1.Cloning, expression and purification of Plasmodium knowlesi circumsporozoite protein and immunoblot analysis with P. knowlesi strain A1H1 protein extract
Tropical Biomedicine 2022;39(No.2):209-214
Circumsporozoite protein (CSP) is a sporozoite major surface protein of Plasmodium species. The protein
showed promising protection level as a vaccine candidate against Plasmodium falciparum infection.
There is a lack of studies on P. knowlesi CSP (PkCSP) as a vaccine candidate due to the high polymorphic
characteristic of central repeat region. Recent studies showed the protein has a relatively conserved
region at the C-terminal, which consists of T- and B-cell epitopes. This could be the target region for
vaccine development against the pre-erythrocytic stage of the parasite. In this study, recombinant
PkCSP was expressed using Escherichia coli system. Recombinant PkCSP was immunized in animal
models and the antiserum was evaluated using immunoblot analysis. Results showed that PkCSP can
be successfully expressed using the bacterial system. Endpoint titre of the antiserum were ranged up
to 1:819200. Immunoblot analysis showed the antiserum recognized recombinant PkCSP but not total
protein extract from P. knowlesi erythrocytic stage. In conclusion, PkCSP could elicit strong immune
response in animal models. However, serum antibodies could not recognize protein from the parasite’s
erythrocytic stage extract indicating it is not expressed at the erythrocytic stage. Therefore, PkCSP
remains as a potential pre-erythrocytic vaccine candidate against P. knowlesi infection.
2.Plasmodium knowlesi circumsporozoite protein: genetic characterisation and predicted antigenicity of the central repeat region
Tan, J.H. ; Cheong, F.W. ; Lau, Y.L. ; Fong, M.Y.
Tropical Biomedicine 2023;40(No.1):37-44
Circumsporozoite protein (CSP) central repeat region is one of the main target regions of the RTS,S/AS01
vaccine for falciparum infection as it consists of immunodominant B cell epitopes. However, there is a lack
of study for P. knowlesi CSP central repeat region. This study aims to characterise the CSP repeat motifs
of P. knowlesi isolates in Peninsular Malaysia. CSP repeat motifs of 64 P. knowlesi isolates were identified
using Rapid Automatic Detection and Alignment of Repeats (RADAR). Antigenicity of the repeat motifs
and linear B cell epitopes were predicted using VaxiJen 2.0, BepiPred-2.0 and BCPred, respectively. A total
of 35 dominant repeat motifs were identified. The repeat motif “AGQPQAQGDGANAGQPQAQGDGAN”
has the highest repeat frequency (n=15) and antigenicity index of 1.7986. All the repeat regions were
predicted as B cell epitopes. In silico approaches revealed that all repeat motifs were antigenic and
consisted of B cell epitopes which could be designed as knowlesi malaria vaccine.
3.Multimodal prerehabilitation for elderly patients with sarcopenia in colorectal surgery
Jingting WU ; Hannah CHI ; Shawn KOK ; Jason M.W. CHUA ; Xi-Xiao HUANG ; Shipin ZHANG ; Shimin MAH ; Li-Xin FOO ; Hui-Yee PEH ; Hui-Bing LEE ; Phoebe TAY ; Cherie TONG ; Jasmine LADLAD ; Cheryl H.M. TAN ; Nathanelle KHOO ; Darius AW ; Cheryl X.Z. CHONG ; Leonard M.L. HO ; Sharmini S. SIVARAJAH ; Jialin NG ; Winson J.H. TAN ; Fung-Joon FOO ; Bin-Tean TEH ; Frederick H. KOH
Annals of Coloproctology 2024;40(1):3-12
Sarcopenia, which is characterized by progressive and generalized loss of skeletal muscle mass and strength, has been well described to be associated with numerous poor postoperative outcomes, such as increased perioperative mortality, postoperative sepsis, prolonged length of stay, increased cost of care, decreased functional outcome, and poorer oncological outcomes in cancer surgery. Multimodal prehabilitation, as a concept that involves boosting and optimizing the preoperative condition of a patient prior to the upcoming stressors of a surgical procedure, has the purported benefits of reversing the effects of sarcopenia, shortening hospitalization, improving the rate of return to bowel activity, reducing the costs of hospitalization, and improving quality of life. This review aims to present the current literature surrounding the concept of sarcopenia, its implications pertaining to colorectal cancer and surgery, a summary of studied multimodal prehabilitation interventions, and potential future advances in the management of sarcopenia.
4.Complications of Sub-microscopic Plasmodium vivax Malaria among Orang Asli in Pos Lenjang, Kuala Lipis
Mat Salleh, N.H. ; Abdul Rahman, M.F. ; Samsusah, S. ; De Silva, J.R. ; Tan, J.H. ; Amir, A. ; Lau, Y.L.
Tropical Biomedicine 2021;38(No.1):33-35
In recent years, increasing cases of Plasmodium vivax complications had been reported all
over the world. This former benign Plasmodium species is now recognized to be one of the
human malaria parasites that can produce severe disease. In this article, we report two
cases of sub-microscopic P. vivax malaria confirmed by PCR. Both patients were asymptomatic
before treatment. They showed unusual presentations few days after initiation of
antimalarial treatment. Both patients had subsequently completed antimalarial treatment
and recovered completely.