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Ho LC, Yu Chi C, You YS, Hsieh YW, Hou YC, Lin TC, Chen MT, Chou CH, Chen YC, Hsu KC, Yu J, Hsueh PR, Cho DY. Impact of the implementation of the Intelligent Antimicrobial System (iAMS) on clinical outcomes among patients with bacteraemia caused by methicillin-resistant Staphylococcus aureus. Int J Antimicrob Agents 2024; 63:107142. [PMID: 38490572 DOI: 10.1016/j.ijantimicag.2024.107142] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 03/06/2024] [Accepted: 03/09/2024] [Indexed: 03/17/2024]
Abstract
OBJECTIVES This study aimed to investigate the clinical impact of the Intelligent Antimicrobial System (iAMS) on patients with bacteraemia due to methicillin-resistant (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA). METHODS A total of 1008 patients with suspected SA infection were enrolled before and after the implementation of iAMS. Among them, 252 with bacteraemia caused by SA, including 118 in the iAMS and 134 in the non-iAMS groups, were evaluated. RESULTS The iAMS group exhibited a 5.2% (from 55.2% to 50.0%; P = 0.96) increase in the 1-year survival rate. For patients with MRSA and MSSA compared to the non-iAMS group, the 1-year survival rate increased by 17.6% (from 70.9% to 53.3%; P = 0.41) and 7.0% (from 52.3% to 45.3%; P = 0.57), respectively, both surpassing the rate of the non-iAMS group. The iAMS intervention resulted in a higher long-term survival rate (from 70.9% to 52.3%; P = 0.984) for MRSA patients than for MSSA patients. MRSA patients experienced a reduced length of hospital stay (from 23.3% to 35.6%; P = 0.038), and the 45-day discharge rate increased by 20.4% (P = 0.064). Furthermore, the intervention resulted in a significant 97.3% relative decrease in near miss medication incidents reported by pharmacists (P = 0.013). CONCLUSIONS Implementation of iAMS platform improved long-term survival rates, discharge rates, hospitalization days, and medical cost (although no significant differences were observed) among patients with MRSA bacteraemia. Additionally, it demonstrated significant benefits in ensuring drug safety.
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Affiliation(s)
- Lu-Ching Ho
- School of Pharmacy, China Medical University, Taichung, Taiwan; Department of Pharmacy, China Medical University Hospital, Taichung, Taiwan
| | - Chih Yu Chi
- Division of Infectious Diseases, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan; School of Medicine, China Medical University, Taichung, Taiwan
| | - Ying-Shu You
- Department of Pharmacy, China Medical University Hospital, Taichung, Taiwan; Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Yow-Wen Hsieh
- School of Pharmacy, China Medical University, Taichung, Taiwan; Department of Pharmacy, China Medical University Hospital, Taichung, Taiwan
| | - Yu-Chi Hou
- School of Pharmacy, China Medical University, Taichung, Taiwan
| | - Tzu-Ching Lin
- Department of Pharmacy, China Medical University Hospital, Taichung, Taiwan
| | - Ming Tung Chen
- Information Office, China Medical University Hospital, Taichung, Taiwan
| | - Chia-Hui Chou
- Division of Infectious Diseases, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Yu-Chieh Chen
- School of Pharmacy, China Medical University, Taichung, Taiwan; Department of Pharmacy, China Medical University Hospital, Taichung, Taiwan
| | - Kai-Cheng Hsu
- Artificial Intelligence Center, China Medical University Hospital, Taichung, Taiwan
| | - Jiaxin Yu
- Artificial Intelligence Center, China Medical University Hospital, Taichung, Taiwan
| | - Po-Ren Hsueh
- Division of Infectious Diseases, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan; Department of Laboratory Medicine, China Medical University Hospital, China Medical University, Taichung, Taiwan.
| | - Der-Yang Cho
- Department of Neurosurgery, China Medical University Hospital, Taichung, Taiwan.
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Yu CP, Li PY, Chen SY, Lin SP, Chen YC, Ho LC, Hsieh YW, Hou YC. An acute herb-drug interaction of Magnoliae Officinalis Cortex with methotrexate via inhibiting multidrug resistance-associated protein 2. J Food Drug Anal 2024; 32:103-111. [PMID: 38526588 PMCID: PMC10962649 DOI: 10.38212/2224-6614.3495] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 01/08/2024] [Indexed: 03/26/2024] Open
Abstract
Magnoliae Officinalis Cortex (MOC), an herbal drug, contains polyphenolic lignans mainly magnolol (MN) and honokiol (HK). Methotrexate (MTX), a critical drug for cancers and autoimmune deseases, is a substrate of multidrug resistance-associated protein 2 (MRP2) and breast cancer resistance protein (BCRP). This study investigated the effect of coadministration of MOC on the pharmacokinetics of MTX and relevant mechanisms. Sprague-Dawley rats were orally administered MTX alone and with single dose (2.0 and 4.0 g/kg) and repeated seven doses of MOC (2.0 g/kg thrice daily for 2 days, the 7th dose given at 0.5 h before MTX). The serum concentrations of MTX were determined by a fluorescence polarization immunoassay. The results showed that a single dose of MOC at 2.0 g/kg significantly increased the AUC0-t and MRT of MTX by 352% and 308%, and a single dose at 4.0 g/kg significantly enhanced the AUC0-t and MRT by 362% and 291%, respectively. Likewise, repeated seven doses of MOC at 2.0 g/kg significantly increased the AUC0-t and MRT of MTX by 461% and 334%, respectively. Mechanism studies indicated that the function of MRP2 was significantly inhibited by MN, HK and the serum metabolites of MOC (MOCM), whereas BCRP was not inhibited by MOCM. In conclusion, coadministration of MOC markedly enhanced the systemic exposure and mean residence time of MTX through inhibiting the MRP2-mediated excretion of MTX.
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Affiliation(s)
- Chung-Ping Yu
- School of Pharmacy, College of Pharmacy, China Medical University, Taichung,
Taiwan 406040, ROC
- Department of Pharmacy, China Medical University Hospital, Taichung,
Taiwan 404327, ROC
| | - Pei-Ying Li
- School of Pharmacy, College of Pharmacy, China Medical University, Taichung,
Taiwan 406040, ROC
| | - Szu-Yu Chen
- School of Pharmacy, College of Pharmacy, China Medical University, Taichung,
Taiwan 406040, ROC
| | - Shiuan-Pey Lin
- School of Pharmacy, College of Pharmacy, China Medical University, Taichung,
Taiwan 406040, ROC
| | - Ying-Chen Chen
- Institute of Chinese Pharmaceutical Sciences, China Medical University, Taichung,
Taiwan 404333, ROC
| | - Lu-Ching Ho
- School of Pharmacy, College of Pharmacy, China Medical University, Taichung,
Taiwan 406040, ROC
- Department of Pharmacy, China Medical University Hospital, Taichung,
Taiwan 404327, ROC
| | - Yow-Wen Hsieh
- School of Pharmacy, College of Pharmacy, China Medical University, Taichung,
Taiwan 406040, ROC
- Department of Pharmacy, China Medical University Hospital, Taichung,
Taiwan 404327, ROC
| | - Yu-Chi Hou
- School of Pharmacy, College of Pharmacy, China Medical University, Taichung,
Taiwan 406040, ROC
- Department of Pharmacy, China Medical University Hospital, Taichung,
Taiwan 404327, ROC
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Yu J, Lin HH, Tseng KH, Lin YT, Chen WC, Tien N, Cho CF, Liang SJ, Ho LC, Hsieh YW, Hsu KC, Ho MW, Hsueh PR, Cho DY. Prediction of methicillin-resistant Staphylococcus aureus and carbapenem-resistant Klebsiella pneumoniae from flagged blood cultures by combining rapid Sepsityper MALDI-TOF mass spectrometry with machine learning. Int J Antimicrob Agents 2023; 62:106994. [PMID: 37802231 DOI: 10.1016/j.ijantimicag.2023.106994] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 09/13/2023] [Accepted: 09/26/2023] [Indexed: 10/08/2023]
Abstract
This study investigated combination of the Rapid Sepsityper Kit and a machine learning (ML)-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) approach for rapid prediction of methicillin-resistant Staphylococcus aureus (MRSA) and carbapenem-resistant Klebsiella pneumoniae (CRKP) from positive blood culture bottles. The study involved 461 patients with monomicrobial bloodstream infections. Species identification was performed using the conventional MALDI-TOF MS Biotyper system and the Rapid Sepsityper protocol. The data underwent preprocessing steps, and ML models were trained using preprocessed MALDI-TOF data and corresponding labels. The interpretability of the model was enhanced using SHapely Additive exPlanations values to identify significant features. In total, 44 S. aureus isolates comprising 406 MALDI-TOF MS files and 126 K. pneumoniae isolates comprising 1249 MALDI-TOF MS files were evaluated. This study demonstrated the feasibility of predicting MRSA among S. aureus and CRKP among K. pneumoniae isolates using MALDI-TOF MS and Sepsityper. Accuracy, area under the receiver operating characteristic curve, and F1 score for MRSA/methicillin-susceptible S. aureus were 0.875, 0.898 and 0.904, respectively; for CRKP/carbapenem-susceptible K. pneumoniae, these values were 0.766, 0.828 and 0.795, respectively. In conclusion, the novel ML-based MALDI-TOF MS approach enables rapid identification of MRSA and CRKP from flagged blood cultures within 1 h. This enables earlier initiation of targeted antimicrobial therapy, reducing deaths due to sepsis. The favourable performance and reduced turnaround time of this method suggest its potential as a rapid detection strategy in clinical microbiology laboratories, ultimately improving patient outcomes.
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Affiliation(s)
- Jiaxin Yu
- AI Centre, China Medical University Hospital, Taichung, Taiwan
| | - Hsiu-Hsien Lin
- Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Kun-Hao Tseng
- Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Yu-Tzu Lin
- Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan; Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
| | - Wei-Cheng Chen
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan; Graduate Institute of Biomedical Sciences and School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan
| | - Ni Tien
- Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan; Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
| | - Chia-Fong Cho
- AI Centre, China Medical University Hospital, Taichung, Taiwan
| | - Shinn-Jye Liang
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Lu-Ching Ho
- Department of Pharmacy, China Medical University Hospital, Taichung, Taiwan; School of Pharmacy, China Medical University, Taichung, Taiwan
| | - Yow-Wen Hsieh
- Department of Pharmacy, China Medical University Hospital, Taichung, Taiwan; School of Pharmacy, China Medical University, Taichung, Taiwan
| | - Kai Cheng Hsu
- AI Centre, China Medical University Hospital, Taichung, Taiwan; Department of Medicine, China Medical University, Taichung, Taiwan; Department of Neurology, China Medical University Hospital, Taichung, Taiwan
| | - Mao-Wang Ho
- Department of Medicine, China Medical University, Taichung, Taiwan; Division of Infectious Diseases, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Po-Ren Hsueh
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan; Department of Medicine, China Medical University, Taichung, Taiwan; Division of Infectious Diseases, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan.
| | - Der-Yang Cho
- Department of Neurosurgery, China Medical University Hospital, Taichung, Taiwan.
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Yu J, Lin YT, Chen WC, Tseng KH, Lin HH, Tien N, Cho CF, Huang JY, Liang SJ, Ho LC, Hsieh YW, Hsu KC, Ho MW, Hsueh PR, Cho DY. Direct prediction of carbapenem-resistant, carbapenemase-producing, and colistin-resistant Klebsiella pneumoniae isolates from routine MALDI-TOF mass spectra using machine learning and outcome evaluation. Int J Antimicrob Agents 2023; 61:106799. [PMID: 37004755 DOI: 10.1016/j.ijantimicag.2023.106799] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 03/14/2023] [Accepted: 03/26/2023] [Indexed: 04/03/2023]
Abstract
The objective of this study was to develop a rapid prediction method for carbapenem-resistant Klebsiella pneumoniae (CRKP) and colistin-resistant K. pneumoniae (ColRKP) based on routine MALDI-TOF mass spectrometry (MS) results in order to formulate a suitable and rapid treatment strategy. In total, 830 CRKP and 1,462 carbapenem-susceptible K. pneumoniae (CSKP) isolates were collected; 54 ColRKP isolates and 1,592 colistin-intermediate K. pneumoniae (ColIKP) isolates were also included. Routine MALDI-TOF MS, antimicrobial susceptibility testing, NG-Test CARBA 5, and resistance gene detection were followed by machine learning (ML). Using the ML model, the accuracy and area under the curve for differentiating CRKP and CSKP were 0.8869 and 0.9551, and those for ColRKP and ColIKP were 0.8361 and 0.8447, respectively. The most important MS features of CRKP and ColRKP were m/z 4520-4529 and m/z 4170-4179, respectively. Of the CRKP isolates, MS m/z 4520-4529 was a potential biomarker for distinguishing KPC from OXA, NDM, IMP, and VIM. Of the 34 patients who received preliminary CRKP ML prediction results (by texting), 24 (70.6%) were confirmed to have CRKP infection. The mortality rate was lower in patients who received antibiotic regimen adjustment based on the preliminary ML prediction (4/14, 28.6%). In conclusion, the proposed model can provide rapid results for differentiating CRKP and CSKP, as well as ColRKP and ColIKP. The combination of ML-based CRKP with preliminary reporting of results can help physicians alter the regimen approximately 24 h earlier, resulting in improved survival of patients with timely antibiotic intervention.
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Chiang HY, Chen TC, Lin CC, Ho LC, Kuo CC, Chi CY. Trend and Predictors of Short-term Mortality of Adult Bacteremia at Emergency Departments: A 14-Year Cohort Study of 14 625 Patients. Open Forum Infect Dis 2021; 8:ofab485. [PMID: 34805430 PMCID: PMC8598924 DOI: 10.1093/ofid/ofab485] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 09/22/2021] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Bacteremia is a life-threatening condition with a high mortality rate in critical care and emergency settings. The current study investigated the trend of mortality and developed predictive models of mortality for adults with bacteremia at emergency departments (EDs). METHODS We conducted a retrospective cohort study of adults with bacteremia at the ED of China Medical University Hospital. Patient data were obtained from the Clinical Research Data Repository, and mortality information was obtained from the National Death Registry. We developed a new model to predict 7-day mortality in the derivation population and compared the model performance of the new model with Pitt Bacteremia Score (PBS) and Bloodstream Infection Mortality Risk Score (BSIMRS) in the validation population. RESULTS We identified 14625 adult patients with first-time bacteremia at the ED, of whom 8.4% died within 7 days. From 2003 to 2016, both the cumulative incidence and 7-day mortality rate of bacteremia decreased significantly. The ED bacteremia mortality (ED-BM) model included PBS parameters, age, infection source, baseline steroid use, and biochemical profiles (estimated glomerular filtration rate, platelet, blood urea nitrogen, potassium, and hemoglobin) for predicting 7-day mortality. The discrimination performance of the ED-BM model (area under curve [AUC], 0.903) was significantly better than that of PBS (AUC, 0.848) or BSIMRS (AUC, 0.885). CONCLUSIONS Although the cumulative incidence and mortality of ED bacteremia decreased, its mortality burden remains critical. The proposed ED-BM model had significantly better model performance than other scoring systems in predicting short-term mortality for adult patients with bacteremia at EDs.
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Affiliation(s)
- Hsiu-Yin Chiang
- Big Data Center, China Medical University Hospital, Taichung, Taiwan
| | - Tsung-Chia Chen
- Division of Infectious Diseases, Department of Internal Medicine, Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan
| | - Che-Chen Lin
- Big Data Center, China Medical University Hospital, Taichung, Taiwan
| | - Lu-Ching Ho
- Department of Pharmacy, China Medical University Hospital, Taichung, Taiwan
| | - Chin-Chi Kuo
- Big Data Center, China Medical University Hospital, Taichung, Taiwan
- Division of Nephrology, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Chih-Yu Chi
- Division of Infectious Diseases, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan
- School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan
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Affiliation(s)
- M Mezcua
- Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Magrans, 08193 Barcelona, Spain
- Institut d’Estudis Espacials de Catalunya (IEEC), Carrer Gran Capità, 08034 Barcelona, Spain
| | - M Kim
- Korea Astronomy and Space Science Institute, Daejeon 305-348, Korea
- University of Science and Technology, Daejeon 305-350, Korea
- Department of Astronomy and Atmospheric Sciences, Kyungpook National University, Daegu 702-701, Korea
| | - L C Ho
- Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China
- Department of Astronomy, School of Physics, Peking University, Beijing 100871, China
| | - C J Lonsdale
- National Radio Astronomy Observatory, Charlottesville, VA 22903, USA
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Lin SP, Yu CP, Hou YC, Huang CY, Ho LC, Chan SL. Transporter-mediated interaction of indican and methotrexate in rats. J Food Drug Anal 2018; 26:S133-S140. [PMID: 29703382 PMCID: PMC9326885 DOI: 10.1016/j.jfda.2017.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/31/2017] [Accepted: 11/01/2017] [Indexed: 01/24/2023] Open
Abstract
Indican (indoxyl-β-D-glucoside) is present in several Chinese herbs e.g. Isatis indigotica, Polygonum tinctorium and Polygonum perfoliatum. The major metabolite of indican was indoxyl sulfate (IS), an uremic toxin which was a known substrate/inhibitor of organic anion transporter (OAT) 1, OAT 3 and multidrug resistance-associated protein (MRP) 4. Methotrexate (MTX), an important immunosuppressant with narrow therapeutic window, is a substrate of OAT 1, 2, 3, 4 and MRP 1, 2, 3, 4. We hypothesized that IS, the major metabolite of oral indican, might inhibit the renal excretion of MTX mediated by OAT 1, OAT 3 and MRP 4. Therefore, this study investigated the effect of oral indican on the pharmacokinetics of MTX. Rats were orally given MTX with and without indican (20.0 and 40.0 mg/kg) in a parallel design. The serum MTX concentration was determined by a fluorescence polarization immunoassay. For mechanism clarification, phenolsulfonphthalein (PSP, 5.0 mg/kg), a probe substrate of OAT 1, OAT 3, MRP 2 and MRP 4, was intravenously given to rats with and without a intravenous bolus of IS (10.0 mg/kg) to measure the effect of IS on the elimination of PSP. The results indicated that 20.0 and 40.0 mg/kg of oral indican significantly increased the area under concentration–time curve0-t (AUC0-t) of MTX by 231% and 259%, prolonged the mean residence time (MRT) by 223% and 204%, respectively. Furthermore, intravenous IS significantly increased the AUC0-t of PSP by 204% and decreased the Cl by 68%. In conclusion, oral indican increased the systemic exposure and MRT of MTX through inhibition on multiple anion transporters including OAT 1, OAT 3 and MRP 4 by the major metabolite IS.
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Affiliation(s)
- Shiuan-Pey Lin
- School of Pharmacy, China Medical University, Taichung 404, Taiwan.
| | - Chung-Ping Yu
- Department of Pharmacy, China Medical University Hospital, Taichung 404, Taiwan
| | - Yu-Chi Hou
- School of Pharmacy, China Medical University, Taichung 404, Taiwan; Department of Pharmacy, China Medical University Hospital, Taichung 404, Taiwan
| | - Ching-Ya Huang
- Department of Pharmacy, China Medical University Hospital, Taichung 404, Taiwan
| | - Lu-Ching Ho
- Department of Pharmacy, China Medical University Hospital, Taichung 404, Taiwan
| | - Shu-Ling Chan
- Graduate Institute of Pharmaceutical Chemistry, China Medical University, Taichung 404, Taiwan
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Chiang JB, Lo SSM, Ho LC, Chan CM, Poon WL, Tang KW, Cheung YL. Posterior Cranial Fossa Neurenteric Cyst with Malignant Transformation. Hong Kong J Radiol 2014. [DOI: 10.12809/hkjr1413223] [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: 11/05/2022] Open
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Abstract
Impalement rectal injuries with intraperitoneal organ injuries are rare. It is even rarer for such injuries to result in pelvic, abdominal and thoracic internal injuries. We present the case of a 39-year-old man who was admitted after an assault where a broken broomstick was inserted forcibly into his rectum. Surgery revealed penetration through the rectum, dome of the bladder, mesentery, liver and right lung. The patient survived following management by a multispecialty surgical team. Our literature review identified four similar cases with one fatality only. Prognosis seems to be good in these types of injuries provided there is an early presentation, the penetrating object is left in situ before the operation and, most importantly, an organised team approach to deal with the various injuries.
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Affiliation(s)
- L C Ho
- University of Aberdeen, UK
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Shia CS, Hou YC, Juang SH, Tsai SY, Hsieh PH, Ho LC, Chao PDL. Metabolism and pharmacokinetics of san-huang-xie-xin-tang, a polyphenol-rich chinese medicine formula, in rats and ex-vivo antioxidant activity. Evid Based Complement Alternat Med 2011; 2011:721293. [PMID: 19737807 PMCID: PMC3137274 DOI: 10.1093/ecam/nep124] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Accepted: 06/25/2009] [Indexed: 01/12/2023]
Abstract
San-Huang-Xie-Xin-Tang (SHXXT), a widely used Chinese herbal formula, consists of rhizomes of Rheum officinale, roots of Scutellaria baicalensis and rhizomes of Coptis chinesis. This study investigated the metabolism and pharmacokinetics of polyphenols in SHXXT, including baicalin, baicalein, wogonin, emodin, aloe-emodin, rhein and chrysophanol. The quantitation methods of SHXXT decoction and rat serum using high performance liquid chromatography were developed and validated in this study. After oral administration of SHXXT decoction to rats, the parent forms of various constituents and their conjugated metabolites in serum were determined before and after hydrolysis with β-glucuronidase and sulfatase. The results showed that only free form of rhein can be quantitated, whereas the parent forms of coptisine, palmatine, berberine, baicalein, wogonin, emodin, aloe-emodin and chrysophanol were not detected in serum. The glucuronides of baicalein, wogonin, emodin, aloe-emodin, rhein and chrysophanol were the predominant forms in bloodstream. In order to evaluate the in vivo antioxidant activity of SHXXT, the serum metabolite of SHXXT was prepared, characterized and followed by evaluation of the effect on AAPH-induced hemolysis. The results indicated that metabolites of SHXXT exhibited significant free radical scavenging activity. We suggest that biologists redirect their focus to the bioactivity of the conjugated metabolites of these polyphenols.
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Lam CM, Wong SF, Chow KM, Ho LC. Women with placenta praevia and antepartum haemorrhage have a worse outcome than those who do not bleed before delivery. J OBSTET GYNAECOL 2009; 20:27-31. [PMID: 15512459 DOI: 10.1080/01443610063417] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
We set out to assess the maternal and neonatal outcomes of women with placenta praevia and antepartum haemorrhage (APH) between 1991 and 1997, compared with woman with a diagnosed placenta praevia who did not bleed. The demographic data, maternal and perinatal outcomes of 159 women with antepartum haemorrhage were compared with 93 women without antepartum haemorrhage in a retrospective study. Women with antepartum haemorrhage had the diagnosis of placenta praevia confirmed at an earlier gestation. More women with antepartum haemorrhage received antenatal steroids and tocolytic agents, and had emergency caesarean sections. The majority of women with bleeding had an emergency caesarean section for antepartum haemorrhage and more delivered early because of fetal distress. There were more preterm deliveries in women with antepartum haemorrhage. The mean birth weight was 2.69 kg in the women with antepartum haemorrhage and 3.06 kg in those without. More infants in the bleeding group had a low Apgar score at the first minute, respiratory distress syndrome, and admission to special baby care and neonatal intensive care unit. It is concluded that there is an increased risk of premature delivery in women with antepartum haemorrhage and placenta praevia. Aggressive management, tocolysis and cervical cerclage should be explored further to improve the perinatal outcome. Women without antepartum haemorrhage can be managed on an outpatient basis.
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Affiliation(s)
- C M Lam
- Department of Obstetrics and Gynaecology, Princess Margaret Hospital, Hong Kong
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Zynger DL, Dimov ND, Ho LC, Laskin WB, Yeldandi AV. Differential expression of neural-cadherin in pulmonary epithelial tumours. Histopathology 2008; 52:348-54. [DOI: 10.1111/j.1365-2559.2007.02952.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ng WF, Wong SF, Lam A, Mak YF, Yao H, Lee KC, Chow KM, Yu WC, Ho LC. The placentas of patients with severe acute respiratory syndrome: a pathophysiological evaluation. Pathology 2006; 38:210-8. [PMID: 16753741 PMCID: PMC7131423 DOI: 10.1080/00313020600696280] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aims The pathology of the placentas delivered from pregnant women who had severe acute respiratory syndrome (SARS) in Hong Kong was studied. Methods The pathology of the placentas was retrospectively studied in detail and compared with control sets. The clinical data of the women and neonates were also reviewed. Results A total of seven placentas were studied. The placentas from two women convalescent from SARS in the first trimester were normal. In three placentas delivered in the acute stage of SARS, there were increases in intervillous or subchorionic fibrin which might be related to disturbances in maternal placental blood flow due to the hypoxic respiratory disease. Extensive fetal thrombotic vasculopathy (FTV) with sharply demarcated zones of avascular fibrotic villi was noted in the placentas of two patients convalescent from SARS in the third trimester. Both pregnancies had intrauterine growth retardation, oligohydramnios and newborns small for gestation. The aetiology of the FTV might be related to thrombotic tendency due to SARS or placental hypoxia. Conclusions This report highlights placental pathology that was probably the result of pathophysiological alteration of the maternal fetal unit during SARS. Further studies are required to delineate the relationship between severe maternal respiratory disease, placental pathology and pregnancy outcome.
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Affiliation(s)
- W F Ng
- Department of Pathology, Princess Margaret Hospital, Lai Chi Kok, Kowloon, Hong Kong Special Administrative Region, China.
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14
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Abstract
Meningeal involvement in multiple myeloma is rare. We report a case in which a patient with a history of multiple myeloma presented with neurological deficit due to meningeal involvement.
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Affiliation(s)
- Chi-Sum Tsang
- Department of Neurosurgery and Pathology, Queen Elizabeth Hospital, Kowloon, Hong Kong, SAR, China.
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15
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Hui SK, Lee L, Ong C, Yu V, Ho LC. General gynaecology: Intrauterine lignocaine as an anaesthetic during endometrial sampling: a randomised double-blind controlled trial. BJOG 2005; 113:53-7. [PMID: 16398772 DOI: 10.1111/j.1471-0528.2005.00812.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [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: 11/27/2022]
Abstract
OBJECTIVE To evaluate the effectiveness of intrauterine lignocaine as an anaesthetic during endometrial sampling. DESIGN Prospective, randomised, double-blind, placebo-controlled trial. SETTING Outpatient gynaecological minor operation unit in a public hospital. POPULATION Two hundred premenopausal women scheduled for endometrial sampling because of abnormal uterine bleeding. METHODS Transcervical intrauterine instillation of 5 mL of 2% lignocaine or 5 mL of normal saline before performing endometrial sampling with vacuum aspirator. MAIN OUTCOME MEASURES Evaluation of pain associated with the procedure using a visual analogue scale. RESULTS The use of intrauterine lignocaine reduced pain during suction curettage in endometrial sampling. CONCLUSIONS Transcervical instillation of lignocaine reduced pain during endometrial sampling.
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Affiliation(s)
- S K Hui
- Department of Obstetrics and Gynaecology, Princess Margaret Hospital, Hong Kong, China
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16
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Wong CW, Fan YS, Chan TL, Chan ASW, Ho LC, Ma TKF, Yuen ST, Leung SY. BRAF and NRAS mutations are uncommon in melanomas arising in diverse internal organs. J Clin Pathol 2005; 58:640-4. [PMID: 15917418 PMCID: PMC1770697 DOI: 10.1136/jcp.2004.022509] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2004] [Indexed: 01/22/2023]
Abstract
BACKGROUND Malignant melanoma arising from different body compartments may be associated with differing aetiological factors and clinical behaviour, and may manifest diverse molecular genetic profiles. Although many studies have focused on cutaneous melanoma, little is known of mucosal and other types of melanoma. In particular, malignant melanoma of soft parts is different from other melanomas in many respects, yet manifests a common melanocytic differentiation. Mutation of BRAF is now known to be common in cutaneous melanomas, and raises possible new therapeutic options of anti-RAF treatment for these patients. Few data are available for non-cutaneous melanomas. AIMS To study the incidence of BRAF and NRAS mutations in melanomas arising in diverse internal organs. METHODS Fifty one melanomas from various internal organs were investigated for BRAF and NRAS mutation by direct DNA sequencing. RESULTS BRAF and NRAS mutations were found in two and five mucosal melanomas arising from the aerodigestive and female genital tracts (n = 36). Their occurrence is mutually exclusive, giving a combined mutation incidence rate of 19.4% in mucosal melanomas. Both BRAF and NRAS mutations were absent in malignant melanoma of soft parts (n = 7). BRAF mutation was also absent in uveal melanoma (n = 6), but was seen in two of five cutaneous melanomas. The incidence of BRAF or combined BRAF/NRAS mutations in all non-cutaneous groups was significantly lower than published rates for cutaneous melanomas. CONCLUSION Each melanoma subtype may have a unique oncogenetic pathway of tumour development, and only a small fraction of non-cutaneous melanomas may benefit from anti-RAF treatment.
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Affiliation(s)
- C W Wong
- Department of Pathology, University of Hong Kong, Queen Mary Hospital, Hong Kong
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17
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Abstract
Cutaneous melanoma is rare among Chinese people. The clinicopathologic features and prognostic factors of 63 Hong Kong ethnic Chinese cases were analysed. We found that the mean age of onset was 65.5 years with a female : male ratio of 1 : 1.33. Forty-two (66.7%) patients had their tumours on their feet. More than 50% had the acral lentiginous histologic subtype. The mean tumour thickness was 5.73 mm with 92.1% (n = 58) having a Clark's level of III or more. Of the tumours, 57.1% were ulcerated. Stage I and II tumours comprised 73% (n = 46) while stage III and IV tumours made up of 26% (n = 17). The 1-, 3- and 5-year survival rates were 75%, 30% and 17%, respectively. Univariate analysis for overall survival showed that advanced clinical staging (stage III and IV), tumour ulceration and thicker tumour (>4 mm) had a significantly poorer prognosis. Multivariate analysis demonstrated that advanced clinical staging was the most decisive prognostic factor followed by tumour ulceration. Our study showed that cutaneous melanoma in Chinese people is a disease predominantly of an older age group with the acral lentiginous histologic type located mainly on the feet. The prognosis depends on clinical staging and ulceration status.
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Affiliation(s)
- N M Luk
- Social Hygiene Service, Department of Health, Hong Kong, China.
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18
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Wong SF, Chow KM, Shek CC, Leung YP, Chiu A, Lam PWY, Ho LC. Measures to prevent healtcare workers from contracting severe acute respiratory syndrome during high-risk surgical procedures. Eur J Clin Microbiol Infect Dis 2004; 23:131-3. [PMID: 14712366 PMCID: PMC7087897 DOI: 10.1007/s10096-003-1068-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- S F Wong
- Department of Obstetrics and Gynaecology, Maternal Fetal Medicine Unit, Princess Margaret Hospital, Lai Chi Kok, Kowloon, Hong Kong.
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19
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Abstract
Recent reports of absent nasal bone in fetuses with Down syndrome have sparked much interest in the use of this finding for the screening of Down syndrome. We describe the histopathological findings of nasal bones of two fetuses with Down syndrome, one with absence and the other with normal ossification of the nasal bone. We propose that histopathological examination of the nasal bone could improve the accuracy of diagnosis of nasal hypoplasia among Down syndrome abortuses.
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Affiliation(s)
- S F Wong
- Department of Obstetrics and Gynaecology, Princess Margaret Hospital, Princess Margaret Hospital Road, Lai Chi Kok, Hong Kong SAR, Hong Kong.
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20
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Abstract
Pregnancies complicated with meconium-stained liquor are regarded as at risk of fetal distress. Evidence from animal and human studies indicate that passage of meconium may be related to fetal maturity. This retrospective study attempts to quantify the relative risk of non-reassuring cardiotocography or 'fetal distress' in pregnant women complicated by meconium-stained liquor for preterm, term and post-term pregnancies. A total of 9542 singleton pregnancies, delivered in a tertiary obstetric unit in Hong Kong between 1 July 1996 and 31 June 1999, were included in the study. Of these pregnancies, 1946 (20.4%) were identified as having meconium-stained liquor, ranging from thin to thick staining. There was a strong association between incidence of meconium-stained liquor (P < 0.0005) and moderate/thick meconium-stained liquor with advanced gestational age. The incidence of non-reassuring cardiotocography in women presenting with meconium-stained liquor was significantly higher (9.8% vs. 6.4%). The relative risk of non-reassuring cardiotocography in women with meconium-stained liquor increased with more advanced gestation. Close fetal surveillance during labour is required among these pregnancies. Premature labour is associated with higher incidence of fetal distress but the presence of meconium did not pose an additional risk.
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Affiliation(s)
- S F Wong
- Department of Obstetrics and Gynaecology, Princess Margaret Hospital, Kowloon, Hong Kong SAR.
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21
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Abstract
We report a fetus with fetal bradycardia at 13 weeks of gestation secondary to atrial extrasystoles. The fetus subsequently developed paroxysmal supraventricular tachycardia and hydrops fetalis. The cardiac arrhythmia recovered spontaneously without any medical intervention. This case illustrates that atrial ectopic beats can present in the first trimester with fetal bradycardia. Rapidly evolving hydrops fetalis secondary to supraventricular tachycardia can develop, warranting close monitoring with weekly heart rate assessment. Fetal bradycardia secondary to atrial extrasystole should be differentiated from first trimester sinus bradycardia and those associated with major structural cardiac abnormality, which have a high fetal loss rate.
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Affiliation(s)
- S F Wong
- Department of Obstetrics and Gynaecology, Princess Margaret Hospital, Hong Kong.
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22
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Abstract
An ion-sensitive field effect transistor (ISFET)-based immunosensor was developed to detect/quantitate beta-Bungarotoxin (beta-BuTx), a potent presynaptic neurotoxin from the venom of Bungarus multicinctus. A murine monoclonal antibody (mAb 15) specific to beta-BuTx was immobilized onto silicon nitride wafers after silanization and activation with glutaraldehyde. A chip based enzyme linked-immunosorbantassay (ELISA) was performed to ascertain antigen binding to the immobilized antibody. To develop an electrochemical immunosensing system for the detection/quantitation of beta-BuTx, an ISFET was used as a solid phase detector. MAb 15 was immobilized on the gate region of the ISFET. The antigen antibody reaction was monitored by the addition of urease conjugated rabbit anti-beta-BuTx antibodies. The sensor can detect toxin level as low as 15.6 ng/ml. The efficacy of the sensor for the determination of beta-BuTx from B. multicinctus venom was demonstrated in mouse model. Toxin concentration was highest at the site of injection (748.0+/-26 ng/ml) and moderate amount was found in the plasma (158.5+/-13 ng/ml).
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Affiliation(s)
- Z Emmanuel Selvanayagam
- Department of Anatomy, Venom and Toxin Research Programme, Faculty of Medicine, National University of Singapore, 4 Medical Drive, Singapore, 117597, Singapore.
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23
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Abstract
OBJECTIVE To assess the efficacy of sweeping of membranes beyond 40 weeks of gestation in reducing the incidence of induction of labour, when induction was planned at 42 weeks. DESIGN Prospective randomised controlled trial. SETTING A regional obstetric unit in Hong Kong. POPULATION AND METHODS A total of 120 women with certain gestational age, determined by early pregnancy ultrasound scan, were recruited from 1st July, 1998 to 31st December, 1999. Sixty women were randomly allocated to sweeping of membranes and the other 60 women acted as control. The satisfaction for women allocated to sweeping of membranes was assessed by a questionnaire after the procedure. The two groups were assessed on intention-to-treat basis. MAIN OUTCOME MEASURES The incidence of formal induction of labour was compared between the two groups. Possible complications of sweeping of membranes such as rupture of membranes, intrapartum infection, postpartum infection, and neonatal infection were also assessed. Maternal and perinatal outcomes were also assessed. RESULTS The recruitment to delivery interval was significantly shorter among women who had sweeping of membranes (3.2 versus 4.2 days, P < 0.05). The incidence of induction of labour was comparable (35.5% versus 38%, RR 0.91, 95% CI 0.57 - 1.46). The incidences of caesarean section and assisted vaginal delivery were comparable. The incidences of premature rupture of membranes, intrapartum, and postpartum infection were comparable. The perinatal outcomes were also comparable between the two groups. Up to 70% of women found that this procedure was associated with significant discomfort. One third of these women complained of significant pain. CONCLUSIONS Sweeping of membranes beyond 40 weeks does not reduce the need for formal induction of labour at 42 weeks. Although it is safe, the majority of women felt uncomfortable during the procedure.
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Affiliation(s)
- S F Wong
- Department of Obstetrics and Gynaecology, Princess Margaret Hospital, Hong Kong, SAR, People's Republic of China
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24
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Abstract
OBJECTIVE To investigate the effectiveness of misoprostol given vaginally for cervical priming before hysteroscopy in postmenopausal women. DESIGN Double-blind randomised controlled study. SETTING Regional hospital, Hong Kong. PARTICIPANTS One hundred women with postmenopausal bleeding scheduled for hysteroscopy from October 1998 to September 2001 were randomly assigned to receive either misoprostol or placebo vaginally before the operation. MAIN OUTCOME MEASURES The number of women requiring cervical dilatation, outcome of hysteroscopy and side effects of the medication were assessed. RESULTS Forty-eight women receiving misoprostol and 48 women receiving placebo were compared. The mean degree of endocervical diameter estimated by Hegar's dilator was similar between the treatment group and the control group. A similar number of women in the treatment group and the control group required cervical dilatation. The operative times for both groups were similar. The incidence of side effects was comparable in both groups. The most common side effects for misoprostol were febrile episodes and diarrhoea. There was no cervical tear nor uterine perforation encountered in both groups. The mean duration of hospital stay in both groups were similar. Subanalysis of results were similar in women receiving vaginal medication at least five hours before the operation. CONCLUSION Vaginal misoprostol was not shown to reduce the need for cervical dilatation in postmenopausal women. It cannot convert diagnostic hysteroscopy from a hospital procedure into an office one in postmenopausal women with tight cervical os.
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Affiliation(s)
- T M Fung
- Obstetrics and Gynaecology Unit, Princess Margaret Hospital, Lai Chi Kok, Hong Kong
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25
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Abstract
The aim of this study is to identify factor(s) influencing imbalance in the sex distribution of children (more children of the same sex) of the multiparous women attending an antenatal clinic in Hong Kong. A retrospective study was carried out to compare the expected and observed sex ratios of babies born to women with one previous live birth and women with two. All singleton pregnant women of parities 1 and 2 delivering after 22 weeks of gestation, between 1 July 1996 and 30 June 1998, were included. A total of 2604 women of parity 1 and 752 women of parity 2 were included. The sexes of the children of parity 1 women and the sex distribution of their newborns were consistent with the predicted value. The parity 2 women were more likely to have third children if their previous children were of the same sex (p-value < 0.001). This implies that the parity 2 women attending our antenatal clinic had third pregnancies because of social, economical or environmental reasons. Our parity 2 women with two daughters were more likely to have sons (p < 0.05). Thus, biological or parental factors were unlikely to be important in influencing the sex of the newborn. This suggested that sex selection or sex-selective abortion might be practiced among Hong Kong Chinese women.
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Affiliation(s)
- S F Wong
- Department of Obstetrics & Gynaecology, Princess Margaret Hospital, Lai Chi Kok, Kowloon, Hong Kong.
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26
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Abstract
A recently described cytotoxic monoclonal antibody (mAb 1D5) raised against Blastocystis hominis isolate B, was tested for reactivity with 13 different isolates of Blastocystis. The isolates used were previously isolated from humans, rats and reptiles and were maintained as axenised cultures throughout the course of this study. Five B. hominis isolates (B, C, E, G and H) were found to react with mAb 1D5 in immunoblotting studies and the indirect fluorescence antibody test. The pattern of fluorescence observed for all five isolates was diffuse and patchy. Immunoblotting studies revealed that mAb 1D5 reacted with a 29-30-kDa protein found in all five isolates. Results of a cytotoxic assay showed that the mAb exhibited a complement-independent cytotoxic effect on all the exposed isolates. Microscopic observations showed differences in morphology between the Blastocystis cells exposed and unexposed to mAb. Acridine orange staining performed on both exposed and unexposed cells showed similar internal structures when viewed under fluorescence microscopy.
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Affiliation(s)
- K S Tan
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore
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27
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Tan TC, Ho LC, Chiu HM, Leung SC. Subfrontal schwannoma masquerading as meningioma. Singapore Med J 2001; 42:275-7. [PMID: 11547967] [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: 02/21/2023]
Abstract
Intracranial schwannomas not associated with cranial nerves are rare and seldom encountered in the subfrontal region. We report a case of subfrontal schwannoma in a 21-year-old man who presented with seizures. Radiological features resembled an olfactory groove meningioma. The histological diagnosis of schwannoma was confirmed by immunohistochemical staining with S-100 and electron microscopy. We advocate the use of immunohistochemistry and electron microscopy as adjuncts to conventional light microscopy in differentiating schwannomas from meningiomas. Surgery remains the main therapeutic modality and complete excision is associated with cure.
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Affiliation(s)
- T C Tan
- Department of Neurosurgery, Queen Elizabeth Hospital, Hong Kong, China
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28
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Cheng KM, Chan CM, Fu YT, Ho LC, Tsang YW, Lee MK, Cheung YL, Law CK. Brain abscess formation in radiation necrosis of the temporal lobe following radiation therapy for nasopharyngeal carcinoma. Acta Neurochir (Wien) 2001; 142:435-40; discussion 440-1. [PMID: 10883341 DOI: 10.1007/s007010050454] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [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: 10/27/2022]
Abstract
BACKGROUND Radiation necrosis is a known complication following radiation therapy for extracranial as well as intracranial tumours. However, brain abscess formation in radiation necrosis has not been reported in the literature. We report the clinical data of 6 patients suffering from this condition. METHOD Twenty-eight patients with radiation necrosis of the temporal lobe following radiotherapy for nasopharyngeal carcinoma were treated surgically at the Department of Neurosurgery, Queen Elizabeth Hospital, Hong Kong between January 1992 and July 1999. Of these, 6 cases were complicated by brain abscess formation. The clinical data of these 6 patients are retrospectively reviewed. FINDINGS The patients were 5 males and 1 female, ranging in age from 41 to 67 years. Three patients had previous treatment with steroids for the symptomatic radiation necrosis. A history of nasal infection or otitis media was recognised in all 6 patients. All patients were treated surgically by temporal lobectomy and excision of the necrotic tissue together with the abscess cavity. Intra-operatively, a bony defect was observed between the middle cranial fossa and the sphenoid sinus in 3 patients and the bony defect was repaired with a temporalis muscle flap. The species of organisms could only be identified in 3 patients. In 3 patients, the pus smear was positive but the culture was negative. Subsequently, 4 patients recovered and 2 patients died. INTERPRETATION Cerebral radiation necrosis is a predisposing cause of brain abscess formation. Surgical excision is recommended as the treatment of choice in this group of patients.
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Affiliation(s)
- K M Cheng
- Department of Neurosurgery, Queen Elizabeth Hospital, Hong Kong, China
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29
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Ho LC, Jeyaseelan K, Singh M. Use of the elongation factor-1 alpha gene in a polymerase chain reaction-based restriction-fragment-length polymorphism analysis of genetic heterogeneity among Blastocystis species. Mol Biochem Parasitol 2001; 112:287-91. [PMID: 11223135 DOI: 10.1016/s0166-6851(00)00358-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- L C Ho
- Department of Microbiology, Faculty of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597, Singapore
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30
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Cheng KM, Chan CM, Fu YT, Ho LC, Cheung FC, Law CK. Acute hemorrhage in late radiation necrosis of the temporal lobe: report of five cases and review of the literature. J Neurooncol 2001; 51:143-50. [PMID: 11386411 DOI: 10.1023/a:1010631112015] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [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: 11/12/2022]
Abstract
Hemorrhage in late cerebral radiation necrosis is a rare complication after radiotherapy for intracranial and extracranial neoplasms. We report 5 cases of acute hemorrhage in late radiation necrosis of the temporal lobe following radiation therapy for nasopharyngeal carcinoma. In a review of the literature, the authors identified a total of 27 such cases. The interval period between the onset of hemorrhage and cranial irradiation is long (mean = 7.8 years). The most prominent histological feature was the proliferation of large, dilated and thin-walled new blood vessels in a background of gliosis and fibrinoid necrosis of vessels. Rupture of these thin-walled new blood vessels is the proposed mechanism of hemorrhage in this condition.
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Affiliation(s)
- K M Cheng
- Department of Neurosurgery, Queen Elizabeth Hospital, Kowloon, Hong Kong, China.
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31
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Chan LY, Yu VS, Ho LC, Lok YH, Hui SK. Spontaneous uterine perforation of pyometra. A report of three cases. J Reprod Med 2000; 45:857-60. [PMID: 11077640] [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] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
BACKGROUND Spontaneous perforation of pyometra is a rare cause of generalized peritonitis; only 17 cases have been reported. CASES Three cases of spontaneous perforation of pyometra occurred; two were associated with carcinoma of the cervix. All were treated with exploratory laparotomy and drainage. The first patient died of recurrent carcinoma of the cervix five months after laparotomy. The second patient died of septic shock shortly after the operation. The third patient made a good postoperative recovery. CONCLUSION Pyometra is a serious medical condition, because of both its association with malignant disease and the danger of spontaneous perforation, which carries significant morbidity and mortality. Although rare, ruptured pyometra should be considered in the differential diagnosis of acute abdomen in elderly women, especially those with malignant disorders of the genital tract. The treatment of pyometra rupture is immediate laparotomy, peritoneal lavage and drainage, or simple hysterectomy.
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Affiliation(s)
- L Y Chan
- Department of Obstetrics and Gynecology, Princess Margaret Hospital, Lai Chi Kok, Kowloon, Hong Kong
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32
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Ho LC, Armiugam A, Jeyaseelan K, Yap EH, Singh M. Blastocystis elongation factor-1alpha: genomic organization, taxonomy and phylogenetic relationships. Parasitology 2000; 121 ( Pt 2):135-44. [PMID: 11085233 DOI: 10.1017/s0031182099006113] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [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: 12/14/2022]
Abstract
The elongation factor-1 alpha (EF-1alpha) is a highly conserved ubiquitous protein that is involved in translation and is desirable for use in phylogenetic studies on Blastocystis, an enigmatic intestinal parasite with a contentious taxonomic position. In the present study, a PCR product (BEalpha) that codes for a major part of the coding region of the EF-lalpha protein was amplified. Genome walking experiments together with cloning were implemented to elucidate the 5' and 3' ends of the EF-1alpha gene of the human isolate, Blastocystis hominis C. The genomic organization and the potential transcription factor binding sites of the 5' end of B. hominis C EF-1alpha were identified. A comparative study on the deduced amino acid sequences of BEalpha of 13 Blastocystis isolates from various hosts was done to evaluate the phylogenetic relationship among the species. A phylogenetic reconstruction analysis with other eukaryotic EF-1alpha sequences was carried out to trace the phylogenetic position of Blastocystis among eukaryotic organisms.
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Affiliation(s)
- L C Ho
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore
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33
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Terashima Y, Ho LC, Ptak AF, Yaqoob T, Kunieda H, Misaki K, Serlemitsos PJ. Iron K Line Variability in the Low-Luminosity Active Galactic Nucleus NGC 4579. Astrophys J 2000; 535:L79-L82. [PMID: 10835303 DOI: 10.1086/312710] [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] [Received: 03/15/2000] [Accepted: 04/27/2000] [Indexed: 05/23/2023]
Abstract
We present results of new ASCA observations of the low-luminosity active galactic nucleus (LLAGN) NGC 4579 obtained on 1998 December 18 and 28, and we report on the detection of variability of an iron K emission line. The X-ray luminosities in the 2-10 keV band for the two observations are nearly identical (LX approximately 2x1041 ergs s(-1)), but they are approximately 35% larger than that measured in 1995 July by Terashima et al. An Fe K emission line is detected at 6.39+/-0.09 keV (source rest frame), which is lower than the line energy 6.73+0.13-0.12 keV in the 1995 observation. If we fit the Fe lines with a blend of two Gaussians centered at 6.39 and 6.73 keV, the intensity of the 6.7 keV line decreases, while the intensity of the 6.4 keV line increases, within an interval of 3.5 yr. This variability rules out thermal plasmas in the host galaxy as the origin of the ionized Fe line in this LLAGN. The detection and variability of the 6.4 keV line indicates that cold matter subtends a large solid angle viewed from the nucleus and that it is located within approximately 1 pc from the nucleus. It could be identified with an optically thick standard accretion disk. If this is the case, a standard accretion disk is present at the Eddington ratio of Lbol/LEdd approximately 2x10-3. A broad disk-line profile is not clearly seen, and the structure of the innermost part of accretion disk remains unclear.
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Shields JC, Rix HW, McIntosh DH, Ho LC, Rudnick G, Filippenko AV, Sargent WL, Sarzi M. Evidence for a Black Hole and Accretion Disk in the LINER NGC 4203. Astrophys J 2000; 534:L27-L30. [PMID: 10790063 DOI: 10.1086/312660] [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] [Received: 12/31/1999] [Accepted: 03/17/2000] [Indexed: 05/23/2023]
Abstract
We present spectroscopic observations from the Hubble Space Telescope that reveal for the first time the presence of a broad pedestal of Balmer line emission in the LINER galaxy NGC 4203. The emission-line profile is suggestive of a relativistic accretion disk and is reminiscent of double-peaked transient Balmer emission observed in a handful of other LINERs. The very broad line emission thus constitutes clear qualitative evidence for a black hole, and spatially resolved narrow-line emission in NGC 4203 can be used to constrain its mass, MBH</=6x106 M middle dot in circle, at 99.7% confidence. This value implies a ratio of black hole mass to bulge mass of less, similar7x10-4 in NGC 4203, which is less by a factor of approximately 3-9 than the mean ratio obtained for other galaxies. The availability of an independent constraint on central black hole mass makes NGC 4203 an important testbed for probing the physics of weak active galactic nuclei. Assuming MBH near the detection limit, the ratio of the observed luminosity to the Eddington luminosity is approximately 10-4. This value is consistent with advection-dominated accretion and hence with scenarios in which an ion torus irradiates an outer accretion disk that produces the observed double-peaked line emission. Follow-up observations will make it possible to improve the black hole mass estimate and study variability in the nuclear emission.
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35
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Abstract
Aging of the face is staged. Rejuvenation by restoration of structural volume deficit with sedimented autogenous fat micrografts harvested by gentle syringe lipoaspiration is described. Atraumatic technique, avoidance of desiccation, and gentleness in handling the fat micrografts are required for successful vascularization and take of the grafts.
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36
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Quataert E, Narayan R, Ho LC. Possible Evidence for Truncated Thin Disks in the Low-Luminosity Active Galactic Nuclei M81 and NGC 4579. Astrophys J 1999; 525:L89-L92. [PMID: 10525461 DOI: 10.1086/312353] [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: 05/23/2023]
Abstract
M81 and NGC 4579 are two of the few low-luminosity active galactic nuclei that have an estimated mass for the central black hole, detected hard X-ray emission, and detected optical/UV emission. In contrast to the canonical "big blue bump," both have optical/UV spectra that decrease with increasing frequency in a nuLnu plot. Barring significant reddening by dust and/or large errors in the black hole mass estimates, the optical/UV spectra of these systems require that the inner edge of a geometrically thin, optically thick accretion disk lies at approximately 100 Schwarzschild radii. The observed X-ray radiation can be explained by an optically thin, two-temperature, advection-dominated accretion flow at smaller radii.
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37
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Affiliation(s)
- K W Lee
- Department of Obstetrics and Gynaecology, Princess Margaret Hospital, Kowloon, Hong Kong
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38
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Chen XQ, Singh M, Ho LC, Tan SW, Yap EH. Characterization of protein profiles and cross-reactivity of Blastocystis antigens by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis. Parasitol Res 1999; 85:343-6. [PMID: 10099019 DOI: 10.1007/s004360050559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [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: 12/20/2022]
Abstract
The protein profiles of Blastocystis hominis, B. lapemi, and B. ratti were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and species could be differentiated by this means as well as by Western-blot analysis with polyclonal antibodies. No intraspecies difference could be distinguished between the two B. hominis isolates or the three B. ratti isolates. Western-blot analysis showed extensive cross-reactivity of B. lapemi and B. hominis antigens with anti-B. ratti serum. Some of the cross-reactive antigens were glycoproteins as determined on the basis of their sensitivity to periodate treatment.
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Affiliation(s)
- X Q Chen
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore
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Abstract
The development of cysts of Blastocystis hominis isolated from human feces by the Ficoll-Paque concentration method and cultured in Jones' medium containing 10% horse serum is described. The morphological changes were studied by light and transmission electron microscopy at different intervals for up to 48 h. The cysts developed into a large number of vacuolar forms within 24 h, and binary fission was the only mode of reproduction observed.
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Affiliation(s)
- K T Moe
- Department of Microbiology, Faculty of Medicine, National University of Singapore
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Abstract
Cysts of Blastocystis ratti were produced in vitro by culturing the parasite in Iscove's modified Dulbecco's medium (IMDM) with increasing concentrations of horse serum. Yields up to 3 x 10(6) cysts/ml of culture medium were obtained after 72 h. Encystation efficiency was time, strain and inoculum size dependent. A viability of > 70% was determined by flow cytometry employing fluorescein diacetate and propidium iodide staining. The presence of chitin as a cyst wall component was demonstrated by Calcofluor White M2R staining with which cystic stages showed blue fluorescence. The changes in morphology during excystation were examined by transmission electron microscopy. The cyst enlarged in size and some vacuoles appeared within the condensed cytoplasm. The vacuoles were full of inclusions and small glycogen aggregates. Coalescence of the vacuoles led to central body formation. Glycogen deposits were prominent throughout the excystation process. Some cysts divided by binary fission before the completion of the excystation.
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Affiliation(s)
- X Q Chen
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore
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Ho LC, Olivi A, Cho CH, Burger PC, Simeone F, Tihan T. Well-differentiated papillary adenocarcinoma arising in a supratentorial enterogenous cyst: case report. Neurosurgery 1998; 43:1474-7. [PMID: 9848864 DOI: 10.1097/00006123-199812000-00131] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [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: 11/26/2022] Open
Abstract
OBJECTIVE AND IMPORTANCE We report a case of a well-differentiated papillary adenocarcinoma arising in an supratentorial enterogenous cyst. The clinicopathological features of this case and a brief review of the literature are presented. CLINICAL PRESENTATION A 45-year-old woman presented with abrupt onset of sensory seizures and abnormal sensation on the left side of her face, left leg, and left arm. Radiological studies showed a cystic extraaxial tumor with mass effect in the right parietal area. The initial clinical impression was a metastatic lesion, and a comprehensive metastatic workup revealed no evidence of tumor elsewhere. INTERVENTION A gross total resection of the solid cystic tumor was achieved by a frontoparietal craniotomy. Sixteen months after the initial surgery, the patient presented with signs of increased intracranial pressure and a large parietal cyst. The cyst was fenestrated at the time of the second craniotomy. CONCLUSION A pathological study of the initial surgical material revealed it to be a well-differentiated papillary adenocarcinoma in association with an enterogenous cyst. The second surgical specimen consisted only of the benign cyst wall. The patient recovered uneventfully from the second surgery and was free of symptoms 6 months postoperatively. The importance of recognizing the rare possibility of malignant progression of a benign enterogenous cyst in the central nervous system is discussed.
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Affiliation(s)
- L C Ho
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
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Abstract
Between January 1, 1994 and December 31, 1997 a total of 76 low-risk multiparas of 40 years and older with spontaneous onset of labour were delivered and were compared with 152 younger (25-30 years-old) low-risk multiparas of similar parity in a case-control study. The labour and perinatal outcomes of the 2 groups were compared. The duration of the first stage of labour was longer (233 minutes versus 149 minutes, p<0.0005) in the older women. Significantly more labours of older multiparas were complicated by intrapartum fetal distress (6.6% versus 1.3%, p<0.05); received intramuscular analgesia (11.8% versus 2.6%, p<0.01); and had operative deliveries (17.1% versus 4.6%, p<0.01). The incidence of instrumental delivery (11.8% versus 3.9%, p<0.05) and Caesarean section (5.3% versus 0.7%, p<0.05) were higher among older multiparas. The incidences of Syntocinon augmentation of labour, prolonged second stage, episiotomy and third stage complications such as perineal tear, primary postpartum haemorrhage, and retained placenta were similar in both groups. Both groups had similar perinatal outcomes. These women should be treated as others with high-risk pregnancies with appropriate careful attention during labour such as continuous fetal heart rate monitoring. They should be counselled to be made aware of the increased risks during labour.
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Affiliation(s)
- S F Wong
- Department of Obstetrics and Gynaecology, Princess Margaret Hospital, Lai Chi Kok, New Territory, Hong Kong
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Moe KT, Singh M, Gopalakrishnakone P, Ho LC, Tan SW, Chen XQ, Yap EH. Cytopathic effect of Blastocystis hominis after intramuscular inoculation into laboratory mice. Parasitol Res 1998; 84:450-4. [PMID: 9660133 DOI: 10.1007/s004360050428] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [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: 12/22/2022]
Abstract
The present study investigated the pathogenesis of Blastocystis hominis by intramuscular injection of the organism into experimental mice. A total of 27 naïve BALB/c mice aged 6-8 weeks were injected in the leg muscle with axenic culture isolate B of B. hominis. Histological examination at different times revealed that B. hominis could produce a severe inflammatory reaction and myonecrosis. Most changes were observed at 6 h after injection and for up to 2-3 days. By 2 weeks the muscle had regained normal histology. There was infiltration of polymorphonuclear leukocytes (PML) into the injection site, indicating that B. hominis had a strong chemoattractant activity for PML.
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Affiliation(s)
- K T Moe
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore
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Tan SW, Singh M, Ho LC, Howe J, Moe KT, Chen XQ, Ng GC, Yap EH. Survival of Blastocystis hominis clones after exposure to a cytotoxic monoclonal antibody. Int J Parasitol 1997; 27:947-54. [PMID: 9292311 DOI: 10.1016/s0020-7519(97)00066-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [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: 02/05/2023]
Abstract
Our previous studies have shown that monoclonal antibodies (MAbs) to Blastocystis hominis react mainly with carbohydrate epitopes, while 1 MAb (1D5) reacts specifically with a protein of 30.5 kDa. In the present study, 3 monoclonal antibodies (1D5, 1E7 and 4F7) were used in immunogold localization. 1E7 and 4F7 were found to react primarily with the surface coat, while 1D5 was plasma membrane-specific. In the presence of complement, only 1D5 exhibited a cytotoxic effect on B. hominis whereas 1E7 and 4F7 did not, suggesting that the surface coat of B. hominis could serve as an immunological barrier against host antibodies. Using a recently described agar plating method, only 1D5 exhibited significant (P < 0.01) complement-independent cytotoxicity to B. hominis, inhibiting colony growth at low concentrations. Parasites that had been exposed to 1D5 were morphologically smaller than those that were not exposed to this MAb. Colonies that grew in the presence of 1D5 were isolated and grown in liquid medium containing increasing amounts of the cytotoxic MAb. Two clones that grew well in liquid medium containing 1D5 were also able to develop into colonies in soft agar. This study has shown that the 30.5 kDa protein found on the plasma membrane of B. hominis is a functionally important protein and that not all cells within a certain population would be susceptible to the cytotoxic effects of 1D5. These findings suggest that a heterogenous population exists in continuously maintained cultures of B. hominis.
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Affiliation(s)
- S W Tan
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore.
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Chen XQ, Singh M, Ho LC, Moe KT, Tan SW, Yap EH. A survey of Blastocystis sp. in rodents. Lab Anim Sci 1997; 47:91-4. [PMID: 9051654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- X Q Chen
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore
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Abstract
Young (less than 8 weeks old) immunocompetent BALB/c mice became infected with Blastocystis hominis after inoculation of fecal cysts orally and of in vitro axenic-culture forms intracecally. This study confirmed that the fecal cyst was the form responsible for external transmission and that the mode of transmission was by the fecal-oral route. The infection was self-limiting and the infected BALB/c mice appeared normal except that some of them showed weight loss and lethargy. Both vacuolar and granular forms were found in the cecum, but only cyst forms were observed in the colon. Histological examination of the cecum and colon showed intense inflammatory-cell infiltration, edematous lamina propria, and mucosal sloughing. It is apparent that although B. hominis is not invasive, it is capable of causing pathogenesis in BALB/c mice.
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Affiliation(s)
- K T Moe
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Republic of Singapore
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Abstract
Two isolates (WR1 and WR2) of Blastocystis from laboratory-bred Wistar rats were axenized by a method of colony growth in soft agar combined with antibiotic treatment. The colonies were cultured in Iscove's modified Dulbecco's medium (IMDM) and Bacto agar mixture supplemented with 10% horse serum in the presence of thioglycollate. The cells from the colonies had an ameboid outline with a central body. Large inclusions were seen in the central body of some cells. Some granular forms were also found. In the axenic culture of isolate WR2, about one-third of the organisms were granular forms. Cysts were found in the axenic culture of both isolates. This is the first report of such cyst formation in in vitro culture. The karyotypic patterns of both isolates of the rat Blastocystis were analyzed by pulsed-field gel electrophoresis (PFGE). A total of 13 chromosomal bands were separated, ranging from 1.86 Mb to 295 kb. The karyotypic patterns of the rat Blastocystis were different from those of B. hominis and reptilian Blastocystis. On the basis of the above-mentioned differences, the rat Blastocystis is assigned as B. ratti sp. nov.
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Affiliation(s)
- X Q Chen
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore
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Tan SW, Singh M, Thong KT, Ho LC, Moe KT, Chen XQ, Ng GC, Yap EH. Clonal growth of Blastocystis hominis in soft agar with sodium thioglycollate. Parasitol Res 1996; 82:737-9. [PMID: 8897510 DOI: 10.1007/s004360050194] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [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: 02/02/2023]
Abstract
The present report describes a method for establishment of colonies of Blastocystis hominis from single cells in soft agar. The percentage of colony-forming efficiency (% CFE = number of colonies grown/number of cells inoculated x 100) for the cultures was greatly improved by the addition of sodium thioglycollate. Five human Blastocystis isolates chosen for this study showed no apparent variation in colonial morphology. Isolated colonies were also successfully grown in liquid medium, providing a means of obtaining large numbers of B. hominis cells that had arisen from a single clone.
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Affiliation(s)
- S W Tan
- Department of Microbiology, Faculty of Medicine, National University of Singapore
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Ho LC. The mechanism of assimilate partitioning and carbohydrate compartmentation in fruit in relation to the quality and yield of tomato. J Exp Bot 1996; 47 Spec No:1239-1243. [PMID: 21245255 DOI: 10.1093/jxb/47.special_issue.1239] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The limitation of tomato yield was investigated in a number of cultivars with contrasting fruiting habits. Unless light is limiting, yield is mainly restricted by the number or the size of the fruit (i.e. the sink strength) rather than the supply of assimilate (i.e. the source strength). Fruit size is determined by both cell number and cell size. The rate of fruit expansion is affected by assimilate supply, temperature and water relations in the plant. The size or the growth rate of a tomato fruit is regulated by the import of assimilate and water. The sink strength for assimilate of a tomato fruit measured by the rate of assimilate import may be related to the routes of sugar transport into the sink cells during fruit development. Enzymic regulation of the hydrolysis of sucrose by sucrose synthase and the accumulation of starch by ADPG pyrophosphorylase may determine the rate of assimilate import in the young fruit. Vacuolar invertase activity may determine the sugar composition of a mature fruit, but may not affect the overall dry matter accumulation of a tomato fruit. While yield is determined by the balance between source and sink strengths of the plant, quality is determined by the transport and metabolism of sugars within the fruit.
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Affiliation(s)
- L C Ho
- Department of Annual Crops, Horticulture Research International, Wellesbourne, Warwick CV35 9EF, UK
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