MyMedR

Displaying publications 41 - 60 of 249 in total

Abstract:

Sort:

Synthesis and Characterization of PLGA-PEG Thymoquinone Nanoparticles and Its Cytotoxicity Effects in Tamoxifen-Resistant Breast Cancer Cells

Ahmad R, Kaus NHM, Hamid S

Adv Exp Med Biol, 2020;1292:65-82.
PMID: 30560443 DOI: 10.1007/5584_2018_302

INTRODUCTION: Drug resistance has been a continuous challenge in cancer treatment. The use of nanotechnology in the development of new cancer drugs has potential. One of the extensively studied compounds is thymoquinone (TQ), and this work aims to compare two types of TQ-nanoformulation and its cytotoxicity toward resistant breast cancer cells.
METHOD: TQ-nanoparticles were prepared and optimized by using two different formulations with different drugs to PLGA-PEG ratio (1:20 and 1:7) and different PLGA-PEG to Pluronic F68 ratio (10:1 and 2:1). The morphology and size were determined using TEM and DLS. Characterization of particles was done using UV-VIS, ATR-IR, entrapment efficiency, and drug release. The effects of drug, polymer, and surfactants were compared between the two formulations. Cytotoxicity assay was performed using MTS assay.
RESULTS: TEM finding showed 96% of particles produced with 1:7 drug to PLGA-PEG were less than 90 nm in size and spherical in shape. This was confirmed with DLS which showed smaller particle size than those formed with 1:20 drug to PLGA-PEG ratio. Further analysis showed zeta potential was negatively charged which could facilitate cellular uptake as reported previously. In addition, PDI value was less than 0.1 in both formulations indicating monodispersed and less broad in size distribution. The absorption peak of PLGA-PEG-TQ-Nps was at 255 nm. The 1:7 drug to polymer formulation was selected for further analysis where the entrapment efficiency was 79.9% and in vitro drug release showed a maximum release of TQ of 50%. Cytotoxicity result showed IC50 of TQ-nanoparticle at 20.05 μM and free TQ was 8.25 μM.
CONCLUSION: This study showed that nanoparticle synthesized with 1:7 drug to PLGA-PEG ratio and 2:1 PLGA-PEG to Pluronic F68 formed nanoparticles with less than 100 nm and had spherical shape as confirmed with DLS. This could facilitate its transportation and absorption to reach its target. There was conserved TQ stability as exhibited slow release of this volatile oil. The TQ-nanoparticles showed selective cytotoxic effect toward UACC 732 cells compared to MCF-7 breast cancer cells.
The effect of ammonia on carbon nanotube growth using simple thermal chemical vapour deposition

Teh AA, Ahmad R, Kara M, Rusop M, Awang Z

J Nanosci Nanotechnol, 2012 Oct;12(10):8201-4.
PMID: 23421197

We report the use of a new precursor as active agents to promote the growth of carbon nanotubes (CNT) in methane ambient using a simple thermal chemical vapour deposition method. The agents consist of ammonia and methanol mixed at different ratios and was found to enhance the growth of CNTs. The optimum methanol to ammonia ratio was found to be 8 to 5, whereby longer and denser CNTs were produced compared to other ratios. The result was found otherwise when the experiment was done solely in methane ambient. In addition, CNT growth on substrates coated with double layer Ni catalyst was improved in terms of quality and density compared to a single coated substrates. This finding is supported by Raman spectrometry analysis.
Dental health care providers' views on child physical abuse in Malaysia

Hussein AS, Ahmad R, Ibrahim N, Yusoff A, Ahmad D

Eur Arch Paediatr Dent, 2016 Jul 15.
PMID: 27421713

To assess the knowledge, attitudes and experience of a group of Malaysian dental health care providers regarding child physical abuse (CPA) cases in terms of frequency of occurrence, diagnosis, risk factors and reporting.
A hybrid method for evaluating enterprise architecture implementation

Nikpay F, Ahmad R, Yin Kia C

Eval Program Plann, 2017 02;60:1-16.
PMID: 27665066 DOI: 10.1016/j.evalprogplan.2016.09.001

Enterprise Architecture (EA) implementation evaluation provides a set of methods and practices for evaluating the EA implementation artefacts within an EA implementation project. There are insufficient practices in existing EA evaluation models in terms of considering all EA functions and processes, using structured methods in developing EA implementation, employing matured practices, and using appropriate metrics to achieve proper evaluation. The aim of this research is to develop a hybrid evaluation method that supports achieving the objectives of EA implementation. To attain this aim, the first step is to identify EA implementation evaluation practices. To this end, a Systematic Literature Review (SLR) was conducted. Second, the proposed hybrid method was developed based on the foundation and information extracted from the SLR, semi-structured interviews with EA practitioners, program theory evaluation and Information Systems (ISs) evaluation. Finally, the proposed method was validated by means of a case study and expert reviews. This research provides a suitable foundation for researchers who wish to extend and continue this research topic with further analysis and exploration, and for practitioners who would like to employ an effective and lightweight evaluation method for EA projects.
Repellent effect of microencapsulated essential oil in lotion formulation against mosquito bites

Misni N, Nor ZM, Ahmad R

J Vector Borne Dis, 2017 Jan-Mar;54(1):44-53.
PMID: 28352045

BACKGROUND & OBJECTIVES: Many essential oils have been reported as natural sources of insect repellents; however, due to high volatility, they present low repellent effect. Formulation technique by using microencapsulation enables to control the volatility of essential oil and thereby extends the duration of repellency. In this study, the effectiveness of microencapsulated essential oils of Alpinia galanga, Citrus grandis and C. aurantifolia in the lotion formulations were evaluated against mosquito bites.

METHODS: Essential oils and N,N-Diethyl-3-methylbenzamide (DEET) were encapsulated by using interfacial pre- cipitation techniques before incorporation into lotion base to form microencapsulated (ME) formulation. The pure essential oil and DEET were also prepared into lotion base to produce non-encapsulated (NE) formulation. All the prepared formulations were assessed for their repellent activity against Culex quinquefasciatus under laboratory condition. Field evaluations also were conducted in three different study sites in Peninsular Malaysia. In addi- tion, Citriodiol® (Mosiquard®) and citronella-based repellents (KAPS®, MozAway® and BioZ Natural®) were also included for comparison.

RESULTS: In laboratory conditions, the ME formulations of the essential oils showed no significant difference with regard to the duration of repellent effect compared to the microencapsulated DEET used at the highest con- centration (20%). It exhibited >98% repellent effect for duration of 4 h (p = 0.06). In the field conditions, these formulations demonstrated comparable repellent effect (100% for a duration of 3 h) to Citriodiol® based repellent (Mosiguard®) (p = 0.07). In both test conditions, the ME formulations of the essential oils presented longer duration of 100% repellent effect (between 1 and 2 h) compared to NE formulations.

INTERPRETATION & CONCLUSION: The findings of the study demonstrate that the application of the microencapsulation technique during the preparation of the formulations significantly increases the duration of the repellent effect of the essential oils, suggesting that the ME formulation of essential oils have potential to be commercialized as an alternative plant-based repellent in the market against the mosquitoes.
Fulltext Thyroglossal duct carcinoma

Kahairi A, Ahmad RL, Wan Islah L, Hasmah H

Singapore Med J, 2009 Dec;50(12):e404-6.
PMID: 20087540

We report a 56-year-old Malay woman with a tumour that involved the skin and caused hyoid bone erosion. There was no clinical or radiological evidence of regional lymph node involvement. A modified radical neck dissection with preservation of the accessory nerve and internal jugular vein was performed, followed by an "extended" Sistrunk operation. The surgical defect was reconstructed with a pectoralis major myocutaneous flap. Our literature review showed that this is the first reported thyroglossal duct carcinoma which involved the skin and required a pedicle flap reconstruction.
Fulltext Does the US regional greenhouse gas initiative affect green innovation?

Rahman MA, Ahmad R, Ismail I

Environ Sci Pollut Res Int, 2023 Feb;30(6):15689-15707.
PMID: 36173521 DOI: 10.1007/s11356-022-23189-0

This study measures the impact of the implementation of the Regional Greenhouse Gas Initiative (RGGI) on firms' green innovation initiatives. We used 20 years of panel data from the Fortune 500 list of the US largest companies. Based on DID, a benchmark regression, the RGGI has a significant adverse effect on the green innovation of Fortune 500 companies, and we verified these findings with multiple robustness tests. As we investigate how energy-intensive industries were affected by RGGI, we found that it slowed down green innovation, but it was not statistically significant. This study provides a novel perspective on how the RGGI influences green innovation in firms and how different types of sectors respond to the policy. The findings indicate that the "weak" Porter Hypothesis has not been confirmed in the present carbon trading market (particularly the RGGI) for Fortune 500 firms in the USA. In terms of policy, we believe that a well-covered and differentiated legislation that fosters green innovation while being realistic about the policy's goal and the firm's environmental attitude, like emissions reduction through green innovation, is essential.
Editorial: Diet and nutrition for non-communicable diseases in low and middle-income countries

Ahmad R, Akter F, Haque M

Front Nutr, 2023;10:1179640.
PMID: 37057068 DOI: 10.3389/fnut.2023.1179640
Regulatory Oversight of Cell and Gene Therapy Products in Malaysia

Loh EYX, Ab Ghani A, Ahmad R

Adv Exp Med Biol, 2023;1430:181-195.
PMID: 37526848 DOI: 10.1007/978-3-031-34567-8_10

The National Pharmaceutical Regulatory Agency (NPRA) is the agency responsible for the registration of pharmaceutical, natural, and health supplement products and notification of cosmetic products that are marketed in Malaysia. The implementation of regulatory oversight of the different types of product was in a progressive manner, with the latest addition to be regulated being the cell and gene therapy products (CGTPs), beginning January 1, 2021. CGTP can be classified as low risk (that does not require registration) or high risk (that needs to be registered). Generally, the regulation of high-risk CGTP is similar to other biological products. This chapter describes the chronology of the CGTP framework, classification of CGTP, how CGTPs fit into the current registration pathways and registration procedure, dossier requirements, and what is the current status and future direction of CGTP in Malaysia.
Microencapsulation of Citrus Grandis Peel Oil Using Interfacial Precipitation Chemistry Technique for Repellent Application

Misni N, Mohamed Nor Z, Ahmad R

Iran J Pharm Res, 2019;18(1):198-209.
PMID: 31089355

Essential oil of Citrus family plant is known to have repellent effect against mosquito. Unfortunately, due to its high volatility effect, its repellency effect was compromised. The incorporation of essential oil in a microencapsulation formulation has been shown to help improve the stability and potency of the repellent. In this study, Citrus grandis peel oil (CGPO) was encapsulated by using the interfacial precipitation chemistry technique. The microencapsulated CGPO was then formulated into lotion form to produce topical repellent formulation. This study includes the characterization of microcapsules with regards to the morphology, size distribution, zeta potential, Fourier Transmission Infrared spectrophotometer (FTIR), and Thermogravity analysis (TGA). The effectiveness of the microencapsulated CGPO-lotion formulation against mosquitoes was evaluated in the laboratory setting. Results indicated that CGPO have been successfully encapsulated with 6.5 µm in diameter and zeta potential values, -47.9 mV. The FTIR analysis spectrum indicated the presence of interaction between the wall materials in microcapsules. The TGA analysis demonstrated that microencapsulation improved the thermal stability of CGPO. Repellency assay revealed that microencapsulated CGPO- based formulation possessed excellent effect compared with pure CGPO. In conclusion, CGPO was successfully encapsulated and the microencapsulation aid to improve the repellency effect of CGPO against mosquito bites.
Bibliometric Analysis of Research Papers on Academic Stress (1989-2023)

Dagli N, Ahmad R, Haque M, Kumar S

Cureus, 2024 Mar;16(3):e55536.
PMID: 38449911 DOI: 10.7759/cureus.55536

This extensive study provides a comprehensive overview of the contemporary research landscape about academic stress, emphasizing on identifying the most relevant contributors and understanding prevalent trends. The analysis included 5,375 results from the PubMed database and revealed a consistent upward trajectory with fluctuations in research paper publications over the years. Network analysis and visualization were performed using the Biblioshiny app and VOSviewer software. The analysis identified that the University of Oslo has published the highest number of research papers related to academic stress. In contrast, the Netherlands, the USA, and Australia demonstrated the highest frequency of collaboration. Analysis of keywords and their co-occurrence provides an overview of the research focus and the areas associated with psychological stress due to academics. Thematic evaluation and topic trend analysis provided insights into the evolving nature of research in academic stress. The thematic map depicts two categories of themes - motor themes, including psychological stress, its epidemiology, the influence of the COVID-19 pandemic, and the mental health of university students, particularly those in medical programs; and emerging themes, including oxidative stress and risk factors, indicated evolving areas of interest. A notable observation was the scarcity of research on primary school students, signaling a gap in the existing academic stress literature. Citation analysis identified the most cited authors, countries, universities, and sources. This multifaceted examination provides a nuanced understanding of academic stress research's current state and dynamics, offering valuable insights into trends, collaborations, and thematic shifts that will guide future research in this critical field.
Fulltext Effect of sublethal dosages of malathion on the oral susceptibility of Aedes aegypti to dengue-2 virus infection

Lee HL, Argubano RA, Ahmad R

Southeast Asian J Trop Med Public Health, 1997 Sep;28(3):664-5.
PMID: 9561626
Fulltext Detection of dengue virus from field Aedes aegypti and Aedes albopictus adults and larvae

Ahmad R, Ismail A, Saat Z, Lim LH

Southeast Asian J Trop Med Public Health, 1997 Mar;28(1):138-42.
PMID: 9322296

Mosquito adults and larvae were collected from dengue high risk areas and transported to the laboratory for identification. Identified mosquitos were pooled according to the species, date and locality and stored at -70 degrees C. A total of 1,385 pools of Aedes albopictus and 267 pools of Ae. Aegypti were collected from major towns in 12 states in Peninsular Malaysia. Virus isolation was carried out using cell culture (C6/36 clone) of Ae. albopictus and detection of dengue virus by the peroxidase anti-peroxidase staining. All positive isolations were further re-confirmed by the reverse transcriptase-polymerase chain reaction (RT-PCR). Most of the pools were negative with PAP staining and RT-PCR. However, 11 mosquito pools were positive with PAP staining. On the other hand, samples from Terengganu, Pulau Pinang and Johor were positive using both methods.
Fulltext A traditional Malay myth leading to unintentional self intoxication with kecubung fruit

Mohamad N, Baharuddin KA, Ahmad R

Southeast Asian J Trop Med Public Health, 2009 Nov;40(6):1331-4.
PMID: 20578469

Traditional Malay herbal medicine is still used in Malaysia especially in rural areas, instead of using modern medicine. Datura or "kecubung" has been used to treat allergic rhinitis in certain places. Inaccurate doses can potentially cause severe or fatal neurologic anti-cholinergic toxidromes. A good knowledge of toxidromes with optimization of supportive care can prevent fatal complications and lead to a more speedy recovery. We present a case of kecubung poisoning.
The association between sleep apnea and young adults with hypertension

Asha'ari ZA, Hasmoni MH, Ab Rahman J, Yusof RA, Ahmad RA

Laryngoscope, 2012 Oct;122(10):2337-42.
PMID: 22753136 DOI: 10.1002/lary.23379

To study the association between sleep apnea and hypertension in a younger age group than previously studied, adding upper airway sizes at endoscopy as important compounding variables not often included in the past.
Oncologic outcome in surgical management of jugular paraganglioma and factors influencing outcomes

Lope Ahmad RA, Sivalingam S, Konishi M, De Donato G, Sanna M

Head Neck, 2013 Apr;35(4):527-34.
PMID: 22544660 DOI: 10.1002/hed.22987

The purpose of this study was to identify the factors that may influence the management outcome in patients with jugular paragangliomas.
Fulltext The influence of agitation on oil substrate dispersion and oxygen transfer in Pseudomonas aeruginosa USM-AR2 fermentation producing rhamnolipid in a stirred tank bioreactor

Nur Asshifa MN, Zambry NS, Salwa MS, Yahya ARM

3 Biotech, 2017 Jul;7(3):189.
PMID: 28664380 DOI: 10.1007/s13205-017-0828-0

Water-immiscible substrate, diesel, was supplied as the main substrate in the fermentation of Pseudomonas aeruginosa USM-AR2 producing rhamnolipid biosurfactant, in a stirred tank bioreactor. In addition to the typical gas-aqueous system, this system includes gas-hydrocarbon-aqueous phases and the presence of surfactant (rhamnolipid) in the fermentation broth. The effect of diesel dispersion on volumetric oxygen transfer coefficient, k L a, and thus oxygen transfer, was evaluated at different agitations of 400, 500 and 600 rpm. The oxygen transfer in this oil-water-surfactant system was shown to be affected by different oil dispersion at those agitation rates. The highest diesel dispersion was obtained at 500 rpm or impeller tip speed of 1.31 m/s, compared to 400 and 600 rpm, which led to the highest k L a, growth and rhamnolipid production by P. aeruginosa USM-AR2. This showed the highest substrate mixing and homogenization at this agitation speed that led to the efficient substrate utilization by the cells. The oxygen uptake rate of P. aeruginosa USM-AR2 was 5.55 mmol/L/h, which showed that even the lowest k L a (48.21 h-1) and hence OTR (57.71 mmol/L/h) obtained at 400 rpm was sufficient to fulfill the oxygen demand of the cells. The effect of rhamnolipid concentration on k L a showed that k L a increased as rhamnolipid concentration increased to 0.6 g/L before reaching a plateau. This trend was similar for all agitation rates of 400, 500 and 600 rpm, which might be due to the increase in the resistance to oxygen transfer (k L decrease) and the increase in the specific interfacial area (a).
Agroforestry orchards support greater butterfly diversity than monoculture plantations in the tropics

Wan Zaki WM, Yahya MS, Norhisham AR, Sanusi R, van der Meer PJ, Azhar B

Oecologia, 2023 Mar;201(3):863-875.
PMID: 36914820 DOI: 10.1007/s00442-023-05348-3

Large-scale deforestation in the tropics, triggered by logging and subsequent agricultural monoculture has a significant adverse impact on biodiversity due to habitat degradation. Here, we measured the diversity of butterfly species in three agricultural landscapes, agroforestry orchards, oil palm, and rubber tree plantations. Butterfly species were counted at 127 sampling points over the course of a year using the point count method. We found that agroforestry orchards supported a greater number of butterfly species (74 species) compared to rubber tree (61 species) and oil palm plantations (54 species) which were dominated by generalist (73%) followed by forest specialists (27%). We found no significant difference of butterfly species composition between agroforestry orchards and rubber tree plantation, with both habitats associated with more butterfly species compared to oil palm plantations. This indicates butterflies were able to persist better in certain agricultural landscapes. GLMMs suggested that tree height, undergrowth coverage and height, and elevation determined butterfly diversity. Butterfly species richness was also influenced by season and landscape-level variables such as proximity to forest, mean NDVI, and habitat. Understanding the factors that contributed to butterfly species richness in an agroecosystem, stakeholders should consider management practices to improve biodiversity conservation such as ground vegetation management and retaining adjacent forest areas to enhance butterfly species richness. Furthermore, our findings suggest that agroforestry system should be considered to enhance biodiversity in agricultural landscapes.
Fulltext MicroRNAs and Target Genes As Biomarkers for the Diagnosis of Early Onset of Parkinson Disease

Arshad AR, Sulaiman SA, Saperi AA, Jamal R, Mohamed Ibrahim N, Abdul Murad NA

Front Mol Neurosci, 2017;10:352.
PMID: 29163029 DOI: 10.3389/fnmol.2017.00352

Among the neurodegenerative disorders, Parkinson's disease (PD) ranks as the second most common disorder with a higher prevalence in individuals aged over 60 years old. Younger individuals may also be affected with PD which is known as early onset PD (EOPD). Despite similarities between the characteristics of EOPD and late onset PD (LODP), EOPD patients experience much longer disease manifestations and poorer quality of life. Although some individuals are more prone to have EOPD due to certain genetic alterations, the molecular mechanisms that differentiate between EOPD and LOPD remains unclear. Recent findings in PD patients revealed that there were differences in the genetic profiles of PD patients compared to healthy controls, as well as between EOPD and LOPD patients. There were variants identified that correlated with the decline of cognitive and motor symptoms as well as non-motor symptoms in PD. There were also specific microRNAs that correlated with PD progression, and since microRNAs have been shown to be involved in the maintenance of neuronal development, mitochondrial dysfunction and oxidative stress, there is a strong possibility that these microRNAs can be potentially used to differentiate between subsets of PD patients. PD is mainly diagnosed at the late stage, when almost majority of the dopaminergic neurons are lost. Therefore, identification of molecular biomarkers for early detection of PD is important. Given that miRNAs are crucial in controlling the gene expression, these regulatory microRNAs and their target genes could be used as biomarkers for early diagnosis of PD. In this article, we discussed the genes involved and their regulatory miRNAs, regarding their roles in PD progression, based on the findings of significantly altered microRNAs in EOPD studies. We also discussed the potential of these miRNAs as molecular biomarkers for early diagnosis.
Fulltext Larvicidal activity, inhibition effect on development, histopathological alteration and morphological aberration induced by seaweed extracts in Aedes aegypti (Diptera: Culicidae)

Yu KX, Wong CL, Ahmad R, Jantan I

Asian Pac J Trop Med, 2015 Dec;8(12):1006-1012.
PMID: 26706671 DOI: 10.1016/j.apjtm.2015.11.011

OBJECTIVE: To investigate the larvicidal activity, inhibition effect on development, histopathological alteration and morphological aberration induced by the extracts derived from seaweeds Bryopsis pennata (B. pennata), Sargassum binderi (S. binderi) and Padina australis in Aedes aegypti (Ae. aegypti) larvae and to characterize the phytochemical components of the three seaweeds.
METHODS: Larvicidal activity of the seaweeds towards the larvae of Ae. aegypti was determined according to WHO. The inhibition effect of seaweeds was assessed by determining the mortality, adult emergence rate, larval and pupa duration of the treated larvae. Histopathological effect on midgut epithelium of larvae and morphological aberration induced by the methanol extracts were examined. Phytochemical analysis was done to determine the presence of alkaloids, saponins, steroids and terpenoids in the seaweeds.
RESULTS: Chloroform partition of B. pennata extract exhibited the strongest larvicidal activity (LC50 = 82.55 μg/mL), followed by methanol extract of B. pennata (LC50 = 160.07 μg/mL) and chloroform partition of S. binderi extract (LC50 = 192.43 μg/mL). The methanol extract of S. binderi exhibited the strongest effect on prolongation of larval period (1.5-fold longer as compared to control) and resulted in strongest inhibition effect in adult emergence (98.67%). The histopathological study showed that larvae treated with seaweed extracts had cytopathological alteration of the midgut epithelium. The morphological observation revealed that the anal papillae and terminal spiracles of larvae were the common sites of aberrations.
CONCLUSIONS: The study provided information on various effects of seaweed extracts on Ae. aegypti. Further investigation on identifying the active compounds and their mechanisms of action is recommended.

Filters

Please provide feedback to Administrator ([email protected])

External Links