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Fulltext Knowledge, Awareness, and Perception of Genetic Testing for Hereditary Disorders Among Malaysians in Klang Valley

Chin JJ, Tham HW

Front Genet, 2020;11:512582.
PMID: 33343613 DOI: 10.3389/fgene.2020.512582

Genetic testing aids patients in making important decisions in the prevention, treatment, or early detection of hereditary disorders. Low awareness of the importance of genetic testing contributes to the increase in the incidence of hereditary disorders. This study aims to explore the knowledge, awareness, and perception of genetic testing for hereditary disorders among local residents of the Klang Valley, Malaysia, and the potential variables that influence their understanding of genetic testing. A survey was conducted in different municipalities of the Klang Valley through self-administered questionnaire assessing the public's knowledge, awareness, and perception of genetic testing. Overall, the results revealed adequate knowledge and positive awareness of genetic testing, in which both were influenced by the respondent's educational level (P < 0.001), field of study (P < 0.001), and status of heard or unheard of genetic testing (P < 0.001). The perception of genetic testing was generally positive and influenced by the respondent's differences in age (P < 0.016), educational level (P < 0.001), field of study (P < 0.001), and status of heard or unheard of genetic testing (P < 0.001). Although positive responses were obtained, ~20.2% of the respondents had never heard of genetic testing. Of the respondents, 24.5% were unwilling to undergo genetic testing, with 25.1% believing that genetic testing tampers with nature and 18% believing that it opposes religion and their beliefs. Such attitude calls for the need to conduct programs to eliminate any misconception, as well as to educate the public to lessen any perceived misunderstanding of the concepts of genetic testing.
Fulltext Knowledge, Awareness, and Perception of Community Pharmacists to Zika Virus Infection in Klang Valley, Malaysia

Lim KY, Tham HW

Health services insights, 2020;13:1178632920921425.
PMID: 32528223 DOI: 10.1177/1178632920921425

Background: Zika fever is a mosquito-borne disease with global health concern. It has been underreported or misdiagnosed due to its unspecific clinical manifestations, including mild-influenza like and subclinical symptoms. However, its associated serious complications which include fetal microcephaly and Guillain-Barré syndrome remained a challenge to the public health sectors. This research aimed to evaluate the knowledge, awareness, and perception toward Zika virus infection among community pharmacists in the Klang Valley of Malaysia and to determine the association between the knowledge of Zika virus infectious disease and years of community practice experience among community pharmacists in this region.
Methods: This survey research was conducted from August to December 2018 through a pre-tested, self-administration, and cross-sectional random convenient sampling at various districts in the Klang Valley. A total of 275 registered community pharmacists were involved in this study by completing a pilot-tested questionnaire. Descriptive analysis, Mann-Whitney U test, and Kruskal-Wallis H test were used to analyze the data.
Results: The knowledge toward Zika virus infection of respondents was classified into "poor" (5.1%), "basic" (70.9%), and "broad" (24.0%). Most of the participants (n = 195, 70.9%) presented with basic knowledge toward Zika virus infection. A total of 268 (97.5%) participants presented with high awareness toward Zika virus infection. The mean score of respondents' knowledge and awareness was 15.88 ± 3.61 (maximum score = 28) and 13.96 ± 1.60 (maximum score = 16), respectively. There was a statistically significant difference between the years of practice of community pharmacists and the level of knowledge toward Zika virus infection.
Conclusions: In conclusion, our respondents demonstrated a basic level of knowledge and high awareness toward Zika virus infection. Also, we highlighted some possible pitfalls in the knowledge of Zika virus infection, including the virus transmission, symptoms, diagnosis, treatment, prevention, and complications of the disease.
Anti-dengue virus serotype 2 activity and mode of action of a novel peptide

Chew MF, Tham HW, Rajik M, Sharifah SH

J Appl Microbiol, 2015 Oct;119(4):1170-80.
PMID: 26248692 DOI: 10.1111/jam.12921

To identify a novel antiviral peptide against dengue virus serotype 2 (DENV-2) by screening a phage display peptide library and to evaluate its in vitro antiviral activity and mode of action.
Fulltext Viral Determinants and Vector Competence of Zika Virus Transmission

Tham HW, Balasubramaniam V, Ooi MK, Chew MF

Front Microbiol, 2018;9:1040.
PMID: 29875751 DOI: 10.3389/fmicb.2018.01040

Zika virus (ZIKV) has emerged as a new global health threat. Since its first discovery in Zika forest in Uganda, this virus has been isolated from several mosquito species, including Aedes aegypti and Aedes albopictus. The geographical distribution of these mosquito species across tropical and subtropical regions has led to several outbreaks, including the recent pandemic in Brazil, followed by the Pacific islands and other areas of North and South America. This has gained attention of the scientific community to elucidate the epidemiology and transmission of ZIKV. Despite its strong attention on clinical aspects for healthcare professionals, the relationships between ZIKV and its principal vectors, A. aegypti and A. albopictus, have not gained substantial interest in the scientific research community. As such, this review aims to summarize the current knowledge on ZIKV tropism and some important mechanisms which may be employed by the virus for effective strategies on viral survival in mosquitoes. In addition, this review identifies the areas of research that should be placed attention to, for which to be exploited for novel mosquito control strategies.
Fulltext Protein-protein interactions between A. aegypti midgut and dengue virus 2: two-hybrid screens using the midgut cDNA library

Tham HW, Balasubramaniam VR, Chew MF, Ahmad H, Hassan SS

J Infect Dev Ctries, 2015 Dec 30;9(12):1338-49.
PMID: 26719940 DOI: 10.3855/jidc.6422

INTRODUCTION: Dengue virus (DENV) is principally transmitted by the Aedes aegypti mosquito. To date, mosquito population control remains the key strategy for reducing the continuing spread of DENV. The focus on the development of new vector control strategies through an understanding of the mosquito-virus relationship is essential, especially targeting the midgut, which is the first mosquito organ exposed to DENV infection.
METHODOLOGY: A cDNA library derived from female adult A. aegypti mosquito midgut cells was established using the switching mechanism at the 5' end of the RNA transcript (SMART), in combination with a highly potent recombination machinery of Saccharomyces cerevisiae. Gal4-based yeast two-hybrid (Y2H) assays were performed against DENV-2 proteins (E, prM, M, and NS1). Mammalian two-hybrid (M2H) and double immunofluorescence assays (IFA) were conducted to validate the authenticity of the three selected interactions.
RESULTS: The cDNA library was of good quality based on its transformation efficiency, cell density, titer, and the percentage of insert size. A total of 36 midgut proteins interacting with DENV-2 proteins were identified, some involved in nucleic acid transcription, oxidoreductase activity, peptidase activity, and ion binding. Positive outcomes were obtained from the three selected interactions validated using M2H and double IFA assays.
CONCLUSIONS: The identified proteins have different biological activities that may aid in the virus replication pathway. Therefore, the midgut cDNA library is a valuable tool for identifying DENV-2 interacting proteins. The positive outcomes of the three selected proteins validated supported the quality of the cDNA library and the robustness of the Y2H mechanisms.
Fulltext CPB1 of Aedes aegypti interacts with DENV2 E protein and regulates intracellular viral accumulation and release from midgut cells

Tham HW, Balasubramaniam VR, Tejo BA, Ahmad H, Hassan SS

Viruses, 2014 Dec;6(12):5028-46.
PMID: 25521592 DOI: 10.3390/v6125028

Aedes aegypti is a principal vector responsible for the transmission of dengue viruses (DENV). To date, vector control remains the key option for dengue disease management. To develop new vector control strategies, a more comprehensive understanding of the biological interactions between DENV and Ae. aegypti is required. In this study, a cDNA library derived from the midgut of female adult Ae. aegypti was used in yeast two-hybrid (Y2H) screenings against DENV2 envelope (E) protein. Among the many interacting proteins identified, carboxypeptidase B1 (CPB1) was selected, and its biological interaction with E protein in Ae. aegypti primary midgut cells was further validated. Our double immunofluorescent assay showed that CPB1-E interaction occurred in the endoplasmic reticulum (ER) of the Ae. aegypti primary midgut cells. Overexpression of CPB1 in mosquito cells resulted in intracellular DENV2 genomic RNA or virus particle accumulation, with a lower amount of virus release. Therefore, we postulated that in Ae. aegypti midgut cells, CPB1 binds to the E protein deposited on the ER intraluminal membranes and inhibits DENV2 RNA encapsulation, thus inhibiting budding from the ER, and may interfere with immature virus transportation to the trans-Golgi network.
Fulltext Geraniin extracted from the rind of Nephelium lappaceum binds to dengue virus type-2 envelope protein and inhibits early stage of virus replication

Abdul Ahmad SA, Palanisamy UD, Tejo BA, Chew MF, Tham HW, Syed Hassan S

Virol J, 2017 11 21;14(1):229.
PMID: 29162124 DOI: 10.1186/s12985-017-0895-1

BACKGROUND: The rapid rise and spread in dengue cases, together with the unavailability of safe vaccines and effective antiviral drugs, warrant the need to discover and develop novel anti-dengue treatments. In this study the antiviral activity of geraniin, extracted from the rind of Nephelium lappaceum, against dengue virus type-2 (DENV-2) was investigated.
METHODS: Geraniin was prepared from Nephelium lappaceum rind by reverse phase C-18 column chromatography. Cytotoxicity of geraniin towards Vero cells was evaluated using MTT assay while IC50 value was determined by plaque reduction assay. The mode-of-action of geraniin was characterized using the virucidal, attachment, penetration and the time-of-addition assays'. Docking experiments with geraniin molecule and the DENV envelope (E) protein was also performed. Finally, recombinant E Domain III (rE-DIII) protein was produced to physiologically test the binding of geraniin to DENV-2 E-DIII protein, through ELISA competitive binding assay.
RESULTS: Cytotoxicity assay confirmed that geraniin was not toxic to Vero cells, even at the highest concentration tested. The compound exhibited DENV-2 plaque formation inhibition, with an IC50 of 1.75 μM. We further revealed that geraniin reduced viral infectivity and inhibited DENV-2 from attaching to the cells but had little effect on its penetration. Geraniin was observed to be most effective when added at the early stage of DENV-2 infection. Docking experiments showed that geraniin binds to DENV E protein, specifically at the DIII region, while the ELISA competitive binding assay confirmed geraniin's interaction with rE-DIII with high affinity.
CONCLUSIONS: Geraniin from the rind of Nephelium lappaceum has antiviral activity against DENV-2. It is postulated that the compound inhibits viral attachment by binding to the E-DIII protein and interferes with the initial cell-virus interaction. Our results demonstrate that geraniin has the potential to be developed into an effective antiviral treatment, particularly for early phase dengue viral infection.