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Harris TR, Bhutta ZA, Qureshi I, Kharma N, Raza T, Hssain AA, Pathare AS, D'Silva A, Khatib MY, Mohamedali MGH, Macineira IMG, Garcia Hernandez VR, Garcia JR, Thomas SH, Pathan SA. A randomised clinical trial of awake prone positioning in COVID-19 suspects with acute hypoxemic respiratory failure. Contemp Clin Trials Commun 2024; 39:101295. [PMID: 38689829 PMCID: PMC11059337 DOI: 10.1016/j.conctc.2024.101295] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 02/22/2024] [Accepted: 03/27/2024] [Indexed: 05/02/2024] Open
Abstract
Background Awake prone position (APP) has been reported to improve oxygenation in patients with COVID-19 disease and to reduce the requirement for invasive mechanical ventilation for patients requiring support with high flow nasal cannula. There is conflicting data for patients requiring lower-level oxygen support. Research question Does APP reduce escalation of oxygen support in COVID-19 patients requiring supplementary oxygen?The primary outcome was defined as an escalation of oxygen support from simple supplementary oxygen (NP, HM, NRB) to NIV (CPAP or BiPAP), HFNC or IMV; OR from NIV (CPAP or BiPAP) or HFNC to IMV by day30. Study design Two center, prospective, non-blind, randomised controlled trial. Patients with confirmed or suspected COVID-19 pneumonia requiring ≥ 5 liters/min oxygen to maintain saturations ≥ 94 % were randomised to either APP or control group. The APP group received a 3-h APP session three times per day for three days. Results Between 9 May and July 13, 2021, 89 adults were screened and 61 enrolled, 31 to awake prone position and 30 controls. There was no difference in the primary outcome, 7 (22.6 %) patients randomised to APP and 9 (30.0 %) controls required escalation of oxygen support (OR 0.68 (0.22-2.14), P = 0.51). There were no differences in any secondary outcomes, in APP did not improve oxygenation. Interpretation In COVID-19 patients, the use of APP did not prevent escalation of oxygen support from supplementary to invasive or non-invasive ventilation or improve patient respiratory physiology. Trial registration NCT04853979 (clinicaltrials.gov).
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Affiliation(s)
- Tim R.E. Harris
- Corporate Department of Emergency Medicine, Hamad Medical Corporation, Qatar
- Queen Mary University London, United Kingdom
| | - Zain A. Bhutta
- Corporate Department of Emergency Medicine, Hamad Medical Corporation, Qatar
- Department of Emergency Medicine and Services, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Isma Qureshi
- Corporate Department of Emergency Medicine, Hamad Medical Corporation, Doha, Qatar
| | - Nadir Kharma
- Corporate Department Medical Intensive Care, Hamad General Hospital, Doha, Qatar
- Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Tasleem Raza
- Corporate Department Medical Intensive Care, Hamad General Hospital, Doha, Qatar
| | - Ali Ait Hssain
- Corporate Department Medical Intensive Care, Hamad General Hospital, Doha, Qatar
| | - Ankush Suresh Pathare
- Corporate Department of Emergency Medicine, Hazm Mebaireek General Hospital, Hamad Medical Corporation, Doha, Qatar
| | - Ashwin D'Silva
- Corporate Department of Emergency Medicine, Hazm Mebaireek General Hospital, Hamad Medical Corporation, Doha, Qatar
| | - Mohamad Yahya Khatib
- Corporate Medical Intensive Care, Head of Unit, Hazm Mebaireek General Hospital, Doha, Qatar
| | - Mohamed Gafar Hussein Mohamedali
- Corporate Department Internal Medicine, Head of Unit, Hazm Mebaireek General Hospital, Doha, Qatar
- Instructor in Clinical Medicine, Weill Cornell Medicine, Qatar
| | | | | | - Jorge Rosales Garcia
- Corporate Department Medical Intensive Care, The Cuban Hospital, Hamad Medical Corporation, Doha, Qatar
| | - Stephen H. Thomas
- Department of Emergency Medicine, Beth Israel Deaconess Medical Center & Harvard Medical School, Boston, MA, USA
- Queen Mary University London, United Kingdom
| | - Sameer A. Pathan
- Corporate Department of Emergency Medicine, Hamad Medical Corporation, Qatar
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia
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Omrani AS, Pathan SA, Thomas SA, Harris TR, Coyle PV, Thomas CE, Qureshi I, Bhutta ZA, Mawlawi NA, Kahlout RA, Elmalik A, Azad AM, Daghfal J, Mustafa M, Jeremijenko A, Soub HA, Khattab MA, Maslamani MA, Thomas SH. Randomized double-blinded placebo-controlled trial of hydroxychloroquine with or without azithromycin for virologic cure of non-severe Covid-19. EClinicalMedicine 2020; 29:100645. [PMID: 33251500 PMCID: PMC7678437 DOI: 10.1016/j.eclinm.2020.100645] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Hydroxychloroquine (HC) ± azithromycin (AZ) is widely used for Covid-19. The Qatar Prospective RCT of Expediting Coronavirus Tapering (Q-PROTECT) aimed to assess virologic cure rates of HC±AZ in cases of low-acuity Covid-19. METHODS Q-PROTECT employed a prospective, placebo-controlled design with blinded randomization to three parallel arms: placebo, oral HC (600 mg daily for one week), or oral HC plus oral AZ (500 mg day one, 250 mg daily on days two through five). At enrollment, non-hospitalized participants had mild or no symptoms and were within a day of Covid-19 positivity by polymerase chain reaction (PCR). After six days, intent-to-treat (ITT) analysis of the primary endpoint of virologic cure was assessed using binomial exact 95% confidence intervals (CIs) and χ2 testing. (ClinicalTrials.gov NCT04349592, trial status closed to new participants.). FINDINGS The study enrolled 456 participants (152 in each of three groups: HC+AZ, HC, placebo) between 13 April and 1 August 2020. HC+AZ, HC, and placebo groups had 6 (3·9%), 7 (4·6%), and 9 (5·9%) participants go off study medications before completing the medication course (p = 0·716). Day six PCR results were available for all 152 HC+AZ participants, 149/152 (98·0%) HC participants, and 147/152 (96·7%) placebo participants. Day six ITT analysis found no difference (p = 0·821) in groups' proportions achieving virologic cure: HC+AZ 16/152 (10·5%), HC 19/149 (12·8%), placebo 18/147 (12·2%). Day 14 assessment also showed no association (p = 0·072) between study group and viral cure: HC+AZ 30/149 (20·1%,), HC 42/146 (28·8%), placebo 45/143 (31·5%). There were no serious adverse events. INTERPRETATION HC±AZ does not facilitate virologic cure in patients with mild or asymptomatic Covid-19. FUNDING The study was supported by internal institutional funds of the Hamad Medical Corporation (government health service of the State of Qatar).
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Affiliation(s)
- Ali S. Omrani
- Department of Medicine, Hamad Medical Corporation Communicable Diseases Center, Doha, Qatar
| | - Sameer A. Pathan
- Department of Emergency Medicine, Hamad General Hospital, Doha 3050, Qatar
- Blizard Institute, Barts and The London School of Medicine, Queen Mary Univ. of London, UK
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia
| | - Sarah A. Thomas
- BSc Candidate in Medical Biosciences, Faculty of Medicine, Imperial College London, UK
| | - Tim R.E. Harris
- Department of Emergency Medicine, Hamad General Hospital, Doha 3050, Qatar
- Blizard Institute, Barts and The London School of Medicine, Queen Mary Univ. of London, UK
| | - Peter V. Coyle
- Departments of Virology and Laboratory Medicine and Pathology, Hamad Medical Corporation, Doha
| | - Caroline E. Thomas
- Department of Emergency Medicine, Hamad General Hospital, Doha 3050, Qatar
| | - Isma Qureshi
- Department of Emergency Medicine, Hamad General Hospital, Doha 3050, Qatar
| | - Zain A. Bhutta
- Department of Emergency Medicine, Hamad General Hospital, Doha 3050, Qatar
| | - Naema Al Mawlawi
- Departments of Virology and Laboratory Medicine and Pathology, Hamad Medical Corporation, Doha
| | - Reham Al Kahlout
- Departments of Virology and Laboratory Medicine and Pathology, Hamad Medical Corporation, Doha
| | - Ashraf Elmalik
- Department of Pharmacy, Hamad General Hospital, Doha, Qatar
| | - Aftab M. Azad
- Department of Emergency Medicine, Hamad General Hospital, Doha 3050, Qatar
| | - Joanne Daghfal
- Department of Medicine, Hamad Medical Corporation Communicable Diseases Center, Doha, Qatar
| | - Mulham Mustafa
- Department of Medicine, Hamad Medical Corporation Communicable Diseases Center, Doha, Qatar
| | - Andrew Jeremijenko
- Department of Medicine, Hamad Medical Corporation Communicable Diseases Center, Doha, Qatar
| | - Hussam Al Soub
- Department of Medicine, Hamad Medical Corporation Communicable Diseases Center, Doha, Qatar
| | - Mohammed Abu Khattab
- Department of Medicine, Hamad Medical Corporation Communicable Diseases Center, Doha, Qatar
| | - Muna Al Maslamani
- Department of Medicine, Hamad Medical Corporation Communicable Diseases Center, Doha, Qatar
- Department of Medicine, Weill Cornell Medical College in Qatar, Doha, Qatar
| | - Stephen H. Thomas
- Department of Emergency Medicine, Hamad General Hospital, Doha 3050, Qatar
- Blizard Institute, Barts and The London School of Medicine, Queen Mary Univ. of London, UK
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Arandjelovic M, Guschanski K, Schubert G, Harris TR, Thalmann O, Siedel H, Vigilant L. Two-step multiplex polymerase chain reaction improves the speed and accuracy of genotyping using DNA from noninvasive and museum samples. Mol Ecol Resour 2008; 9:28-36. [PMID: 21564562 DOI: 10.1111/j.1755-0998.2008.02387.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Many studies in molecular ecology rely upon the genotyping of large numbers of low-quantity DNA extracts derived from noninvasive or museum specimens. To overcome low amplification success rates and avoid genotyping errors such as allelic dropout and false alleles, multiple polymerase chain reaction (PCR) replicates for each sample are typically used. Recently, two-step multiplex procedures have been introduced which drastically increase the success rate and efficiency of genotyping. However, controversy still exists concerning the amount of replication needed for suitable control of error. Here we describe the use of a two-step multiplex PCR procedure that allows rapid genotyping using at least 19 different microsatellite loci. We applied this approach to quantified amounts of noninvasive DNAs from western chimpanzee, western gorilla, mountain gorilla and black and white colobus faecal samples, as well as to DNA from ~100-year-old gorilla teeth from museums. Analysis of over 45 000 PCRs revealed average success rates of > 90% using faecal DNAs and 74% using museum specimen DNAs. Average allelic dropout rates were substantially reduced compared to those obtained using conventional singleplex PCR protocols, and reliable genotyping using low (< 25 pg) amounts of template DNA was possible. However, four to five replicates of apparently homozygous results are needed to avoid allelic dropout when using the lowest concentration DNAs (< 50 pg/reaction), suggesting that use of protocols allowing routine acceptance of homozygous genotypes after as few as three replicates may lead to unanticipated errors when applied to low-concentration DNAs.
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Affiliation(s)
- M Arandjelovic
- Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, D-04103 Leipzig, Germany
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Walters ST, Vader AM, Harris TR. A DISMANTLING TRIAL OF MOTIVATIONAL INTERVIEWING AND FEEDBACK AMONG HEAVY DRINKING COLLEGE STUDENTS. Alcohol Clin Exp Res 2008. [DOI: 10.1111/j.1530-0277.2008.00689_6.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gatchell DW, Linsenmeier RA, Harris TR. Determination of the core undergraduate BME curriculum--the 1st step in a Delphi study. Conf Proc IEEE Eng Med Biol Soc 2007; 2004:5200-1. [PMID: 17271504 DOI: 10.1109/iembs.2004.1404447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The VaNTH Engineering Research Center for Bioengineering Education Technologies has completed the first round of a Delphi study to determine the key concepts that comprise the core curriculum of undergraduate programs in biomedical engineering. The study was conducted as a Web-based survey, consisting of eighty questions divided among nineteen topics, including eleven biomedical engineering domains, four biology domains, and mathematical and scientific prerequisites. Participants included representatives from academia, industry, and young alumni of undergraduate BME programs. Results from the survey will be available at: http://www.vanth.org/curriculum/.
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Affiliation(s)
- D W Gatchell
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
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Momcilović B, Alkhatib HA, Duerre JA, Cooley M, Long WM, Harris TR, Lykken GI. Environmental lead-210 and bismuth-210 accrue selectively in the brain proteins in Alzheimer disease and brain lipids in Parkinson disease. Alzheimer Dis Assoc Disord 2001; 15:106-15. [PMID: 11403330 DOI: 10.1097/00002093-200104000-00012] [Citation(s) in RCA: 21] [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: 11/26/2022]
Abstract
We studied the occurrence of the environmental radon daughters, 210Po (alpha particles), and 210Bi (beta particles), in the protein and lipid fractions of cortical gray and subcortical white matter from the frontal and temporal lobes of human brains of persons with Alzheimer disease (AD), persons with Parkinson disease (PD), smokers, or persons with no previous evidence of clinical neurologic disease (controls). We found a 10-fold increase in 210Po and 210Pb radioactivity in the protein fraction from both the cortical gray and subcortical white matter in AD and smokers, and a similar increase in the lipid fraction in PD. The pathognomonic distribution of the radon daughters to the lipids in PD and to the proteins in AD was inferred to reflect the increase of local chlorine availability to which radon daughters bound selectively. Cigarette smoking strongly increases radon daughter retention in the central nervous system.
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Affiliation(s)
- B Momcilović
- Institute for Medical Research and Occupational Health, Zagreb, Croatia
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Slotnick HB, Harris TR, Antonenko DR. Changes in learning-resource use across physicians' learning episodes. Bull Med Libr Assoc 2001; 89:194-203. [PMID: 11337951 PMCID: PMC31727] [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: 02/20/2023]
Abstract
INTRODUCTION This study explores the numbers of learning resources physicians use at each stage in self-directed learning episodes addressing general problems. MATERIALS AND METHODS A survey of a statewide random sample of doctors estimated the number of resources used at each stage in solving various general problems. RESULTS The 50% response rate for faculty allowed generalization of findings to the population of these physicians; the rate for nonfaculty physicians was too low to allow generalization. Faculty findings showed (1) broader resource use in learning about diseases than diagnosis or therapeutics (2) comparable numbers of resources used in deciding whether to take on the learning problem and learning the required skills and knowledge, (3) greater numbers of resources selected to evaluate the problem and to learn the required skills and knowledge than to gain experience with the newly learned skills and knowledge, and (4) support for assertions that doctors value learning resources that are accessible, applicable, familiar, and time effective. DISCUSSION The findings were interpreted in light of theory describing physicians' self-directed learning episodes, and implications are presented for physicians-in-training, physicians, and medical librarians.
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Affiliation(s)
- H B Slotnick
- Department of Neuroscience, University of North Dakota, Grand Forks, North Dakota, USA
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Abstract
A bolus injection of hypertonic NaCl into the pulmonary arterial circulation of an isolated perfused dog lung causes the osmotic movement of water first into, and then out of the capillary. The associated changes in blood constituent concentrations and density are referred to as the osmotic transient (OT). Measurement of the sound conduction velocity of effluent blood during an OT is a highly sensitive way to monitor water movement between the vascular and extravascular spaces. It was our objective to develop a mathematical model that adequately describes this transient change in the sound conduction velocity and evaluate its application under conditions of homogeneous and heterogeneous capillary flow distributions. The model accounts for osmotic water exchange between the capillary and two parallel extravascular compartments, and includes as parameters the osmotic conductances (sigmaK1 ,sigmaK2) of the two compartments. The osmotic conductance parameters incorporate the filtration coefficient for water and reflection coefficient for salt for the two pathways of water exchange. The partition of total extravascular lung water (EVLW) between the two extravascular compartments is a third parameter of the model. The homogeneous model parameter estimates (per gram wet lung weight +/-95% confidence limits) from the best-fit analysis of a typical curve were sigmaK1=2.15 +/-0.07, sigmaK2 = 0.03 + 0.00 [ml h(-1) (mosmol/liter)(-1) g(-1)] and V1 = 23.83+/-0.12 ml, with a coefficient of variation (CV) of 0.08. The heterogeneous parameter estimates for a capillary transit time distribution with mean transit time (MTTc) = 1.72 s, and relative dispersion (RDc) = 0.35 were KI = 2.38+/-0.05, or K2 = 0.03+/-0.00 [ml h(-1) (mosmol/liter)(-1) g(-1)], V1 = 23.91+/-0.08 ml, and CV=0.05. EVLW was 42.1 ml for both models. We conclude that the three-compartment mathematical model adequately describes a typical OT under both homogeneous and heterogeneous blood flow assumptions.
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Affiliation(s)
- K T Seale
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
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Rosell FI, Harris TR, Hildebrand DP, Döpner S, Hildebrandt P, Mauk AG. Characterization of an alkaline transition intermediate stabilized in the Phe82Trp variant of yeast iso-1-cytochrome c. Biochemistry 2000; 39:9047-54. [PMID: 10913318 DOI: 10.1021/bi001095k] [Citation(s) in RCA: 29] [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: 11/30/2022]
Abstract
In general, mutation of the phylogenetically conserved residue Phe82 in yeast iso-1-cytochrome c destabilizes the native conformation of the protein by facilitating the ligand exchange reactions that are associated with the alkaline conformational transitions of the ferricytochrome. Of the Phe82 variants surveyed thus far, Phe82Trp is unique in that it adopts a thermodynamically stable, high-spin conformation at mildly alkaline pH. This species exhibits spectroscopic features that can only be detected transiently in other ferricytochromes c within the first 100 ms immediately after a pH-jump from neutrality to pH >10. Spectroscopic characterization of this high-spin reaction intermediate suggests that in addition to an obligatory pentacoordinate heme iron, a group within the heme pocket coordinates the heme iron but is then replaced either by Met80, to revert to the native conformation, or by Lys73 or Lys79, to yield one of the conventional alkaline conformers. Evidence is presented to suggest that this group is either a hydroxide ion or Tyr67 rather than a loosely bound Met80.
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Affiliation(s)
- F I Rosell
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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Lykken GI, Ong HS, Alkhatib HA, Harris TR, Momcilovć B, Penland JG. Perquisite spin-off from twenty-two years of measuring background in the whole body counter steel room. Ann N Y Acad Sci 2000; 904:267-70. [PMID: 10865753 DOI: 10.1111/j.1749-6632.2000.tb06464.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- G I Lykken
- Physics Department, University of North Dakota, Grand Forks 58202-7129, USA.
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Wilsnack RW, Vogeltanz ND, Wilsnack SC, Harris TR, Ahlström S, Bondy S, Csémy L, Ferrence R, Ferris J, Fleming J, Graham K, Greenfield T, Guyon L, Haavio-Mannila E, Kellner F, Knibbe R, Kubicka L, Loukomskaia M, Mustonen H, Nadeau L, Narusk A, Neve R, Rahav G, Spak F, Teichman M, Trocki K, Webster I, Weiss S. Gender differences in alcohol consumption and adverse drinking consequences: cross-cultural patterns. Addiction 2000; 95:251-65. [PMID: 10723854 DOI: 10.1046/j.1360-0443.2000.95225112.x] [Citation(s) in RCA: 448] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To examine the consistency and/or variability of gender differences in drinking behavior cross-culturally. DESIGN, SETTING, PARTICIPANTS Women's and men's responses in 16 general population surveys from 10 countries, analyzed by members of the International Research Group on Gender and Alcohol. MEASUREMENTS Comparable measures of drinking, versus abstention, typical drinking frequencies and quantities, heavy episodic drinking, intoxication, morning drinking, and alcohol-related family and occupational problems. FINDINGS Women and men differed little in the probability of currently drinking versus abstaining, but men consistently exceeded women in typical drinking frequencies and quantities and in rates of heavy drinking episodes and adverse drinking consequences, while women were consistently more likely than men to be life-time abstainers. In older age groups, both men and women drank smaller quantities of alcohol and were more likely to stop drinking altogether, but drinking frequencies did not change consistently with age. CONCLUSIONS A theoretical synthesis proposes that gender roles may amplify biological differences in reactions to alcohol, and that gender differences in drinking behavior may be modified by macrosocial factors that modify gender role contrasts.
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Affiliation(s)
- R W Wilsnack
- University of North Dakota School of Medicine and Health Sciences, Department of Neuroscience, Grand Forks 58202-9037, USA
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Vogeltanz ND, Wilsnack SC, Harris TR, Wilsnack RW, Wonderlich SA, Kristjanson AF. Prevalence and risk factors for childhood sexual abuse in women: national survey findings. Child Abuse Negl 1999; 23:579-92. [PMID: 10391515 DOI: 10.1016/s0145-2134(99)00026-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
OBJECTIVE We interviewed a U.S. national sample of women, aged 18 years and older to determine the prevalence and characteristics of childhood sexual abuse. We also examined which family and background variables were predictive of CSA in this sample. METHOD The study employed a series of detailed descriptive questions regarding childhood sexual experiences that were administered in a highly structured format by trained female interviewers. CSA prevalence rates were calculated using two definitions of CSA, one of which was slightly more inclusive. RESULTS Prevalence rates for the more inclusive CSA definition ranged from 21% to 32%, depending on how respondents who provided incomplete information about their sexual experiences were classified. The less inclusive CSA definition resulted in prevalence rates ranging from 15% to 26%. Additional information about the types of abuse experienced, perpetrator characteristics, age at first abuse, and physical and affective consequences of the abusive experiences are reported. The risk of CSA was related to higher scores on a measure of father's rejection, and the interaction between parental drinking status and whether the respondent had lived with both parents during childhood. Further analysis of this interaction suggests that when respondents reported living with both biological parents, they were most at risk for CSA when their father was a nondrinker and their mother was a drinker.
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Affiliation(s)
- N D Vogeltanz
- Department of Neuroscience, University of North Dakota School of Medicine and Health Sciences, Grand Forks 58202-9037, USA
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Abstract
A three-dimensional magnetic resonance imaging (MRI) method to measure pulmonary edema and lung microvascular barrier permeability was developed and compared with conventional methods in nine mongrel dogs. MRIs were obtained covering the entire lungs. Injury was induced by injection of oleic acid (0.021-0.048 ml/kg) into a jugular catheter. Imaging followed for 0.75-2 h. Extravascular lung water and permeability-related parameters were measured from multiple-indicator dilution curves. Edema was measured as magnetic resonance signal-to-noise ratio (SNR). Postinjury wet-to-dry lung weight ratio was 5.30 +/- 0.38 (n = 9). Extravascular lung water increased from 2.03 +/- 1.11 to 3.00 +/- 1.45 ml/g (n = 9, P < 0.01). Indicator dilution studies yielded parameters characterizing capillary exchange of urea and butanediol: the product of the square root of equivalent diffusivity of escape from the capillary and capillary surface area (D1/2S) and the capillary permeability-surface area product (PS). The ratio of D1/2S for urea to D1/2S for butanediol increased from 0.583 +/- 0.027 to 0.852 +/- 0.154 (n = 9, P < 0.05). Whole lung SNR at baseline, before injury, correlated with D1/2S and PS ratios (both P < 0.02). By using rate of SNR change, the mismatch of transcapillary filtration flow and lymph clearance was estimated to be 0.2-1.8 ml/min. The filtration coefficient was estimated from these values. Results indicate that pulmonary edema formation during oleic acid injury can be imaged regionally and quantified globally, and the results suggest possible regional quantification by using three-dimensional MRI.
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Affiliation(s)
- S D Caruthers
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, USA
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Abstract
The objective of this study was a validation of an optical multiple indicator dilution technique for measuring microvascular exchange parameters in edematous lungs by comparison to conventional radioisotope multiple indicator dilution methods. Six anesthetized dogs were studied at baseline and after alloxan infusion to increase capillary permeability. In addition, 11 isolated, perfused dog lungs were studied at baseline and after edema was created by increasing venous pressure or by infusing alloxan to increase vascular permeability. Increased capillary permeability from alloxan infusion led to increases in most but not all capillary exchange parameters as analyzed by mathematical models and measured by both optical and radioisotope methods. Increased vascular pressure led to increased edema but no significant increases in capillary exchange parameters. Two-way analysis of variance (ANOVA; variations in baseline versus pressure or alloxan and variation in optical versus radioisotope for each transport parameter derived from the mathematical models) indicated few significant differences in capillary exchange parameters between optical and radioisotope measures. Newman-Keuls multiple comparison tests did uncover some variations between a few of the group-mean values derived from optical and radioisotope methods. However, optical and radioisotope parameter measurements were highly correlated for all studies regardless of the mathematical model used for analysis.
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Affiliation(s)
- S DeMarino
- Johnson and Johnson Medical, Inc., Tampa, FL, USA
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Abstract
We present a methodology, based on N-dimensional computer visualization, for analyzing multiparameter models. This approach originally consisted of three steps: behavior analysis, sensitivity analysis, identifiability analysis. We have now developed a new way of calculating sensitivity based on the statistical measure of the coefficient of variation. Furthermore, we extended the methodology through the addition of an extra step, visual regression. Visual regression allows the user to visualize the process of actual parameter identification and presents a combined, empirical view of the first three steps in a single image. Next we applied this methodology to pulmonary capillary-transport models. Finally, we implemented the model analysis process as a stand-alone program. EN-DIMAN, the resulting software, allows researchers to carry out model analysis in a graphical user interface (GUI)-based environment.
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Affiliation(s)
- S Bosan
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, USA
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Abstract
Pulmonary edema is a debilitating effect of acute respiratory distress syndrome. The ability to measure it noninvasively with high sensitivity and in three dimensions could be useful in not only detection but also in assessment and guidance of treatment. To this end, a three-dimensional MRI pulse sequence to measure the formation of edema was developed and tested. Another sequence was tested to measure blood flow in distal pulmonary arteries. Pulmonary edema was induced in nine dogs via venous injections of oleic acid. Edema was verified by wet-to-dry weight ratio (5.30 +/- .38) and extra-vascular lung water at baseline (2.03 +/- 1.12 ml/g dry lung weight) versus postinjury (3.00 +/- 1.45 ml/g) (P < .005). The signal-to-noise ratio within the lungs increased from 5.47 +/- 1.00 at baseline to 7.51 +/- 1.96 (P < .005), and the time course of edema formation was resolved. Results from MR phase-contrast blood flow measurements were variable. The authors conclude that the three-dimensional scan provides a sensitive relative quantification of pulmonary edema formation without the use of contrast agents or ionizing radiation.
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Affiliation(s)
- S D Caruthers
- Department of Biomedical Engineering, Vanderbilt University Medical Center, Nashville, TN 37232-2675, USA
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Abstract
OBJECTIVE Clinical studies have found elevated rates of childhood sexual abuse (CSA) in women seeking treatment for alcohol or drug abuse, and elevated rates of alcohol and drug disorders among female psychiatric patients with histories of CSA. The present study examines the relationship of CSA to women's use of alcohol and other drugs in a large, nationally representative sample of U.S. women. METHOD As part of a national survey of women's drinking, 1,099 women were asked about sexual experiences occurring before age 18. Women who reported sexual experiences classified as abusive were compared to women without histories of CSA on nine measures of substance use, self-perception of anxiousness, the occurrence of one or more lifetime depressive episodes, five measures of sexual dysfunction, and early onset of masturbation and consensual sexual intercourse. RESULTS Results of logit analyses, controlling for age, ethnicity and parental education, indicated that women with histories of CSA were significantly more likely than women without CSA histories to report recent alcohol use, intoxication, drinking-related problems and alcohol dependence symptoms; lifetime use of prescribed psychoactive drugs and illicit drugs; depression and anxiety; pain that prevented intercourse; and consensual sexual intercourse before age 15. CONCLUSIONS Findings from this U.S. national sample support those of previous clinical studies and suggest that women's experience of sexual abuse in childhood may be an important risk factor for later substance abuse, psychopathology and sexual dysfunction. Implications of these findings for future research, treatment and prevention are discussed.
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Affiliation(s)
- S C Wilsnack
- Department of Neuroscience, University of North Dakota, School of Medicine and Health Sciences, Grand Forks 58202-9037, USA
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18
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Abstract
A mathematical model of fluid, solute, and red cell transport in the lung has been developed that includes the effects of simultaneous changes in lung vascular and interstitial volumes. The model provides separate arterial, microvascular, and venous pulmonary regions and a systemic vascular region in addition to a pulmonary interstitial compartment. Pressure, volume, hematocrit, flow, and concentration of up to 12 solutes and tracers can be computed in each compartment. Computer code is written in the C programming language, with Microsoft Excel serving as a user interface. Implementation is currently on PC-486 microcomputer systems, but the core program can easily be moved to other computer systems. The user can select different models for the blood-interstitial barrier (e.g., multiple pore, nonlinear Patlak equation), osmotic pressure-concentration relationships (e.g., Nitta, Navar-Navar), solute reflection coefficients interstitial macromolecule exclusion, or lymph barrier characteristics. Each model parameter or a combination of parameters can be altered with time in a predetermined fashion. The model is particularly useful in interpreting lung experimental data where simultaneous changes occur in vascular and extravascular compartments. Several applications are presented and discussed, including interpretation of optical filtration experiments, venous occlusion experiments, external detection of macromolecular exchange, and blood-lymph studies that use exogenous tracers. A number of limitations of the model are identified and improvements are proposed. A major strength of the model is that it is specifically designed to incorporate newly discovered relationships as the field of lung physiology expands.
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Affiliation(s)
- R J Roselli
- Department of Biomedical Engineering, Vanderbilt University, School of Engineering, Nashville, TN 37235, USA
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19
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Abstract
OBJECTIVES This study examines whether childhood sexual abuse is a significant risk factor for the development of bulimic behavior in women. METHODS Interviews were conducted among a representative national sample of 1099 US women regarding their sexual experiences during childhood as well as their lifetime prevalence of bulimic behavior. Logistic regression was used to calculate adjusted odds ratios to measure the contribution of childhood sexual abuse to the odds of several measures of bulimic behavior in the population, controlling for the respondent's age, ethnic group, and parents' educational level. Attributable risk analyses were conducted to estimate how much risk for bulimic behavior was due to childhood sexual abuse. RESULTS Victims of childhood sexual abuse were significantly more likely to display bulimic behavior, and a substantial fraction of cases of bulimic behavior could be attributed to such abuse. CONCLUSIONS Childhood sexual abuse is a risk factor for bulimic behavior. Between one sixth and one third of the cases of significant bulimic disturbance could be attributed to childhood sexual abuse.
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Affiliation(s)
- S A Wonderlich
- School of Medicine, University of North Dakota, Fargo 58102, USA
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20
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Abstract
The study of transport across the pulmonary vasculature is an important aspect of the study of the lung. Models have often been used in conjunction with experimental work to further the information which can be obtained from experimental work alone. GLANSE was developed as an environment to carry out such analysis on microcomputers. The main model employed is a three region, homogeneous model which includes provisions for tracer diffusion in the extravascular region, hydrophilic and lipophyilic tracers as well as physiological parameters such as blood flow. Several heterogeneous models based on simplified versions of the three region model as well as two models which are not related to the three region model are also included. Computationally efficient routines for model simulations are used so as to enable their execution on microcomputers with large data sets. In addition, several methods for models analysis, such as parameter sensitivity and curve-fitting, as well as statistical analysis of results are also included. GLANSE has been tested and has been in use for several years for routine analysis of experimental data.
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Affiliation(s)
- S Bosan
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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21
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Stead WW, Borden R, Bourne J, Giuse D, Giuse N, Harris TR, Miller RA, Olsen AJ. The Vanderbilt University fast track to IAIMS: transition from planning to implementation. J Am Med Inform Assoc 1996; 3:308-17. [PMID: 8880678 PMCID: PMC116315 DOI: 10.1136/jamia.1996.97035022] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Vanderbilt University Medical Center is implementing an Integrated Advanced Information Management System (IAIMS) using a fast-track approach. The elapsed time between start-up and completion of implementation will be 7.5 years. The Start-Up and Planning phases of the project are complete. The Implementation phase asks one question: How does an organization create an environment that redirects and coordinates a variety of individual activities so that they come together to provide an IAIMS? Four answers to this question are being tested. First, design resources to be "scalable"--i.e., capable of supporting enterprise-wide use. Second, provide information technology planning activities as ongoing core functions that direct local efforts. Third, design core infrastructure resources to be both reusable and expandable at the local level. Fourth, use milestones to measure progress toward selected endpoints to permit early refinement of plans and strategies.
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Affiliation(s)
- W W Stead
- Annette and Irwin Eskind Biomedical Laboratory, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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22
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Abstract
In order to successfully use a model for parameter identification, it must be carefully analyzed. Current analysis methods, however, are ad hoc and provide only partial information. We extended these methods through the application of stacked dimensions, a scientific visualization method. The end result of our extensions are multi-dimensional parametric model-images. These images depict a model as a function of all its parameters in a single graphic. We applied parametric model-images to model verification (behavioral analysis), sensitivity analysis, and identifiability analysis. We applied our methodology to the evaluation of pulmonary vascular capillary-transport models. Results have shown that the visualization-based method provides a more complete view of a model's behavior and its other characteristics. Furthermore, our method has also proven to be more computationally efficient than the traditional approaches.
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Affiliation(s)
- S Bosan
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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23
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Grabenstein JD, Filby CL, Vauter RA, Harris TR, Wilson JP. Prescribed medication use among troops deploying to Somalia: pharmacoepidemiologic analysis. Mil Med 1995; 160:571-7. [PMID: 8538893] [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: 01/31/2023] Open
Abstract
To describe the frequency of chronic ambulatory prescriptions dispensed to troops, pharmacists analyzed records of soldiers deploying to Somalia for Operation Restore Hope. Prescriptions recorded in the Fort Drum pharmacy data base for soldiers deploying between November 24, 1992, and January 12, 1993, were compared to the roster of troops deployed. Among 3,701 deploying soldiers, 273 patients (7.4%) received 425 prescriptions. For each 1,000 troops, 114.8 prescriptions were dispensed. Of 333 presumptive diagnoses, the most common diagnostic groups were contraceptive, musculoskeletal, dermatologic, respiratory, and cardiovascular. Of 425 prescriptions, the most common therapeutic classes of medication dispensed were oral contraceptives, anti-inflammatory drugs, acne treatments, and beta-adrenergic agonists. Generically, the common prescribed substances were contraceptives, ibuprofen, pirbuterol, temazepam, piroxicam, and beclomethasone. Although women represented 6.8% of troops, women represented 31.5% of prescription recipients and received 29.4% of prescriptions. Women were 6.5 times as likely to receive a prescription as men (p < 0.0001); this relative risk was 3.4 if contraceptives were omitted from analysis (p < 0.0001). Two hospitalizations in Somalia may have been related to medication use.
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Affiliation(s)
- J D Grabenstein
- Clinical Investigation Regulatory Office, AMEDD Center & School, Fort Sam Houston, TX 78234-6125, USA
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24
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Caruthers SD, Harris TR, Overholser KA, Pou NA, Parker RE. Effects of flow heterogeneity on the measurement of capillary exchange in the lung. J Appl Physiol (1985) 1995; 79:1449-60. [PMID: 8594000 DOI: 10.1152/jappl.1995.79.5.1449] [Citation(s) in RCA: 4] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The effects of flow heterogeneity on the measurement of transcapillary escape of small molecules for perfused in situ sheep lungs were evaluated. Lungs were studied at five flows (1.5-5.0 l/min) ranging from zone 1 to zone 3 conditions. At each flow, multiple indicator-dilution curves were collected using 14C-labeled urea (U) or butanediol (B) as the diffusing tracer, and radiolabeled 15-microns microspheres were injected. The lungs were removed, dried, sectioned, weighed, and counted for microsphere radioactivity. Flow heterogeneity expressed as relative dispersion, decreased with increasing flow, from 0.838 +/- 0.179 (mean +/- SD, n = 8) to 0.447 +/- 0.119 (n = 6). We applied homogeneous flow models of capillary exchange to compute permeability-surface area product (PS) and a related parameter, D1/2S, for diffusing tracers. (D is effective diffusivity of capillary exchange.) PS and D1/2S increased to a maximum with increasing flow, but the ratio of D1/2SU to D1/2SB remained constant. A new model incorporating flow heterogeneity and recruitment (the variable recruitment model) was used. The variable recruitment model described the effects of flow on capillary recruitment, but incorporating heterogeneity into the computation did not alter D1/2S values from those computed assuming homogeneous flow.
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Affiliation(s)
- S D Caruthers
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, USA
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25
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Abstract
We used Microsoft Excel 4.0 for Windows running on a PC-486 to develop a user interface for two biological simulation models: a lung fluid balance model and a fractal model of the pulmonary circulation. The simulation programs were written in the C programming language, while the user interface was written in the macro language of Excel. The interface builds input data files for the simulation programs and provides a mechanism for displaying relevant information from output files produced from the simulations. Input fields are partially protected so that the user cannot modify certain portions of the spreadsheet. The Excel interface is used to build models from different available components and to select appropriate parameters for these models. The developed interface was also useful for running models in the batch mode. After selecting changes in lung fluid balance parameters, the interface allows users to find new steady state values by automatically running the model and adjusting initial conditions. Several different graphical options allow users to easily investigate the effects of selecting particular models and parameters. Techniques used in developing our user interface can be extended to most biological simulation programs which manipulate input and output data files.
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Affiliation(s)
- G Tack
- Department of Biomedical Engineering, Vanderbilt University, School of Engineering, Nashville, Tennessee 37235, USA
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26
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Abstract
The confident identification of parameters is important in the practical application of physiological models. However, the task of parameter identification is often complicated by interactions among parameters and by the fact that the sensitivity of the model to changes in a given parameter is generally a function of all the other parameters. Here we illustrate a graphical approach to parameter identification that allows the modeler to visualize the behavior of the model, the sensitivity functions, and certain functions characteristic of parameter interdependence. The visual display can be generated over any desired portion of parameter space. The technique is applied to a simple, four-parameter, myocardial pump model of the coronary circulation. The results indicate that over specified ranges of parameters, it is possible to distinguish among the four parameters of the model: the ratio of proximal-to-distal resistance, alpha; the overall resistance of the vascular bed, R; the compliance of the vascular bed, C; and a parameter, kappa, relating tissue pressure to left ventricular pressure. It was found that in order to identify all parameters uniquely, it was necessary to regress upon both coronary inflow and outflow.
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Affiliation(s)
- P A Harris
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235
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27
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Abstract
This work examined the relationships between lung microvascular permeability-surface area products (PS) for small solutes in animals of different size and for columns of endothelial-covered microcarrier beads. We assembled PS data (humans, sheep, lambs, and rabbits) for labeled sucrose, mannitol, urea, 1,2-propanediol, 1,3-propanediol, and 1,4-butanediol. In addition, PS for cell columns using sucrose, mannitol, and sodium fluorescein were evaluated. A new mathematical model for the analysis of cell columns that accounts for transit time variations was derived and compared with models neglecting this variation. Allometric relationships between PS and body weight or exchange surface (S) were examined. Permeability relative to diffusivity (P/D) correlated inversely with S for all animals. In addition, P/D for the cell columns fell near this regression line. The results suggest either that permeability for hydrophilic tracers is higher for smaller animals or that the indicator-dilution measurement is a fractal process dependent on scale. Furthermore, the P/D-S correlations may help relate cell column experiments to animal studies.
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Affiliation(s)
- T R Harris
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235
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28
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Abstract
The spatial heterogeneity of pulmonary blood flow can be described by the relative dispersion (RD) of weight-flow histograms (RD = SD/mean). Glenny and Robertson (J. Appl. Physiol. 69: 532-545, 1990) showed that RD of flow in the lung is fractal in nature, characterized by the fractal dimension (D) and RD for the smallest realizable volume element (RDref). We studied the effects of increasing total pulmonary blood flow on D and RDref. In eight in situ perfused sheep lung preparations, 15-microns radio-labeled microspheres were injected into the pulmonary artery at five different blood flows ranging, in random order, from 1.5 to 5.0 l/m. The lungs were in zone 2 at the lower flows and in zone 3 at the higher flows. The lungs were removed, dried, cut into 2 x 2 x 2-cm3 pieces, weighed, and then counted for microsphere radioactivity. Fractal plots of log(weight) vs. log(RD) were constructed by iteratively combining neighboring pieces and then calculating RD with the increasingly larger portion size. D, which is one minus the slope of the fit through this plot, was 1.14 +/- 0.09 and did not change as blood flow increased. However, RDref decreased significantly (P < 0.01) as total flow increased. We conclude that the fractal nature of pulmonary blood flow distribution is not altered by changes in overall flow.
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Affiliation(s)
- S D Caruthers
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235
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29
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Overholser KA, Lomangino NA, Parker RE, Pou NA, Harris TR. Pulmonary vascular resistance distribution and recruitment of microvascular surface area. J Appl Physiol (1985) 1994; 77:845-55. [PMID: 8002538 DOI: 10.1152/jappl.1994.77.2.845] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
To test the hypothesis that the distribution of hemodynamic resistance is involved in the control of pulmonary capillary surface area, we measured permeability-surface area product (PS) and longitudinal resistance distribution (LRD) as functions of perfusion rate in isolated rabbit lungs under zone II conditions (n = 10) and through the zone II-III transition (n = 4). PS, considered to be indicative of functioning capillary surface area, was measured with the aid of the diffusion-limited tracer [14C]propanediol, whereas LRD was determined using a viscous bolus technique. LRD was seen to change character with increasing flow and increasing PS/surface area, becoming bimodal with low central resistance as full capillary recruitment was approached in zone III. Effects of hypoxic ventilation were studied in zone II in five lungs; it was found that hypoxia altered the LRD and eradicated the normoxic dependence of PS/surface area on perfusion rate. It was concluded that LRD is involved in the determination of functioning capillary surface area.
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Affiliation(s)
- K A Overholser
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235
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30
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Abstract
Sulfhemoglobinated erythrocytes (SHb-RBC's) were examined for utility as an optical multiple indicator dilution tracer in lung studies. A device was developed to measure this tracer optically in flowing blood. Arterial blood was sampled from cannulated, anesthetized dogs and pumped through the device that measured the optical density (OD) of blood at 620 nm. This system was calibrated for increasing SHb-RBC concentrations using an unsteady-state indicator dilution procedure. Areas under optical density (delta OD) profiles were well correlated with injected SHb-RBC volumes using linear regression (r2 > 0.9). This linearity was independent of blood oxygenation, hematocrit, or pH. In vivo lung indicator dilution studies in the intact dog were performed and compared to radioisotope indicator studies using 51Cr labeled erythrocytes. Coefficient of variation (CV) between the two curves was 0.065 under baseline conditions, 0.085 for studies performed during hypoxia, and 0.073 after pH was lowered. We conclude that this device linearly measured SHb-RBC content in whole blood and that SHb-RBC is as accurate a lung indicator dilution tracer as 51Cr-erythrocytes.
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Affiliation(s)
- L E Olson
- Vanderbilt University, Department of Biomedical Engineering, Nashville, TN 37235
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31
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Harris TR, Wilsnack RW, Klassen AD. Reliability of retrospective self-reports of alcohol consumption among women: data from a U.S. national sample. J Stud Alcohol 1994; 55:309-14. [PMID: 8022179 DOI: 10.15288/jsa.1994.55.309] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Drinking histories (retrospective self-reports) can be a valuable resource for time-ordered analyses of causes and consequences of drinking. However, there is a scarcity of data on the reliability of drinking histories from general population samples. We report here on the reliability and consistency of reported ages of onset and typical drinking frequencies, quantities and volume, from drinking histories provided in 1981 and 1986 by national samples of women drinkers with and without drinking problems. Statistical reliability was generally modest, yet large percentages of women gave exactly the same reports 5 years apart. Reliability was apparently reduced by limited response options, and was lower among younger drinkers, whose drinking was more changeable between 1981 and 1986. We discuss ways to improve reliability and to make best use of drinking histories.
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Affiliation(s)
- T R Harris
- Department of Mathematics, University of North Dakota, Grand Forks 58202-8376
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32
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Abstract
We have developed a new model describing the relationship between plasma and red cell tracers flowing through the lung. The model is the result of an analysis of the transport of radiolabeled plasma albumin between two flowing phases and shows that differences between red cell and plasma tracer curves are related to microvascular hematocrit. The model was tested in an isolated, blood-perfused dog lung preparation in which we injected 51Cr-labeled red cells and 125I-labeled plasma albumin into the pulmonary artery. From the tracer concentration-time curves at the venous outflow, we calculated hr, the ratio of microvascular hematocrit to large-vessel hematocrit. In 18 baseline experiments, hr = 0.92 +/- 0.01 (mn +/- sem) at a blood flow rate of 10.7 +/- 0.3 ml s-1. We determined the effects of (a) glass bead embolization, (b) alloxan, and (c) lobe ligation on hr. Embolization attenuated the separation between plasma and red cells (increased hr), probably as a consequence of passive vasodilation. Alloxan enhanced separation of plasma and red cells (decreased hr), possibly as a result of arteriolar vasoconstriction. Ligation of a fraction of the perfused tissue at constant flow did not cause significant change in hr in the remaining perfused tissue. The model assumes that large-vessel transit times are uniform and that all dispersion occurs in the microvasculature. A theoretical analysis apportioning dispersion between large and small vessels disclosed that the error associated with these assumptions is likely to be less than 15% of the measured hr. We conclude from this study that the microvascular hematocrit model describes experimental plasma and red cell curves. The results imply that hr can be readily deduced from tagged red cells and plasma and can be accounted for in calculating permeability-surface area in diffusing tracer experiments.
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Affiliation(s)
- K A Overholser
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235
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33
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Abstract
Perilla ketone (PK) is a potent lung toxin that causes increased microvascular permeability pulmonary edema in grazing animals. Because the mechanism of action of PK is not know, we investigated whether PK directly affects endothelial cells. Bovine aortic endothelial cells were grown to confluence on Cytodex-3 microcarrier beads and placed in a chromatographic cell column. Monolayer permeability was evaluated from the elution profiles of three optical tracers: blue dextran (2 x 10(6) mol wt), sodium fluorescein (NaF, 342 mol wt), and cyanocobalamin (B12, 1,355 mol wt). Perfusion with 1.2 mM PK increased permeability within 15 min to NaF and B12 by 51 +/- 6 and 54 +/- 11%, respectively. Permeability returned to baseline after PK removal. These in vitro results suggest that PK produces a rapid and reversible increase in endothelial permeability directly. Staining of fixed cells with rhodamine-phalloidin revealed a major disruption of actin microfilaments after PK treatment. Because previous reports suggested that PK may be activated via cytochrome P-450, we attempted to block this using the cytochrome P-450 inhibitor ketoconazole. Ketoconazole alone did not significantly affect permeability, and the combination of PK and ketoconazole resulted in permeability increases similar to those measured for PK alone. This suggests that PK may not require cytochrome P-450 to increase vascular permeability.
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Affiliation(s)
- C M Waters
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235
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Stead WW, Baker W, Harris TR, Hodges TM, Sittig DF. A fast track to IAIMS: the Vanderbilt University strategy. Proc Annu Symp Comput Appl Med Care 1992:527-31. [PMID: 1336415 PMCID: PMC2248037 DOI: pmid/1336415] [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: 02/08/2023]
Abstract
In July 1991, Vanderbilt University Medical Center (VUMC) initiated a fast track approach to the implementation of an Integrated Academic Information Management System (IAIMS). The fast track approach has four elements: 1) an integrated organizational structure combining various operational information management units and the academic informatics program into a single entity to enhance efficiency; 2) technology transfer and network access to remote resources in preference to de novo development; 3) parallel IAIMS planning and infrastructure construction; 4) restriction of the scope of the initial IAIMS to permit a manageable implementation project. The fast track approach is intended to provide a truly functional IAIMS within a time period (7 years) associated with other major construction projects such as the building of a replacement hospital.
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Affiliation(s)
- W W Stead
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232-8143
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35
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Harris TR. Serving two masters: conflicts in practice. Internist 1991; 32:12-5. [PMID: 10111362] [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: 02/11/2023]
Abstract
Accustomed to putting patients' needs first, internists now face daily pressure to contain health care costs. With a view from the trenches, a practicing internist and former ASIM president enumerates the dilemmas physicians confront in trying to serve patients and payers.
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Affiliation(s)
- T R Harris
- Council on Medical Service, American Medical Association
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36
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Abstract
A combination of an amphipathic-indicator-dilution (ID) diffusing tracer 1,4[14C]butanediol (B) and a hydrophilic tracer ([14C]urea) (U) was hypothesized to provide a capillary surface area- (S) independent assessment of lung microvascular permeability (P). We performed ID studies on isolated perfused dog lungs and administered randomly two interventions, increasing P by alloxan infusion and reduction in S by lobar ligation. The ratio of PS product of U (PSU) to that for butanediol (PSB) was sensitive to changes in P yet insensitive to changes in S. We performed ID studies in which the dependence of PSU and PSB on flow, hematocrit, and plasma protein binding were examined. Measurements of PSU and PSB after flow and hematocrit were changed suggested that these factors have no significant independent effects. From ID and in vitro studies we also found that no significant binding of B to plasma proteins (albumin) occurred. We concluded that ID techniques using B and U provide a consistent measure of P, despite changes in S, hematocrit, plasma protein concentration, and recruitment.
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Affiliation(s)
- L E Olson
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232
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37
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Abstract
In isolated blood-perfused dog lungs, the capillary filtration coefficient (Kf) and the permeability-surface area product of urea (PS) were measured to determine their responses to two different methods of altering filtration area: lobe ligation (LL, n = 5) and glass bead embolization (GBE, n = 4) during constant perfusion rates (700 +/- 45 ml/min). When two of three lobes were ligated, Kf decreased (1.36 +/- 0.13 to 0.58 +/- 0.23 g.min-1.cmH2O-1; P less than 0.05), but PS did not change (2.02 +/- 0.4 to 1.71 +/- 0.3 ml/s). Kf per gram of perfused blood-free dry lung weight was unchanged by LL (0.051 +/- 0.17 to 0.052 +/- 0.18 g.min-1.cmH2O-1), indicating that surface area per gram measured by Kf remained the same. However, PS per gram dry lung doubled (0.07 +/- 0.016 to 0.146 +/- 0.06 ml/s; P less than 0.05) after LL, suggesting that recruitment occurred in the remaining lobe. When three lobes were embolized with 200-microns glass beads (0.48 +/- 0.01 g beads/kg body wt), PS decreased (2.1 +/- 0.22 to 0.94 +/- 0.09 ml/s; P less than 0.05), but Kf was not altered (1.01 +/- 0.17 to 1.04 +/- 0.18 g.min-1.cmH2O-1). The constancy of Kf after GBE implies that the vascular pressure increase during the Kf measurement was transmitted to both blocked and flowing vessels and thereby measured the same filtration area before and after GBE. PS decreased significantly after GBE because of a loss of perfused surface area by the beads blocking flow in small arterial vessels.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J D Bradley
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235
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Harris TR, Bernard GR, Brigham KL, Higgins SB, Rinaldo JE, Borovetz HS, Sibbald WJ, Kariman K, Sprung CL. Lung microvascular transport properties measured by multiple indicator dilution methods in patients with adult respiratory distress syndrome. A comparison between patients reversing respiratory failure and those failing to reverse. Am Rev Respir Dis 1990; 141:272-80. [PMID: 2405756 DOI: 10.1164/ajrccm/141.2.272] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We conducted indicator dilution studies on the lungs of patients in the early phases of adult respiratory distress syndrome (ARDS) to test the hypothesis that capillary permeability was increased in patients with respiratory failure. Indicator dilution studies were performed using 51Cr-erythrocytes, 125I-albumin, 14C-urea, and 3H-water as tracers. The injectate was infused as a bolus into a central venous line. Peripheral arterial blood was collected and counted for radioactivity. Mathematical analysis of the indicator curves yielded cardiac output, measures of the product of capillary permeability and surface area for urea (PS and D1/2S), the intravascular lung volume (Vv), and the extravascular lung water volume (Ve). Permeability was separated from surface area by normalizing PS and D1/2S to Vv. Patients could be divided into 16 in whom blood gas determinations and radiologic criteria for ARDS were reversed and 23 in whom they were not. We examined indicator dilution and other measures of lung function in the two groups to determine whether significant differences in microvascular function existed. PS and PS/Vv were significantly higher in the nonreversal patients. Ve was above normal, but not different between groups. Linear regression analysis showed significant correlations for all of the following in the nonreversal group: Ve and all measures of permeability, pulmonary vascular resistance (PVR), and the inverse of permeability-surface area measures and AaDO2 and PVR. Only measures of Ve and PS correlated in the reversal group. These results support the hypothesis that capillary permeability is increased in patients with early ARDS and continuing respiratory failure.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T R Harris
- Center for Lung Research, Vanderbilt University, Nashville, TN 37232-2155
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Harris TR. Physician activity: an independent practitioner's view. Rep Natl Forum Hosp Health Aff 1989:79-84. [PMID: 10160832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Abstract
A radioactive tracer technique was used to determine interstitial diethylenetriaminepentaacetic acid (DTPA) and albumin distribution volume in sheep lungs. 125I- and/or 131I-labeled albumin were injected intravenously and allowed to equilibrate for 24 h. 99mTc-labeled DTPA and 51Cr-labeled erythrocytes were injected and allowed to equilibrate (2 h and 15 min, respectively) before a lethal dose of thiamylal sodium. Two biopsies (1-3 g) were taken from each lung and the remaining tissue was homogenized for wet-to-dry lung weight and volume calculations. Estimates of distribution volumes from whole lung homogenized samples were statistically smaller than biopsy samples for extravascular water, interstitial 99mTc-DTPA, and interstitial albumin. The mean fraction of the interstitium (Fe), which excludes albumin, was 0.68 +/- 0.04 for whole lung samples compared with 0.62 +/- 0.03 for biopsy samples. Hematocrit may explain the consistent difference. To make the Fe for biopsy samples match that for homogenized samples, a mean hematocrit, which was 82% of large vessel hematocrit, was required. Excluded volume fraction for exogenous sheep albumin was compared with that of exogenous human albumin in two sheep, and no difference was found at 24 h.
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Affiliation(s)
- N A Pou
- Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232
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Galloway RL, Staton DJ, Harris TR. The optical measurement of 1,2-propanediol for the determination of lung capillary permeability surface area. IEEE Trans Biomed Eng 1989; 36:591-7. [PMID: 2659492 DOI: 10.1109/10.29453] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A technique has been developed which allows for the optical measurement of the concentration-time relationship for a diffusion-limited material in indicator dilution studies. The material, 1-2 propanediol, is used as a probe of the permeability of capillaries in the lung. Comparisons between standard radioisotope measurements and the optical measurements are provided and show excellent agreement. The optical method represents an improvement over the standard radioisotope method in that it provides the same data at lower cost, lower risk, and without the delay required by the radiographic methods.
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Abstract
We analyzed the effects of Escherichia coli endotoxin infusion on pulmonary microvessels in sheep by using a two-pore mathematical model of the microvascular barrier. Five sheep were prepared with lung lymph fistulas and instrumented to measure pulmonary arterial and left atrial pressures. Multiple indicator-dilution curves (with 125I-labeled albumin, 51Cr-labeled erythrocytes, [14C]urea, and 3H2O) were measured at base line and during phases 1 and 2 of the endotoxin response. Alterations in the membrane integrity in response to endotoxin infusion were quantified by using a two-pore theory of the microvascular barrier that incorporated lymph, protein, pressure, and multiple indicator measurements. The modeling results showed a slight change in the size of the pores during phase 1 but a 56% decrease in the number of small pores and a twofold increase in the number of large pores with respect to base-line values. During phase 2 the large pore size increased by 40%, and the total number of pores returned to base-line values. The analysis showed that endotoxin effects on fluid and protein exchange in the lung cannot be explained by hemodynamic and surface area changes alone. An apparent increase in lung microvascular permeability occurs during phases 1 and 2 of the endotoxin reaction, with a substantial decrease in perfused microvascular surface area during phase 1.
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Affiliation(s)
- J D Bradley
- Department of Chemical Engineering, Vanderbilt University, Nashville, Tennessee 37235
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Harris TR. Physician dispensing: a new prescription? Internist 1987; 28:18-20, 24. [PMID: 10284544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Sundell HW, Harris TR, Cannon JR, Lindstrom DP, Green R, Rojas J, Brigham KL. Lung water and vascular permeability-surface area in premature newborn lambs with hyaline membrane disease. Circ Res 1987; 60:923-32. [PMID: 3647851 DOI: 10.1161/01.res.60.6.923] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Extravascular lung water and vascular permeability-surface area products were measured with a multiple indicator dilution method in 6 premature lambs with hyaline membrane disease 1-5 hours following delivery by cesarean section. The indicators used were 51Cr-labelled erythrocytes, 125I-albumin, 3H-water, and 14C-urea. Results were compared with previously obtained data in newborn lambs without hyaline membrane disease also delivered by cesarean section. Extravascular lung water was significantly higher in lambs with hyaline membrane disease [23.2 +/- 1.0 (SEM) vs. 10.7 +/- 1.4 ml/kg body wt]. Vascular permeability-surface area products for 14C-urea were significantly lower in lambs with hyaline membrane disease (0.30 +/- 0.10 vs 0.78 +/- 0.11 ml/s per kg). It is concluded that extravascular lung water is high in lambs with hyaline membrane disease. Permeability-surface area products for 14C-urea is low in lambs with hyaline membrane disease, which probably indicates a decrease in detectable surface area for exchange due to derecruitment or hypoperfusion of pulmonary exchange vessels in edematous and hypoxic areas of the lungs.
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Harris TR, Roselli RJ, Maurer CR, Parker RE, Pou NA. Comparison of labeled propanediol and urea as markers of lung vascular injury. J Appl Physiol (1985) 1987; 62:1852-9. [PMID: 3597258 DOI: 10.1152/jappl.1987.62.5.1852] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The purpose of these studies was a comparison of [14C]urea (U) and 1,3-[14C]propanediol (Pr) as measures of lung vascular permeability-surface area (PS) under base-line conditions and after lung injury caused by alloxan infusion in isolated perfused dog lungs. Indicator mixtures of 125I-albumin, 51Cr-red blood cells, 3HOH, and U or Pr were injected under base-line conditions, after 1.2 g of alloxan, and after an additional 0.8 g of alloxan. Indicator-dilution curves were analyzed from sampled outflow blood to provide PS, the square root of effective extravascular diffusivity multiplied by exchange surface area (D1/2S), and extravascular lung water (EVLW) from the tracer mean transit times (VW). Results show that alloxan increases PS and D1/2S for U, D1/2S for Pr, and VW and EVLW by desiccation. All indicator-dilution parameters correlate significantly with alloxan dose. Interpretation of Pr transport suggests that materials with lipid and hydrophilic pathways might be used in conjunction with U to minimize the effects of surface area changes and increase the sensitivity of these tracers to permeability alteration. In addition Pr may be a useful alternative to U as a marker of vascular damage.
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Abstract
Transport theory has been applied to lymph flow (QL), protein lymph to plasma concentration ratios (L/P), and permeability surface area for urea (PSu) in unanesthetized sheep. Three models of the plasma-interstitial barrier have been used: a single pathway fiber matrix model, a continuous cylindrical-pore model with log normal distribution of filtration coefficients, and a cylindrical two-pore model. The fiber matrix model was unable to match measured PSu, QL, and L/P. The continuous-pore model was capable of describing the data, but the fitted median pore size was inconsistent with a continuum theory. The two-pore model described steady-state data and was used in additional model applications. We explored the 90% confidence limits for the fitted structural parameters of the two-pore theory. We found that many sets of model parameters were capable of fitting the available experimental data. We therefore sought combinations of parameters that might characterize the microvascular barrier under baseline and altered permeability situations. One combination that looks promising is the ratio of large-pore to small-pore radius raised to the sixth power and multiplied by the large-pore frequency. This value remains relatively constant following elevations in microvascular pressure, saline infusions, and plasma infusions but increases dramatically after endotoxin infusion.
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Parker RE, Roselli RJ, Haselton FR, Harris TR. Effect of perfusate hematocrit on urea permeability-surface area in isolated dog lung. J Appl Physiol (1985) 1986; 61:1383-7. [PMID: 3781954 DOI: 10.1152/jappl.1986.61.4.1383] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Seven dog lower left lung lobes were statically inflated and perfused at a constant rate for each lobe with a perfusate in which the hematocrit was altered over a wide range. The permeability-surface area of urea was calculated from multiple indicator dilution curves using two separate injectates for each hematocrit level. One injectate contained only 125I-albumin as the vascular reference tracer and the other contained both 51Cr-erythrocytes and 125I-albumin as the vascular reference tracers; both contained [14C]urea as the permeating tracer. The results strongly indicate that the phenomenon of "erythrocyte trapping" of urea does not affect the calculation of urea permeability-surface area product provided the appropriate albumin-erythrocyte composite reference tracer is utilized in its calculation.
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Jacques KA, Axe DE, Harris TR, Harmon DL, Bolsen KK, Johnson DE. Effect of sodium bicarbonate and sodium bentonite on digestion, solid and liquid flow, and ruminal fermentation characteristics of forage sorghum silage-based diets fed to steers. J Anim Sci 1986; 63:923-32. [PMID: 3019979 DOI: 10.2527/jas1986.633923x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Six ruminally cannulated steers, five Holsteins and one Hereford (250 to 295 kg), were fed 84% forage sorghum silage plus 16% supplement or 50% forage sorghum silage plus concentrate and supplement diets containing either no addition (controls), 1% sodium bicarbonate (NaHCO3) or 2% sodium bentonite in a 2 X 3 factorial arrangement of treatments in a 6 X 6 Latin-square experiment with 3-wk periods. Sodium bicarbonate increased dry matter (DM) intake when concentrate was included, but neither compound affected intake of the 84% silage diet. Bentonite lowered DM, neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibilities, but NDF disappearance from nylon bags was unchanged. Ruminal pH, osmolality and L(+) and D(-) lactate were not affected by treatment. Both NaHCO3 and bentonite tended to lower ruminal NH3-N concentrations. Bentonite lowered the molar proportion of isobutyrate in ruminal fluid relative to controls, but proportions of other volatile fatty acids (VFA) and total VFA concentrations were unchanged. Neither NaHCO3 nor bentonite affected ruminal liquid or solid volumes, dilution rate constants or ruminal outflow rates. Markers overestimated volumes, but correction with measured volumes did not change interpretation of treatment effects. It was concluded that control diets had sufficiently high baseline values of pH, dilution rate and acetate proportion to preclude changes induced by either compound, especially at 1 or 2% of DM intake. An effect on palatibility through neutralization of silage acids may have been responsible for the intake response to NaHCO3.
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Parker RE, Wickersham NE, Roselli RJ, Harris TR, Brigham KL. Effects of hypoproteinemia on lung microvascular protein sieving and lung lymph flow. J Appl Physiol (1985) 1986; 60:1293-9. [PMID: 3700307 DOI: 10.1152/jappl.1986.60.4.1293] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Experiments were conducted on five chronically instrumented unanesthetized sheep to determine the effects of sustained hypoproteinemia on lung fluid balance. Plasma total protein concentration was decreased from a control value of 6.17 +/- 0.019 to 3.97 +/- 0.17 g/dl (mean +/- SE) by acute plasmapheresis and maintained at this level by chronic thoracic lymph duct drainage. We measured pulmonary arterial pressure, left atrial pressure, aortic pressure, central venous pressure, cardiac output, oncotic pressures of both plasma and lung lymph, lung lymph flow rate, and lung lymph-to-plasma ratio of total proteins and six protein fractions for both control base-line conditions and hypoproteinemia base-line conditions. Moreover, we estimated the average osmotic reflection coefficient for total proteins and the solvent drag reflection coefficients for the six protein fractions during hypoproteinemia. Hypoproteinemia caused significant decreases in lung lymph total protein concentration, lung lymph-to-plasma total protein concentration ratio, and oncotic pressures of plasma and lung lymph. There were no significant alterations in the vascular pressures, lung lymph flow rate, cardiac output, or oncotic pressure gradient. The osmotic reflection coefficient for total proteins was found to be 0.900 +/- 0.004 for hypoproteinemia conditions, which is equal to that found in a previous investigation for sheep with a normal plasma protein concentration. Our results suggest that hypoproteinemia does not alter the lung filtration coefficient nor the reflection coefficients for plasma proteins. Possible explanations for the reported increase in the lung filtration coefficient during hypoproteinemia by other investigators are also made.
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Collins JC, Harris TR. Lung vascular transport at controlled pressures with reduced coronary flow in sheep. Microvasc Res 1985; 30:154-75. [PMID: 4046868 DOI: 10.1016/0026-2862(85)90047-0] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This study was performed to measure the effects of sustained coronary flow reduction on lung lymph flow and protein clearance at normal and elevated lung microvascular pressures. Eleven halothane-anesthetized sheep were provided with lung lymph and carotid-to-left-anterior-descending coronary artery cannulas. Six sheep (ischemic group) were observed in a protocol of five periods, each of 2 hr duration: baseline, left atrial pressure (PLA) increased by mitral valve obstruction, return to baseline, reduced coronary flow, and reduced coronary flow plus increased PLA. Five sheep (control group) were studied in an identical protocol except that coronary flow was not reduced. PLAS were equal in the second and fifth periods. Lung lymph flow QL and protein clearance (QL times the lymph-to-plasma protein concentration ratio) normalized to second baseline were greater during ischemia than in the comparable control period, and clearance was also greater during the second increased-pressure period. We conclude that reduced coronary flow is related to sustained, significant increases in lung vascular transport at elevated as well as at normal vascular pressures.
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