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Tan LP, Tan GW, Sivanesan VM, Goh SL, Ng XJ, Lim CS, Kim WR, Mohidin TBBM, Mohd Dali NS, Ong SH, Wong CY, Sawali H, Yap YY, Hassan F, Pua KC, Koay CE, Ng CC, Khoo ASB. Systematic comparison of plasma EBV DNA, anti-EBV antibodies and miRNA levels for early detection and prognosis of nasopharyngeal carcinoma. Int J Cancer 2019; 146:2336-2347. [PMID: 31469434 PMCID: PMC7065012 DOI: 10.1002/ijc.32656] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [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: 03/08/2019] [Revised: 07/17/2019] [Accepted: 08/15/2019] [Indexed: 12/31/2022]
Abstract
Nasopharyngeal carcinoma (NPC) is originated from the epithelial cells of nasopharynx, Epstein–Barr virus (EBV)‐associated and has the highest incidence and mortality rates in Southeast Asia. Late presentation is a common issue and early detection could be the key to reduce the disease burden. Sensitivity of plasma EBV DNA, an established NPC biomarker, for Stage I NPC is controversial. Most newly reported NPC biomarkers have neither been externally validated nor compared to the established ones. This causes difficulty in planning for cost‐effective early detection strategies. Our study systematically evaluated six established and four new biomarkers in NPC cases, population controls and hospital controls. We showed that BamHI‐W 76 bp remains the most sensitive plasma biomarker, with 96.7% (29/30), 96.7% (58/60) and 97.4% (226/232) sensitivity to detect Stage I, early stage and all NPC, respectively. Its specificity was 94.2% (113/120) against population controls and 90.4% (113/125) against hospital controls. Diagnostic accuracy of BamHI‐W 121 bp and ebv‐miR‐BART7‐3p were validated. Hsa‐miR‐29a‐3p and hsa‐miR‐103a‐3p were not, possibly due to lower number of advanced stage NPC cases included in this subset. Decision tree modeling suggested that combination of BamHI‐W 76 bp and VCA IgA or EA IgG may increase the specificity or sensitivity to detect NPC. EBNA1 99 bp could identify NPC patients with poor prognosis in early and advanced stage NPC. Our findings provided evidence for improvement in NPC screening strategies, covering considerations of opportunistic screening, combining biomarkers to increase sensitivity or specificity and testing biomarkers from single sampled specimen to avoid logistic problems of resampling. What's new? Plasma Epstein–Barr virus (EBV) DNA is an established nasopharyngeal carcinoma (NPC) biomarker, but not all cases are associated with EBV and its sensitivity for stage I NPC remains controversial. Meanwhile, most newly‐reported NPC biomarkers have neither been externally validated nor compared to established biomarkers. This study systematically evaluates six established and four new biomarkers in NPC cases, population controls, and hospital controls. The findings provide evidence to policymakers for improvement in NPC screening and monitoring strategies, covering considerations of opportunistic screening, combining biomarkers to increase sensitivity/specificity, and testing multiple biomarkers on single specimens to avoid the logistic problems of resampling.
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Affiliation(s)
- Lu Ping Tan
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Kuala Lumpur, Malaysia.,Department of Medical Sciences, School of Healthcare and Medical Sciences, Sunway University, Selangor, Malaysia
| | - Geok Wee Tan
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Kuala Lumpur, Malaysia.,Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Vijaya Mohan Sivanesan
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Kuala Lumpur, Malaysia
| | - Siang Ling Goh
- Faculty of Science, University of Malaya, Institute of Biological Sciences, Kuala Lumpur, Malaysia
| | - Xun Jin Ng
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Kuala Lumpur, Malaysia
| | - Chun Shen Lim
- Faculty of Science, University of Malaya, Institute of Biological Sciences, Kuala Lumpur, Malaysia.,Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Wee Ric Kim
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Kuala Lumpur, Malaysia
| | | | - Nor Soleha Mohd Dali
- Haematology Unit, Cancer Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Kuala Lumpur, Malaysia
| | - Siew Hoon Ong
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Kuala Lumpur, Malaysia
| | - Chun Ying Wong
- Department of Otorhinolaryngology, Sarawak General Hospital, Ministry of Health Malaysia, Jalan Hospital, Kuching, Sarawak, Malaysia
| | - Halimuddin Sawali
- Department of Otorhinolaryngology, Queen Elizabeth Hospital, Ministry of Health Malaysia, Kota Kinabalu, Sabah, Malaysia
| | - Yoke Yeow Yap
- Department of Otorhinolaryngology, Kuala Lumpur Hospital, Ministry of Health Malaysia, Kuala Lumpur, Malaysia.,Department of Surgery, Clinical Campus Faculty of Medicine and Health Sciences, University Putra Malaysia at Kuala Lumpur Hospital, Ministry of Health Malaysia, Kuala Lumpur, Malaysia
| | - Faridah Hassan
- Department of Otorhinolaryngology, Selayang Hospital, Ministry of Health Malaysia, Batu Caves, Selangor, Malaysia
| | - Kin Choo Pua
- Department of Otorhinolaryngology, Pulau Pinang Hospital, Ministry of Health Malaysia, Georgetown, Pulau Pinang, Malaysia
| | - Cheng Eng Koay
- Gleneagles Kuala Lumpur Hospital, Kuala Lumpur, Malaysia.,Sunway Medical Centre, Bandar Sunway, Selangor, Malaysia
| | - Ching Ching Ng
- Faculty of Science, University of Malaya, Institute of Biological Sciences, Kuala Lumpur, Malaysia
| | - Alan Soo-Beng Khoo
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Kuala Lumpur, Malaysia
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Lim CS, Goh SL, Kariapper L, Krishnan G, Lim YY, Ng CC. Inclusion bodies of recombinant Epstein-Barr virus capsid antigen p18 as potential immobilized antigens in enzyme immunoassays for detection of nasopharyngeal carcinoma. Clin Chim Acta 2015; 448:206-10. [PMID: 26164385 DOI: 10.1016/j.cca.2015.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/07/2015] [Accepted: 07/07/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND Development of indirect enzyme-linked immunosorbent assays (ELISAs) often utilizes synthetic peptides or recombinant proteins from Escherichia coli as immobilized antigens. Because inclusion bodies (IBs) formed during recombinant protein expression in E. coli are commonly thought as misfolded aggregates, only refolded proteins from IBs are used to develop new or in-house diagnostic assays. However, the promising utilities of IBs as nanomaterials and immobilized enzymes as shown in recent studies have led us to explore the potential use of IBs of recombinant Epstein-Barr virus viral capsid antigen p18 (VCA p18) as immobilized antigens in ELISAs for serologic detection of nasopharyngeal carcinoma (NPC). METHODS Thioredoxin fusion VCA p18 (VCA-Trx) and IBs of VCA p18 without fusion tags (VCA-IBs) were purified from E. coli. The diagnostic performances of IgG/VCA-IBs, IgG/VCA-Denat-IBs (using VCA-IBs coated in 8mol/l urea), IgG/VCA-Trx, and IgG/VCA-Peptide assays were compared by screening 100 NPC case-control pairs. RESULTS The IgG/VCA-Denat-IBs assay showed the best area under the receiver operating characteristic curve (AUC: 0.802; p<0.05), while the AUCs for the IgG/VCA-IBs, IgG/VCA-Trx, and IgG/VCA-Peptide assays were comparable (AUC: 0.740, 0.727, and 0.741, respectively). CONCLUSION We improved the diagnostic performance of the ELISA significantly using IBs of recombinant VCA p18.
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Affiliation(s)
- Chun Shen Lim
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Siang Ling Goh
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Leena Kariapper
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Gopala Krishnan
- Department of Otorhinolaryngology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yat-Yuen Lim
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Ching Ching Ng
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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Lim CS, Goh SL, Krishnan G, Ng CC. Recombinant production of Epstein-Barr virus BZLF1 trans-activator and characterization of its DNA-binding specificity. Protein Expr Purif 2013; 95:8-12. [PMID: 24291446 DOI: 10.1016/j.pep.2013.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/15/2013] [Accepted: 11/18/2013] [Indexed: 10/26/2022]
Abstract
This paper describes the recombinant production of a biologically active Epstein-Barr virus BZLF1 trans-activator, i.e., Z-encoded broadly reactive activator (ZEBRA), that recognized specific DNA motifs. We used auto-induction for histidine-tagged BZLF1 expression in Escherichia coli and immobilized cobalt affinity membrane chromatography for protein purification under native conditions. We obtained the purified BZLF1 at a yield of 5.4mg per gram of wet weight cells at 75% purity, in which 27% of the recombinant BZLF1 remained biologically active. The recombinant BZLF1 bound to oligonucleotides containing ZEBRA response elements, either AP-1 or ZIIIB, but not a ZIIIB mutant. The recombinant BZLF1 showed a specific DNA-binding activity which could be useful for functional studies.
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Affiliation(s)
- Chun Shen Lim
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Siang Ling Goh
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Gopala Krishnan
- Department of Otorhinolaryngology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Ching Ching Ng
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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Setyawati MI, Tay CY, Chia SL, Goh SL, Fang W, Neo MJ, Chong HC, Tan SM, Loo SCJ, Ng KW, Xie JP, Ong CN, Tan NS, Leong DT. Titanium dioxide nanomaterials cause endothelial cell leakiness by disrupting the homophilic interaction of VE-cadherin. Nat Commun 2013; 4:1673. [PMID: 23575677 DOI: 10.1038/ncomms2655] [Citation(s) in RCA: 332] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 02/27/2013] [Indexed: 02/07/2023] Open
Abstract
The use of nanomaterials has raised safety concerns, as their small size facilitates accumulation in and interaction with biological tissues. Here we show that exposure of endothelial cells to TiO₂ nanomaterials causes endothelial cell leakiness. This effect is caused by the physical interaction between TiO₂ nanomaterials and endothelial cells' adherens junction protein VE-cadherin. As a result, VE-cadherin is phosphorylated at intracellular residues (Y658 and Y731), and the interaction between VE-cadherin and p120 as well as β-catenin is lost. The resulting signalling cascade promotes actin remodelling, as well as internalization and degradation of VE-cadherin. We show that injections of TiO₂ nanomaterials cause leakiness of subcutaneous blood vessels in mice and, in a melanoma-lung metastasis mouse model, increase the number of pulmonary metastases. Our findings uncover a novel non-receptor-mediated mechanism by which nanomaterials trigger intracellular signalling cascades via specific interaction with VE-cadherin, resulting in nanomaterial-induced endothelial cell leakiness.
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Affiliation(s)
- M I Setyawati
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576, Singapore
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Goh SL, Mokhtar AH, Mohamad Ali MR. Badminton injuries in youth competitive players. J Sports Med Phys Fitness 2013; 53:65-70. [PMID: 23470913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
AIM The aim of the study was to examine sports injury pattern and establish cost of injuries in relation to training of 58 competitive badminton players in a Malaysian National Sports School. METHODS This one-year prospective observational study recruited all the 13-16 year old students after obtaining informed consent from their appointed guardian. All participants were requested to report any injuries, which were pain or disabilities that occur within the study period (September 1, 2008 to August 31, 2009) either during training or competition. Injured students were to seek treatment from the researcher(s) who made weekly visits and they were then followed up accordingly until they return to full training. Details and progress of the injuries were documented during each visit. RESULTS Sixty-three injuries were recorded. Soft tissue sprains/strains were the commonest injury (64%). About one third of the injuries occurred in the lower limb especially the knees and was followed by back injuries; 38% of the injuries did not require training modification, half of these injuries resumed training within one week. Upon full training, half of them were still symptomatic. Injury risk was 57%; injury rate was 0.9 injuries/ player/1000 training hours. CONCLUSION Badminton injuries mostly involved the lower limb and almost all overuse injuries occurred in the lower limb. However, badminton injuries as a whole were predominantly sprains and strains, and not overuse in nature as widely believed.
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Affiliation(s)
- S L Goh
- Sports Medicine Unit, University Malaya, Kuala Lumpur, Malaysia.
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Fisher AA, Goh SL, Srikusalankul W, Southcott EN, Davis MW. Serum leptin levels in older patients with hip fracture--impact on peri-operative myocardial injury. ACTA ACUST UNITED AC 2010; 7:9-16. [PMID: 19742442 DOI: 10.15420/ahhj.2009.7.1.9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
To evaluate whether there is a relationship between admission serum leptin concentrations and peri-operative myocardial injury, 238 consecutive older patients (mean age 81.9+/-7.9 years; 172 women) with low-trauma hip fracture were assessed. Myocardial injury as defined by elevated serum cardiac troponin I was associated with lower leptin levels analyzed as continuous or categorical variables. Patients with serum leptin concentrations <12ng/ml (medium value) had a two-fold greater increased risk for such complications compared with those with higher leptin levels (odd ratio 2.13, 95% confidence interval 1.06-4.28; p=0.033). This association remained significant after adjustments for age, gender, clinical (history of coronary artery disease [CAD], stroke, hypertension, diabetes, dementia), hematological (red, white, and lymphocyte count, hemoglobin, hematocrit), metabolic (parathyroid hormone [PTH], albumin), renal(creatinine, urea, glomerular filtration rate [GFR]), and inflammatory (C-reactive protein [CRP], ferritin) factors. The predictive value of lower leptin levels increased significantly when used in combination with traditional risk factors for myocardial injury.
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Affiliation(s)
- A A Fisher
- Department of Geriatric Medicine, The Canberra Hospital and Australian National University Medical School, ACT, Australia.
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Fisher AA, Southcott EN, Goh SL, Srikusalanukul W, Hickman PE, Davis MW, Potter JM, Budge MM, Smith PN. Elevated serum cardiac troponin I in older patients with hip fracture: incidence and prognostic significance. Arch Orthop Trauma Surg 2008; 128:1073-9. [PMID: 18193436 DOI: 10.1007/s00402-007-0554-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Indexed: 10/22/2022]
Abstract
INTRODUCTION Cardiovascular complications are the main causes of morbidity and mortality in patients with osteoporotic hip fracture (HF). The aim of this prospective study was to evaluate the incidence and prognostic significance of elevated cardiac troponin I (cTnI) in the early peri-operative period in older patients with HF. MATERIALS AND METHODS A blind evaluation of myocardial injury as detected by cTnI elevation in 238 consecutive older patients with low-trauma HF (mean age 81.9 +/- 7.8 (SD) years; 72% females). Data on demographic and clinical characteristics, in-hospital mortality, hospital length of stay and discharge destination were collected prospectively. Serum cTnI level was analysed from blood collected routinely in the first 72 h of hospital admission. RESULTS Sixty-nine (29%) patients had elevated cTnI (>0.06 microg/l) but myocardial injury was clinically recognised in only 23 (33%) and only 24 (34.8%) had a history of coronary artery disease (CAD). Patients with elevated cTnI were significantly older, more often had American Society of Anaesthesiologist status score >or=3, a history of CAD or stroke and more often were current smokers than the patients without cTnI elevation. In multivariate regression analysis only age was an independent predictor of cTnI elevation. Patients with cTnI release were twice as likely to have a length of stay >or=20 days (P = 0.047) and 2.7 times more likely to be discharged to a long-term residential care facility (RCF) (P = 0.013). cTnI level >or=1 microg/l was a strong independent predictor of all-cause mortality with 98.3% specificity and 89.1% negative predictive value. CONCLUSION Peri-operative myocardial injury is common in older HF patients but is frequently unrecognised clinically. Elevated blood cTnI level is an independent predictor of prolonged length of hospital stay (>or=20 days), need for long-term RCF and mortality (if cTnI >or=1 microg/l).
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Affiliation(s)
- A A Fisher
- Department of Geriatric Medicine, The Canberra Hospital, Woden, ACT 2606, Australia.
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Goh SL, Tan JVK, Kwek KYC, Yeo GSH. Recurrent neural tube defects. Singapore Med J 2006; 47:728-9. [PMID: 16865218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We report a case of recurrent neural tube defects in a 30-year-old multigravida with no medical or family history of note. She presented with a significant history of having three (out of four) previous pregnancies affected by neural tube defects diagnosed at the 20-week foetal anomaly ultrasonographical scans, and which resulted in mid-trimester pregnancy terminations. Previous investigations for the foetuses did not yield any obvious cause. We discuss the possible differential diagnoses and aetiological factors. Rare causes of neural tube defects need to be excluded in recurrent cases with no obvious aetiology.
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Affiliation(s)
- S L Goh
- Department of General Obstetrics and Gynaecology, KK Women's and Children's Hospital, 100, Bukit Timah Road, Singapore 229899.
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Goh SL, Goh LL, Sim TS. Cysteine protease falcipain 1 in Plasmodium falciparum is biochemically distinct from its isozymes. Parasitol Res 2005; 97:295-301. [PMID: 16041608 DOI: 10.1007/s00436-005-1430-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2005] [Accepted: 06/07/2005] [Indexed: 12/01/2022]
Abstract
Falcipains form a class of papain-like cysteine proteases found in Plasmodium falciparum. This group of proteases has been suggested to be promising targets for anti-malarial chemotherapy. Despite being the first falcipain to be identified, the physiological role(s) of falcipain 1 (fp1) remains a mystery. Its suggested functions include haemoglobin degradation, erythrocytic invasion and oocyst production. In this study, the procurement of the gene coding for fp1 and its soluble expression in a heterologous host, Escherichia coli, have enabled further enzyme characterization. The recombinant fp1 protease was found to be unlike falcipain 2 (fp2A) in being more active at neutral pH than at acidic pH against the Z-LR-AMC fluorogenic substrate, suggesting a probable localization in the cytosol and not in the food vacuole. Interestingly, a common cysteine specific inhibitor, E64, did not inhibit fp1 activity, indicating dissimilar biochemical characteristics of fp1 from the other falcipains. This may be explained by computational analysis of the primary structures of the falcipain isozymes, as well as that of papain. The analysis revealed that Tyr61 (papain numbering), which is correspondingly absent in fp1, might be an important residue involved in E64 substrate binding.
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Affiliation(s)
- S L Goh
- Department of Microbiology, Faculty of Medicine, National University of Singapore, MD4A, 5 Science Drive 2, Singapore, 117597, Singapore
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Goh SL, Davey KG. Localization and distribution of catecholaminergic structures in the nervous system of phocanema decipiens (Nematoda). Int J Parasitol 1976; 6:403-11. [PMID: 965145 DOI: 10.1016/0020-7519(76)90026-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Kassis AI, Goh SL, Tanner CE. Lesions induced by complement in vitro on the protoscoleces of Echinococcus multilocularis: a study by electron microscopy. Int J Parasitol 1976; 6:199-211. [PMID: 1279075 DOI: 10.1016/0020-7519(76)90035-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Goh SL, Davey KG. Acetylcholinesterase and synapses in the nervous system of Phocanema decipiens (Nematoda): a histochemical and ultrastructural study. CAN J ZOOL 1976; 54:752-71. [PMID: 949651 DOI: 10.1139/z76-086] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The nervous system of Phocanema decipiens was examined histochemically for acetylcholinesterases (EC 3.1.1.7) using the acetylthiocholine method with specific inhibitors (eserine and diisopropylfluorophosphate) and different substrates (butyrylthiocholine and acetylthiocholine). The enzymes, which are localized mainly as small discrete granules, are found in the nerve ring, the six longitudinal nerve cords, and the three pharyngeal nerves. With the electron microscope, these neurons are found to contain presumptive cholinergic synaptic contacts with aggregations of small lucent vesicles in the presynaptic axons. In the nerve ring, such synapses are observed in axoaxonal, neuromuscular and axoglial cell contacts. The longitudinal nerve cords have neuromuscular junctions similar to those observed in other nematodes. In the four sublateral nerve cords, the alternating regions with and without synaptic contacts correspond to the discontinuous histochemical pattern of enzymatic activity. The pharyngeal nerves have axoaxonal and axooesophageal musculature synapses. In most of the synapses, some large dense or dense-core vesicles are found intermingled with the small lucent vesicles. This coexistence of different vesicles is discussed in the light of the cholinergic link hypothesis, whereby acetylcholine is initially released to facilitate the release of other neurotransmitters.
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Goh SL, Davey KG. Selective uptake of noradrenaline, dopa, and 5-hydroxytryptamine by the nervous system of Phocanema decipiens (Nematoda): a light autoradiographic and ultrastructural study. Tissue Cell 1976; 8:421-35. [PMID: 982420 DOI: 10.1016/0040-8166(76)90003-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
As determined by light microscopic autoradiography, parts of the nervous system of Phocanema decipiens have selective and high affinity mechanisms for the uptake of tritiated noradrenaline, dihydroxyphenylalanine (dopa) and 5-hydroxytryptamine. In the nervous system, noradrenaline is accumulated only by the four papillary nerves and two fibers in the nerve ring. The precursor dopa is also taken up by these neurons and, in addition, by the lateral nerves. 5-Hydroxytryptamime is accumulated by the three pharyngeal nerves, two cells in each lateral ganglion, and two other fibers in the nerve ring. With adjacent ultrathin sections, the labelled papillary nerve and lateral ganglion were examined ultrastructurally and found to contain various dense core vesicles which are similar to those in other aminergic neurons. The adjoining unlabelled cells of the same neurons are found, on the other hand, to contain dense agranular vesicles. With these results, the noradrenaline accumulating neurons are suggested to be noradrenergic and to contain the amine synthesizing enzymes. The lateral nerves are regarded, for the present, as dopaminergic neurons. These suggestions are in agreement with the previous demonstration of catecholaminergic neurons in this nematode. The 5-hydroxytryptamine accumulating neurons are tentatively identified as tryptaminergic.
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