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Santandrea E, Aliakbari F, Truscott E, McCaig L, Donison NS, Graham D, Strong MJ, Volkening K. A technique for repeated blood and cerebrospinal fluid sampling from individual rats over time without the need for repeated anesthesia. Sci Rep 2024; 14:5171. [PMID: 38431711 PMCID: PMC10908789 DOI: 10.1038/s41598-024-55666-6] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 02/26/2024] [Indexed: 03/05/2024] Open
Abstract
Ethical animal use follows the 3R's: Replacement, Reduction and Refinement. Here, we present the use of simultaneous jugular vein and cisterna magna catheterization via a port system in rats for repeated fluid sampling for 14 consecutive days without loss of catheter patency. This technique allows repeated intra-animal sampling without anesthesia and, if used with pooling samples from a cohort of animals, replaces the need for terminal collections for sufficient sample volumes.
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Affiliation(s)
- Erin Santandrea
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Farhang Aliakbari
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Emily Truscott
- Animal Care and Veterinary Services, University of Western Ontario, London, Canada
| | - Lynda McCaig
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Neil S Donison
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Danielle Graham
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Michael J Strong
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada.
- Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.
| | - Kathryn Volkening
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
- Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
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Rizzo A, Haeger S, Wallbank A, Yang Y, Oshima K, Langouet Astrie C, Colbert J, Kopf K, Voelker D, Bastarache J, McCaig L, Veldhuizen R, Ochs M, Kuebler W, Smith B, Schmidt E. Experimental Degradation of the Alveolar Epithelial Glycocalyx Decreases Lung Compliance in Young and Old Mice, Potentially by Inducing Surfactant Dysfunction. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Yimu Yang
- MedicineUniversity of Colorado DenverAuroraCO
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3
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Abstract
Background Lung inflammation is associated with many respiratory conditions. Consequently, anti-inflammatory medications, like glucocorticoids, have become mainstay intrapulmonary therapeutics. However, their effectiveness for treating inflammation occurring in the alveolar regions of the lung is limited by suboptimal delivery. To improve the pulmonary distribution of glucocorticoids, such as budesonide to distal regions of the lung, exogenous surfactant has been proposed as an ideal delivery vehicle for such therapies. It was therefore hypothesized that fortifying an exogenous surfactant (BLES) with budesonide would enhance efficacy for treating pulmonary inflammation in vivo. Methods An intratracheal instillation of heat-killed bacteria was used to elicit an inflammatory response in the lungs of male and female rats. Thirty minutes after this initial instillation, either budesonide or BLES combined with budesonide was administered intratracheally. To evaluate the efficacy of surfactant delivery, various markers of inflammation were measured in the bronchoalveolar lavage and lung tissue. Results Although budesonide exhibited anti-inflammatory effects when administered alone, delivery with BLES enhanced those effects by lowering the lavage neutrophil counts and myeloperoxidase activity in lung tissue. Combining budesonide with BLES was also shown to reduce several other pro-inflammatory mediators. These results were shown across both sexes, with no observed sex differences. Conclusion Based on these findings, it was concluded that exogenous surfactant can enhance the delivery and efficacy of budesonide in vivo.
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Affiliation(s)
- Brandon Baer
- Department of Physiology and Pharmacology, Western University, London, ON, Canada.
| | - Lynda McCaig
- Department of Physiology and Pharmacology, Western University, London, ON, Canada
| | - Cory Yamashita
- Department of Physiology and Pharmacology, Western University, London, ON, Canada
- Department of Medicine, Western University, London, ON, Canada
| | - Ruud Veldhuizen
- Department of Physiology and Pharmacology, Western University, London, ON, Canada
- Department of Medicine, Western University, London, ON, Canada
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Daniher D, McCaig L, Ye Y, Veldhuizen R, Lewis J, Ma Y, Zhu J. Protective effects of aerosolized pulmonary surfactant powder in a model of ventilator-induced lung injury. Int J Pharm 2020; 583:119359. [PMID: 32334066 DOI: 10.1016/j.ijpharm.2020.119359] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 04/14/2020] [Accepted: 04/19/2020] [Indexed: 01/22/2023]
Abstract
Mechanical ventilation may contribute to the impairment of the pulmonary surfactant system, which is one of the mechanisms leading to the progression of acute lung injury. To investigate the potential protective effects of pulmonary surfactant in a rat model of ventilator-induced lung injury, the surfactant powder was aerosolized using an in-house made device designed to deliver the aerosolized powder to the inspiratory line of a rodent ventilator circuit. Rats were randomized to (i) administration of aerosolized recombinant surfactant protein C based pulmonary surfactant, (ii) intratracheally instillation of the same surfactant re-constituted in saline, and (iii) no treatment. Animals were monitored during 2 h of high-tidal volume mechanical ventilation, after which rats were sacrificed, and further analysis of lung mechanics and surfactant function were completed. Blood gas measurements during ventilation showed extended maintenance of oxygen levels above 400 mmHg in aerosol treated animals over non-treated and instilled groups, while total protein analysis showed reduced levels in the aerosol compared to non-treated groups. Dynamic captive bubble surface tension measurements showed the activity of surfactant recovered from aerosol treated animals is maintained below 1 mN/m. The prophylactic treatment of aerosolized surfactant powder reduced the severity of lung injury in this model.
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Affiliation(s)
- Derek Daniher
- Biomedical Engineering Graduate Program, The University of Western Ontario, London, Canada
| | - Lynda McCaig
- Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Yuqing Ye
- Biomedical Engineering Graduate Program, The University of Western Ontario, London, Canada
| | - Ruud Veldhuizen
- Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - James Lewis
- Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Canada
| | - Yingliang Ma
- Department of Chemical & Biochemical Engineering, The University of Western Ontario, London, Canada
| | - Jesse Zhu
- Biomedical Engineering Graduate Program, The University of Western Ontario, London, Canada; Department of Chemical & Biochemical Engineering, The University of Western Ontario, London, Canada.
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5
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Baer B, McCaig L, Sivasri T, Sun E, Yamashita C, Veldhuizen R. Exogenous Surfactant as a Pulmonary Drug Delivery Vehicle for Budesonide in the Treatment of ARDS. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.03484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Khazaee R, McCaig L, Huang J, Hardy D, Yamashita C, Veldhuizen R. Effect of Maternal Protein Restriction on the Surfactant System during Early Postnatal Life. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.627.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - John Huang
- University of Western OntarioLondonONCanada
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7
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McCaig L, Khazaee R, Huang Z, Hardy D, Yamashita C, Veldhuizen R. Effects of Intrauterine Growth Restriction (IUGR) on the Surfactant System in Response to Sepsis. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.817.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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8
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Baer B, Arsenault C, McCaig L, Yamashita C, Veldhuizen R. Developing a Novel Therapy for Bacterial Pneumonia. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.627.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Brandon Baer
- Physiology and PharmacologyUniversity of WesternLondonONCanada
| | | | - Lynda McCaig
- Physiology and PharmacologyUniversity of WesternLondonONCanada
| | - Cory Yamashita
- Physiology and PharmacologyUniversity of WesternLondonONCanada
| | - Ruud Veldhuizen
- Physiology and PharmacologyUniversity of WesternLondonONCanada
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Ford NL, McCaig L, Jeklin A, Lewis JF, Veldhuizen RAW, Holdsworth DW, Drangova M. A respiratory-gated micro-CT comparison of respiratory patterns in free-breathing and mechanically ventilated rats. Physiol Rep 2017; 5:5/2/e13074. [PMID: 28100723 PMCID: PMC5269405 DOI: 10.14814/phy2.13074] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 11/14/2016] [Accepted: 11/19/2016] [Indexed: 11/24/2022] Open
Abstract
In this study, we aim to quantify the differences in lung metrics measured in free-breathing and mechanically ventilated rodents using respiratory-gated micro-computed tomography. Healthy male Sprague-Dawley rats were anesthetized with ketamine/xylazine and scanned with a retrospective respiratory gating protocol on a GE Locus Ultra micro-CT scanner. Each animal was scanned while free-breathing, then intubated and mechanically ventilated (MV) and rescanned with a standard ventilation protocol (56 bpm, 8 mL/kg and PEEP of 5 cm H2O) and again with a ventilation protocol that approximates the free-breathing parameters (88 bpm, 2.14 mL/kg and PEEP of 2.5 cm H2O). Images were reconstructed representing inspiration and end expiration with 0.15 mm voxel spacing. Image-based measurements of the lung lengths, airway diameters, lung volume, and air content were compared and used to calculate the functional residual capacity (FRC) and tidal volume. Images acquired during MV appeared darker in the airspaces and the airways appeared larger. Image-based measurements showed an increase in lung volume and air content during standard MV, for both respiratory phases, compared with matched MV and free-breathing. Comparisons of the functional metrics showed an increase in FRC for mechanically ventilated rats, but only the standard MV exhibited a significantly higher tidal volume than free-breathing or matched MV Although standard mechanical ventilation protocols may be useful in promoting consistent respiratory patterns, the amount of air in the lungs is higher than in free-breathing animals. Matching the respiratory patterns with the free-breathing case allowed similar lung morphology and physiology measurements while reducing the variability in the measurements.
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Affiliation(s)
- Nancy L Ford
- Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada .,Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lynda McCaig
- Lawson Health Research Institute, London, Ontario, Canada
| | - Andrew Jeklin
- Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - James F Lewis
- Lawson Health Research Institute, London, Ontario, Canada.,Departments of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Ruud A W Veldhuizen
- Lawson Health Research Institute, London, Ontario, Canada.,Departments of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - David W Holdsworth
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada.,Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,Medical Imaging, University of Western Ontario, London, Ontario, Canada
| | - Maria Drangova
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada.,Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,Medical Imaging, University of Western Ontario, London, Ontario, Canada
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10
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Yamashita CM, Fessler MB, Vasanthamohan L, Lac J, Madenspacher J, McCaig L, Yao L, Wang L, Puntorieri V, Mehta S, Lewis JF, Veldhuizen RAW. Apolipoprotein E-deficient mice are susceptible to the development of acute lung injury. Respiration 2014; 87:416-27. [PMID: 24662316 DOI: 10.1159/000358438] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 12/24/2013] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Apolipoprotein E (apoE) has been shown to play a pivotal role in the development of cardiovascular disease, attributable to its function in lipid trafficking and immune modulating properties; however, its role in modulating inflammation in the setting of acute lung injury (ALI) is unknown. OBJECTIVE To determine whether apoE-deficient mice (apoE-/-) are more susceptible to ALI compared to wild-type (WT) animals. METHODS Two independent models of ALI were employed. Firstly, WT and apoE-/- mice were randomized to acid aspiration (50 μl of 0.1 N hydrochloric acid) followed by 4 h of mechanical ventilation. Secondly, WT and apoE-/- mice were randomized to 72 h of hyperoxia exposure or room air. Thereafter, the intrinsic responses of WT and apoE-/- mice were assessed using the isolated perfused mouse lung (IPML) setup. Finally, based on elevated levels of oxidized low-density lipoprotein (oxLDL) in apoE-/-, the effect of oxLDL on lung endothelial permeability and inflammation was assessed. RESULTS In both in vivo models, apoE-/- mice demonstrated greater increases in lung lavage protein levels, neutrophil counts, and cytokine expression (p < 0.05) compared to WT mice. Experiments utilizing the IPML setup demonstrated no differences in intrinsic lung responses to injury between apoE-/- and WT mice, suggesting the presence of a circulating factor as being responsible for the in vivo observations. Finally, the exposure of lung endothelial cells to oxLDL resulted in increased monolayer permeability and IL-6 release compared to native (nonoxidized) LDL. CONCLUSIONS Our findings demonstrate a susceptibility of apoE-/- animals to ALI that may occur, in part, due to elevated levels of oxLDL.
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11
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Suri LNM, McCaig L, Picardi MV, Ospina OL, Veldhuizen RAW, Staples JF, Possmayer F, Yao LJ, Perez-Gil J, Orgeig S. Adaptation to low body temperature influences pulmonary surfactant composition thereby increasing fluidity while maintaining appropriately ordered membrane structure and surface activity. Biochim Biophys Acta 2013; 1818:1581-9. [PMID: 22387458 DOI: 10.1016/j.bbamem.2012.02.021] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 02/14/2012] [Accepted: 02/17/2012] [Indexed: 01/19/2023]
Abstract
The interfacial surface tension of the lung is regulated by phospholipid-rich pulmonary surfactant films. Small changes in temperature affect surfactant structure and function in vitro. We compared the compositional, thermodynamic and functional properties of surfactant from hibernating and summer-active 13-lined ground squirrels (Ictidomys tridecemlineatus) with porcine surfactant to understand structure-function relationships in surfactant membranes and films. Hibernating squirrels had more surfactant large aggregates with more fluid monounsaturated molecular species than summer-active animals. The latter had more unsaturated species than porcine surfactant. Cold-adapted surfactant membranes displayed gel-to-fluid transitions at lower phase transition temperatures with reduced enthalpy. Both hibernating and summer-active squirrel surfactants exhibited lower enthalpy than porcine surfactant. LAURDAN fluorescence and DPH anisotropy revealed that surfactant bilayers from both groups of squirrels possessed similar ordered phase characteristics at low temperatures. While ground squirrel surfactants functioned well during dynamic cycling at 3, 25, and 37 degrees C, porcine surfactant demonstrated poorer activity at 3 degrees C but was superior at 37 degrees C. Consequently the surfactant composition of ground squirrels confers a greater thermal flexibility relative to homeothermic mammals, while retaining tight lipid packing at low body temperatures. This may represent the most critical feature contributing to sustained stability of the respiratory interface at low lung volumes. Thus, while less effective than porcine surfactant at 37 degrees C, summer-active surfactant functions adequately at both 37 degrees C and 3 degrees C allowing these animals to enter hibernation. Here further compositional alterations occur which improve function at low temperatures by maintaining adequate stability at low lung volumes and when temperature increases during arousal from hibernation.
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Affiliation(s)
- Lakshmi N M Suri
- Sansom Institute for Health Research and School of Pharmacy & Medical Sciences, University of South Australia, Adelaide SA 5000, Australia
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12
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Cvijanovic V, McCaig L, Staples J, Veldhuizen R. Investigating the effect of temperature on large aggregate conversion of surfactant from ground squirrels. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.723.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Lynda McCaig
- Lawson Health Research InstituteLondonONCanada
- Physiology and PharmacologyUniversity of Western OntarioLondonONCanada
| | - Jim Staples
- BiologyUniversity of Western OntarioLondonONCanada
| | - Ruud Veldhuizen
- Lawson Health Research InstituteLondonONCanada
- MedicineUniversity of Western OntarioLondonONCanada
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13
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Banaschewski BJH, Hiansen JQ, McCaig L, Yamashita C, Lewis J, Veldhuizen R. Hypercholesterolemia does not affect pulmonary surfactant or the development of acute lung injury in rats. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.723.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Joshua Qua Hiansen
- Lawson Health Research InstituteLondonONCanada
- PhysiologyUniversity of Western OntarioLondonONCanada
| | - Lynda McCaig
- Lawson Health Research InstituteLondonONCanada
- PhysiologyUniversity of Western OntarioLondonONCanada
| | - Cory Yamashita
- Lawson Health Research InstituteLondonONCanada
- Department of MedicineUniversity of Western OntarioLondonONCanada
| | - James Lewis
- Lawson Health Research InstituteLondonONCanada
- Department of MedicineUniversity of Western OntarioLondonONCanada
| | - Ruud Veldhuizen
- Lawson Health Research InstituteLondonONCanada
- Department of MedicineUniversity of Western OntarioLondonONCanada
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14
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Walker MG, Tessolini JM, McCaig L, Yao LJ, Lewis JF, Veldhuizen RA. ELEVATED ENDOGENOUS SURFACTANT REDUCES INFLAMMATION IN AN ACUTE LUNG INJURY MODEL. Exp Lung Res 2009; 35:591-604. [DOI: 10.1080/01902140902780460] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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15
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Zenri H, Rodriquez-Capote K, McCaig L, Yao LJ, Brackenbury A, Possmayer F, Veldhuizen R, Lewis J. Hyperoxia exposure impairs surfactant function and metabolism. Crit Care Med 2004; 32:1155-60. [PMID: 15190966 DOI: 10.1097/01.ccm.0000126264.00551.c8] [Citation(s) in RCA: 30] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To evaluate the effects of hyperoxia exposure on lung function and the endogenous surfactant system in spontaneously breathing adult rats. DESIGN Analysis of the pulmonary surfactant system isolated from adult rats following exposure to > 90% oxygen or room air for 48 or 72 hrs. SETTING A basic science research laboratory in a university setting. SUBJECTS Sixty pathogen-free Sprague-Dawley rats. INTERVENTIONS Exposure to > 90% oxygen for 72 hrs. MEASUREMENTS AND MAIN RESULTS Exposure to > 90% oxygen for 72 hrs resulted in significant lung dysfunction and an increase in neutrophils and total protein concentrations within the airspace compared with animals exposed to room air or 48 hrs of 90% oxygen exposure. Total alveolar surfactant and large aggregate pool sizes were increased after 72 hrs of hyperoxia compared with the other groups, and there was evidence of lipid peroxidation within these large aggregate subtractions. The biophysical function of large aggregate isolated from 72-hr hyperoxia-exposed animals was also impaired and converted into small aggregate forms faster than large aggregate from normoxia-exposed animals when assessed using in vitro surface area cycling techniques. CONCLUSIONS Oxidative stress on the endogenous surfactant system may represent an important mechanism contributing to the surfactant dysfunction and abnormal surfactant metabolism associated with hyperoxia-induced lung injury.
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Affiliation(s)
- Hiromi Zenri
- Department of Medicine, Lawson Health Research Institute, St. Joseph's Health Centre, The University of Western Ontario, London, Ontario, Canada
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Velasquez A, Bechara RI, Lewis JF, Malloy J, McCaig L, Brown LAS, Guidot DM. Glutathione replacement preserves the functional surfactant phospholipid pool size and decreases sepsis-mediated lung dysfunction in ethanol-fed rats. Alcohol Clin Exp Res 2002; 26:1245-51. [PMID: 12198401 DOI: 10.1097/01.alc.0000024269.05402.97] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Alcohol abuse increases the incidence of acute respiratory distress syndrome (ARDS). Previous evidence from our laboratory links ethanol-mediated glutathione depletion to impaired surfactant production by alveolar epithelial cells in vitro and to endotoxin-mediated edematous injury in isolated lungs ex vivo. ARDS patients have an imbalance between the inactive small aggregate (SA) and the bioactive large aggregate (LA) forms of surfactant phospholipid (as reflected by increased SA/LA ratios). Therefore, we hypothesized that ethanol ingestion, via glutathione depletion, could alter surfactant phospholipid distribution between LA and SA forms and thereby exacerbate sepsis-mediated lung dysfunction in vivo. METHODS Rats fed an isocaloric diet with or without ethanol (36% total calories) for 6 weeks were made septic via cecal ligation and perforation. Some ethanol-fed rats had their diets supplemented with the glutathione precursor procysteine (>L-2-oxothiaxolidine-4-carboxylate). Sepsis physiology was assessed by determining respiratory rates, arterial blood pressures, and plasma lactate levels, and lung dysfunction was assessed by determining lung lavage fluid protein levels (index of alveolar endothelial/epithelial barrier disruption), arterial hypoxemia (index of impaired gas exchange) and surfactant phospholipid SA and LA fractions (index of the alveolar epithelium's ability to maintain a functional surfactant pool during sepsis). RESULTS Ethanol ingestion decreased (p< 0.05) lung lavage fluid glutathione levels, and this defect was prevented by procysteine. Although ethanol ingestion had no effect (p< 0.05) on any of the indices of sepsis, it increased (p< 0.05) lung lavage fluid protein levels, worsened hypoxemia, and decreased the functional (LA) surfactant phospholipid pool after sepsis, all of which was prevented by procysteine. CONCLUSIONS Ethanol ingestion, via glutathione depletion, increased sepsis-mediated lung dysfunction, and these effects could contribute to the increased risk of ARDS seen in alcoholic patients.
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Affiliation(s)
- Alvaro Velasquez
- Atlanta Veterans Affairs Medical Center, 1670 Clairmont Road, Decatur, GA 30033, USA
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17
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Velasquez A, Bechara RI, Lewis JF, Malloy J, McCaig L, Brown LAS, Guidot DM. Glutathione Replacement Preserves the Functional Surfactant Phospholipid Pool Size and Decreases Sepsis-Mediated Lung Dysfunction in Ethanol-Fed Rats. Alcohol Clin Exp Res 2002. [DOI: 10.1111/j.1530-0277.2002.tb02663.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Campbell H, Bosma K, Brackenbury A, McCaig L, Yao LJ, Veldhuizen R, Lewis J. Polyethylene glycol (PEG) attenuates exogenous surfactant in lung-injured adult rabbits. Am J Respir Crit Care Med 2002; 165:475-80. [PMID: 11850339 DOI: 10.1164/ajrccm.165.4.2106109] [Citation(s) in RCA: 19] [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: 11/16/2022] Open
Abstract
Exogenous surfactant administration in patients with the acute respiratory distress syndrome is currently being evaluated, although resource limitations and the potential expense are existing concerns. Previous in vitro and in vivo studies have shown that substances such as polyethylene glycol (PEG) added to exogenous surfactant improved the function of the surfactant. Based on these data, we hypothesized that PEG would augment surfactant function in an adult rabbit model of lung injury induced by lung lavage and mechanical ventilation, and that this would be accomplished by altering surfactant metabolism. Contrary to our hypothesis, however, mean Pa(O(2)), Pa(CO(2)), and peak inspiratory pressures values 3 h after treatment were significantly worse in the surfactant + PEG treatment groups compared with the surfactant alone groups. These effects were observed for two different doses of surfactant tested. Lavage analyses after sacrifice showed that animals given PEG with their surfactant had significantly lower total and large aggregate surfactant pool sizes compared with animals given surfactant alone. We conclude that in this lung injury model, PEG attenuated surfactant responses, suggesting that further preclinical studies are required before testing this approach in humans.
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Affiliation(s)
- Holly Campbell
- Department of Medicine, Lawson Health Research Institute, The University of Western Ontario, London, Canada
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19
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Nakamura T, Malloy J, McCaig L, Yao LJ, Joseph M, Lewis J, Veldhuizen R. Mechanical ventilation of isolated septic rat lungs: effects on surfactant and inflammatory cytokines. J Appl Physiol (1985) 2001; 91:811-20. [PMID: 11457798 DOI: 10.1152/jappl.2001.91.2.811] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effects of mechanical ventilation (MV) on the surfactant system and cytokine secretion were studied in isolated septic rat lungs. At 23 h after sham surgery or induction of sepsis by cecal ligation and perforation (CLP), lungs were excised and randomized to one of three groups: 1) a nonventilated group, 2) a group subjected to 1 h of noninjurious MV (tidal volume = 10 ml/kg, positive end-expiratory pressure = 3 cmH(2)O), or 3) a group subjected to 1 h of injurious MV (tidal volume = 20 ml/kg, positive end-expiratory pressure = 0 cmH(2)O). Nonventilated sham and CLP lungs had similar compliance, normal lung morphology, surfactant, and cytokine concentrations. Injurious ventilation decreased compliance, altered surfactant, increased cytokines, and induced morphological changes compared with nonventilation in sham and CLP lungs. In these lungs, the surfactant system was similar in sham and CLP lungs; however, tumor necrosis factor-alpha and interleukin-6 levels were significantly higher in CLP lungs. We conclude that injurious ventilation altered surfactant independent of sepsis and that the CLP lungs were predisposed to the secretion of larger amounts of cytokines because of ventilation.
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Affiliation(s)
- T Nakamura
- Department of Physiology, Lawson Health Research Institute, St. Joseph's Health Centre, University of Western Ontario, London, Ontario, Canada N6A 4V2
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20
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Yao LJ, Fraher LJ, Veldhuizen RA, Samuelson S, Borron P, Malloy J, McCaig L, Lewis JF. Effects of alveolar surfactant aggregates on T-lymphocyte proliferation. Biochim Biophys Acta 2001; 1535:266-74. [PMID: 11278166 DOI: 10.1016/s0925-4439(01)00023-0] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The effects of alveolar large aggregate (LA) and small aggregate (SA) surfactant subfractions isolated from healthy adult rats on mitogen-stimulated proliferative responses of human peripheral blood mononuclear cells (PBMC) was examined. Various concentrations of total surfactant suppressed proliferation of stimulated lymphocytes by up to 95% of mitogen-stimulated cells alone. LA subfractions of total surfactant had no effect on proliferation, whereas SA significantly enhanced the lymphocyte proliferation at lower concentrations (7.8 microg/ml) compared to mitogen-stimulated cells alone. Higher concentrations of SA (62.5 microg/ml) inhibited lymphocyte proliferation. This concentration-dependent effect of SA on proliferation of PBMC was also present when cells were stimulated with various lectins including anti-CD3, concanavalin A and phytohemagglutinin. Analysis of the supernatant of mitogen-stimulated cell cultures treated with inhibitory concentrations of SA showed decreased amounts of interleukin (IL)-2, compared to cells alone, which could be reversed by adding exogenous IL-2 to the cell cultures with the SA. These results suggest that alveolar surfactant subfractions have distinct functions within the alveoli, both biophysically and with respect to their effects on the host's immunomodulatory responses.
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Affiliation(s)
- L J Yao
- Department of Medicine, The Lawson Research Institute, The University of Western Ontario, London, Canada
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21
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Abstract
Mechanical ventilation of the lung is an essential but potentially harmful therapeutic intervention for patients with acute respiratory distress syndrome. The objective of the current study was to establish and characterize an isolated mouse lung model to study the harmful effects of mechanical ventilation. Lungs were isolated from BalbC mice and randomized to either a nonventilated group, a conventionally ventilated group (tidal volume 7 mL x kg(-1), 4 cm positive endexpiratory pressure (PEEP)) or an injuriously ventilated group (20 mL x kg(-1), 0 cm PEEP). Lungs were subsequently analysed for lung compliance, morphology, surfactant composition and inflammatory cytokines. Injurious ventilation resulted in significant lung dysfunction, which was associated with a significant increase in pulmonary surfactant, and surfactant small aggregates compared to the other two groups. Injurious ventilation also led to a significantly increased concentration of interleukin-6 and tumour necrosis factor-a in the lavage. It was concluded that the injurious effects of mechanical ventilation can effectively be studied in isolated mouse lung, which offers the potential of studying genetically altered animals. It was also concluded that in this model, the lung injury is, in part, mediated by the surfactant system and the release of inflammatory mediators.
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Affiliation(s)
- R A Veldhuizen
- Dept of Medicine, University of Western Ontario, Toronto, Canada
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22
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Lewis J, McCaig L, Häfner D, Spragg R, Veldhuizen R, Kerr C. Dosing and delivery of a recombinant surfactant in lung-injured adult sheep. Am J Respir Crit Care Med 1999; 159:741-7. [PMID: 10051245 DOI: 10.1164/ajrccm.159.3.9806069] [Citation(s) in RCA: 32] [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: 11/16/2022] Open
Abstract
The purpose of this study was to evaluate a surfactant based on a recombinant surfactant protein-C (rSP-C) at three different doses (25, 100, and 200 mg lipid/kg) in the saline lavage adult sheep model of acute lung injury. All three doses resulted in significant improvements in gas exchange, although the 100 and 200 mg/kg doses were superior to the 25 mg/kg dose. There were no significant differences in effect of the 100 and 200 mg/kg doses. In addition, the physiologic efficacy and lobar surfactant distribution patterns were similar when two different surfactant delivery methods were compared. This comparison involved administering the surfactant directly into each lobe under bronchoscopic guidance, versus instilling the surfactant through an endotracheal tube into the lungs. However, the former technique took significantly longer to perform (24.5 +/- 3.3 min versus 11.6 +/- 2.5 min, p < 0.05) and required a skilled bronchoscopist. In conclusion, rSP-C surfactant was effective in improving gas exchange in this model of lung injury, although higher doses were required for optimal responses. The bronchoscopic administration technique produced results similar to those of the tracheal instillation method, but had some disadvantages that may limit the widespread clinical use of this technique in patients with lung injury.
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Affiliation(s)
- J Lewis
- Department of Medicine, Lawson Research Institute, London, Ontario, Canada.
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23
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Vanderzwan J, McCaig L, Mehta S, Joseph M, Whitsett J, McCormack DG, Lewis JF. Characterizing alterations in the pulmonary surfactant system in a rat model of Pseudomonas aeruginosa pneumonia. Eur Respir J 1998; 12:1388-96. [PMID: 9877497 DOI: 10.1183/09031936.98.12061388] [Citation(s) in RCA: 23] [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: 11/05/2022]
Abstract
Bacterial pneumonia remains a significant cause of patient morbidity and mortality worldwide. Pulmonary surfactant serves to maintain homeostasis in the lung through the maintenance of alveolar stability and the regulation of the alveolar immune response. The purpose of this study was to characterize the lung injury and associated surfactant alterations in a rat model of acute Pseudomonas aeruginosa pneumonia. Pneumonia was induced in male Sprague-Dawley rats via intratracheal injection of 0.2 ml, phosphate-buffered saline (PBS) containing P. aeruginosa (6x10(8) colony-forming units x mL(-1)). Control animals received 0.2 mL sterile PBS. Twenty-four hours after inoculation, the pneumonia group (PN) exhibited clinical signs of pneumonia including deficits in gas exchange, leukopenia and elevated arterial lactate levels. Morphological assessment confirmed the presence of pneumonia with airspaces filled with polymorphonuclear cells. Lung homogenate analysis demonstrated evidence of bacterial colonization of pneumonic lung tissue. Lung compliance was also significantly lower in the PN group. Lung lavage analysis of PN rats revealed the pooled surfactant levels to be lower and the surfactant function reduced compared to control rats. Surfactant composition was also found to be altered in PN rats. These results demonstrate that in Pseudomonas aeruginosa pneumonia, the pulmonary surfactant system is both poorly functioning and reduced in quantity. These alterations may contribute to the lung dysfunction characteristic of this disorder.
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Affiliation(s)
- J Vanderzwan
- Dept of Physiology, Lawson Research Institute, St Joseph's Health Centre, University of Western Ontario, London, Canada
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24
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Malloy J, McCaig L, Veldhuizen R, Yao LJ, Joseph M, Whitsett J, Lewis J. Alterations of the endogenous surfactant system in septic adult rats. Am J Respir Crit Care Med 1997; 156:617-23. [PMID: 9279248 DOI: 10.1164/ajrccm.156.2.9608009] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [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: 02/05/2023] Open
Abstract
Sepsis is the most common factor leading to the acute respiratory distress syndrome (ARDS) and is associated with the highest mortality rate. It has been suggested that the pulmonary surfactant system is altered and contributes to the lung dysfunction associated with ARDS. The objective of this study was to characterize the lung injury, specifically the endogenous surfactant system in septic adult rats. Sepsis was induced in male Sprague-Dawley rats by cecal ligation and perforation and resulted in significant increases in heart rates, respiratory rates, and lactate levels along with positive blood cultures in septic animals compared with a sham control group. Two distinct septic groups were developed, a septic group and a sepsis with lung injury (septic+LI) group. The septic group had no significant differences in oxygenation compared with the sham group, whereas the septic+LI group had significantly lower PaO2 and higher A-a gradient values compared to both the sham and septic groups. The total surfactant pool size was significantly lower in the septic+LI group compared with the sham group. The small surfactant aggregate to large surfactant aggregate ratio was significantly lower in the septic group and was further reduced in the septic+LI group. There were also significantly higher levels of surfactant protein A (SP-A) in both septic and septic+LI groups compared to the sham group. These results demonstrated that the endogenous surfactant system was altered in systemic sepsis without lung dysfunction and is further altered when a lung injury is present.
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Affiliation(s)
- J Malloy
- Department of Physiology, Lawson Research Institute, St. Joseph's Health Centre, University of Western Ontario, London, Canada.
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25
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Veldhuizen RA, Ito Y, Marcou J, Yao LJ, McCaig L, Lewis JF. Effects of lung injury on pulmonary surfactant aggregate conversion in vivo and in vitro. Am J Physiol 1997; 272:L872-8. [PMID: 9176251 DOI: 10.1152/ajplung.1997.272.5.l872] [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] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Within the alveolar space pulmonary surfactant is converted from the surface active large aggregates (LA) to the inactive small aggregates (SA). This conversion is affected by a change in surface area, lung injury, breathing pattern, and protease activity. This study examined the effect of N-nitroso-N-methylurethane-induced acute lung injury on aggregate conversion in mechanically ventilated and spontaneously breathing rabbits. Both the in vitro surface area cycling techniques and the in vivo technique of intratracheally injecting radiolabeled LA were used for analyzing aggregate conversion. Mechanical ventilation of injured lungs resulted in increased aggregate conversion and increased surfactant aggregate ratios compared with controls. Spontaneously breathing injured animals had aggregate conversion and aggregate ratios that were not significantly different from controls. In vitro aggregate conversion was slower for LA obtained from injured animals compared with normal animals. We conclude that the mechanical stress of mechanical ventilation results in increased aggregate conversion and aggregate ratios. Furthermore, in vitro conversion of isolated LA does not necessarily reflect the conversion of aggregates within the alveoli.
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Affiliation(s)
- R A Veldhuizen
- Department of Physiology, University of Western Ontario, London, Canada
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Hoff B, Hood D, McCaig L, Moore A. Eperythrozoonosis in sheep. Can Vet J 1996; 37:747-8. [PMID: 9111697 PMCID: PMC1576680] [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: 02/04/2023]
Affiliation(s)
- B Hoff
- Ontario Ministry of Agriculture, Food and Rural Affairs, Guelph, Qntario
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Abstract
A study was undertaken to determine the extent to which physician assistants (PAs) and/or nurse practitioners (NPs) are a source of health care delivery in emergency departments (EDs) in the United States. The National Hospital Ambulatory Medical Survey (NHAMCS) uses a multistage probability sample that examines patient visits within EDs. The sample included 437 hospitals with EDs. Visits were mostly from self-referred patients to EDs within nonfederal, short-stay hospitals, or general hospitals. Analysis of NHAMCS data found that a PA and/or NP was seen for 3.5 million ED visits in 1992. Remarkably little difference in gender, reason for visit, diagnosis, and medication prescribed was found between PA/NP visits and visits to all providers. This was the first study that systematically identified the extent of PA/NP-delivered ED services in the United States and compared it with physician services. Overall, PAs and NPs were found to be significant sources of health care service for hospital EDs. They are involved in care for almost 4% of all ED visits nationally and manage a wider range of conditions than has been previously reported. When types of visits are analyzed, including reasons for ED care, diagnosis, and treatment, it appears that visits associated with care by ED-based PA/NPs are similar to all ED visits, including those attended by emergency medicine physicians. More studies are needed to better understand the role of PAs and/or NPs in various ED settings. Recruitment and use of PAs and NPs may be a cost-effective strategy for improved delivery of emergency services.
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Affiliation(s)
- R S Hooker
- Kaiser Permanente, Portland OR 97227-1098, USA
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28
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Ito Y, Goffin J, Veldhuizen R, Joseph M, Bjarneson D, McCaig L, Yao LJ, Marcou J, Lewis J. Timing of exogenous surfactant administration in a rabbit model of acute lung injury. J Appl Physiol (1985) 1996; 80:1357-64. [PMID: 8926267 DOI: 10.1152/jappl.1996.80.4.1357] [Citation(s) in RCA: 16] [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: 02/03/2023] Open
Abstract
The purpose of this study was to evaluate early vs. late administration of exogenous surfactant in an adult rabbit model of acute lung injury. Lung injury was induced by repetitive whole lung saline lavage and subsequent mechanical ventilation. Bovine lipid extract surfactant was instilled either 1 (Early) or 4 h (Late) after the last lavage. Animals were monitored for 7 h after the last lavage. Although arterial PO2 values increased significantly immediately after treatment in both the Early and Late groups, this improvement was not sustained in the Late group. There was also a higher incidence of pneumothoraxes in the Late group vs. both the Early group and a nontreated control group. The ratio of poorly functioning small surfactant aggregates to superior functioning large aggregates was higher in the Late group compared with the Early group. Morphological analysis revealed that early surfactant treatment prevented the progression of lung injury over time. We conclude that administration of exogenous surfactant at an early time point in lung injury resulted in superior responses compared with later treatments.
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Affiliation(s)
- Y Ito
- Lawson Research Institute, St. Joseph's Health Centre, Department of Physiology, University of Western Ontario, London, Canada
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Veldhuizen RA, Marcou J, Yao LJ, McCaig L, Ito Y, Lewis JF. Alveolar surfactant aggregate conversion in ventilated normal and injured rabbits. Am J Physiol 1996; 270:L152-8. [PMID: 8772538 DOI: 10.1152/ajplung.1996.270.1.l152] [Citation(s) in RCA: 24] [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] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Alveolar surfactant can be separated into two subtypes; large aggregates and small aggregates. Large aggregates represent the surface active form of surfactant and are the metabolic precursors of small aggregates. Previous studies examined the mechanism by which large aggregates are converted into small aggregates in vitro. We used intratracheal injection of radiolabeled large aggregates in rabbits to probe the aggregate conversion in vivo. After this injection, animals were mechanically ventilated for 60 min. After the animals were killed, the lungs were lavaged, and the percentage of radiolabel present in the small aggregate fraction was determined. Our results showed that ventilation resulted in aggregate conversion and that increases in tidal volume, but not in respiratory rate, correlated with increased conversion. Aggregate conversion in rabbits with acute lung injury correlated significantly with severity of injury. We conclude that a change in surface area (i.e., respiration) is necessary for aggregate conversion in vivo and that the ventilation strategy can affect this conversion. Furthermore, increased aggregate conversion in injured lungs might contribute to increased small-to-large aggregate ratios in these lungs compared with normal lungs.
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Affiliation(s)
- R A Veldhuizen
- Department of Physiology, University of Western Ontario, London, Canada
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30
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Lewis JF, Veldhuizen R, Possmayer F, Sibbald W, Whitsett J, Qanbar R, McCaig L. Altered alveolar surfactant is an early marker of acute lung injury in septic adult sheep. Am J Respir Crit Care Med 1994; 150:123-30. [PMID: 8025737 DOI: 10.1164/ajrccm.150.1.8025737] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [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: 01/28/2023] Open
Abstract
The purpose of this study was to characterize changes in the endogenous surfactant system in adult sheep rendered septic via cecal ligation and perforation (CLP). Forty-eight hours after CLP, septic animals had significant increases in mean pulmonary artery pressure (PAP) (p < 0.01), cardiac index (CI) (p < 0.01), and arterial lactate (p < 0.05) values compared with their respective baseline values, while the same measurements in a sham-operated control group did not change significantly. The changes in the septic group were associated with significantly lower PaO2 (p < 0.05) and alveolar to arterial (A-a) oxygen gradient values (p < 0.01) at 48 h compared with baseline measurements. No changes in oxygenation occurred within the sham-operated group. Surfactant phospholipid (PL) composition and surface activity measurements of isolated alveolar surfactant aggregate forms were similar for the two groups at 48 h. However, the ratio of poorly functioning small aggregate forms (SA) to superior functioning large aggregates (LA) was significantly increased in the septic versus the sham-operated animals (p < 0.01). This was associated with significantly decreased surfactant protein A (SP-A), B (SP-B), and C (SP-C) levels in septic versus sham-operated animals (p < 0.05). We conclude that sepsis-associated lung injury resulted in altered alveolar surfactant aggregate forms. These changes, together with altered surfactant protein levels, may represent a very sensitive marker of acute lung injury in high-risk patients. Furthermore, these findings suggest that exogenous surfactant given at an early stage of lung injury may mitigate progressive lung dysfunction.
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Affiliation(s)
- J F Lewis
- Department of Medicine, Lawson Research Institute, St. Joseph's Health Centre, London, Ontario, Canada
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Abstract
Previous studies have shown that the underlying patterns of lung injury influence subsequent responses to aerosolized exogenous surfactant. The purpose of this study was to compare aerosolized versus tracheally instilled surfactant in a nonuniform lung injury. Adult sheep underwent whole lung lavage with subsequent HCl instillation into the right middle lobe (RML) and lingula (LING) to create a nonuniform injury. Animals were treated with either nebulized surfactant (Neb.Surf.), tracheally instilled surfactant (Inst.Surf.), or nebulized saline (Neb. Saline). PaO2, alveolar-arterial O2 gradient (PAO2-PaO2), PaCO2, and peak inspiratory pressure (PIP) values all significantly improved during 180 min of continuous aerosolization for Neb.Surf. animals compared with pretreatment values (p < 0.01) and with the other two treatment groups (p < 0.01). Although PaO2 and (PAO2-PaO2) values improved for the Inst.Surf. group by 180 min after treatment (p < 0.05), PaCO2 and PIP values were significantly increased 30 min after surfactant instillation (p < 0.05). Neb. Saline animals had no significant changes in physiologic parameters over 180 min. Approximately 8% of the total aerosolized surfactant deposited in lung tissue was recovered from the more severely damaged RML and LING, compared with approximately 50% of the total instilled surfactant recovered from these lobes. This resulted in significantly greater percentages of the total aerosolized surfactant deposited in each of the remaining lobes compared with the percent deposition of instilled surfactant (p < 0.05). Both the underlying pattern of lung injury and the exogenous surfactant delivery technique may influence clinical responses to surfactant therapy in patients with the adult respiratory distress syndrome (ARDS).
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Affiliation(s)
- J F Lewis
- Department of Medicine, Lawson Research Institute, St. Joseph's Health Centre, London, Ontario, Canada
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Stehr-Green JK, McCaig L, Remsen HM, Rains CS, Fox M, Juranek DD. Shedding of oocysts in immunocompetent individuals infected with Cryptosporidium. Am J Trop Med Hyg 1987; 36:338-42. [PMID: 3826492 DOI: 10.4269/ajtmh.1987.36.338] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In June 1985, we investigated an outbreak of cryptosporidiosis at a day-care center in Florida. Through day-care center-wide stool screening, 33% (28/84) of the children and 22% (4/18) of the staff members submitting stool specimens were found to have cryptosporidiosis. Children 12-35 months of age and their teachers were at highest risk. All but 1 of the Cryptosporidium-positive patients reported diarrhea, which lasted between 1-44 days. Serial stool specimens were obtained from 8 infected individuals (5 children and 3 adults). Duration of oocyst shedding ranged from 8 to more than 50 days and continued in 5 individuals after diarrhea ceased. No relationship was found between duration of oocyst shedding and the age of the patient or duration or severity of diarrhea. Results of the investigation indicate that infected individuals may continue to excrete oocysts and, therefore, may remain infectious for days or weeks after gastrointestinal symptoms disappear.
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Abstract
One hundred consecutive female patients attending an inner-city clinic for treatment of sexually transmitted diseases were evaluated for the presence of Trichomonas vaginalis by history, physical examination, 0.85% NaCl wet mount, Papanicolaou smear, and culture. Of the 100 women, 54 were found to be harboring the parasite, as determined by one or more positive diagnostic tests. This prevalence corresponds with that reported previously. The information gained from the history (symptoms and phase of menstrual cycle) and physical examination correlated poorly with results of cultures for T. vaginalis; the organism was isolated more often than symptoms or physical findings would have indicated. Culture was the most sensitive of diagnostic techniques; 48 (89%) of the 54 patients were identified by this method. The Papanicolaou smear detected 35 infections (65%), and the 0.85% NaCl wet mount, 28 (59%). The simplest and most efficient technique for screening women for infection with T. vaginalis may be the Papanicolaou smear, since it is part of the annual physical examination.
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