thiourea in the internal phase, and 1 to 5 of treat ratio. PRACTITIONER POINTS: Hexavalent chromium, emanating primarily from electroplating industries, can be reduced to the less toxic trivalent using ELM process. The developed method was tested for its applicability with predominant species of Cr2 O7 2- in real rinse electroplating wastewater. The extraction efficiency (%) of Cr (VI) was almost 100% for 40 ppm Cr in the external feed phase within 3 to 5 min. The result showed the simulation model is found to be in good agreement with the experimental result.
Cellulose hydrogel development from unbleached oil palm biomass pulps for dermal drug delivery

Wong LC, Poh JH, Tan WT, Khor BK, Murugaiyah V, Leh CP, et al.

Int J Biol Macromol, 2023 Jan 01;224:483-495.
PMID: 36273545 DOI: 10.1016/j.ijbiomac.2022.10.138

Hydrogels are an attractive platform for drug delivery to the skin. Current cellulose hydrogel developments commonly focus on readily available bleached woody cellulose. Considering the detrimental environmental impacts of bleaching reagents, unbleached non-woody biomass was proposed as an alternative. Herein, this study aims to develop hydrogel from native cellulose extracted from oil palm empty fruit bunches for dermal drug delivery with an emphasis on evaluating the effect of alkali solvent compositions on hydrogel formation. Unbleached dissolving pulps were solubilized in alkali solvents containing sodium hydroxide (NaOH) (6-8%w/v) and urea (4-6%w/v) before crosslinking. Hydrogels were loaded with ibuprofen for skin permeation studies. Light brownish hydrogels formed are aesthetically acceptable and biodegradable with low cytotoxicity. NaOH content has a dominant role over urea where thinner and deformable crosslinked network walls in a porous hydrogel structure are associated with high NaOH content. Synergistic effects (cellulose solubility: 94 %; swelling ratio: ~2800 %) were observed at 7%w/v NaOH and 4%w/v urea with low toxicity. Most hydrogels showed >80 % of ibuprofen permeated into the skin and this increased with the swelling ratio of hydrogels. Unbleached cellulose pulps have excellent potential for hydrogel fabrication with outstanding physicomechanical properties for dermal drug delivery.
Effect of Vessel Tortuosity on Stress Concentration at the Distal Stent-Vessel Interface: Possible Link With New Entry Formation Through Biomechanical Simulation

Tan WT, Liew YM, Mohamed Mokhtarudin MJ, Pirola S, Wan Ab Naim WN, Amry Hashim S, et al.

J Biomech Eng, 2021 Aug 01;143(8).
PMID: 33764388 DOI: 10.1115/1.4050642

A computational approach is used to investigate potential risk factors for distal stent graft-induced new entry (dSINE) in aortic dissection (AD) patients. Patient-specific simulations were performed based on computed tomography images acquired from six AD patients (three dSINE and three non-dSINE) to analyze the correlation between anatomical characteristics and stress/strain distributions. Sensitivity analysis was carried out using idealized models to independently assess the effect of stent graft length, stent tortuosity and wedge apposition angle at the landing zone on key biomechanical variables. Mismatch of biomechanical properties between the stented and nonstented regions led to high stress at the distal stent graft-vessel interface in all patients, as well as shear strain in the neighboring region, which coincides with the location of tear formation. Stress was observed to increase with the increase of stent tortuosity (from 263 kPa at a tortuosity angle of 50 deg to 313 kPa at 30 deg). It was further amplified by stent graft landing at the inflection point of a curve. Malapposition of the stent graft led to an asymmetrical segment within the aorta, therefore changing the location and magnitude of the maximum von Mises stress substantially (up to +25.9% with a +25 deg change in the distal wedge apposition angle). In conclusion, stent tortuosity and wedge apposition angle serve as important risk predictors for dSINE formation in AD patients.
Development and validation of patient diabetes knowledge questionnaire (PDKQ)

Lim PC, Rajah R, Lim YL, Kam JLH, Wong TY, Krishnanmurthi V, et al.

J Pharm Policy Pract, 2023 Oct 19;16(1):121.
PMID: 37858279 DOI: 10.1186/s40545-023-00631-3

BACKGROUND: Evaluation of diabetes knowledge plays a pivotal role in identifying and addressing patients' knowledge gaps. The implementation of a standardized diabetes knowledge assessment tool is important to ensure consistent scoring and facilitating the development of effective and standardized education programs.
AIM: To develop and validate a patient diabetes knowledge questionnaire (PDKQ) to assess knowledge of diabetes mellitus patients.
METHODS: The development of the PDKQ questionnaire involved three phases: item development, content validation, and reliability testing. In the item development phase, the initial draft of the PDKQ, comprising a multiple-choice answer questionnaire was developed. The content validation phase comprised two stages. Firstly, ten experts participated in the expert validation process, followed by face validation involving six patients. In the final phase, test-retest analysis was performed among diabetes mellitus patients to assess reliability.
RESULTS: The first draft of PDKQ consisted of 11 patient characteristics items and 37 items of multiple choices questions. During the expert validation, three items were eliminated due to low clarity, and an additional six items were removed as they were deemed irrelevant or unimportant. During the face validation, three patients' characteristic items and eight multiple-choice questions were excluded due to a content validity index of less than 0.83. In the test-retest phase, 36 subjects responded to 8 items pertaining to patients' characteristics and 20 multiple-choice questions. The test-retest analysis yielded an intraclass correlation coefficient of 0.88, indicating good reliability.
CONCLUSION: The 20-item PDKQ is a reliable and robust tool in assessing the knowledge of diabetes mellitus patients in Malaysia. Its implementation allows standardized assessment of diabetic patients' knowledge levels, enabling targeted interventions to empower patients and optimize diabetes care practices.