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Satheesan MK, Tsang TW, Wong LT, Mui KW. The air we breathe: Numerical investigation of ventilation strategies to mitigate airborne dispersion of MERS-CoV in inpatient wards. Heliyon 2024; 10:e26159. [PMID: 38404798 PMCID: PMC10884507 DOI: 10.1016/j.heliyon.2024.e26159] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 01/03/2024] [Accepted: 02/08/2024] [Indexed: 02/27/2024] Open
Abstract
Ventilation strategies for infection control in hospitals has been predominantly directed towards isolation rooms and operating theatres, with relatively less emphasis on perceived low risk spaces, such as general wards. Typically, the ventilation systems in general wards are intended to optimize patient thermal comfort and energy conservation. The emission of pathogens from exhalation activity, such as sneezing, by an undiagnosed infectious patient admitted to general wards, is a significant concern for infection outbreaks. However, the ventilation guidelines for general wards with respect to infection control are vague. This research article presents a numerical study on the effect of varying air change rates (3 h-1, 6 h-1, 9 h-1, 13 h-1) and exhaust flow rates (10%, 50% of supply air quantity) on the concentration of airborne pathogens in a mechanically ventilated general inpatient ward. The findings imply that the breathing zone directly above the source patient has the highest level of pathogen exposure, followed by the breathing zones at the bedside and adjacent patients close to the source patient. The dispersion of pathogens throughout the ward over time is also apparent. However, a key difference while adopting a lower ACH (3 h-1) and a higher ACH (13 h-1) in this study was that the latter had a significantly lower number of suspended pathogens in the breathing zone than the former. Thus, this research suggests high ventilation rates for general wards, contrary to current ventilation standards. In addition, combining a higher air change rate (13 h-1) with a high exhaust flow rate (50% of supply air) through a local exhaust grille dramatically reduced suspended pathogens within the breathing zone, further mitigating the risk of pathogen exposure for ward users. Therefore, this study presents an effective ventilation technique to dilute and eliminate airborne infectious pathogens, minimizing their concentration and the risk of infection.
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Affiliation(s)
- Manoj Kumar Satheesan
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Tsz Wun Tsang
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Ling Tim Wong
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Kwok Wai Mui
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
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Satheesan MK, Mui KW, Wong LT. A numerical study of ventilation strategies for infection risk mitigation in general inpatient wards. Build Simul 2020; 13:887-896. [PMID: 32211123 PMCID: PMC7090571 DOI: 10.1007/s12273-020-0623-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/16/2020] [Accepted: 02/15/2020] [Indexed: 05/03/2023]
Abstract
Aerial dispersion of human exhaled microbial contaminants and subsequent contamination of surfaces is a potential route for infection transmission in hospitals. Most general hospital wards have ventilation systems that drive air and thus contaminants from the patient areas towards the corridors. This study investigates the transport mechanism and deposition patterns of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) within a typical six bedded general inpatient ward cubicle through numerical simulation. It demonstrates that both air change and exhaust airflow rates have significant effects on not only the airflow but also the particle distribution within a mechanically ventilated space. Moreover, the location of an infected patient within the ward cubicle is crucial in determining the extent of infection risk to other ward occupants. Hence, it is recommended to provide exhaust grilles in close proximity to a patient, preferably above each patient's bed. To achieve infection prevention and control, high exhaust airflow rate is also suggested. Regardless of the ventilation design, all patients and any surfaces within a ward cubicle should be regularly and thoroughly cleaned and disinfected to remove microbial contamination. The outcome of this study can serve as a source of reference for hospital management to better ventilation design strategies for mitigating the risk of infection.
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Affiliation(s)
- Manoj Kumar Satheesan
- Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Kwok Wai Mui
- Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Ling Tim Wong
- Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China
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3
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Abstract
Bioaerosol (i.e. biological aerosol) exposures in the office environment are associated with a wide range of health effects. The potential bioaerosol emission from mechanical ventilation and air conditioning (MVAC) systems can endanger the building occupants in office, especially as over 90% of commercial buildings in Hong Kong that are equipped with MVAC systems, due to the microbial growths inside MVAC systems, such as cooling coils and mixing chamber, were reported. This study evaluated the exposure risk of the bioaerosol emission from the MVAC systems to the building occupants. A two-phase flow computational fluid dynamics approach was adopted to simulate the emission, dispersion, deposition, and exhaustion of bioaerosol particles from the MVAC systems in a typical office cubicle by altering the ventilation strategies with four ventilation rates, four emission concentrations, and two microorganism species. The results reported that about 5% contribution of concentration level from the MVAC system including the ventilation rate is sufficient to dilute the biocontainment. This study suggested the importance of the maintenance strategies of MVAC systems for minimizing bioaerosol exposures in offices.
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Affiliation(s)
- HC Yu
- Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - KW Mui
- Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - LT Wong
- Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China
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4
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Davidson AG, Wong LT, Kirby L, Tze WJ, Rigg JM, Applegarth DA. Glycogen storage disease type I: effect of continuous nocturnal nasogastric feeding. Monogr Hum Genet 2015; 9:29-36. [PMID: 104148 DOI: 10.1159/000401607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
UNLABELLED Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death. The relationship between urban air pollution and its short-term health effects on patients suffering from COPD is confirmed. However, information about the impact of air pollutants upon the quality of life (QOL) in patients with COPD is lacking. Through a cross-sectional survey, this study investigates such impact in terms of the scores of the (Chinese) chronic respiratory questionnaire (CCRQ) and the measurements of indoor air quality (IAQ), lung function and Moser's activities of daily living (ADL). Using Yule's Q statistic with a cutoff |Q|>0.7 to identify the strong relationships between environmental parameters and CRQ sub-scores, this study reveals that patient emotion is strongly associated with indoor environmental quality although the evidence of a causal relationship between them needs further research. PRACTICAL IMPLICATIONS As QOL in patients with COPD and indoor environmental parameters are strongly associated, indoor air pollutants must be monitored for related studies in the future.
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Affiliation(s)
- K N K Fong
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, China
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Mui KW, Wong LT, Chung LY. Mathematical models for accurate prediction of atmospheric visibility with particular reference to the seasonal and environmental patterns in Hong Kong. Environ Monit Assess 2009; 158:333-341. [PMID: 18951139 DOI: 10.1007/s10661-008-0587-9] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Accepted: 09/29/2008] [Indexed: 05/27/2023]
Abstract
Atmospheric visibility impairment has gained increasing concern as it is associated with the existence of a number of aerosols as well as common air pollutants and produces unfavorable conditions for observation, dispersion, and transportation. This study analyzed the atmospheric visibility data measured in urban and suburban Hong Kong (two selected stations) with respect to time-matched mass concentrations of common air pollutants including nitrogen dioxide (NO(2)), nitrogen monoxide (NO), respirable suspended particulates (PM(10)), sulfur dioxide (SO(2)), carbon monoxide (CO), and meteorological parameters including air temperature, relative humidity, and wind speed. No significant difference in atmospheric visibility was reported between the two measurement locations (p > or = 0.6, t test); and good atmospheric visibility was observed more frequently in summer and autumn than in winter and spring (p < 0.01, t test). It was also found that atmospheric visibility increased with temperature but decreased with the concentrations of SO(2), CO, PM(10), NO, and NO(2). The results showed that atmospheric visibility was season dependent and would have significant correlations with temperature, the mass concentrations of PM(10) and NO(2), and the air pollution index API (correlation coefficients mid R: R mid R: > or = 0.7, p < or = 0.0001, t test). Mathematical expressions catering to the seasonal variations of atmospheric visibility were thus proposed. By comparison, the proposed visibility prediction models were more accurate than some existing regional models. In addition to improving visibility prediction accuracy, this study would be useful for understanding the context of low atmospheric visibility, exploring possible remedial measures, and evaluating the impact of air pollution and atmospheric visibility impairment in this region.
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Affiliation(s)
- K W Mui
- Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
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Inayat-Hussain SH, Wong LT, Chan KM, Rajab NF, Din LB, Harun R, Kizilors A, Saxena N, Mourtada-Maarabouni M, Farzaneh F, Williams GT. RACK-1 overexpression protects against goniothalamin-induced cell death. Toxicol Lett 2009; 191:118-22. [PMID: 19698770 PMCID: PMC2845802 DOI: 10.1016/j.toxlet.2009.08.012] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 08/12/2009] [Accepted: 08/12/2009] [Indexed: 01/05/2023]
Abstract
Goniothalamin, a styryllactone, has been shown to induce cytotoxicity via apoptosis in several tumor cell lines. In this study, we have examined the potential role of several genes, which were stably transfected into T-cell lines and which regulate apoptosis in different ways, on goniothalamin-induced cell death. Overexpression of full-length receptor for activated protein C-kinase 1 (RACK-1) and pc3n3, which up-regulates endogenous RACK-1, in both Jurkat and W7.2 T cells resulted in inhibition of goniothalamin-induced cell death as assessed by MTT and clonogenic assays. However, overexpression of rFau (antisense sequence to Finkel-Biskis-Reilly murine sarcoma virus-associated ubiquitously expressed gene) in W7.2 cells did not confer resistance to goniothalamin-induced cell death. Etoposide, a clinically used cytotoxic agent, was equipotent in causing cytotoxicity in all the stable transfectants. Assessment of DNA damage by Comet assay revealed goniothalamin-induced DNA strand breaks as early as 1 h in vector control but this effect was inhibited in RACK-1 and pc3n3 stably transfected W7.2 cells. This data demonstrate that RACK-1 plays a crucial role in regulating cell death signalling pathways induced by goniothalamin.
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Affiliation(s)
- S H Inayat-Hussain
- Toxicology and Biocompatibility Laboratory, Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia.
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Mui KW, Wong LT, Hui PS. An approach to assessing the probability of unsatisfactory radon in air-conditioned offices of Hong Kong. J Environ Radioact 2008; 99:248-59. [PMID: 17850935 DOI: 10.1016/j.jenvrad.2007.07.013] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 07/16/2007] [Accepted: 07/25/2007] [Indexed: 05/17/2023]
Abstract
In order to maintain an acceptable Indoor Air Quality (IAQ), policies, strategies and guidelines have been developed worldwide and exposure concentrations of the indoor radon have been specified. Mapping indoor radon levels for a region could be done with intensive measurements on a large number of samples. To obtain the most accurate estimate of the levels with the uncertainties specified, a statistical model has been developed in this study to predict the fractions of samples in a region having an average radon level above the action levels of 150Bqm(-3) and 200Bqm(-3). The model was based on a transformation of the variation from a small sample set of data to a population geometric distribution via an estimator, known as the 'sample correction factor'. Using a dataset from a cross-sectional measurement of indoor radon levels in 216 Hong Kong offices, where the mean was 37.2Bqm(-3) and the 68% range was from 17.3Bqm(-3) to 80.3Bqm(-3), the 'sample correction factor' was evaluated and tested by the Monte-Carlo simulations. The model estimates of the fractions above the indoor radon action levels 150Bqm(-3) and 200Bqm(-3) (1.2-7.7% and 0.4-4.1% for a sample size of 20, 2.8-5.1% and 0.8-2.4% for a sample size of 60) were demonstrated to be consistent with those determined from the dataset (3.5% and 1.4%). With the 'sample correction factor' thus quantified, it will be possible to provide the required data for the policymakers making appropriate decisions on resources and manpower management.
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Affiliation(s)
- K W Mui
- Department of Building Services Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
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Abstract
INTRODUCTION Patients diagnosed with peritoneal carcinomatous usually survive for less than 6 months. Cytoreductive surgery allows relief of the obstruction and improvement in functional status, while intraperitoneal chemotherapy infusion provides high local concentrations of chemotherapeutic agents. Our institutional experience is reviewed to assess the selection criteria, peri-operative complications, and outcomes. MATERIALS AND METHODS We carried out a retrospective review of nine patients who had undergone aggressive cytoreductive surgery and hyperthermic intra- and early post-operative chemotherapy by a single surgeon between April 2000 and October 2004. The inclusion criteria were: (1) a demonstrated absence of extra-peritoneal and hepatic spread, (2) fitness of the patient and ability to tolerate cytoreductive surgery and intra-operative chemotherapy, and (3) the presence of a primary tumor originating form the gastro-intestinal tract (colonic, appendiceal, and gastric primaries). RESULTS Seven women and two men, with a median age of 55 years, were treated. The median duration of the operation was 12 hours and 55 minutes. Seven of the nine patients required the insertion of at least one chest tube. All patients were monitored in the surgical intensive care unit (SICU) for a median of 1 day, started on feeds after a median of 6 days, and were hospitalized for a median of 16 days (range:11-18 days). There was no peri-operative mortality and only one major peri-operative complication (11.1%). At the time of analysis, the median follow-up was 16 months (range: 2-40 months), and the median disease-free survival was 8 months, with four of the nine patients showing no evidence of recurrence. To date, all of the patients are still alive. A 1-year survival rate of 100% is also documented. CONCLUSIONS This article describes our initial experience with peritonectomy and intra-operative, intra-peritoneal chemotherapy infusion. Our initial problems included difficulty with leakage of the chemotherapeutic agents into the thoracic cavity that had to be overcome by the early insertion of chest-tubes. With appropriate patient selection, cytoreductive surgery with the infusion of intra-operative chemotherapy can be considered to be a therapeutic option for some patients with diffuse peritoneal metastases, and good disease-free and overall survival can be achieved with minimal morbidity.
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Affiliation(s)
- M Teo
- Department of Surgical, National Cancer Centre of Singapore, Singapore.
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10
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Poopalalingam R, Chow MYH, Wong LT. Patient-controlled epidural analgesia after thoracic and upper abdominal surgery using sufentanil with and without bupivacaine 0.125%. Singapore Med J 2003; 44:126-30. [PMID: 12953725] [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: 03/04/2023]
Abstract
BACKGROUND Epidural sufentanil can relieve postoperative pain after thoracic and upper abdominal surgery but it has some unwanted side effects. Patient-controlled epidural analgesia (PCEA) allows patients to titrate and reduce their analgesic requirements. OBJECTIVE The study aims to assess the use of demand-only PCEA after thoracotomy and upper abdominal surgery using sufentanil with or without bupivacaine in terms of pain control, amount of analgesic required and side effect profile. METHODS After the Hospital Ethics Committee approval and written informed consent, 34 ASA I and II patients were enrolled in this prospective, randomised, double-blinded controlled study. Post-operatively, after achieving adequate analgesia in the recovery, the patients were randomised to receive either sufentanil 1 microg/ml in normal saline (Group S) or sufentanil 1 microg/ml with bupivacaine 0.125% (Group SB) in a demand-only PCEA programme. Pain scores, side effects and amount of analgesia used were reviewed every hour. RESULTS The demographic profile of both groups was similar. The amount of sufentanil used was higher in Group S than in Group SB but it was not statistically significant. The numbers of patients with high pain scores at rest and during movement were not significantly different between the two groups. The side effect profiles of both groups were similar. CONCLUSIONS The PCEA demand-only programme using sufentanil 1 microg/ml with and without bupivacaine 0.125% was satisfactory after thoracotomy and upper abdominal surgery in our patient population. The addition of bupivacaine to sufentanil did not significantly reduce the amount of sufentanil required, the pain scores or the side effects.
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Affiliation(s)
- R Poopalalingam
- Department of Anaesthesia and Surgical Intensive Care, Singapore General Hospital, Outram Road, Singapore 169608.
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Mahenthiralingam E, Vandamme P, Campbell ME, Henry DA, Gravelle AM, Wong LT, Davidson AG, Wilcox PG, Nakielna B, Speert DP. Infection with Burkholderia cepacia complex genomovars in patients with cystic fibrosis: virulent transmissible strains of genomovar III can replace Burkholderia multivorans. Clin Infect Dis 2001; 33:1469-75. [PMID: 11588691 DOI: 10.1086/322684] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2001] [Revised: 04/04/2001] [Indexed: 11/03/2022] Open
Abstract
Infection with Burkholderia cepacia complex in patients with cystic fibrosis (CF) results in highly variable clinical outcomes. The purpose of this study was to determine if there are genomovar-specific disparities in transmission and disease severity. B. cepacia complex was recovered from 62 patients with CF on > or =1 occasions (genomovar III, 46 patients; genomovar II [B. multivorans], 19 patients; genomovar IV [B. stabilis], 1 patient; genomovar V [B. vietnamiensis], 1 patient; and an unclassified B. cepacia complex strain, 1 patient). Patient-to-patient spread was observed with B. cepacia genomovar III, but not with B. multivorans. Genomovar III strains replaced B. multivorans in 6 patients. Genomovar III strains were also associated with a poor clinical course and high mortality. Infection control practices should be designed with knowledge about B. cepacia complex genomovar status; patients infected with transmissible genomovar III strains should not be cohorted with patients infected with B. multivorans and other B. cepacia genomovars.
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Affiliation(s)
- E Mahenthiralingam
- Department of Pediatrics, University of British Columbia and British Columbia's Children's Hospital, British Columbia's Research Institute for Children's and Women's Health, Vancouver, British Columbia, Canada
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McIlwaine PM, Wong LT, Peacock D, Davidson AG. Long-term comparative trial of positive expiratory pressure versus oscillating positive expiratory pressure (flutter) physiotherapy in the treatment of cystic fibrosis. J Pediatr 2001; 138:845-50. [PMID: 11391327 DOI: 10.1067/mpd.2001.114017] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The objective was to evaluate the long-term effects of physiotherapy with an oscillating positive pressure device ("flutter") compared with physiotherapy with the use of a positive expiratory pressure (PEP) mask in patients with cystic fibrosis (CF). STUDY DESIGN Forty children with CF were randomly assigned to performing physiotherapy with the PEP mask or the flutter device for 1 year. Clinical status, pulmonary function, and compliance were measured at regular intervals throughout the study. RESULTS The flutter group demonstrated a greater mean annual rate of decline in forced vital capacity compared with the PEP group (-8.62 +/- 15.5 vs 0.06 +/- 7.9; P =.05) with a similar trend in forced expiratory volume in 1 second (-10.95 +/- 19.96 vs -1.24 +/- 9.9; P =.08). There was a significant decline in Huang scores (P =.05), increased hospitalizations (18 vs 5; P =.03), and antibiotic use in the flutter group. CONCLUSION Flutter was not as effective in maintaining pulmonary function in this group of patients with CF compared with PEP and was more costly because of the increased number of hospitalizations and antibiotic use.
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Affiliation(s)
- P M McIlwaine
- Department of Paediatrics, University of British Columbia, B.C.'s Children's Hospital, 4480 Oak Street, Vancouver, British Columbia V6H 3V4, Canada
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Abstract
Photoonycholysis in association with a generalized phototoxic reaction or as an isolated event is a well-recognized complication of the tetracycline group of antibiotics. We describe a 14-year-old white girl with cystic fibrosis who developed photoonycholysis of all 20 nails while receiving treatment with doxycycline. Pediatricians who prescribe tetracyclines should be aware of this potential complication.
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Affiliation(s)
- C K Yong
- Division of Biochemical Diseases, Department of Pediatrics, British Columbia's Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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Ning J, Wong LT, Christoff B, Carmichael FJ, Biro GP. Haemodynamic response following a 10% topload infusion of HemolinkTM in conscious, anaesthetized and treated spontaneously hypertensive rats. Transfus Med 2000; 10:13-22. [PMID: 10760199 DOI: 10.1046/j.1365-3148.2000.00225.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
HemolinkTM (HLK), a haemoglobin-based oxygen carrier (HBOC), is currently undergoing Phase II/III clinical trials in surgical patients. It causes some blood pressure rise in animal and human tests. This study was designed to investigate the systemic haemodynamic response to HemolinkTM in spontaneously hypertensive rats (SHR rats). Conscious or anaesthetized SHR rats and control Wistar Kyoto rats (WKY rats) received either HemolinkTM or homologous plasma as a 10% topload infusion. Some awake animals were pretreated with nifedipine and followed by HLK infusion. In the conscious animal study, HLK induced a greater pressure rise and less bradycardia in SHR rats than in WKY rats. In the anaesthetized animal experiment, HLK-induced pressure rise and bradycardia were similar in both strains and less pronounced than in the conscious animals. In the nifedipine pretreated SHR rats, HLK-induced pressure rise was significantly smaller than that observed in nontreated SHR rats and was not different from that of nontreated WKY rats. The HLK-induced bradycardia was significantly smaller in nifedipine-treated animals than in the nontreated SHR or WKY rats. This study suggests that the pressor effect of HemolinkTM can be attenuated in hypertensive animals with general anaesthesia or treatment with antihypertensive agents.
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Affiliation(s)
- J Ning
- Hemosol Inc., Etobicoke, Ontario, Canada.
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Xue S, Paterson W, Valdez D, Miller D, Christoff B, Wong LT, Diamant NE. Effect of an o-raffinose cross-linked haemoglobin product on oesophageal and lower oesophageal sphincter motor function. Neurogastroenterol Motil 1999; 11:421-30. [PMID: 10583849 DOI: 10.1046/j.1365-2982.1999.00171.x] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The present experiments evaluate the effects on oesophageal motility of an o-raffinose cross-linked haemoglobin-based oxygen carrier (HBOC) purified from outdated donated human blood cells (HemolinkTM), with attention to dose-response (0.6-2.4 g kg-1), oxygenation status and low molecular weight components (4.4-36.4% 64 kDa or less). In ketamine-anaesthetized cats, lower oesophageal sphincter (LES) function and oesophageal peristalsis were monitored 0.5 h before, during and up to 3.5 h after HBOC infusion, and in some cats at 24 h. (1) All products significantly inhibited LES relaxation and increased peristaltic velocity in the distal smooth muscle oesophagus, without consistently altering resting LES pressure. (2) Effects on peristaltic velocity reached a maximum at the smallest dose, whereas the effects on LES relaxation had a maximum effect at 1.2 g kg-1. (3) Effects were not significantly altered by the haemoglobin oxygenation status or presence of low molecular weight components. (4) Repetitive oesophageal contractions occurred. In the cat, an o-raffinose cross-linked human haemoglobin product produces changes in oesophageal body and LES function, which are independent of the HBOC oxygenation status and composition of the low molecular weight components tested. Changes may persist for at least 24 h. These motility changes are likely due to scavenging of nitric oxide by the haemoglobin.
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Affiliation(s)
- S Xue
- University of Toronto, Ontario, Canada
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Wong LT, Er SS, Ning J, Christoff B, Carmichael FJ. Hemolink-induced effects on intestinal motor function and attenuation of these effects by selected agents. Artif Cells Blood Substit Immobil Biotechnol 1998; 26:529-48. [PMID: 9844719 DOI: 10.3109/10731199809117473] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Hemolink, an oxidized, ring-opened raffinose-crosslinked hemoglobin-based oxygen carrier produced by Hemosol Inc., stimulates esophageal peristalsis, possibly by interference with neural NO-mediated effects. The effects of Hemolink on jejunal tone and contractions, arterial pressure and heart rate were measured in anesthetized rats, and the effect of selected agents in attenuating or reversing these effects was studied. Infusion of L-NAME was used to validate the study model; it caused an immediate increase in tone and initiated phasic contractions indicating that the model was responsive to NO-mediated effects. Hemolink administration caused effects on intestinal motor function similar to those caused by L-NAME, including increases in basal tone and contraction amplitude. Rat whole blood caused none of these changes. The Hemolink-induced effects were less immediate in some animals compared to those observed after L-NAME. As well there was greater inter-animal variability on the effects. Hemolink administration also caused a mild increase in arterial blood pressure and a reciprocal decrease in heart rate in some animals. Co-administration of morphine, a common analgesic that has been reported to influence the motility of the GI tract; L-arginine, a substrate for NO synthesis; and glycopyrrolate, an anti-cholinergic agent, did not significantly modulate the Hemolink effects, whereas nitroglycerin, an NO donor; and nifedipine, a slow calcium-channel blocker, attenuated or reversed these effects.
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Affiliation(s)
- L T Wong
- Hemosol Inc., Etobicoke, Ontario, Canada
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McIlwaine PM, Wong LT, Peacock D, Davidson AG. Long-term comparative trial of conventional postural drainage and percussion versus positive expiratory pressure physiotherapy in the treatment of cystic fibrosis. J Pediatr 1997; 131:570-4. [PMID: 9386661 DOI: 10.1016/s0022-3476(97)70064-7] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We report the results of a long-term comparative trial of physiotherapy by the positive expiratory pressure (PEP) technique with a PEP mask (Astra Meditec) versus conventional postural drainage and percussion (PD&P). Forty patients, ages 6 to 17 years, with Shwachman scores between 52 and 93, attending the cystic fibrosis clinic were enrolled in the study and randomly assigned to one of two groups. Group A (control) continued to perform physiotherapy by using PD&P for a 1-year period, whereas patients assigned to group B performed physiotherapy with the PEP technique for the same period. Compliance with physiotherapy was closely monitored for both groups throughout the study. Clinical status and pulmonary function (forced vital capacity [FVC], FEV1, and FEF25-75) were measured at 3-month intervals. Group B (PEP) demonstrated improved pulmonary function in all parameters as measured by change in percent predicted value for age, gender, and height. The changes in pulmonary function over the study period were: FVC, +6.57; FEV1, +5.98; and FEF25-75, +3.32. This improvement was significantly different from that of group A (PD&P) whose pulmonary function declined in all parameters (FVC, -2.17; FEV1, -2.28; FEF25-75, -0.24). The differences between treatment groups were statistically significant for the changes in FVC (p = 0.02) and FEV(1) (p = 0.04). Our results indicate that for our patients with cystic fibrosis, pulmonary physiotherapy with the PEP technique was superior to conventional physiotherapy with the PD&P technique.
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Affiliation(s)
- P M McIlwaine
- Department of Paediatrics, University of British Columbia, Vancouver, Canada
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18
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Wong LT, Koh LH, Kaur K, Boey SK. A two-year experience of an acute pain service in Singapore. Singapore Med J 1997; 38:209-13. [PMID: 9259601] [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: 02/05/2023]
Abstract
The first anaesthesia-based acute pain service in Singapore is described. The benefits, risks and resource implications of such a service during its first two years are reviewed. One thousand two hundred and sixty-eight (1,268) post-operative patients were treated with either patient-controlled analgesia (310 patients) or epidural opioid analgesia (958 patients). Retrospective analysis of the data revealed good patient satisfaction with a low incidence of potentially life threatening side-effects: more than 79% of patients reported satisfaction with pain control while only 0.2% of patients receiving epidural opioid analgesia experienced clinically significant respiratory depression. There were no reports of respiratory depression in the patient-controlled analgesia group. The authors conclude that the provision of an acute pain service in the local context was safe and resulted in excellent post-operative patient satisfaction.
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Affiliation(s)
- L T Wong
- Department of Anaesthesia & Surgical Intensive Care, Singapore General Hospital, Singapore
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19
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Sim KM, Boey SK, Wong LT. Bone marrow harvesting using local anaesthesia and PCA-alfentanil: a feasible alternative to general or regional anaesthesia. Bone Marrow Transplant 1996; 18:787-90. [PMID: 8899196] [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: 02/02/2023]
Abstract
We examined the feasibility of combined use of local anaesthesia (LA) and patient-controlled analgesia with alfentanil (PCA-alfentanil) for bone marrow harvesting (BMH) in 16 consecutive in-patient donors (nine allogeneic and seven autologous). A loading dose of alfentanil 15 micrograms/kg was delivered at the time of skin preparation followed by a background infusion of alfentanil 0.05 microgram/kg/min. On -demand bolus doses of alfentanil were 4 micrograms/kg with lockout intervals of 3 min. Local anaesthesia was achieved using 1% lignocaine (up to 7 mg/kg) with 1:200,000 adrenaline. All donors were mildly sedated during BMH, tolerated the procedure well, and experienced no cardiovascular or respiratory complications. Post-operative nausea and vomiting were the only side-effects. All donors indicated that the combined use of LA with PCA-alfentanil was acceptable for BMH. Our preliminary results suggest that although optimal PCA settings have yet to be determined, this technique may be a feasible and effective alternative for BMH in situations where general or regional anaesthesia is undesirable.
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MESH Headings
- Adult
- Alfentanil/administration & dosage
- Alfentanil/adverse effects
- Analgesia, Patient-Controlled/adverse effects
- Analgesia, Patient-Controlled/methods
- Analgesics, Opioid/administration & dosage
- Analgesics, Opioid/adverse effects
- Anesthesia, Conduction
- Anesthesia, General
- Anesthesia, Local/adverse effects
- Anesthesia, Local/methods
- Bone Marrow Transplantation/methods
- Female
- Humans
- Living Donors
- Male
- Middle Aged
- Nausea/etiology
- Transplantation, Autologous
- Transplantation, Homologous
- Vomiting/etiology
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Affiliation(s)
- K M Sim
- Department of Anaesthesia and Surgical Intensive Care, Singapore General Hospital, Republic of Singapore
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20
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Abstract
The course of a 12-year-old girl with cystic fibrosis (CF) and with recurrent hemoptysis since age 8 years is described. Conservative measures failed to control her bleeding. Hemoptysis was only partially controlled by repeated bronchial arterial embolizations. However, the addition of tranexamic acid (TXA) resulted in complete cessation of bleeding. Attempts to withdraw TXA therapy resulted in recurrence of hemoptysis; this patient has, therefore, been continuously maintained on this therapy for the past 4 years. No side effects of long-term TXA treatment have been noted.
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Affiliation(s)
- L T Wong
- Department of Paediatrics, University of British Columbia, Vancouver, Canada
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21
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Cimolai N, Trombley C, Davidson AG, Wong LT. Selective media for isolation of Burkholderia (Pseudomonas) cepacia from the respiratory secretions of patients with cystic fibrosis. J Clin Pathol 1995; 48:488-90. [PMID: 7543119 PMCID: PMC502631 DOI: 10.1136/jcp.48.5.488] [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: 01/25/2023]
Abstract
One hundred and six specimens from 90 patients with cystic fibrosis were evaluated for the presence of Burkholderia cepacia using a current routine diagnostic protocol as well as a research protocol involving polymyxin B-MacConkey agar without crystal violet, PC agar, OFPVL agar, and a selective brain-heart infusion broth. Ten specimens from eight patients (8.9%) were positive by any method. The selective enrichment broth was the only medium that yielded B cepacia from all 10 positive samples, although the routine protocol was successful for eight of these. Transient carriage was identified in one patient. Epidemiological studies may be better served by the use of selective enrichment rather than selective solid media alone. Carrier status for B cepacia requires more strict definition if positive carrier status is to be accepted as having medical importance.
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Affiliation(s)
- N Cimolai
- Deaprtment of Pathology, British Columbia's Children's Hospital, Vancouver, Canada
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22
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Abstract
Amantadine HCl (3 mg kg-1) was administered orally to 20 young healthy adults. Its apparent volume of distribution (V2/F) was higher in smokers than nonsmokers, 6.05 +/- 0.86 vs 4.87 +/- 0.85 l kg-1; (mean +/- s.d., 10/group, P < 0.011), and no gender-associated effect was observed. Renal clearance did not vary with time-interval, but urinary recovery at 48 h was higher in men than in women (60.2 +/- 7.5% vs 47.0 +/- 15.0%, P < 0.032). Males had higher renal clearances than females when normalised for body mass index (BMI, 0.492 +/- 0.284 vs 0.248 +/- 0.137 l-1 BMI h-1, (10/group, P < 0.032)). On combining data from a previous study, the weight normalised renal clearance was also higher in men than in women, 0.160 +/- 0.075 vs 0.102 +/- 0.053 l kg-1 h-1 (19/group, P < 0.01). Chronic tobacco smoking did not alter the plasma or renal amantadine clearance. We conclude that gender and tobacco smoking are independent variables effecting amantadine disposition.
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Affiliation(s)
- L T Wong
- Department of Pharmacology, University of Manitoba, Winnipeg, Canada
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23
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Escorbar MR, Wong LT, Sitar DS. Bicarbonate-dependent amantadine transport by rat renal cortical proximal and distal tubules. J Pharmacol Exp Ther 1994; 270:979-86. [PMID: 7932210] [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: 01/27/2023] Open
Abstract
Transport of the achiral cationic drug amantadine by purified renal cortical rat tubules was investigated in bicarbonate [Krebs-Henseleit solution (KHS)] and nonbicarbonate buffers. Values of the apparent Km for amantadine accumulation were higher (P < .001, mean +/- S.E., n = 5) for all nonbicarbonate buffers compared with those in KHS in both proximal (76 +/- 5 in KHS, 277 +/- 65 in phosphate, 190 +/- 11 in Tris-HEPES, 268 +/- 46 in acetate and 620 +/- 81 microM in lactate) and distal tubules (68 +/- 4 in KHS, 162 +/- 27 in phosphate, 247 +/- 45 in Tris-HEPES, 281 +/- 50 in acetate buffer and 482 +/- 85 microM for lactate). There was a decrease in Vmax for amantadine transport (P < .001) in phosphate, Tris-HEPES and acetate buffers in both proximal (4.83 +/- 0.43 in KHS, 2.38 +/- 0.43 in phosphate, 1.77 +/- 0.31 in Tris-HEPES and 1.47 +/- 0.40 nmol mg protein-1 min-1 in acetate) and distal (4.58 +/- 0.13 for KHS, 1.37 +/- 0.27 for phosphate, 1.82 +/- 0.37 for Tris-HEPES and 1.76 +/- 0.20 nmol mg protein-1 min-1 for acetate) tubules. However, Vmax was not depressed (P < .09) in lactate buffer for proximal (2.87 +/- 0.24 in KHS and 3.12 +/- 0.34 nmol mg protein-1 min-1 in lactate) or distal tubules (2.42 +/- 0.26 in KHS and 3.21 +/- 0.31 nmol mg protein-1 min-1 in lactate), although a slight increase was observed in distal tubules.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M R Escorbar
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Canada
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24
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Chan KW, Wong LT, Applegarth D, Davidson AG. Bone marrow transplantation in Gaucher's disease: effect of mixed chimeric state. Bone Marrow Transplant 1994; 14:327-30. [PMID: 7994251] [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: 01/28/2023]
Abstract
The effective dose and schedule of enzyme replacement therapy for Gaucher's disease have not been definitely established. We report a case of mixed chimeric state in an allogeneic BMT patient and followed her clinical and laboratory progress. The result shows that a low but sustained glucocerebrosidase level may provide symptomatic relief for this lysosomal disorder.
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Affiliation(s)
- K W Chan
- Department of Paediatrics, B.C.'s Children's Hospital, Vancouver, Canada
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25
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Wong LT, Escobar MR, Smyth DD, Sitar DS. Gender-associated differences in rat renal tubular amantadine transport and absence of stereoselective transport inhibition by quinine and quinidine in distal tubules. J Pharmacol Exp Ther 1993; 267:1440-4. [PMID: 8263806] [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: 01/29/2023] Open
Abstract
The present studies compared male and female rat renal proximal and distal tubular uptake of amantadine, in relation to their transport kinetics and enantioselective inhibition by two diastereoisomers, 8S,9R-(-)-quinine and 8R,9S-(+)-quinidine. Under control conditions, amantadine was concentrated by both tubule fractions with a gender difference for distal tubules (tissue:medium ratio, 18.0 +/- 1.4 for males and 11.0 +/- 0.6 for females; mean +/- S.E.M., P < .05). This was reflected by a higher Km value only in female distal vs. proximal tubular tissue (153 +/- 8 vs. 108 +/- 9 microM; P < .01) but decrease in Vmax values in distal compared to proximal tubules (P < .01) showed no gender-related difference. In proximal tubules, 8S,9R-(-)-quinine and 8R,9S-(+)-quinidine competitively inhibited amantadine transport with apparent inhibitory potency of 2- to 3-fold in favor of 8S,9R-(-)-quinine (P < .01) and without gender preference. Conversely in distal tubules, competitive inhibition of amantadine transport was also elicited by either 8S,9R-(-)-quinine or 8R,9S-(+)-quinidine at a similar concentration range (10-1000 microM), with absence of chiral or gender preference. The present transport data have demonstrated an apparent absence of stereoselectivity in distal tubular uptake inhibition of amantadine, and are suggestive of disparate pathways and/or rate limiting steps involved between renal proximal and distal tubular handling of chiral organic cations for both genders, and between genders for distal tubular transport of amantadine.
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Affiliation(s)
- L T Wong
- Department of Pharmacology, University of Manitoba, Winnipeg, Canada
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26
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Hassall E, Israel DM, Davidson AG, Wong LT. Barrett's esophagus in children with cystic fibrosis: not a coincidental association. Am J Gastroenterol 1993; 88:1934-8. [PMID: 8237944] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Barrett's esophagus (BE) is a premalignant condition, and a recognized complication of severe gastroesophageal (GE) reflux. Children with cystic fibrosis (CF) have a marked predilection to develop GE reflux, but Barrett's esophagus is one complication of GE reflux not previously described in CF. We describe in detail two adolescents with CF who were found to have Barrett's esophagus, and mention three other cases. The presence of Barrett's esophagus in CF patients may be missed because GE reflux is often relatively silent in CF, because patients may consider mild upper gastrointestinal (GI) symptoms as "part of CF," and because of the nature of Barrett's epithelium itself. Upper gastrointestinal (GI) endoscopy with documentation of landmarks and multiple targeted biopsies should be performed in children with CF with even mild symptoms of GE reflux or an abnormal 24 h intra-esophageal pH study. Any biopsies containing columnar epithelium should be stained with Alcian blue at pH 2.5 to look for goblet cell metaplasia, i.e., Barrett's esophagus. Children with CF may be a high-risk group for development of Barrett's esophagus and its complications, especially given the increased survival in CF.
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Affiliation(s)
- E Hassall
- Division of Pediatric Gastroenterology, British Columbia Children's Hospital, Vancouver, Canada
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27
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Abstract
Barrett's esophagus (BE) is a premalignant condition, and a recognized complication of severe gastroesophageal (GE) reflux. Children with cystic fibrosis (CF) have a marked predilection to develop GE reflux, but Barrett's esophagus is one complication of GE reflux not previously described in CF. We describe in detail two adolescents with CF who were found to have Barrett's esophagus, and mention three other cases. The presence of Barrett's esophagus in CF patients may be missed because GE reflux is often relatively silent in CF, because patients may consider mild upper gastrointestinal (GI) symptoms as "part of CF," and because of the nature of Barrett's epithelium itself. Upper gastrointestinal (GI) endoscopy with documentation of landmarks and multiple targeted biopsies should be performed in children with CF with even mild symptoms of GE reflux or an abnormal 24 h intra-esophageal pH study. Any biopsies containing columnar epithelium should be stained with Alcian blue at pH 2.5 to look for goblet cell metaplasia, i.e., Barrett's esophagus. Children with CF may be a high-risk group for development of Barrett's esophagus and its complications, especially given the increased survival in CF.
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Affiliation(s)
- E Hassall
- Division of Pediatric Gastroenterology, British Columbia Children's Hospital, Vancouver, Canada
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28
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Abstract
We have studied 21 families with Wilson disease (WND), using restriction fragment length polymorphisms (RFLPs) in the 13q14.3 region, to measure linkage of these markers to the disease locus. In addition to previously described markers, we include linkage data for a newly isolated marker (D13S86) and an established marker (D13S56), which were previously not placed on the genetic map in the region of the WND locus. Our data, including those from two recombinant families, support the location of WND between the markers D13S31 and D13S59. We have examined the distribution of marker alleles at the loci studied and have found that D13S31 and D13S228, and associated microsatellite marker, show a non-random distribution on chromosomes carrying the WND mutation. The significant linkage disequilibrium indicates that these two markers must be close to the WND locus.
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Affiliation(s)
- G R Thomas
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
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29
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Abstract
Human alpha-mannosidosis is a lysosomal storage disorder characterized by mental retardation, dysostosis multiplex, and hepatosplenomegaly. Deficiency of the enzyme leads to accumulation of mannose-rich glycoconjugates in tissues. Zinc sulphate has been shown to stimulate alpha-mannosidase activity in vitro. Oral zinc therapy was attempted on a 4-year-old boy with alpha-mannosidosis for 3 years. After almost 10 years of follow-up on and off zinc therapy, we must conclude that oral zinc does not substantially affect the clinical course of alpha-mannosidosis.
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Affiliation(s)
- L T Wong
- Department of Pediatrics, B.C.'s Children's Hospital, Vancouver, Canada
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30
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Speert DP, Campbell ME, Davidson AG, Wong LT. Pseudomonas aeruginosa colonization of the gastrointestinal tract in patients with cystic fibrosis. J Infect Dis 1993; 167:226-9. [PMID: 8418173 DOI: 10.1093/infdis/167.1.226] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Respiratory and fecal specimens from 111 patients with cystic fibrosis (CF) were cultured on 394 occasions to determine which site Pseudomonas aeruginosa colonizes first. By an enrichment and selection culture technique, P. aeruginosa was recovered from fecal cultures in 21 (42%) of 50 respiratory tract-positive patients but from only 3 (6.3%) of 48 respiratory tract-negative patients and from 1 (2.2%) of 45 control subjects. In 4 (22%) of the 18 patients who became culture-positive during the study, P. aeruginosa was recovered from a fecal specimen before respiratory colonization. Only 1 of these 4 became persistently colonized with P. aeruginosa in the respiratory tract; however, the serotype of the respiratory isolate was different from that of the fecal isolate. P. aeruginosa is recovered rarely from the feces of patients with CF who are culture-negative in the respiratory tract. In patients with CF, primary colonization with P. aeruginosa probably occurs in the respiratory tract.
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Affiliation(s)
- D P Speert
- Division of Infectious and Immunological Diseases, British Columbia's Children's Hospital, Vancouver, Canada
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31
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Sherman IA, Dlugosz JA, Perelman V, Hsia CJ, Wong LT, Condie RM. Systemic hemodynamic and hepatic microvascular responses to a 33% blood volume exchange with whole blood, stroma-free hemoglobin, and oxypolyhemoglobin solutions. Biomater Artif Cells Immobilization Biotechnol 1993; 21:537-51. [PMID: 8260579 DOI: 10.3109/10731199309117656] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Little is known about the microvascular effects of blood replacement solutions. This study was undertaken to develop an animal model suitable for studies of the microcirculatory effects of such solutions and to investigate microvascular responses to isovolemic transfusion with stroma-free hemoglobin (SFH), whole donor blood, or a new potential blood substitute solution containing oxypolyhemoglobin (OPH) as an oxygen carrier. Hamster livers were exposed and the microcirculation studied using intravital epifluorescent video microscopy. 33% blood volume replacement with SFH elevated systemic blood pressure by 25 Torr. Accompanying this increase in pressure was a 36% decrease in sinusoidal blood flow velocity and a 10% decrease in terminal hepatic venular diameters. Terminal portal venular diameters did not change. Decrease in liver sinusoidal perfusion was not due to neutrophil mediated injury, as myeloperoxidase activity in jejunum, liver, kidney, and lung remained unchanged. The reduction in perfusion was likely due to systemic vasoconstriction produced by SFH. In contrast, transfusion with whole blood did not change any of the measured parameters showing the excellent stability of the model. OPH transfused animals exhibited only a small 10 Torr transient increase in MAP 15 min post-transfusion. By 30 min MAP returned to the pre-infusion value. No significant changes were observed in either venular diameters or sinusoidal velocities in this group of animals. These results demonstrate suitability of this model for studies of the microcirculatory and hemodynamic effects of blood replacement solutions. Furthermore, OPH solution produced only minor transient disturbances in microvascular and systemic parameters.
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Affiliation(s)
- I A Sherman
- Aron M. Rappaport Microcirculation Laboratory, Sunnybrook Health Science Centre, University of Toronto, Ontario, Canada
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32
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Abstract
Amantadine was found to be concentrated by human cortical slices, with apparent Km and Vmax values of 187 +/- 11 microM and 1.37 +/- 0.28 nmol mg-1 min-1 respectively (mean +/- s.e. mean, n = 4). Addition of quinine (8S, 9R-(-)-isomer) or quinidine (8R, 9S-(+)-isomer) competitively inhibited this accumulation (apparent Ki values of 261 +/- 44 (n = 4) and 586 +/- 68 microM (n = 3), respectively). The stereoselectivity of this inhibition is the reverse of that seen with respect to the renal clearances of the diastereoisomers.
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Affiliation(s)
- L T Wong
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Canada
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33
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Wong LT, Smyth DD, Sitar DS. Interference with renal organic cation transport by (-)- and (+)-nicotine at concentrations documented in plasma of habitual tobacco smokers. J Pharmacol Exp Ther 1992; 261:21-5. [PMID: 1560368] [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: 12/27/2022] Open
Abstract
Nicotine is the principal psychoactive Nicotiana alkaloid in tobacco. In the present study, we used amantadine as a marker and investigated the potential ability of nicotine and cotinine to interfere with renal organic cation transport in vitro. [3H]Amantadine is concentrated actively by isolated proximal tubules, distal tubules and cortical slices. In proximal tubules, the addition of (-)- or (+)-nicotine (0.1-100 microM) facilitated amantadine (10 microM) accumulation. Apparent Km for amantadine uptake was decreased by a clinically relevant concentration of (-)- and (+)-nicotine (0.4 microM), from 78 +/- 2 to 52 +/- 2 and 61 +/- 5 microM, respectively (mean +/- S.E.M., P less than .05), whereas Vmax was not altered (6.6 +/- 0.1 to 6.3 +/- 0.1 and 6.5 +/- 0.2 nmol/mg/min). The addition of (-)-cotinine (0.4-100 microM) also facilitated amantadine uptake, but with lesser efficacy. Possible mechanisms underlying the present enhancement of uptake include facilitation of amantadine influx and/or attenuation of efflux. Efflux data indicate a prominent hindrance of amantadine egress from preloaded tubules in the presence of 0.4 microM (-)- and (+)-nicotine (51 +/- 4 to 32 +/- 8 and 27 +/- 4 pmol/mg/30 sec, P less than .05) and are supportive of the latter notion. In distal tubules, (-)- or (+)-nicotine produced inhibition only a high concentrations (greater than or equal to 100 microM). Km was increased by 400 microM (-)- and (+)-nicotine from 76 +/- 5 to 124 +/- 9 and 116 +/- 17 microM, and Vmax was moderately decreased from 3.4 +/- 0.5 to 3.0 +/- 0.4 and 3.0 +/- 0.4 nmol/mg/min (P less than .05). The incorporation of (-)-cotinine did not alter amantadine uptake. Enhancement of uptake by (-)- or (+)-nicotine was absent in cortical slices, in which tubular luminal transport has ben proposed to be insignificant, and only low affinity inhibition was apparent. The present data indicate potent interference of renal proximal tubular transport of amantadine by nicotine at concentrations equivalent to those documented in plasma of habitual tobacco smokers and suggest potential alterations in renal organic cationic drug elimination in these subjects.
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Affiliation(s)
- L T Wong
- Department of Pharmacology, University of Manitoba, Winnipeg, Canada
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34
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Hsia JC, Song DL, Er SS, Wong LT, Keipert PE, Gomez CL, Gonzales A, Macdonald VW, Hess JR, Winslow RM. Pharmacokinetic studies in the rat on a o-raffinose polymerized human hemoglobin. Biomater Artif Cells Immobilization Biotechnol 1992; 20:587-95. [PMID: 1391482 DOI: 10.3109/10731199209119687] [Citation(s) in RCA: 14] [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] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have studied the plasma half-life (T 1/2), oxygen-binding affinity (P50), organ distribution, and excretion of the individual molecular weight (MW) components of human hemoglobin polymerized with periodate-oxidized, ring-opened raffinose (oR poly-Hb), following transfusion in the rat. The model was an isovolemic 50% exchange transfusion in the conscious, chronically catheterized rat. Total plasma Hb levels yielded a (T 1/2) of 10 to 11 hr for oR poly-Hb. The T 1/2 values of individual MW components of the poly-Hb as determined by size-exclusion HPLC were approximately: 4 hr for the monomeric fraction (Hb)1, 9 hr for the dimer (Hb)2, and 15 hr for the fraction representing trimers to nanomers (Hb)3-9. The P50 values of plasma samples containing oR poly-Hb (collected from 0-24 hr after exchange) remained unchanged at 28 +/- 3 mmHg. oR stabilized and polymerized Hb were not excreted via the kidneys. Hepatic and renal distribution as well as plasma and renal clearance were determined by liquid scintillation counting using individual tritium [3H] labelled MW components purified from [3H]-oR poly-Hb: (Hb)1/2, (Hb)1, (Hb)2, (Hb)3&4, and (Hb) greater than 9. In kidney, uptake (determined by the relative concentration of radioactivity) decreased with increasing MW of the labelled component. Conversely, in liver, uptake increased with increasing MW. Plasma and renal clearance results were consistent with those obtained by HPLC analysis. Hematocrit levels returned from a 20% post-transfusion level to normal pre-transfusion levels (44%) within 10 days after the exchange.
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Affiliation(s)
- J C Hsia
- Hemosol Inc., Toronto, Ontario, Canada
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35
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Moore GL, Fishman RM, Ledford ME, Zegna A, Hsia JC, Song DL, Wong LT, Er SS. Molecular weight determinations of o-raffinose-polymerized human hemoglobin. Biomater Artif Cells Immobilization Biotechnol 1992; 20:293-6. [PMID: 1391445 DOI: 10.3109/10731199209119646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- G L Moore
- Letterman Army Institute of Research, San Francisco, CA 94129
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36
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Abstract
Alström disease is a rare disorder; less than 20 cases have been reported. An 11-year-old girl is described with this condition. She has pigmentary retinopathy, sensory neural deafness, obesity, Type II diabetes mellitus, hyperlipidemia, and acanthosis nigricans. However, in addition she developed hepatic dysfunction, pathologically similar to chronic active hepatitis. This may be a further, previously undescribed systemic manifestation of Alström disease.
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Affiliation(s)
- M B Connolly
- Division of Pediatric Neurology, University of British Columbia, Vancouver, Canada
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Wong LT, Smyth DD, Sitar DS. Differential effects of histamine H2 receptor antagonists on amantadine uptake in the rat renal cortical slice, isolated proximal tubule and distal tubule. J Pharmacol Exp Ther 1991; 258:320-4. [PMID: 2072304] [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: 12/30/2022] Open
Abstract
The interaction between amantadine and two histamine receptor antagonists was examined in the rat kidney. Amantadine (10 microM, 30 sec) was actively accumulated by cortical slices (slice/medium ratio = 0.4 +/- 0.3 [3.3 +/- 0.3 at 4 min], mean +/- S.E.M.), isolated proximal tubules (tubule/medium ratio = 35 +/- 1) and distal tubules (tubule/medium ratio = 19 +/- 2). In cortical slices, low cimetidine concentrations facilitated amantadine accumulation, whereas higher concentrations produced inhibition. Uptake in proximal tubules was enhanced by cimetidine and reached a maximum at approximately 100 microM. Cimetidine (20 microM) decreased the apparent Km (88 +/- 5 to 55 +/- 3 microM, P less than .005) without altering Vmax (6.8 +/- 0.5 to 5.8 +/- 0.6 nmol/mg/min). Conversely, cimetidine did not enhance uptake in distal tubules but elicited competitive inhibition at concentrations greater than 1 mM. Although this may partially delineate the differences observed between the cortical slice and proximal tubule data, such a discrepancy may also implicate additional sites of interaction in other segments of the cortical nephron and/or cimetidine inhibition of the relatively more significant luminal amantadine efflux in the proximal tubules. Ranitidine did not enhance amantadine accumulation but produced inhibition at high concentrations. In proximal and distal tubule preparations, ranitidine (10 mM) increased Km from 86 +/- 7 to 121 +/- 8 and 95 +/- 5 to 160 +/- 10 microM, respectively (P less than .05), whereas Vmax was not changed (8.9 +/- 0.7 to 7.9 +/- 0.8 and 4.3 +/- 0.1 to 3.8 +/- 0.2 nmol/mg/min, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L T Wong
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Canada
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Abstract
A girl aged eight months, who presented with developmental delay and dislocated optic lenses, was diagnosed as having combined sulfite oxidase and xanthine dehydrogenase deficiencies consistent with molybdenum cofactor deficiency. The diagnosis was confirmed by demonstrating the absence in urine of urothione, a molybdenum cofactor metabolite. Prenatal diagnosis excluded the disease in the mother's second pregnancy. A summary of an in vitro study of molybdenum cofactor synthesis in the patient is given.
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Affiliation(s)
- F J Bamforth
- Biochemical Diseases Laboratory, B.C.'s Children's Hospital, Vancouver, Canada
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Wong LT, Smyth DD, Sitar DS. Stereoselective inhibition of amantadine accumulation by quinine and quinidine in rat renal proximal tubules and cortical slices. J Pharmacol Exp Ther 1990; 255:271-5. [PMID: 2213561] [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: 12/30/2022] Open
Abstract
The renal organic cation transport system was examined. The accumulation of a nonchiral cation, amantadine, by rat renal proximal tubules and cortical slices was investigated, together with the effects of two diastereoisomers, quinine and quinidine. The proximal tubules actively concentrated amantadine with a tissue/medium ratio of 96.3 +/- 1.7 (mean +/- S.E.M., n = 18). Apparent Km was 85 +/- 2 microM and Vmax was 8.0 +/- 0.2 nmol/mg of tubular protein per min. Amantadine accumulation was inhibited competitively by quinine and quinidine with Ki values of 32 +/- 3 and 84 +/- 11 microM, respectively (n = 4). Amantadine was also concentrated by renal cortical slices with tissue/medium ratio of 3.3 +/- 0.3 (n = 4). Apparent Km and Vmax were 94.0 +/- 5.2 microM and 1.27 +/- 0.08 nmol/mg of tubular protein per min, respectively (n = 10). Quinine and quinidine again inhibited amantadine accumulation competitively by the slices, with Ki values of 368 +/- 28 and 780 +/- 84 microM, respectively (n = 4). A similar affinity (Km) for amantadine was observed in both preparations. However, the lower Vmax value in the slice system may be due to additional amantadine transport sites with lower capacity, lesser luminal accumulation and/or limited substrate(s) penetration in the cortical slices. In either preparation, quinine and quinidine functioned as competitive inhibitors and stereoselectivity was observed for the (-)-isomer, quinine, over the (+)-isomer, quinidine. Additional transport sites, reduced luminal substrate accumulation and/or diffusional restraints in the slices are also feasible mechanisms in explaining the differences in Ki values between the two preparations, and their relative contributions await further investigation.
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Affiliation(s)
- L T Wong
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Canada
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Lockitch G, Taylor GP, Wong LT, Davidson AG, Dison PJ, Riddell D, Massing B. Cardiomyopathy associated with nonendemic selenium deficiency in a Caucasian adolescent. Am J Clin Nutr 1990; 52:572-7. [PMID: 2168125 DOI: 10.1093/ajcn/52.3.572] [Citation(s) in RCA: 40] [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: 12/30/2022] Open
Abstract
We describe a girl aged 17 y who died after a cardiac arrest secondary to septic shock. At autopsy, the enlarged, soft, and flabby heart showed microscopic evidence of acute myocardial infarction, myocardial edema, myocardiocyte loss, replacement fibrosis in the interventricular septum, and right and left ventricular hypertrophic nucleomegaly. The pathological diagnosis was that of cardiomyopathy due to prolonged selenium deficiency. The patient had been on total parenteral nutrition for 17 mo, following extensive bowel resection for intractable pain, nausea, and vomiting caused by chronic idiopathic intestinal pseudoobstruction. Seven months before death, when severe biochemical selenium deficiency was diagnosed, supplemental selenium was added to the infusion, and plasma selenium concentrations increased. In long-standing selenium deficiency, sepsis may contribute the final insult to a damaged myocardium, triggering symptomatic cardiac failure and sudden death.
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Affiliation(s)
- G Lockitch
- Department of Pathology, University of British Columbia, Vancouver, Canada
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41
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Hérve F, Gentin M, Rajkowski KM, Wong LT, Hsia CJ, Cittanova N. Estrogen-binding properties of rat serum alpha 1-fetoprotein and its isoforms. Investigation of the apparent non-integrality of sites on the unfractionated protein. J Steroid Biochem 1990; 36:319-24. [PMID: 1697353 DOI: 10.1016/0022-4731(90)90224-g] [Citation(s) in RCA: 7] [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] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Rat fetal serum alpha 1-fetoprotein (AFP), a heterogeneous glycoprotein, binds estrogens with high affinity but at a fractional number of sites even after treatment with charcoal (n = 0.6), which may mean 60% of the protein has 1 site and the remainder none. To investigate the origin of this fractional number of sites the "native" protein (purified by negative affinity chromatography) was further purified (step 1) and fractionated (step 2) into its two main charge variants (electrophoretically "slow" and "fast") by a two-step fast-protein liquid chromatography method. The binding parameters for estrone and estradiol-17 beta of the "native" and "repurified" proteins and of each charge variant were determined by equilibrium microdialysis. The molar extinction coefficient at 278 nm of each sample was also determined. (1) The "repurified" AFP and each charge variant had a number of binding sites for estrogens close to unity. This increase in the number of sites could neither be explained by the loss of a non-binding isoform (corresponding to 40% of the protein) during chromatography, nor by the existence of complex negative modulatory interactions between isoforms. (2) The affinities for estrogens of the "repurified" protein and the two charge variants were slightly decreased compared to that of "native" AFP, except that the "fast" form had the "native" protein's high affinity for estrone--but not for estradiol-17 beta. (3) The molar extinction coefficients at 278 nm of the "repurified" AFP and the isoforms were much lower than that of the "native" protein. These results suggest that the presence of (an) inhibitor(s) of estrogen binding on the "native" protein which is/are removed by the ion-exchange fast protein liquid chromatography (FPLC) column. A ligand absorbing at 278 nm, which may or may not be the inhibitor, is also removed. The isoform heterogeneity with respect to estrone binding is discussed.
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Affiliation(s)
- F Hérve
- UFR Biomédicale des Saints-Pères, Département de Biochimie, Paris, France
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Appleton RE, Farrell K, Applegarth DA, Dimmick JE, Wong LT, Davidson AG. The high incidence of valproate hepatotoxicity in infants may relate to familial metabolic defects. Neurol Sci 1990; 17:145-8. [PMID: 2113424 DOI: 10.1017/s0317167100030353] [Citation(s) in RCA: 40] [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: 12/30/2022]
Abstract
The incidence of fatal hepatic failure associated with valproic acid (VPA) therapy is highest in children under the age of three years, particularly in those with developmental delay. The pathogenesis of VPA hepatotoxicity is unclear but may relate to the accumulation of a toxic metabolite of VPA which impairs fatty-acid oxidation. We describe two unrelated infants with developmental delay who developed hepatic failure while receiving VPA. Siblings of both children subsequently developed hepatic steatosis and intractable seizures without being exposed to VPA. This suggests that the two children who developed liver failure when receiving VPA may have had a familial metabolic disorder. Familial metabolic disorders may account partly for the higher incidence of fatal hepatotoxicity described in infants receiving VPA.
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Affiliation(s)
- R E Appleton
- Department of Pediatrics, British Columbia's Children's Hospital, University of British Columbia, Vancouver, Canada
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Hervé F, Gentin M, Rajkowski KM, Cittanova N, Wong LT, Hsia JC. Study on estrogen binding by rat alpha-fetoprotein (AFP) isoforms: evidence for the lack of binding-site heterogeneity. Steroids 1988; 52:343-4. [PMID: 2471298 DOI: 10.1016/0039-128x(88)90138-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- F Hervé
- Unité Associée 586 CNRS, Faculté de Médecine, Paris, France
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Wong LT, Lu CY, Tinker DO, Hsia JC. Application of high-performance liquid chromatography for the study of the microheterogeneity changes of mouse alpha-fetoprotein in fetal development. J Biochem Biophys Methods 1988; 15:267-72. [PMID: 2454252 DOI: 10.1016/0165-022x(88)90014-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Changes in the microheterogeneity of mouse alpha-fetoprotein (MAFP) during fetal development were investigated by high-performance liquid chromatography (HPLC). A total of six distinct isoforms (Iso-1, Iso-2, Iso-3, Iso-4, Iso-5, Iso-6) of the heterogeneous MAFP were resolved from mouse amniotic fluid (MAF). Analysis of MAF collected at various times revealed that these isoforms were accumulated at different stages of the fetal development.
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Affiliation(s)
- L T Wong
- Department of Biochemistry, University of Toronto, Ontario, Canada
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Meng GD, Zhu JC, Chen ZW, Wong LT, Zhang GY, Hu YZ, Ding JH, Wang XH, Qian SZ, Wang C. Recovery of sperm production following the cessation of gossypol treatment: a two-centre study in China. Int J Androl 1988; 11:1-11. [PMID: 3356480 DOI: 10.1111/j.1365-2605.1988.tb01211.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A number of variables were investigated in 46 men who had stopped taking gossypol for their predictive association with the degree and time of recovery of spermatogenesis. Thirty-nine (87%) of the men were azoospermic at cessation of gossypol treatment. In those with sperm present the geometric mean concentration and total sperm count were 8.3 X 10(6)/ml and 30.7 X 10(6), respectively. Twenty-eight men (61%) recovered to a defined threshold of spermatogenic function (sperm concentration greater than or equal to 20 X 10(6)/ml), with a median recovery time of 1.1 years. However, 18 men (39%) had not recovered to this degree of spermatogenic function after a median follow-up of 1.9 years and, of these, 10 (22%) remained azoospermic. The influence of individual baseline variables on the time to defined recovery was examined using Kaplan-Meier curves for groups and their joint effect by Cox's regression model. The failure of recovery was strongly associated with longer treatment, greater total dose of gossypol, smaller testicular volume, elevated FSH concentrations and, to a lesser extent, with greater body weight.
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Affiliation(s)
- G D Meng
- People's Hospital, Beijing Medical College
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Meng GD, Zhu JC, Chen ZW, Wong LT, Zhang GY, Hu YZ, Ding JH, Wang XH, Qian SZ, Wang C. Follow-up of men in the recovery period immediately after the cessation of gossypol treatment. Contraception 1988; 37:119-28. [PMID: 3131064 DOI: 10.1016/0010-7824(88)90122-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [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] [Indexed: 01/04/2023]
Abstract
Variables in 46 men who had stopped taking gossypol in two centres in China were investigated for their predictive association with the degree and time of recovery of spermatogenesis. Thirty-nine (87%) were azoospermic at cessation of gossypol treatment. In those with sperm present the geometric mean concentration and total sperm count were 8.3 x 10(6)/ml and 30.7 x 10(6), respectively. Twenty-eight (61%) recovered to a defined threshold spermatogenic function (sperm concentration greater than or equal to 20 x 10(6)/ml), with median recovery time 1.1 years. However, 18 men (39%) had not recovered after a median follow-up of 1.9 years and, of these, 10 (22%) remained azoospermic. The failure of recovery was strongly associated with longer treatment, greater total dose of gossypol, smaller testicular volume, elevated FSH concentrations and, to a lesser extent, with greater body weight.
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Affiliation(s)
- G D Meng
- People's Hospital, Beijing Medical College
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Naylor EW, Ennis D, Davidson AG, Wong LT, Applegarth DA, Niederwieser A. Guanosine triphosphate cyclohydrolase I deficiency: early diagnosis by routine urine pteridine screening. Pediatrics 1987; 79:374-8. [PMID: 3822637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
A deficiency of hepatic guanosine triphosphate cyclohydrolase I is reported in a 4-month-old infant in whom positive results on a Guthrie phenylketonuria test in the neonatal period were found. Because of the significantly elevated serum phenylalanine levels a diagnosis of classical phenylketonuria was made, and dietary therapy was started. Urinary pteridine screening for cofactor variants, however, revealed extremely low levels of both neopterin and biopterin. This suggested the possibility of guanosine triphosphate cyclohydrolase I deficiency and led to additional confirmatory assays. Repeat urine, serum, and CSF pteridine profiles, combined with tetrahydrobiopterin-loading studies and the assay of guanosine triphosphate cyclohydrolase I activity in a liver biopsy, confirmed the defect. It is significant to note that the diagnosis was made before the onset of major clinical symptoms. This case illustrates the need for routine cofactor variant screening of all infants in whom hyperphenylalaninemia is diagnosed in the neonatal period.
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Wong LT, Davidson AG, Applegarth DA, Dimmick JE, Norman MG, Toone JR, Pirie G, Wong J. Biochemical and histologic pathology in an infant with cross-reacting material (negative) pyruvate carboxylase deficiency. Pediatr Res 1986; 20:274-9. [PMID: 3085060 DOI: 10.1203/00006450-198603000-00016] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
An infant with the acute neonatal form of pyruvate carboxylase deficiency (cross-reacting material negative) presented with severe intractable lactic acidosis within 4 h after birth. He also had hyperammonemia, hypercitrullinemia, and hyperlysinemia. Plasma glutamine was not elevated. He had a rapidly deteriorating clinical course with severe liver dysfunction, repeated septicemia and seizures; he was comatose and was on a ventilator throughout; death occurred at 8 wk of age. Skin fibroblast study confirmed the enzyme deficiency. Detailed biochemical parameters and histopathology of the brain and liver are presented. The evidence from this infant suggests that disturbances of intracellular oxaloacetate levels as a result of the primary enzyme defect might also contribute to deficiency in ATP generation which may explain the various other biochemical changes and liver pathology.
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Hsia JC, Wong LT, Deutsch HF. Determination of the distribution of fatty acids and diethylstilbestrol between serum albumin and alpha-fetoprotein by concanavalin A affinity chromatography. Biochim Biophys Acta 1986; 880:117-22. [PMID: 2417630 DOI: 10.1016/0304-4165(86)90070-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The distribution of fatty acids and diethylstilbestrol between serum albumin and alpha-fetoprotein was measured in vitro by a new method based on the separation of the two proteins by virtue of the binding specificity of concanavalin A for the carbohydrate moiety of alpha-fetoprotein. Human and bovine proteins were investigated. It was found that palmitate and oleate were distributed almost equally between albumin and alpha-fetoprotein, while docosahexaenoate and diethylstilbestrol bound preferentially to alpha-fetoprotein even at an albumin: alpha-fetoprotein ratio of 10:1. The results confirm the binding specificity of alpha-fetoprotein for polyunsaturated fatty acids and also show that alpha-fetoprotein binds diethylstilbestrol much more strongly than albumin does. This suggests that alpha-fetoprotein may play a role in the fetal uptake of diethylstilbestrol.
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