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Kong ASY, Lai KS, Hee CW, Loh JY, Lim SHE, Sathiya M. Oxidative Stress Parameters as Biomarkers of Cardiovascular Disease towards the Development and Progression. Antioxidants (Basel) 2022; 11:antiox11061175. [PMID: 35740071 PMCID: PMC9219727 DOI: 10.3390/antiox11061175] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 12/12/2022] Open
Abstract
Cardiovascular disease (CVD) remains the leading cause of death globally, with unhealthy lifestyles today greatly increasing the risk. Over the decades, scientific investigation has been carried out on reactive oxygen species (ROS) and their resultant oxidative stress based on their changes made on biological targets such as lipids, proteins, and DNA. Since the existing clinical studies with antioxidants failed to provide relevant findings on CVD prediction, the focus has shifted towards recognition of oxidised targets as biomarkers to predict prognosis and response to accurate treatment. The identification of redox markers could help clinicians in providing risk stratification for CVD events beyond the traditional prognostic and diagnostic targets. This review will focus on how oxidant-related parameters can be applied as biomarkers for CVD based on recent clinical evidence.
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Affiliation(s)
- Amanda Shen-Yee Kong
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Subang Jaya 47500, Malaysia;
| | - Kok Song Lai
- Health Sciences Division, Abu Dhabi Women’s College, Higher Colleges of Technology, Abu Dhabi 41012, United Arab Emirates; (K.S.L.); (S.H.E.L.)
| | - Cheng-Wan Hee
- Faculty of Health and Life Sciences, INTI International University, Persiaran Perdana BBN, Putra Nilai, Nilai 71800, Malaysia;
| | - Jiun Yan Loh
- Centre of Research for Advanced Aquaculture (CORAA), UCSI University, Cheras, Kuala Lumpur 56000, Malaysia;
| | - Swee Hua Erin Lim
- Health Sciences Division, Abu Dhabi Women’s College, Higher Colleges of Technology, Abu Dhabi 41012, United Arab Emirates; (K.S.L.); (S.H.E.L.)
| | - Maran Sathiya
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Subang Jaya 47500, Malaysia;
- Correspondence:
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Lim SW, Tan KJ, Azuraidi OM, Sathiya M, Lim EC, Lai KS, Yap WS, Afizan NARNM. Functional and structural analysis of non-synonymous single nucleotide polymorphisms (nsSNPs) in the MYB oncoproteins associated with human cancer. Sci Rep 2021; 11:24206. [PMID: 34921182 PMCID: PMC8683427 DOI: 10.1038/s41598-021-03624-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/26/2021] [Indexed: 12/17/2022] Open
Abstract
MYB proteins are highly conserved DNA-binding domains (DBD) and mutations in MYB oncoproteins have been reported to cause aberrant and augmented cancer progression. Identification of MYB molecular biomarkers predictive of cancer progression can be used for improving cancer management. To address this, a biomarker discovery pipeline was employed in investigating deleterious non-synonymous single nucleotide polymorphisms (nsSNPs) in predicting damaging and potential alterations on the properties of proteins. The nsSNP of the MYB family; MYB, MYBL1, and MYBL2 was extracted from the NCBI database. Five in silico tools (PROVEAN, SIFT, PolyPhen-2, SNPs&GO and PhD-SNP) were utilized to investigate the outcomes of nsSNPs. A total of 45 nsSNPs were predicted as high-risk and damaging, and were subjected to PMut and I-Mutant 2.0 for protein stability analysis. This resulted in 32 nsSNPs with decreased stability with a DDG score lower than - 0.5, indicating damaging effect. G111S, N183S, G122S, and S178C located within the helix-turn-helix (HTH) domain were predicted to be conserved, further posttranslational modifications and 3-D protein analysis indicated these nsSNPs to shift DNA-binding specificity of the protein thus altering the protein function. Findings from this study would help in the field of pharmacogenomic and cancer therapy towards better intervention and management of cancer.
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Affiliation(s)
- Shu Wen Lim
- Faculty of Applied Sciences, UCSI University, No. 1, Jalan Menara Gading UCSI Height, 56000, Cheras, Kuala Lumpur, Malaysia
| | - Kennet JunKai Tan
- Faculty of Applied Sciences, UCSI University, No. 1, Jalan Menara Gading UCSI Height, 56000, Cheras, Kuala Lumpur, Malaysia
| | - Osman Mohd Azuraidi
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, 43400, Serdang, Selangor, Malaysia
| | - Maran Sathiya
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia
| | - Ee Chen Lim
- Faculty of Applied Sciences, UCSI University, No. 1, Jalan Menara Gading UCSI Height, 56000, Cheras, Kuala Lumpur, Malaysia
| | - Kok Song Lai
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, 41012, Abu Dhabi, United Arab Emirates
| | - Wai-Sum Yap
- Faculty of Applied Sciences, UCSI University, No. 1, Jalan Menara Gading UCSI Height, 56000, Cheras, Kuala Lumpur, Malaysia.
| | - Nik Abd Rahman Nik Mohd Afizan
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, 43400, Serdang, Selangor, Malaysia.
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Ashaari NS, Ab Rahim MH, Sabri S, Lai KS, Song AAL, Abdul Rahim R, Ong Abdullah J. Kinetic studies and homology modeling of a dual-substrate linalool/nerolidol synthase from Plectranthus amboinicus. Sci Rep 2021; 11:17094. [PMID: 34429465 PMCID: PMC8385045 DOI: 10.1038/s41598-021-96524-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 08/11/2021] [Indexed: 02/07/2023] Open
Abstract
Linalool and nerolidol are terpene alcohols that occur naturally in many aromatic plants and are commonly used in food and cosmetic industries as flavors and fragrances. In plants, linalool and nerolidol are biosynthesized as a result of respective linalool synthase and nerolidol synthase, or a single linalool/nerolidol synthase. In our previous work, we have isolated a linalool/nerolidol synthase (designated as PamTps1) from a local herbal plant, Plectranthus amboinicus, and successfully demonstrated the production of linalool and nerolidol in an Escherichia coli system. In this work, the biochemical properties of PamTps1 were analyzed, and its 3D homology model with the docking positions of its substrates, geranyl pyrophosphate (C10) and farnesyl pyrophosphate (C15) in the active site were constructed. PamTps1 exhibited the highest enzymatic activity at an optimal pH and temperature of 6.5 and 30 °C, respectively, and in the presence of 20 mM magnesium as a cofactor. The Michaelis-Menten constant (Km) and catalytic efficiency (kcat/Km) values of 16.72 ± 1.32 µM and 9.57 × 10-3 µM-1 s-1, respectively, showed that PamTps1 had a higher binding affinity and specificity for GPP instead of FPP as expected for a monoterpene synthase. The PamTps1 exhibits feature of a class I terpene synthase fold that made up of α-helices architecture with N-terminal domain and catalytic C-terminal domain. Nine aromatic residues (W268, Y272, Y299, F371, Y378, Y379, F447, Y517 and Y523) outlined the hydrophobic walls of the active site cavity, whilst residues from the RRx8W motif, RxR motif, H-α1 and J-K loops formed the active site lid that shielded the highly reactive carbocationic intermediates from the solvents. The dual substrates use by PamTps1 was hypothesized to be possible due to the architecture and residues lining the catalytic site that can accommodate larger substrate (FPP) as demonstrated by the protein modelling and docking analysis. This model serves as a first glimpse into the structural insights of the PamTps1 catalytic active site as a multi-substrate linalool/nerolidol synthase.
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Affiliation(s)
- Nur Suhanawati Ashaari
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia
| | - Mohd Hairul Ab Rahim
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia
- Department of Industrial Biotechnology, Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, 26300, Gambang, Kuantan, Pahang, Malaysia
| | - Suriana Sabri
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia
| | - Kok Song Lai
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, 41012, Abu Dhabi, United Arab Emirates
| | - Adelene Ai-Lian Song
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia
| | - Raha Abdul Rahim
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia
| | - Janna Ong Abdullah
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia.
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Foo RQ, Ahmad S, Lai KS, Idrus Z, Yusoff K, Liang JB. Palm Kernel Cake Oligosaccharides Acute Toxicity and Effects on Nitric Oxide Levels Using a Zebrafish Larvae Model. Front Physiol 2020; 11:555122. [PMID: 33071816 PMCID: PMC7541901 DOI: 10.3389/fphys.2020.555122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/02/2020] [Indexed: 01/19/2023] Open
Abstract
One of the beneficial effects of non-digestible oligosaccharides (NDOs) is their anti-inflammatory effects on host animals. While conventional animal studies require that analysis be done after samples have been taken from the host, zebrafish larvae are optically transparent upon hatching and this provides an opportunity for observations to be made within the living zebrafish larvae. This study aimed to take advantage of the optical transparency of zebrafish larvae to study the nitric oxide (NO) reducing effects of NDOs through the use of lipopolysaccharide (LPS) from Salmonella enterica serovar (ser.) Enteritidis (S. Enteritidis) to induce cardiac NO production. Prior to running the above experiment, an acute toxicity assay was conducted in order to determine the appropriate concentration of oligosaccharides to be used. The oligosaccharides tested consisted of oligosaccharides which were extracted from palm kernel cake with a degree of polymerization (DP) equal to or less than six (OligoPKC), commercial mannanoligosaccharide (MOS) and commercial fructooligosaccharide (FOS). Acute toxicity test results revealed that the OligoPKC has a LC50 of 488.1 μg/ml while both MOS and FOS were non-toxic up to 1,000 μg/ml. Results of the in vivo NO measurements revealed that all three NDOs were capable of significantly reducing NO levels in LPS stimulated zebrafish embryos. In summary, at 250 μg/ml, OligoPKC was comparable to MOS and better than FOS at lowering NO in LPS induced zebrafish larvae. However, at higher doses, OligoPKC appears toxic to zebrafish larvae. This implies that the therapeutic potential of OligoPKC is limited by its toxicity.
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Affiliation(s)
- Rui Qing Foo
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Kuala Lumpur, Malaysia
| | - Syahida Ahmad
- Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Kuala Lumpur, Malaysia
| | - Kok Song Lai
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, Abu Dhabi, United Arab Emirates
| | - Zulkifli Idrus
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Kuala Lumpur, Malaysia.,Office of the Deputy Vice Chancellor (Research & Innovation), Universiti Putra Malaysia, Kuala Lumpur, Malaysia
| | - Khatijah Yusoff
- Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Kuala Lumpur, Malaysia
| | - Juan Boo Liang
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Kuala Lumpur, Malaysia
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Ashaari NS, Ab. Rahim MH, Sabri S, Lai KS, Song AAL, Abdul Rahim R, Wan Abdullah WMAN, Ong Abdullah J. Functional characterization of a new terpene synthase from Plectranthus amboinicus. PLoS One 2020; 15:e0235416. [PMID: 32614884 PMCID: PMC7332032 DOI: 10.1371/journal.pone.0235416] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 06/15/2020] [Indexed: 12/21/2022] Open
Abstract
Plectranthus amboinicus (Lour.) Spreng is an aromatic medicinal herb known for its therapeutic and nutritional properties attributed by the presence of monoterpene and sesquiterpene compounds. Up until now, research on terpenoid biosynthesis has focused on a few mint species with economic importance such as thyme and oregano, yet the terpene synthases responsible for monoterpene production in P. amboinicus have not been described. Here we report the isolation, heterologous expression and functional characterization of a terpene synthase involved in P. amboinicus terpenoid biosynthesis. A putative monoterpene synthase gene (PamTps1) from P. amboinicus was isolated with an open reading frame of 1797 bp encoding a predicted protein of 598 amino acids with molecular weight of 69.6 kDa. PamTps1 shares 60–70% amino acid sequence similarity with other known terpene synthases of Lamiaceae. The in vitro enzymatic activity of PamTps1 demonstrated the conversion of geranyl pyrophosphate and farnesyl pyrophosphate exclusively into linalool and nerolidol, respectively, and thus PamTps1 was classified as a linalool/nerolidol synthase. In vivo activity of PamTps1 in a recombinant Escherichia coli strain revealed production of linalool and nerolidol which correlated with its in vitro activity. This outcome validated the multi-substrate usage of this enzyme in producing linalool and nerolidol both in in vivo and in vitro systems. The transcript level of PamTps1 was prominent in the leaf during daytime as compared to the stem. Gas chromatography-mass spectrometry (GC-MS) and quantitative real-time PCR analyses showed that maximal linalool level was released during the daytime and lower at night following a diurnal circadian pattern which correlated with the PamTps1 expression pattern. The PamTps1 cloned herein provides a molecular basis for the terpenoid biosynthesis in this local herb that could be exploited for valuable production using metabolic engineering in both microbial and plant systems.
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Affiliation(s)
- Nur Suhanawati Ashaari
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Mohd Hairul Ab. Rahim
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Suriana Sabri
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Kok Song Lai
- Health Sciences Division, Abu Dhabi Women’s College, Higher Colleges of Technology, Abu Dhabi, United Arab of Emirates
| | - Adelene Ai-Lian Song
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | - Raha Abdul Rahim
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Selangor, Malaysia
| | | | - Janna Ong Abdullah
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Selangor, Malaysia
- * E-mail:
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Foo RQ, Jahromi MF, Chen WL, Ahmad S, Lai KS, Idrus Z, Liang JB. Oligosaccharides from Palm Kernel Cake Enhances Adherence Inhibition and Intracellular Clearance of Salmonella enterica Serovar Enteritidis In Vitro. Microorganisms 2020; 8:E255. [PMID: 32075189 PMCID: PMC7074813 DOI: 10.3390/microorganisms8020255] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/16/2019] [Accepted: 12/19/2019] [Indexed: 01/15/2023] Open
Abstract
Salmonella enterica serovar (ser.) Enteritidis (S. Enteritidis) is a foodborne pathogen often associated with contaminated poultry products. This study evaluated the anti-adherence and intracellular clearance capability of oligosaccharides extracted from palm kernel cake (PKC), a by-product of the palm oil industry, and compared its efficacy with commercial prebiotics- fructooligosaccharide (FOS) and mannanoligosaccharide (MOS)-against S. Enteritidis in vitro. Based on the degree of polymerization (DP), PKC oligosaccharides were further divided into 'Small' (DP ≤ 6) and 'Big' (DP > 6) fractions. Results showed that the Small and Big PKC fractions were able to reduce (p < 0.05) S. Enteritidis adherence to Cancer coli-2 (Caco-2) cells at 0.1 mg/ mL while MOS and FOS showed significant reduction at 1.0 mg/mL and 10.0 mg/mL, respectively. In terms of S. Enteritidis clearance, oligosaccharide-treated macrophages showed better S. Enteritidis clearance over time at 50 µg/mL for Small, Big and MOS, while FOS required a concentration of 500 µg/mL for a similar effect. This data highlights that oligosaccharides from PKC, particularly those of lower DP, were more effective than MOS and FOS at reducing S. Enteritidis adherence and enhancing S. Enteritidis clearance in a cell culture model.
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Affiliation(s)
- Rui Qing Foo
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400 UPM, Selangor, Malaysia; (R.Q.F.); (M.F.J.); (W.L.C.); (Z.I.)
| | - Mohammad Faseleh Jahromi
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400 UPM, Selangor, Malaysia; (R.Q.F.); (M.F.J.); (W.L.C.); (Z.I.)
- Arianabiotech co. No 118, Parsian Industrial Zone, Mashad 9354195366, Khorasan Razavi, Iran
| | - Wei Li Chen
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400 UPM, Selangor, Malaysia; (R.Q.F.); (M.F.J.); (W.L.C.); (Z.I.)
| | - Syahida Ahmad
- Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400 UPM, Selangor, Malaysia;
| | - Kok Song Lai
- Health Sciences Division, Abu Dhabi Women’s College, Higher Colleges of Technology, Abu Dhabi 41012, UAE;
| | - Zulkifli Idrus
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400 UPM, Selangor, Malaysia; (R.Q.F.); (M.F.J.); (W.L.C.); (Z.I.)
- Office of the Deputy Vice Chancellor (Research & Innovation), Universiti Putra Malaysia, Serdang 43400 UPM, Selangor, Malaysia
| | - Juan Boo Liang
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400 UPM, Selangor, Malaysia; (R.Q.F.); (M.F.J.); (W.L.C.); (Z.I.)
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Tan ZQ, Leow HY, Lee DCW, Karisnan K, Song AAL, Mai CW, Yap WS, Lim SHE, Lai KS. Co-Culture Systems for the Production of Secondary Metabolites: Current and Future Prospects. ACTA ACUST UNITED AC 2019. [DOI: 10.2174/1874070701913010018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Microorganisms are the great sources of Natural Products (NPs); these are imperative to their survival apart from conferring competitiveness amongst each other within their environmental niches. Primary and secondary metabolites are the two major classes of NPs that help in cell development, where antimicrobial activity is closely linked with secondary metabolites. To capitalize on the effects of secondary metabolites, co-culture methods have been often used to develop an artificial microbial community that promotes the action of these metabolites. Different analytical techniques will subsequently be employed based on the metabolite specificity and sensitivity to further enhance the metabolite induction. Liquid Chromatography-Mass Spectrometry (LC-MS) and Gas Chromatography (GC)-MS are commonly used for metabolite separation while Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) have been used as tools to elucidate the structure of compounds. This review intends to discuss current systems in use for co-culture in addition to its advantages, with discourse into the investigation of specific techniques in use for the detailed study of secondary metabolites. Further advancements and focus on co-culture technologies are required to fully realize the massive potential in synthetic biological systems.
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Razali NA, Nazarudin NA, Lai KS, Abas F, Ahmad S. Curcumin derivative, 2,6-bis(2-fluorobenzylidene)cyclohexanone (MS65) inhibits interleukin-6 production through suppression of NF-κB and MAPK pathways in histamine-induced human keratinocytes cell (HaCaT). BMC Complement Altern Med 2018; 18:217. [PMID: 30012134 PMCID: PMC6048808 DOI: 10.1186/s12906-018-2223-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 04/27/2018] [Indexed: 12/29/2022]
Abstract
Background Histamine is a well-known mediator involved in skin allergic responses through up-regulation of pro-inflammatory cytokines. Antihistamines remain the mainstay of allergy treatment, but they were found limited in efficacy and associated with several common side effects. Therefore, alternative therapeutic preferences are derived from natural products in an effort to provide safe yet reliable anti-inflammatory agents. Curcumin and their derivatives are among compounds of interest in natural product research due to numerous pharmacological benefits including anti-inflammatory activities. Here, we investigate the effects of chemically synthesized curcumin derivative, 2,6-bis(2-fluorobenzylidene)cyclohexanone (MS65), in reducing cytokine production in histamine-induced HaCaT cells. Methods Interleukin (IL)-6 cytokine production in histamine-induced HaCaT cells were measured using enzyme-linked immunosorbent assay (ELISA) and cytotoxicity effects were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Real-time polymerase chain reaction (RT-qPCR) was carried out to determine the inhibitory effects of MS65 on nuclear factor-kappa B (NF-κB) and mitogen activated protein kinase (MAPK) pathways. Results Histamine enhanced IL-6 production in HaCaT cells, with the highest production of IL-6 at 97.41 ± 2.33 pg/mL after 24 h of exposure. MS65 demonstrated a promising anti-inflammatory activity by inhibiting IL-6 production with half maximal inhibitory concentration (IC50) value of 4.91 ± 2.50 μM and median lethal concentration (LC50) value of 28.82 ± 7.56 μM. In gene expression level, we found that MS65 inhibits NF-κB and MAPK pathways through suppression of IKK/IκB/NFκB and c-Raf/MEK/ERK inflammatory cascades. Conclusion Taken together, our results suggest that MS65 could be used as a lead compound on developing new medicinal agent for the treatment of allergic skin diseases.
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Daud NSM, Zaidel DNA, Lai KS, Khairuddin N, Jusoh YMM, Muhamad II. Crude Oil Yield and Properties of Rice Bran Oil from Different Varieties as Affected by Extraction Conditions Using Soxhterm Method. Arab J Sci Eng 2018. [DOI: 10.1007/s13369-018-3438-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Yap WS, Yeo YL, Lai KS, Wee CY. Epigenetic of DNA Methylation Patterns in Lowland and Upland Malaysian Rice Cultivars under Induced Drought and Salinity. N Biotechnol 2016. [DOI: 10.1016/j.nbt.2016.06.1299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Phua PB, Tan BS, Wu RF, Lai KS, Chia L, Lau E. High-average-power mid-infrared ZnGeP2 optical parametric oscillator with a wavelength-dependent polarization rotator. Opt Lett 2006; 31:489-91. [PMID: 16496896 DOI: 10.1364/ol.31.000489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A wavelength-dependent polarization rotator is used to transform the orthogonal polarizations of the signal and idler of a near-degenerate type II KTP optical parametric oscillator (OPO) into a common polarization state. This common polarization allows a single ZnGeP2 OPO to fully utilize the 2 microm signal and idler KTP OPO outputs in a mid-IR conversion. The simple design of the wavelength-dependent polarization rotator yields a compact source that simultaneously generates four mid-JR wavelengths collinearly with a total mid-IR average power of 5.5 W at a >15 kHz pulse repetition rate.
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Affiliation(s)
- P B Phua
- DSO National Laboratories, 20, Science Park Drive, S118230 Singapore.
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Wu RF, Lai KS, Wong H, Xie WJ, Lim Y, Lau E. Multiwatt mid-IR output from a Nd:YALO laser pumped intracavity KTA OPO. Opt Express 2001; 8:694-698. [PMID: 19421260 DOI: 10.1364/oe.8.000694] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have achieved 4.1W of 3.5-micron output from a non-critically phasematched (NCPM), type II, KTiOAsO4 (KTA) optical parametric oscillator (OPO) pumped within the cavity of a Q-switched diode-pumped Nd: YALO laser operating at 10kHz. We adopted the simplest configuration with a compact diode-pumped Nd: YALO module pumping the singly resonant KTA OPO. Besides 4.1W of 3.5um, 10.9W of 1.5 micron and 11.3W of 1-micron radiation were obtained simultaneously.
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Abstract
We present a 120-W cw diode-pumped Tm:YAG laser. The Tm:YAG rod is side pumped by three diode arrays whose radiation is coupled through compound parabolic concentrators. The maximum optical-to-optical conversion efficiency of the 2.02-mum laser output is 25.2%, with a slope efficiency of 31.2%.
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Affiliation(s)
- K S Lai
- DSO National Laboratories, 20, Science Park Drive, S118230, Singapore
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Wu RF, Phua PB, Lai KS, Lim YL, Lau E, Chng A, Bonnin C, Lupinski D. Compact 21-W 2-mum intracavity optical parametric oscillator. Opt Lett 2000; 25:1460-1462. [PMID: 18066248 DOI: 10.1364/ol.25.001460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report on an intracavity optical parametric oscillator (OPO) placed within a compact diode-pumped Nd:YALO laser cavity. This OPO utilizes a pair of KTP crystals, which are diffusion bonded together in a walk-off-compensated configuration. We have generated up to 21.4 W of 2-mum radiation, operating in a few-kilohertz range.
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Phua PB, Lai KS, Wu R. Multiwatt High-Repetition-Rate 2-microm Output from an Intracavity KTiOPO(4) Optical Parametric Oscillator. Appl Opt 2000; 39:1435-1439. [PMID: 18338029 DOI: 10.1364/ao.39.001435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We have obtained 6.5 W of 2-mum output from a near-degenerate, type II KTiOPO(4) (KTP) optical parametric oscillator (OPO) pumped within the cavity of a Q-switched diode-pumped Nd:YAG laser that operates at 3 kHz. We adopted the simplest configuration with a compact diode-pumped Nd:YAG module pumping the doubly resonant KTP OPO in its randomly polarized resonator with an acousto-optic Q switch. Attempts to increase the 2-mum output power by pumping this intracavity KTP OPO with a polarized laser beam by use of thermal birefringence compensation configurations are discussed.
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Abstract
We demonstrate a compact cw diode-pumped Nd:YAlO laser that can produce 100 W of power at 1079 nm and 18.3 W at 1341 nm. Lasing and nonlasing thermal lensing data are presented.
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Affiliation(s)
- R Wu
- DSO National Laboratories, 20 Science Park Drive, S118230 Singapore, Singapore.
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Phua PB, Lai KS, Wu RF, Chong TC. High-efficiency mid-infrared ZnGeP2 optical parametric oscillator in a multimode-pumped tandem optical parametric oscillator. Appl Opt 1999; 38:563-565. [PMID: 18305647 DOI: 10.1364/ao.38.000563] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We demonstrate a high-efficiency ZnGeP(2) optical parametric oscillator (OPO) pumped by another KTP OPO in a multimode-pumped tandem OPO configuration. The maximum optical-to-optical and slope efficiencies were 32% and 42.5%, respectively. Our setup also provides tunable multiband radiation in the 2.03-2.32-microm range and the 2.9-6.2-microm range simultaneously.
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Affiliation(s)
- P B Phua
- DSO National Laboratories, 20 Science Park Drive, Singapore.
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18
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Maccabee PJ, Nagarajan SS, Amassian VE, Durand DM, Szabo AZ, Ahad AB, Cracco RQ, Lai KS, Eberle LP. Influence of pulse sequence, polarity and amplitude on magnetic stimulation of human and porcine peripheral nerve. J Physiol 1998; 513 ( Pt 2):571-85. [PMID: 9807005 PMCID: PMC2231292 DOI: 10.1111/j.1469-7793.1998.571bb.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/1997] [Accepted: 08/13/1998] [Indexed: 10/26/2022] Open
Abstract
1. Mammalian phrenic nerve, in a trough filled with saline, was excited by magnetic coil (MC)-induced stimuli at defined stimulation sites, including the negative-going first spatial derivative of the induced electric field along a straight nerve, at a bend in the nerve, and at a cut nerve ending. At all such sites, the largest amplitude response for a given stimulator output setting was elicited by an induced damped polyphasic pulse consisting of an initial quarter-cycle hyperpolarization followed by a half-cycle depolarization compared with a predominantly 'monophasic' quarter-cycle depolarization. 2. Simulation studies demonstrated that the increased efficacy of the induced quarter-cycle hyperpolarizing-half-cycle depolarizing polyphasic pulse was mainly attributed to the greater duration of the outward membrane current phase, resulting in a greater outward charge transfer afforded by the half-cycle (i.e. quarter-cycles 2 and 3). The advantage of a fast rising initial quarter-cycle depolarization was more than offset by the slower rising, but longer duration depolarizing half-cycle. 3. Simulation further revealed that the quarter-cycle hyperpolarization-half-cycle depolarization showed only a 2.6 % lowering of peak outward current and a 3.5 % lowering of outward charge transfer at threshold, compared with a half-cycle depolarization alone. Presumably, this slight increase in efficacy reflects modest reversal of Na+ inactivation by the very brief initial hyperpolarization. 4. In vitro, at low bath temperature, the nerve response to an initial quarter-cycle depolarization declined in amplitude as the second hyperpolarizing phase progressively increased in amplitude and duration. This 'pull-down' phenomenon nearly disappeared as the bath temperature approached 37 C. Possibly, at the reduced temperature, delay in generation of the action potential permitted the hyperpolarization phase to reduce excitation. 5. Pull-down was not observed in the thenar muscle responses to median nerve stimulation in a normal human at normal temperature. However, pull-down emerged when the median nerve was cooled by placing ice over the forearm. 6. In a nerve at subnormal temperature straddled with non-conducting inhomogeneities, polyphasic pulses of either polarity elicited the largest responses. This was also seen when stimulating distal median nerve at normal temperature. These results imply excitation by hyperpolarizing-depolarizing pulse sequences at two separate sites. Similarly, polyphasic pulses elicited the largest responses from nerve roots and motor cortex. 7. The pull-down phenomenon has a possible clinical application in detecting pathologically slowed activation of Na+ channels. The current direction of the polyphasic waveform may become a significant factor with the increasing use of repetitive magnetic stimulators which, for technical reasons, induce a cosine-shaped half-cycle, preceded and followed by quarter-cycles of opposite polarity.
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Affiliation(s)
- P J Maccabee
- Departments of Neurology and Physiology, State University of New York, Health Science Centre at Brooklyn, 450 Clarkson Avenue, Brooklyn, NY 11203-2098,
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19
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Phua PB, Lai KS, Wu RF, Chong TC. Coupled tandem optical parametric oscillator (OPO): an OPO within an OPO. Opt Lett 1998; 23:1262-1264. [PMID: 18087492 DOI: 10.1364/ol.23.001262] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We have demonstrated, for the first time to our knowledge, a coupled tandem optical parametric oscillator (OPO) configuration in which a second ZnGeP(2) OPO is placed within the resonator of the first, KTiOPO(4), OPO. A significant enhancement in the overall cascaded efficiency of this OPO compared with standard two-stage OPO's was observed. With a multimode Nd:YAG laser, an overall optical-to-optical efficiency (from 1.06 microm to the mid IR) of 5.2% was obtained from operating only ~1.4 times above oscillation threshold. The measured overall slope efficiency was attractively high at 35%. With a single set of mirrors we obtained a broad wavelength-tuning range from 2.7 to 8 microm.
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21
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Zhou Y, Chin MK, Lai KS, Wong CC. Low-loss measurement in partially buried opticalwaveguideson glass with a plastic prism. Appl Opt 1997; 36:5089-5090. [PMID: 18259320 DOI: 10.1364/ao.36.005089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Surface and buried planar waveguides have been fabricated in glass microscope slides with purely thermal potassium and sodium ion-exchange techniques. We measured propagation loss as low as 0.08 dB/cm in the partially buried waveguides using an improved two-prism coupling method. The method includes a plastic prism and involves applying heat to soften the base of the outcoupling plastic prism so that the prism is temporarily in extremely close contact with the waveguide surface.
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Hoffman SM, Lai KS, Tomfohrde J, Bowcock A, Gordon LA, Mohrenweiser HW. JAK3 maps to human chromosome 19p12 within a cluster of proto-oncogenes and transcription factors. Genomics 1997; 43:109-11. [PMID: 9226382 DOI: 10.1006/geno.1997.4792] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- S M Hoffman
- Human Genome Center, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
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Lai KS, Jin Y, Graham DK, Witthuhn BA, Ihle JN, Liu ET. A kinase-deficient splice variant of the human JAK3 is expressed in hematopoietic and epithelial cancer cells. J Biol Chem 1995; 270:25028-36. [PMID: 7559633 DOI: 10.1074/jbc.270.42.25028] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Signal transduction of cytokine receptors is mediated by the JAK family of tyrosine kinases. Recently, the kinase partners for the interleukin (IL)-2 receptor have been identified as JAK1 and JAK3. In this study, we report the identification of splice variants that may modulate JAK3 signaling. Three splice variants were isolated from different mRNA sources: breast (B), spleen (S), and activated monocytes (M). Sequence analysis revealed that the splice variants contain identical NH2-terminal regions but diverge at the COOH termini. Analyses of expression of the JAK3 splice isoforms by reverse transcriptase-polymerase chain reaction on a panel of cell lines show splice preferences in different cell lines: the S-form is more commonly seen in hematopoietic lines, whereas the B- and M-forms are detected in cells both of hematopoietic and epithelial origins. Antibodies raised against peptides to the B-form splice variant confirmed that the 125-kDa JAK3B protein product is found abundantly in hematopoietic as well as epithelial cells, including primary breast cancers. The lack of subdomain XI in the tyrosine kinase core of the B-form JAK3 protein suggests that it is a defective kinase. This is supported by the lack of detected autokinase activity of the B-form JAK3. Intriguingly, both the S and B splice isoforms of JAK3 appear to co-immunoprecipitate with the IL-2 receptor from HUT-78 cell lysates. This and the presence of multiple COOH-terminal splice variants coexpressed in the same cells suggest that the JAK3 splice isoforms are functional in JAK3 signaling and may enrich the complexity of the intracellular responses functional in IL-2 or cytokine signaling.
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Affiliation(s)
- K S Lai
- Department of Biology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill 27599-7295, USA
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Witthuhn BA, Silvennoinen O, Miura O, Lai KS, Cwik C, Liu ET, Ihle JN. Involvement of the Jak-3 Janus kinase in signalling by interleukins 2 and 4 in lymphoid and myeloid cells. Nature 1994; 370:153-7. [PMID: 8022486 DOI: 10.1038/370153a0] [Citation(s) in RCA: 527] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Many cytokines function through interaction with receptors of the cytokine receptor superfamily. Although lacking catalytic domains, cytokine receptors couple ligand binding to induction of protein tyrosine phosphorylation. Recent studies have shown that one or more of the Janus kinase family members (Jaks) associate with cytokine receptors and are tyrosine phosphorylated and activated following ligand binding. Here we describe a new Jak family kinase, Jak-3, and demonstrate that Jak-3, and to a lesser extent Jak-1, are tyrosine phosphorylated and Jak-3 is activated in the responses to interleukin-2 and interleukin-4 in T cells and myeloid cells. Jak-3 activation requires the serine-rich, membrane-proximal domain of the interleukin-2 receptor beta-chain, but does not require the acidic domain that is required for association and activation of Src family kinases.
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Affiliation(s)
- B A Witthuhn
- Department of Biochemistry, St Jude Children's Research Hospital, Memphis, Tennessee 38105
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25
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Zhao Z, France RH, Lai KS, Gai M, Wilds EL, Kryger RA, Winger JA, Beard KB. Study of the beta-delayed alpha-particle emission of 16N. Phys Rev C Nucl Phys 1993; 48:429-432. [PMID: 9968837 DOI: 10.1103/physrevc.48.429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Zhao Z, France RH, Lai KS, Rugari SL, Gai M, Wilds EL. Astrophysical S factor of 12C( alpha, gamma )16O from the beta-delayed alpha-particle emission of 16N. Phys Rev Lett 1993; 70:2066-2069. [PMID: 10053462 DOI: 10.1103/physrevlett.70.2066] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Lai KS, Jaweed MM, Seestead R, Herbison GJ, Ditunno JF, McCully K, Chance B. Changes in nerve conduction and Pi/PCr ratio during denervation-reinnervation of the gastrocsoleus muscles of rats. Arch Phys Med Rehabil 1992; 73:1155-9. [PMID: 1463379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The purpose of this investigation was to study the changes in nerve conduction and phosphate metabolites of the gastrocsoleus muscles of rats during denervation-reinnervation. Sixteen male Sprague-Dawley rats underwent unilateral crush-denervation of the left sciatic nerves at the sciatic notch. Six rats were used for measurement of motor conduction latency and action potential amplitude of the gastrocsoleus muscle by stimulating the sciatic nerve at one, two and eight weeks after nerve crush. The other ten rats were designated for evaluation of the ratio of inorganic phosphorous (Pi) to phosphocreatine (PCr) by a 31P-phosphoenergetic spectrometer at two weeks and eight weeks after nerve crush. None of the sciatic nerves showed conduction to the gastrocsoleus at one or two weeks after nerve crush. At eight weeks postcrush, the motor conduction latency returned to within normal limits, whereas the action potential amplitude was only 55% of the normal. For the eight-week period of study, the Pi/PCr ratio of the normal control muscles ranged between 0.09 +/- 0.02 and 0.11 +/- 0.02 (mean +/- SD). The denervated muscles showed an increase of Pi/PCr ratio by 54% at two weeks postcrush, compared to the respective contralateral control sides. The ratios returned to the normal value by eight weeks postcrush. In summary, these data suggested that the metabolic recovery of the crush-denervated muscle followed the same pattern as the parameters of nerve conduction.
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Affiliation(s)
- K S Lai
- Department of Rehabilitation Medicine, Thomas Jefferson University Hospital, Philadelphia
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28
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Abstract
The subcellular distribution of Giardia lamblia virus RNA in infected G. lamblia trophozoites was examined by in situ hybridization using biotinylated DNA probe and riboprobe. In G. lamblia Portland I strain, which is chronically infected by G. lamblia viruses, the viral RNA was detected in the cytoplasm as well as in the twin nuclei. When riboprobe was used to examine the course of virus infection in WB strain, accumulation of viral RNA was detected only in the cytoplasm prior to the first 72 hr of infection. Using DNA probe, further accumulation of viral RNA in increasing number of cells occurred after the 72nd hr of infection, with the RNA found in both the cytoplasm and nuclei. Eventually, the cell nuclei showed damaged morphology that deteriorated rapidly toward the final stage of infection. These observations indicate that early phase of viral RNA replication may take place in the cytoplasm of infected G. lamblia, but the nuclei are also involved during the late phase of viral replication.
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Affiliation(s)
- J H Tai
- Molecular Parasitology Laboratory, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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Maccabee PJ, Amassian VE, Eberle LP, Rudell AP, Cracco RQ, Lai KS, Somasundarum M. Measurement of the electric field induced into inhomogeneous volume conductors by magnetic coils: application to human spinal neurogeometry. Electroencephalogr Clin Neurophysiol 1991; 81:224-37. [PMID: 1710972 DOI: 10.1016/0168-5597(91)90076-a] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We measured the electric fields induced by round and figure "8" magnetic coils (MCs) in homogeneous and inhomogeneous volume conductors. In homogeneous media, the round MC held tangential (i.e., flat) to the volume conductor induced an annular electric field. When the round MC was held on-edge (i.e., orthogonal) to the volume conductor, the induced electric field consisted of two loops mainly parallel to the surface of the volume conductor and which approximated each other directly under the contacting edge of the MC. The tangentially oriented figure "8" MC similarly induced two electric field loops which approximated one another maximally under the region of the junction in its long axis. In a complex inhomogeneous volume conductor, such as a segment of human cervical-thoracic vertebral spine located eccentrically within a large cylindrical tank and submerged in isotonic saline, the direction of electric fields within the spinal canal and across the intervertebral neuroforamina was similar to that observed in the homogeneous volume conductor. However, in and near a single neuroforamen, the electric field and especially its first spatial derivative were markedly elevated compared to that recorded within the long central axis of the vertebral canal. Motor unit and compound muscle action potentials elicited in limb muscles by MC stimulation of human cervical spine confirmed predictions derived from the physical model. The predictions included: (1) absence of spinal cord stimulation compared to relative ease of nerve root stimulation by current that is most likely concentrated at the neuroforamina. When stimulating current is directed towards the periphery, the most likely low threshold site of stimulation is inferred to be just distal to the neuroforamina. It is emphasized that with supramaximal stimulation, more distal sites of excitation may occur; (2) invariant latency shifts at threshold intensities when moving the MC along the rostrocaudal axis of the cervical vertebral column; (3) significant effect (on motor unit activation thresholds) of the direction of induced current flow across the neuroforamina; (4) reduced stimulation when the targeted nerve roots are close to the null point of the electric field, i.e., between locations of high electric field intensity, of opposite polarity; and (5) relatively focal nerve root stimulation by the junction of a transversely orientated figure "8" MC, i.e., parallel to the nerve roots.
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Affiliation(s)
- P J Maccabee
- Department of Neurology, SUNY Health Science Center, Brooklyn 11203
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Chang KW, Chang CS, Lai KS, Chou MJ, Choo KB. High prevalence of human papillomavirus infection and possible association with betel quid chewing and smoking in oral epidermoid carcinomas in Taiwan. J Med Virol 1989; 28:57-61. [PMID: 2542446 DOI: 10.1002/jmv.1890280113] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Seventeen oral epidermoid carcinomas, three oral papillomas, and 17 normal gingival tissues were tested for the presence of human papillomavirus (HPV) types 6, 11, 16, and 18 sequences by Southern blot hybridization. Episomal HPV-16 sequences in various amounts were detected in 76.4% of the oral carcinomas and in all three cases of papilloma. However, only one of the 17 normal tissues was HPV positive with an unknown type. None of the samples contained HPV-6, -11, or -18 sequences. Examination of the habits of the patients showed that 59% of the patients were betel quid chewers and 82% were smokers. Thus, the concurrent incidence of HPV infection and betal quid chewing and/or smoking habits in oral carcinoma patients observed in Taiwan is consistent with the view that both viral and chemical factors may be involved in the process of carcinogenesis.
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Affiliation(s)
- K W Chang
- Department of Medical Research, Veterans General Hospital, Taipei, Taiwan, Republic of China
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Abstract
The appearance of rapidly flowing blood on imaging (MRI) was evaluated using flow phantoms and dye infusion experiments. Laminar flow can be maintained at high velocities in small-diameter vessels. Under such conditions, flow-related enhancement may be observed several slices into a multislice imaging volume. Decreasing cross-sectional area of the unsaturated protons in the midstream is noted on slices further removed from the entry surface. As the velocity increases, turbulence occurs. The increased random motion of the protons causes loss of intensity on the first-echo image, although rephasing with increased intensity can be noted on the second-echo image. The flow pattern of a simple intraluminal obstruction is demonstrated by MRI and dye infusion experiments. Rephasing is noted within the eddy downstream from the obstruction. Clinical examples of the phantom findings are shown and applications are discussed.
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Abstract
A case is presented of the rare adult form of Niemann-Pick disease occurring in a Cantonese. The diagnosis was verified by biochemical analysis of the affected tissues.
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Pearson GP, Lai KS, Jones DF. Effect of barium sulphate on strength of bone cement. Lancet 1976; 2:207. [PMID: 73834 DOI: 10.1016/s0140-6736(76)92388-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Lee SP, Lai KS. Exocrine pancreatic function in hepatic cirrhosis. Am J Gastroenterol 1976; 65:244-8. [PMID: 937324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Exocrine pancreatic function was assessed by the standard test meal method of Lundh in a control group, and 13 patients with nonalcoholic, postnecrotic cirrhosis of the liver. In six of these patients, splenorenal shunts were performed and exocrine pancreatic function was assessed before and three months after operation. In three of the six, the secretin-pancreozymin stimulation test was also performed. An increased volume but normal trypsin output was observed in the unoperated cirrhotic patients. An increase both in volume and in trypsin was found in the cirrhotic patients after shunting using the test meal stimulation. There was no appreciable difference, however, when tested with secretin and pancreozymin. Hypersecretion in cirrhotics, with or without shunts, is probably due to a by-pass of the hepatic degradation of normal pancreatic secretogogues produced by the intestine.
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