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Displaying publications 21 - 27 of 27 in total

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Linear epitopes of the replication-activator protein of Epstein-Barr virus recognised by specific serum IgG in nasopharyngeal carcinoma

Cheng HM, Foong YT, AbuSamah AJ, Dillner J, Sam CK, Prasad U

Cancer Immunol Immunother, 1995 Apr;40(4):251-6.
PMID: 7750123

The linear antigenic epitopes of the Epstein-Barr virus replication activator protein (ZEBRA), recognised by specific serum IgG in nasopharyngeal carcinoma (NPC), were determined. This was achieved by synthesizing the entire amino acid sequence of ZEBRA as a set of 29, 22-residue peptides with an overlap of 14 amino acids. The ZEBRA peptides were tested in enzyme-linked immunosorbent assay (ELISA) for IgG binding in sera from 37 selected NPC patients who had IgG antibodies to the native ZEBRA protein. The most immunogenic epitope was peptide 1 at the amino-terminal end with 36 of the sera reactive against it. Further analysis of peptide 1, using the multipin peptide-scanning technique, defined a 10-amino-acid sequence FTPDPYQVPF, which was strongly bound by IgG. Two other regions of ZEBRA were also identified as immunodominant IgG epitopes, namely peptide 11 (amino acids 82-103) and peptide 19/20 (amino acids 146-175) with 8-13 of the NPC sera reactive against the peptides. The number of peptides reactive with individual NPC serum varies from 1 to 6 or more and there is some correlation between a greater number of peptide (at least 4) bound and a higher (at least 1:40) titre of serum IgA to viral capsid antigen. The immunodominant ZEBRA peptide 1 could be utilised in IgG ELISA for the detection of NPC.
A study of pollen prevalence in relation to pollen allergy in Malaysian asthmatics

Sam CK, Kesavan-Padmaja, Liam CK, Soon SC, Lim AL, Ong EK

Asian Pac J Allergy Immunol, 1998 Mar;16(1):1-4.
PMID: 9681122

In this paper we report results of skin prick tests (SPT) using pollen extracts on 200 patients with clinical symptoms of asthma, and results of a parallel study in which pollen was collected and classified over a period of 18 months. The patients were outpatients from the University Hospital in Kuala Lumpur, Malaysia, while the pollen grains were collected with a spore trap placed in the campus of the University of Malaya, approximately one kilometer from the University Hospital. Pollen extracts of 3 grasses (Bahia, Bermuda, rough pigweed) and 2 flowering trees, Acacia and Melaleuca, were used in the SPT. Of the 29.5% asthmatics with positive SPT reactions, 21.5% were to one or more of the grass pollens, 21.5% to Acacia and 7.5% to Melaleuca pollen. Acacia and Bermuda grass extracts were the most allergenic, which agreed with results of the pollen collection which showed grass and Acacia pollen grains to be the two most commonly found pollens.

Study site: University Malaya Medical Centre (UMMC)
Fulltext MECP2 mutations in Malaysian Rett syndrome patients

Fong CB, Thong MK, Sam CK, Mohamed Noor MN, Ariffin R

Singapore Med J, 2009 May;50(5):529-33.
PMID: 19495527

Rett syndrome (RS) is a severe neurodevelopmental disorder characterised by normal neurological development followed by progressive developmental regression. The X-linked dominant inheritance of RS has been mapped to the gene that encodes the methyl-CpG-binding protein-2 (MECP2) at Xq28. In the present study, denaturing high-performance liquid chromatography (DHPLC) was used to detect mutations in the MECP2 gene in 20 Malaysian RS patients.
Asian sildenafil efficacy and safety study (ASSESS-1): a double-blind, placebo-controlled, flexible-dose study of oral sildenafil in Malaysian, Singaporean, and Filipino men with erectile dysfunction. The Assess-1 Study Group

Tan HM, Moh CL, Mendoza JB, Gana T, Albano GJ, de la Cruz R, et al.

Urology, 2000 Oct 1;56(4):635-40.
PMID: 11018621 DOI: 10.1016/s0090-4295(00)00688-9

OBJECTIVES:
To evaluate the efficacy, safety, and tolerability of oral sildenafil in Asian men with erectile dysfunction of various causes (organic, psychogenic, or mixed) and of more than 6 months' duration.

METHODS:
In this double-blind, parallel-group trial conducted at eight centers in Malaysia, the Philippines, and Singapore, 254 men, 26 to 78 years old, were randomized to 12 weeks of sildenafil or placebo taken as needed 1 hour before anticipated sexual activity. Initially, the sildenafil (n = 127) or matching placebo (n = 127) dose was 50 mg but could be increased to 100 mg or decreased to 25 mg because of a lack of efficacy or intolerance, respectively. Efficacy was assessed by the 15-question International Index of Erectile Function, patients' event logs of sexual activity, and a global efficacy question about erections.

RESULTS:
The two primary efficacy variables relating to achievement and maintenance of an erection sufficient for sexual intercourse, as assessed by the mean scores for International Index of Erectile Function question 3 (4.22 versus 2.59) and question 4 (4.15 versus 2.41), were both significantly higher with sildenafil than with placebo (P <0.0001). In addition, the five separate International Index of Erectile Function domains of sexual function, the percentage of successful intercourse attempts, and the global efficacy assessment of erections revealed significantly greater treatment effects in favor of sildenafil (P <0.0001 versus placebo for all variables). Treatment-related adverse events occurred in 22.8% of patients who received sildenafil and in 10.2% of those who received placebo.

CONCLUSIONS:
Sildenafil is an effective and well-tolerated treatment for Asian men with erectile dysfunction of broad-spectrum etiology.
Sensitization profiles of Malaysian and Singaporean subjects to allergens from Dermatophagoides pteronyssinus and Blomia tropicalis

Yeoh SM, Kuo IC, Wang DY, Liam CK, Sam CK, De Bruyne JA, et al.

Int Arch Allergy Immunol, 2003 Nov;132(3):215-20.
PMID: 14646382 DOI: 10.1159/000074302

BACKGROUND: The house dust mites Dermatophagoides pteronyssinus (Der p) and Blomia tropicalis (Blo t) are the most common house dust mite species in Southeast Asia. To date, there have only been a few studies on the sensitization profile of the general populations in Southeast Asia to house dust mites. The aim of this study was to determine the profiles of Der p and Blo t sensitization among Singaporean and Malaysian subjects.

METHODS: Enzyme-linked immunosorbent assay was used to detect specific IgE to Der p and Blo t mite crude extracts as well as purified Der p 1, Der p 2 and Blo t 5 allergens. Sera used were from 229 Singaporean subjects (124 with rhinitis, 105 without rhinitis) and 143 Malaysian subjects (94 adults and 49 children with asthma).

RESULTS: The sensitization profile of rhinitis subjects to the dust mite allergens used in this study was as follows: Blo t extract positive: 91/124 (73%); Blo t 5 positive: 62/124 (50%); Der p extract positive: 61/124 (49%); Der p 1 positive: 53/124 (43%); Der p 2 positive: 45/124 (36%). The nonrhinitis subjects' sensitization profile was as follows: Blo t extract positive: 60/105 (57%); Blo t 5 positive: 24/105 (23%); Der p extract positive: 38/105 (36%); Der p 1 positive: 14/105 (13%); Der p 2 positive: 17/105 (16%). The study of Malaysian asthmatic adults showed that 39% of them were sensitized to Der p 1, 32% to Der p 2 and 37% to Blo t 5. Among the asthmatic children, sensitization to Blo t 5, Der p 1 and Der p 2 was 90, 57 and 39%, respectively.

CONCLUSION: This study clearly revealed that dual sensitization to B. tropicalis and D. pteronyssinus is common in the general populations of Singapore and Malaysia. Sensitization to Blo t 5 is more prevalent than to Der p 1 and Der p 2.
Fulltext Multilocus sequence typing of clinical Burkholderia pseudomallei isolates from Cambodia

Gyamfi E, Delvallez G, Cheng S, Meng S, Oeurn K, Sam C, et al.

PLoS Negl Trop Dis, 2024 Nov;18(11):e0012652.
PMID: 39541393 DOI: 10.1371/journal.pntd.0012652

Melioidosis is a neglected tropical disease caused by Burkholderia pseudomallei, endemic to Southeast Asia and Northern Australia. Despite its increasing global public health and clinical significance, the molecular epidemiology of melioidosis and genetic diversity of B. pseudomallei in Cambodia remains poorly understood. This study aims to elucidate the genetic diversity and antibiotic susceptibility profiles of B. pseudomallei isolates responsible for melioidosis in humans. For this purpose, 14 clinical isolates cryopreserved at the Medical Biology Laboratory at Institut Pasteur du Cambodge from 2016 to 2020 were subjected to antimicrobial susceptibility testing and Multilocus Sequence Typing (MLST). Phenotypic testing revealed that 92.86% (13/14) of the isolates were sensitive to all tested antibiotics, while one isolate exhibited resistance to trimethoprim-sulfamethoxazole. MLST analysis resolved our isolates into 14 unique Sequence Types (STs), including 10 previously documented in Southeast Asia. Notably, ST1858, ST2064, ST2065, and ST2066 were identified as novel STs, while ST54, ST99, ST211, and ST1359 were reported in Cambodia for the first time in this study. Comparing our MLST data with available sequences on PubMLST (n = 165), our study unveiled a high genetic diversity of B. pseudomallei in Cambodia. The identified STs were closely associated with isolates from other Southeast Asian countries, particularly Thailand, Vietnam, and Malaysia. In conclusion, this study provided insight into the genetic diversity among B. pseudomallei clinical isolates in Cambodia and their close genetic association with Southeast Asian isolates. To further our understanding, a One Health approach, incorporating human, environmental (mainly soil), and animal compartments, is essential to decipher the epidemiology of B. pseudomallei in Cambodia.
Fulltext COVID-19: Four Paediatric Cases in Malaysia

See KC, Liew SM, Ng DCE, Chew EL, Khoo EM, Sam CH, et al.

Int J Infect Dis, 2020 May;94:125-127.
PMID: 32304822 DOI: 10.1016/j.ijid.2020.03.049

OBJECTIVE: This is a brief report of 4 paediatric cases of COVID-19 infection in Malaysia BACKGROUND: COVID-19, a coronavirus, first detected in Wuhan, China has now spread rapidly to over 60 countries and territories around the world, infecting more than 85000 individuals. As the case count amongst children is low, there is need to report COVID-19 in children to better understand the virus and the disease.
CASES: In Malaysia, until end of February 2020, there were four COVID-19 paediatric cases with ages ranging from 20 months to 11 years. All four cases were likely to have contracted the virus in China. The children had no symptoms or mild flu-like illness. The cases were managed symptomatically. None required antiviral therapy.
DISCUSSION: There were 2 major issues regarding the care of infected children. Firstly, the quarantine of an infected child with a parent who tested negative was an ethical dilemma. Secondly, oropharyngeal and nasal swabs in children were at risk of false negative results. These issues have implications for infection control. Consequently, there is a need for clearer guidelines for child quarantine and testing methods in the management of COVID-19 in children.