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Horne BD, Joy EA, Hofmann MG, Gesteland PH, Cannon JB, Lefler JS, Blagev DP, Korgenski EK, Torosyan N, Hansen GI, Kartchner D, Pope CA. Short-Term Elevation of Fine Particulate Matter Air Pollution and Acute Lower Respiratory Infection. Am J Respir Crit Care Med 2019; 198:759-766. [PMID: 29652174 DOI: 10.1164/rccm.201709-1883oc] [Citation(s) in RCA: 204] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Nearly 60% of U.S. children live in counties with particulate matter less than or equal to 2.5 μm in aerodynamic diameter (PM2.5) concentrations above air quality standards. Understanding the relationship between ambient air pollution exposure and health outcomes informs actions to reduce exposure and disease risk. OBJECTIVES To evaluate the association between ambient PM2.5 levels and healthcare encounters for acute lower respiratory infection (ALRI). METHODS Using an observational case-crossover design, subjects (n = 146,397) were studied if they had an ALRI diagnosis and resided on Utah's Wasatch Front. PM2.5 air pollution concentrations were measured using community-based air quality monitors between 1999 and 2016. Odds ratios for ALRI healthcare encounters were calculated after stratification by ages 0-2, 3-17, and 18 or more years. MEASUREMENTS AND MAIN RESULTS Approximately 77% (n = 112,467) of subjects were 0-2 years of age. The odds of ALRI encounter for these young children increased within 1 week of elevated PM2.5 and peaked after 3 weeks with a cumulative 28-day odds ratio of 1.15 per +10 μg/m3 (95% confidence interval, 1.12-1.19). ALRI encounters with diagnosed and laboratory-confirmed respiratory syncytial virus and influenza increased following elevated ambient PM2.5 levels. Similar elevated odds for ALRI were also observed for older children, although the number of events and precision of estimates were much lower. CONCLUSIONS In this large sample of urban/suburban patients, short-term exposure to elevated PM2.5 air pollution was associated with greater healthcare use for ALRI in young children, older children, and adults. Further exploration is needed of causal interactions between PM2.5 and ALRI.
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Affiliation(s)
- Benjamin D Horne
- 1 Intermountain Medical Center Heart Institute, Salt Lake City, Utah.,2 Department of Biomedical Informatics
| | - Elizabeth A Joy
- 4 Department of Family and Preventive Medicine and.,3 Community Health & Food and Nutrition
| | - Michelle G Hofmann
- 6 Department of Pediatrics, University of Utah, Salt Lake City, Utah.,5 Primary Children's Hospital, Salt Lake City, Utah; and
| | - Per H Gesteland
- 2 Department of Biomedical Informatics.,6 Department of Pediatrics, University of Utah, Salt Lake City, Utah.,5 Primary Children's Hospital, Salt Lake City, Utah; and
| | | | | | - Denitza P Blagev
- 8 Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine
| | | | | | - Grant I Hansen
- 10 Business Intelligence, Intermountain Healthcare, Salt Lake City, Utah
| | - David Kartchner
- 9 Population Health, and.,11 Department of Mathematics, Brigham Young University, Provo, Utah
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Abstract
Purpose This article presents a basic exploration of Bayesian inference to inform researchers unfamiliar to this type of analysis of the many advantages this readily available approach provides. Method First, we demonstrate the development of Bayes' theorem, the cornerstone of Bayesian statistics, into an iterative process of updating priors. Working with a few assumptions, including normalcy and conjugacy of prior distribution, we express how one would calculate the posterior distribution using the prior distribution and the likelihood of the parameter. Next, we move to an example in auditory research by considering the effect of sound therapy for reducing the perceived loudness of tinnitus. In this case, as well as most real-world settings, we turn to Markov chain simulations because the assumptions allowing for easy calculations no longer hold. Using Markov chain Monte Carlo methods, we can illustrate several analysis solutions given by a straightforward Bayesian approach. Conclusion Bayesian methods are widely applicable and can help scientists overcome analysis problems, including how to include existing information, run interim analysis, achieve consensus through measurement, and, most importantly, interpret results correctly. Supplemental Material https://doi.org/10.23641/asha.7822592.
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Affiliation(s)
- Garnett P McMillan
- National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, OR
| | - John B Cannon
- National Center for Rehabilitative Auditory Research, Veterans Affairs Portland Health Care System, OR
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Burnett R, Chen H, Szyszkowicz M, Fann N, Hubbell B, Pope CA, Apte JS, Brauer M, Cohen A, Weichenthal S, Coggins J, Di Q, Brunekreef B, Frostad J, Lim SS, Kan H, Walker KD, Thurston GD, Hayes RB, Lim CC, Turner MC, Jerrett M, Krewski D, Gapstur SM, Diver WR, Ostro B, Goldberg D, Crouse DL, Martin RV, Peters P, Pinault L, Tjepkema M, van Donkelaar A, Villeneuve PJ, Miller AB, Yin P, Zhou M, Wang L, Janssen NAH, Marra M, Atkinson RW, Tsang H, Quoc Thach T, Cannon JB, Allen RT, Hart JE, Laden F, Cesaroni G, Forastiere F, Weinmayr G, Jaensch A, Nagel G, Concin H, Spadaro JV. Global estimates of mortality associated with long-term exposure to outdoor fine particulate matter. Proc Natl Acad Sci U S A 2018; 115:9592-9597. [PMID: 30181279 PMCID: PMC6156628 DOI: 10.1073/pnas.1803222115] [Citation(s) in RCA: 906] [Impact Index Per Article: 151.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Exposure to ambient fine particulate matter (PM2.5) is a major global health concern. Quantitative estimates of attributable mortality are based on disease-specific hazard ratio models that incorporate risk information from multiple PM2.5 sources (outdoor and indoor air pollution from use of solid fuels and secondhand and active smoking), requiring assumptions about equivalent exposure and toxicity. We relax these contentious assumptions by constructing a PM2.5-mortality hazard ratio function based only on cohort studies of outdoor air pollution that covers the global exposure range. We modeled the shape of the association between PM2.5 and nonaccidental mortality using data from 41 cohorts from 16 countries-the Global Exposure Mortality Model (GEMM). We then constructed GEMMs for five specific causes of death examined by the global burden of disease (GBD). The GEMM predicts 8.9 million [95% confidence interval (CI): 7.5-10.3] deaths in 2015, a figure 30% larger than that predicted by the sum of deaths among the five specific causes (6.9; 95% CI: 4.9-8.5) and 120% larger than the risk function used in the GBD (4.0; 95% CI: 3.3-4.8). Differences between the GEMM and GBD risk functions are larger for a 20% reduction in concentrations, with the GEMM predicting 220% higher excess deaths. These results suggest that PM2.5 exposure may be related to additional causes of death than the five considered by the GBD and that incorporation of risk information from other, nonoutdoor, particle sources leads to underestimation of disease burden, especially at higher concentrations.
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Affiliation(s)
- Richard Burnett
- Population Studies Division, Health Canada, Ottawa, ON K1A 0K9, Canada
| | - Hong Chen
- Population Studies Division, Health Canada, Ottawa, ON K1A 0K9, Canada
- Department of Environmental and Occupational Health, Public Health Ontario, Toronto, ON M5G 1V2, Canada
| | | | - Neal Fann
- Risk and Benefits Group, Office of Air Quality Planning and Standards, US Environmental Protection Agency, Washington, DC 20460
| | - Bryan Hubbell
- Office of Research and Development, US Environmental Protection Agency, Washington, DC 20460
| | - C Arden Pope
- Department of Economics, Brigham Young University, Provo, UT 84602
| | - Joshua S Apte
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712
| | - Michael Brauer
- School of Population and Public Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Aaron Cohen
- Health Effects Institute, Boston, MA 02110-1817
| | - Scott Weichenthal
- Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC H3A 0G4, Canada
- Gerald Bronfman Department of Oncology, McGill University, Montreal, QC H3A 0G4, Canada
| | - Jay Coggins
- Department of Applied Economics, University of Minnesota, Minneapolis, MN 55455
| | - Qian Di
- Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA 02115
| | - Bert Brunekreef
- Institute for Risk Assessment Sciences, Universiteit Utrecht, 3512 JE Utrecht, The Netherlands
| | - Joseph Frostad
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA 98195
| | - Stephen S Lim
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA 98195
| | - Haidong Kan
- School of Public Health, Fudan University, Shanghai 200433, China
| | | | - George D Thurston
- Environmental Medicine and Population Health, Program in Human Exposures and Health Effects, New York University School of Medicine, New York, NY 10016
| | - Richard B Hayes
- Department of Population Health, NYU Langone Medical Center, New York, NY 10016
| | - Chris C Lim
- Department of Environmental Medicine, New York University School of Medicine, New York, NY 10016
| | - Michelle C Turner
- ISGlobal, Barcelona Institute for Global Health, 08036 Barcelona, Spain
| | - Michael Jerrett
- Department of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles, CA 90095
| | - Daniel Krewski
- McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Susan M Gapstur
- Epidemiology Research Program, American Cancer Society, Inc., Atlanta, GA 30303
| | - W Ryan Diver
- Epidemiology Research Program, American Cancer Society, Inc., Atlanta, GA 30303
| | - Bart Ostro
- Department of Civil and Environmental Engineering, University of California, Davis, CA 95616
| | - Debbie Goldberg
- Cancer Prevention Institute of California, Fremont, CA 94538
| | - Daniel L Crouse
- Department of Sociology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | - Randall V Martin
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Paul Peters
- Department of Health Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada
- Department of Geography and Environment, Carleton University, Ottawa, ON K1S 5B6, Canada
- New Brunswick Institute for Research, Data and Training, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | - Lauren Pinault
- Health Analysis Division, Statistics Canada, Ottawa, ON K1A 0T6, Canada
| | - Michael Tjepkema
- Health Analysis Division, Statistics Canada, Ottawa, ON K1A 0T6, Canada
| | - Aaron van Donkelaar
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Paul J Villeneuve
- Department of Health Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Anthony B Miller
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON M5T 3M7, Canada
| | - Peng Yin
- National Center for Chronic Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100050, China
| | - Maigeng Zhou
- National Center for Chronic Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100050, China
| | - Lijun Wang
- National Center for Chronic Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100050, China
| | - Nicole A H Janssen
- National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands
| | - Marten Marra
- National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands
| | - Richard W Atkinson
- Population Health Research Institute, St. George's, University of London, London SW17 0RE, United Kingdom
- MRC-PHE Centre for Environment and Health, St. George's, University of London, London SW17 0RE, United Kingdom
| | - Hilda Tsang
- School of Public Health, University of Hong Kong, Hong Kong, China
| | - Thuan Quoc Thach
- School of Public Health, University of Hong Kong, Hong Kong, China
| | - John B Cannon
- Department of Economics, Brigham Young University, Provo, UT 84602
| | - Ryan T Allen
- Department of Economics, Brigham Young University, Provo, UT 84602
| | - Jaime E Hart
- Department of Environmental Health, Harvard C.T. Channing School of Public Health, Harvard University, Boston, MA 02115
| | - Francine Laden
- Department of Environmental Health, Harvard C.T. Channing School of Public Health, Harvard University, Boston, MA 02115
| | - Giulia Cesaroni
- Department of Epidemiology, Regional Health Service, ASL Roma 1, 00147 Rome, Italy
| | - Francesco Forastiere
- Department of Epidemiology, Regional Health Service, ASL Roma 1, 00147 Rome, Italy
| | - Gudrun Weinmayr
- Institute of Epidemiology and Medical Biometry, Ulm University, 89081 Ulm, Germany
| | - Andrea Jaensch
- Institute of Epidemiology and Medical Biometry, Ulm University, 89081 Ulm, Germany
| | - Gabriele Nagel
- Institute of Epidemiology and Medical Biometry, Ulm University, 89081 Ulm, Germany
| | - Hans Concin
- Agency for Preventive and Social Medicine, 6900 Bregenz, Austria
| | - Joseph V Spadaro
- Spadaro Environmental Research Consultants (SERC), Philadelphia, PA 19142
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Pope CA, Muhlestein JB, Anderson JL, Cannon JB, Hales NM, Meredith KG, Le V, Horne BD. Short-Term Exposure to Fine Particulate Matter Air Pollution Is Preferentially Associated With the Risk of ST-Segment Elevation Acute Coronary Events. J Am Heart Assoc 2015; 4:JAHA.115.002506. [PMID: 26645834 PMCID: PMC4845284 DOI: 10.1161/jaha.115.002506] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [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] [Indexed: 01/22/2023]
Abstract
Background Air pollution is associated with greater cardiovascular event risk, but the types of events and specific persons at risk remain unknown. This analysis evaluates effects of short‐term exposure to fine particulate matter air pollution with risk of acute coronary syndrome events, including ST‐segment elevation myocardial infarction, non–ST‐segment elevation myocardial infarction, unstable angina, and non–ST‐segment elevation acute coronary syndrome. Methods and Results Acute coronary syndrome events treated at Intermountain Healthcare hospitals in urban areas of Utah's Wasatch Front were collected between September 1993 and May 2014 (N=16 314). A time‐stratified case‐crossover design was performed matching fine particulate matter air pollution exposure at the time of each event with referent periods when the event did not occur. Patients served as their own controls, and odds ratios were estimated using nonthreshold and threshold conditional logistic regression models. In patients with angiographic coronary artery disease, odds ratios for a 10‐μg/m3 increase in concurrent‐day fine particulate matter air pollution >25 μg/m³ were 1.06 (95% CI 1.02–1.11) for all acute coronary syndrome, 1.15 (95% CI 1.03–1.29) for ST‐segment elevation myocardial infarction, 1.02 (95% CI 0.97–1.08) for non–ST‐segment elevation myocardial infarction, 1.09 (95% CI 1.02–1.17) for unstable angina, and 1.05 (95% CI 1.00–1.10) for non–ST‐segment elevation acute coronary syndrome events. Excess risk from fine particulate matter air pollution exposure was not observed in patients without angiographic coronary artery disease. Conclusions Elevated fine particulate matter air pollution exposures contribute to triggering acute coronary events, especially ST‐segment elevation myocardial infarction, in those with existing seriously diseased coronary arteries but not in those with nondiseased coronary arteries.
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Affiliation(s)
- C Arden Pope
- Department of Economics, Brigham Young University, Provo, UT (A.P., J.B.C., N.M.H.)
| | - Joseph B Muhlestein
- Intermountain Heart Institute, Intermountain Medical Center, Murray, UT (J.B.M., J.L.A., K.G.M., V.L., B.D.H.) Department of Internal Medicine, University of Utah, Salt Lake City, UT (J.B.M., J.L.A., B.D.H.)
| | - Jeffrey L Anderson
- Intermountain Heart Institute, Intermountain Medical Center, Murray, UT (J.B.M., J.L.A., K.G.M., V.L., B.D.H.) Department of Internal Medicine, University of Utah, Salt Lake City, UT (J.B.M., J.L.A., B.D.H.)
| | - John B Cannon
- Department of Economics, Brigham Young University, Provo, UT (A.P., J.B.C., N.M.H.)
| | - Nicholas M Hales
- Department of Economics, Brigham Young University, Provo, UT (A.P., J.B.C., N.M.H.)
| | - Kent G Meredith
- Intermountain Heart Institute, Intermountain Medical Center, Murray, UT (J.B.M., J.L.A., K.G.M., V.L., B.D.H.)
| | - Viet Le
- Intermountain Heart Institute, Intermountain Medical Center, Murray, UT (J.B.M., J.L.A., K.G.M., V.L., B.D.H.)
| | - Benjamin D Horne
- Intermountain Heart Institute, Intermountain Medical Center, Murray, UT (J.B.M., J.L.A., K.G.M., V.L., B.D.H.) Department of Internal Medicine, University of Utah, Salt Lake City, UT (J.B.M., J.L.A., B.D.H.)
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Chandrasekhar S, Iyer LK, Panchal JP, Topp EM, Cannon JB, Ranade VV. Microarrays and microneedle arrays for delivery of peptides, proteins, vaccines and other applications. Expert Opin Drug Deliv 2013; 10:1155-70. [PMID: 23662940 DOI: 10.1517/17425247.2013.797405] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Peptide and protein microarray and microneedle array technology provides direct information on protein function and potential drug targets in drug discovery and delivery. Because of this unique ability, these arrays are well suited for protein profiling, drug target identification/validation and studies of protein interaction, biochemical activity, immune responses, clinical prognosis and diagnosis and for gene, protein and drug delivery. AREAS COVERED The aim of this review is to describe and summarize past and recent developments of microarrays in their construction, characterization and production and applications of microneedles in drug delivery. The scope and limitations of various technologies in this respect are discussed. EXPERT OPINION This article offers a review of microarray/microneedle technologies and possible future directions in targeting and in the delivery of pharmacologically active compounds for unmet needs in biopharmaceutical research. A better understanding of the production and use of microarrays and microneedles for delivery of peptides, proteins and vaccines is needed.
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Affiliation(s)
- Saradha Chandrasekhar
- Purdue University, Department of Industrial and Physical Pharmacy, West Lafayette, IN 47907, USA
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Abstract
Chronic gestational cocaine administration has been correlated with high levels of postpartum maternal aggression towards intruders and altered levels of oxytocin in the amygdala. Cocaine may alter both oxytocin and maternal aggression either directly or indirectly through changes in monoamine levels in relevant brain regions. In this study, pregnant female rats were randomly assigned to one of four groups; three cocaine dose groups (7.5, 15 or 30 mg/kg), or a saline-treated group (0.9% normal saline) and given subcutaneous injections twice daily (total volume 2 ml/kg) throughout gestation. Behavioral responses to an inanimate object placed in the homecage were assessed on Postpartum Day (PPD) 6. Immediately following testing, animals were sacrificed and four brain regions implicated in maternal/aggressive behavior (medial preoptic area [MPOA], ventral tegmental area [VTA], hippocampus, and amygdala) were removed for monoamine level analyses using high-performance liquid chromatography. Dams given 30 mg/kg cocaine throughout gestation had significantly higher levels of dopamine (DA) and nonsignificantly elevated serotonin (5-HT) levels relative to saline-treated controls. These dams also exhibited higher frequencies of defensive behavior toward an inanimate object compared to saline-treated controls. Potential mechanisms mediating cocaine-induced increases in responding are proposed.
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Affiliation(s)
- D A Lubin
- Department of Psychiatry, University of North Carolina at Chapel Hill, 436 Taylor Hall, CB# 7096, Chapel Hill, NC 27599-7096, USA.
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White DK, Cannon JB, Traylor TG. A kinetic model for R- and T-state hemoglobin. Flash photolysis of heme-imidazole-carbon monoxide mixtures. J Am Chem Soc 2002. [DOI: 10.1021/ja00503a034] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [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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Schwartz J, Cannon JB. Thermal decomposition of bis(triphenylphosphine)(carbonyl)octyliridium(I). New decomposition mechanism for transition metal long chain alkyls. J Am Chem Soc 2002. [DOI: 10.1021/ja00814a062] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [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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Abstract
A-71623 (BOC-Trp-Lys(epsilon-N-2-methylphenylaminocarbonyl)- Asp-(N-methyl)-Phe-NH2) is a tetrapeptide which has high affinity and selectivity for cholecystokinin receptors; it is a potent appetite suppresser in animal studies. Because of its low (< 1%) oral bioavailability, studies were performed to assess the feasibility of delivery of A-71623 by pulmonary, sublingual, and transdermal routes of administration. The pKa was determined to be 4.2 by spectrophotometric titration; aqueous solubility is increased by increasing pH and by increasing ethanol content. The solubility of A-71623 in ethanol/propellant mixtures was investigated; solubility ranged from 1.0 to 2.5 mg/mL in mixtures of ethanol, propellant 11 (trichlorofluoromethane), and propellant 12 (dichlorodifluoromethane). The log apparent octanol/water partition coefficient was 2.8 at pH 5 and 1.0 at pH 8. Maximum stability at 70 degrees C was seen in the range of pH values of 5.5-7.5; hydrolysis of the N-terminal BOC group appears to be the primary route of degradation. Increasing ethanol content increases the stability; Arrhenius analysis indicated a t90 of 150 days under ambient conditions in 25% ethanol. Intratracheal delivery of 3 mumol/kg A-71623 in 50% ethanol to rats showed rapid and efficient absorption of drug from the lungs, with a Cmax of 2.7 microM and an AUC of 85 microM*min. Similar studies in dogs showed bioavailabilities of 59% and 46% for 2 and 3 mumol/kg intratracheal doses, respectively, relative to intravenous administration. Sublingual administration of 1 mumol/kg A-71623 in a vehicle of 80% ethanol/2% Klucel/2.5% peppermint oil gave high prolonged plasma levels of A-71623, with a Cmax of 0.37 microM, indicating high bioavailability and favorable partitioning and distribution effects from the sublingual cavity for this formulation. Transdermal delivery was examined by in vitro diffusion through human skin; the permeability coefficient of A-71623 in 40% ethanol was 2.6 x 10(-5) cm/hr, suggesting that transdermal delivery of up to 2 mg/day may be feasible. In conclusion, the results provide preliminary indications that delivery of efficacious doses of A-71623, and perhaps other CCK analogs, by alternate routes of delivery is probably feasible.
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Affiliation(s)
- J B Cannon
- Abbott Laboratories, Abbott Park, IL 60064-3500, USA
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Abstract
The physicochemical properties of A-75998, a synthetic antagonist of luteinizing hormone releasing hormone with potential for treatment of hormone-sensitive cancers and endometriosis, are described. An accelerated solution stability study indicated that the compound is relatively stable and showed a U-shaped pH-rate profile, with maximum stability between pH 4.5 and 6.5. The acid dissociation behavior of A-75998 was examined by UV-visible spectrophotometry at 25 degrees C in a series of buffers ranging from pH 1 to 13. The data were fit to a model in which the dissociations of all four ionizable groups contributed to changes in the absorbance. The estimated macroscopic acid dissociation constants were p beta 1 = 3.230 +/- 0.022, p beta 2 = 4.885 +/- 0.030, p beta 3 = 9.871 +/- 0.022, and p beta 4 = 11.026 +/- 0.157. The corresponding microscopic dissociation constants were pk1 = 3.24 (nicotinyl), pk2 = 4.88 (pyridyl), pk5 = 9.91 (tyrosyl), and pk6 = 10.99 (isopropyllysyl). The apparent n-octanol/water partition coefficients were measured from pH 2 to 13, and the profile was consistent with the expected acid-dissociation behavior. While appearing fairly water-soluble at pH < 5, dynamic light scattering of A-75998 in pH 4.5 buffer indicated the formation of aggregates of nonuniform size distribution. A-75998 exhibited reverse or thermal gelation; sodium chloride exacerbates this gel formation and self-association. Surface activity was pH-dependent, but no evidence was found for micelle formation. Based on the results, development of a parenteral formulation of A-75998 appears feasible, provided that aggregation can be minimized.
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Affiliation(s)
- J B Cannon
- Abbott Laboratories, Abbott Park, IL 60064-3500, USA
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Cannon JB, Yunker MH, Luoma N. The effect of aggregation inhibitors and antioxidants on the stability of hemin solutions. PDA J Pharm Sci Technol 1995; 49:77-82. [PMID: 7780749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Despite their importance as infusions for the treatment of porphyrias, aqueous solutions of hemin can be quite unstable, with a reported half-life of a few hours. We have examined factors which affect the stability of hemin solutions in order to identify possible excipients and conditions which would increase the stability. In agreement with previous reports, we have found that human serum albumin leads to stabilization of hemin solutions; polyvinylpyrrolidone is also an effective stabilizer of hemin. Imidazole, caffeine, and niacinamide were also found to stabilize hemin, apparently by complexing to hemin and preventing the formation of hematin dimers. Addition of certain antioxidants, e.g., butylated hydroxyanisole and N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), led to stabilization of hemin, suggesting that radicals are involved in the degradation process. A comparison was also made by HPLC analysis of the hemin autooxidation products with those from the reaction of hemin with hydrogen peroxide; the results indicate that the products are similar but not identical. The implications of the results for clinical use of hemin solutions are discussed.
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Affiliation(s)
- J B Cannon
- Abbott Laboratories, North Chicago, Illinois, USA
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Arneric SP, Anderson DJ, Bannon AW, Briggs CA, Buccafusco JJ, Brioni JD, Cannon JB, Decker MW, Donnelly-Roberts D, Gopalakrishnan M, Holladay MW, Kyncl J, Marsh KC, Pauly J, Radek RJ, Rodrigues AD, Sullivan JP. Preclinical Pharmacology of ABT-418: A Prototypical Cholinergic Channel Activator for the Potential Treatment of Alzheimer's Disease. CNS Drug Reviews 1995. [DOI: 10.1111/j.1527-3458.1995.tb00274.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
The importance of porphyrins and metalloporphyrins as therapeutic drugs has increased significantly over the last decade. This review highlights some of the challenges faced by pharmaceutical scientists in formulating these drugs into stable, effective, and safe dosage forms. Most activity in the clinic has focused on three areas: photodynamic therapy of cancer (e.g., hematoporphyrin derivatives), porphyrias and hematological diseases (e.g., heme), and various forms of jaundice (e.g., tin porphyrins). The biodistribution, stability, aggregation, toxicology, and analytical methodology of porphyrin drugs are all important considerations in the pharmaceutical development of porphyrin drugs. The utility of delivery systems such as liposomes hold promise of increasing the therapeutic potential of these drugs. Future prospects for therapeutic applications of porphyrin drugs are also discussed.
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Affiliation(s)
- J B Cannon
- Abbott Laboratories, North Chicago, IL 60064
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Cannon JB, Martin C, Drummond GS, Kappas A. Targeted delivery of a heme oxygenase inhibitor with a lyophilized liposomal tin mesoporphyrin formulation. Pharm Res 1993; 10:715-21. [PMID: 8321837 DOI: 10.1023/a:1018911816814] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Tin mesoporphyrin (SnMP) is a competitive inhibitor of heme oxygenase being examined clinically for the treatment of hyperbilirubinemia. Since liposomes have been shown to target SnMP to the spleen and increase its efficacy (S. A. Landaw, G. S. Drummond, and A. Kappas, Pediatrics 84, 1091-1096, 1989), we began investigating the feasibility of the preparation and scaleup of a liposomal SnMP formulation for clinical use. SnMP liposomes were prepared by high-pressure homogenization of a suspension of SnMP and egg phosphatidylcholine (1:20, w/w) in lactose-phosphate buffer, resulting in SnMP liposomes that were less than 200 nm in diameter and had encapsulation efficiencies of up to 90% at pH 5. The SnMP liposomes could be sterile filtered and lyophilized in a 1-day cycle with retention of the encapsulation efficiency and particle size. Following injection into rats, the distribution of liposomal SnMP to spleen at 2 and 6 hr after dosing was 5-20 times higher than for aqueous SnMP. Lyophilized SnMP liposomes were also more effective than aqueous SnMP in decreasing bilirubin production in bile-cannulated rats. The results suggest the potential for producing a safe, sterile, and effective lyophilized formulation of SnMP liposomes for targeting of heme oxygenase inhibitors to the spleen.
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Affiliation(s)
- J B Cannon
- Abbott Laboratories, North Chicago, Illinois 60064
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Cannon JB, Kuo FS, Vatandoust F, Liem HH, Muller-Eberhard U. The effect of metalloporphyrins and heme liposomes on delta-aminolevulinate synthase activity in rat liver. Biochem Biophys Res Commun 1985; 130:306-12. [PMID: 4026834 DOI: 10.1016/0006-291x(85)90418-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [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
Heme administration causes inhibition of delta-aminolevulinate synthase (ALAS), best tested in the allylisopropylacetamide (AIA)-treated rat, a model for hepatic porphyrias. Because heme suspended in aqueous media (for injection) is unstable and has adverse effects on coagulation, alternate therapeutic modalities are being explored. The present study tries to answer two questions: 1) are any heme analogs as effective inhibitors of ALAS as heme is; and 2) does heme administration in the form of liposomes increase its effectiveness? None of the liposome compositions tested, even if containing lactosylceramide for preferential hepatocyte uptake, was more effective in inhibiting AIA-induced ALAS activity than heme in buffer. As for the function of the heme analogs, although deuteroheme and heme dimethyl ester proved ineffective, mesoheme and cobalt protoporphyrin were nearly as effective as heme itself, indicating that both hydrophobic side chains in positions 2 and 4 and free propionate groups at 6 and 7 are essential for ALAS inhibition, as is the presence of a central cobalt or iron atom.
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Cannon JB, Kuo FS, Pasternack RF, Wong NM, Muller-Eberhard U. Kinetics of the interaction of hemin liposomes with heme binding proteins. Biochemistry 1984; 23:3715-21. [PMID: 6089878 DOI: 10.1021/bi00311a022] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
As a model for the transport of hemin across biological membranes, sonicated phosphatidylcholine liposomes with incorporated hemin were characterized. The interaction of the hemin liposomes with the heme binding proteins albumin, apomyoglobin, and hemopexin was examined as a function of liposome charge and cholesterol content. In all cases, there was an almost complete transfer of hemin from liposome to protein; a rapid phase and a slow phase were observed for the transfer. For negatively charged liposomes (with 11% dicetyl phosphate), the rapid and slow phases showed observed rates of transfer of ca. 2 and 0.01 s-1, respectively, for all three proteins. The presence of cholesterol in the liposomes decreased the observed rates by a factor of 2, and positively charged liposomes (with 11% stearylamine) showed about one-fifth the observed rates of negatively charged liposomes. The observed rates were independent of protein concentration, indicating that the rate-determining step is hemin efflux from the lipid bilayer. The hemin interaction with the phospholipid bilayer is suggested to be primarily hydrophobic with some electrostatic character. The two phases are suggested to arise from two different populations of hemin within the liposomes and are interpreted as arising from two different orientations of hemin within the bilayer.
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Cannon JB, Erman JE. Determination of the equilibrium constant for the binding of ferricytochrome c to phospholipid vesicles and the effect of binding on the reduction rate of cytochrome c. Biochim Biophys Acta 1980; 600:19-26. [PMID: 6249360 DOI: 10.1016/0005-2736(80)90407-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The rate of reduction of cytochrome c by 2-amino-4-hydroxy-6,7-dimethyl-5,6,7,8-tetrahydropteridine was examined as a function of binding to liposomes prepared from mixed soybean phospholipids, asolectin, and from various purified phospholipids. Binding of cytochrome c to asolectin liposomes caused an increase in the rate of reduction by the pteridine derivative from 2900 to 16 000 M-1 x s-1 at pH 7. At low ionic strength (0.003 M) the binding stoichiometry between cytochrome c and asolectin vesicles is 15 +/- 2 phosphospolipid/cytochrome c (mole ratio), determined by monitoring the change in reduction rate of cytochrome c by pteridine as cytochrome c is bound to the vesicles. A stoichiometry of 14 phospholipid/cytochrome c was obtained from gel filtration studies. Equilibrium association constants for the binding of cytochrome c to sites on the asolectin vesicles varies from 2.2 x 10(6) to 1.8 x 10(3) M-1 between 0.02 and 0.10 M ionic strength, respectively. In general, liposomes prepared from purified phospholipids resulted in less binding of cytochrome c per mole of phospholipid and lower reduction rates than those prepared from asolectin.
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