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Arce-Esquivel AA, Bunker AK, Simmons GH, Yang HT, Laughlin MH, Terjung RL. Impaired Coronary Endothelial Vasorelaxation in a Preclinical Model of Peripheral Arterial Insufficiency. ACTA ACUST UNITED AC 2015; 1. [PMID: 26726316 PMCID: PMC4696773 DOI: 10.15436/2378-6914/15/010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The present study was designed to determine whether adult swine with peripheral artery insufficiency (PAI) would exhibit vascular dysfunction in vessels distinct from the affected distal limbs, the coronary conduit arteries. Moreover, we sought to evaluate the effect of exercise training on coronary vasomotor function in PAI. Eighteen female healthy young Yucatan miniature swine were randomly assigned to either occluded exercise trained (Occl-Ex, n=7), or occluded-sedentary (Occl-Sed, n=5), or non-occluded, non-exercised control (Non-Occl-Con, n=6) groups. Occl-Ex pigs were progressively trained by running on a treadmill (5days/week, 12 weeks). The left descending artery (LAD) and left circumflex (LCX) coronary arteries were harvested. Vasorelaxation to adenosine diphosphate (ADP), bradykinin (BK), and sodium nitro-prusside (SNP) were assessed in LAD’s; while constrictor responses to phenylephrine (PE), angiotensin II (Ang II), and endothelin-1 (ET-1) were assessed in LCX’s. Vasorelaxation to ADP was reduced in LADs from Occl-Sed and Occl-Ex pigs (P<0.001) as compared to Non-Occl-Con pigs; however, Occl-Ex pigs exhibited partial recovery (P<0.001) intermediate to the other two groups. BK induced relaxation was reduced in LADs from Occl-Ex and Occl-Sed pigs (P<0.001), compared to Non-Occl-Con, and exercise modestly increased responses to BK (P<0.05). In addition, SNP, PE, Ang II, and ET-1 responses were not significantly different among the groups. Our results indicate that ‘simple’ occlusion of the femoral arteries induces vascular dysfunction in conduit vessels distinct from the affected hindlimbs, as evident in blunted coronary vasorelaxation responses to ADP and BK. These findings imply that PAI, even in the absence of frank atherogenic vascular disease, contributes to vascular dysfunction in the coronary arteries that could exacerbate disease outcome in patients with peripheral artery disease. Further, regular daily physical activity partially recovered the deficit observed in the coronary arteries.
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Affiliation(s)
- A A Arce-Esquivel
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri ; Department of Health and Kinesiology, The University of Texas at Tyler, Tyler, Texas
| | | | - G H Simmons
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
| | - H T Yang
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
| | - M H Laughlin
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri ; Department of Medical Pharmacology and Physiology, College of Medicine, University of Missouri, Columbia, Missouri ; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - R L Terjung
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri ; Department of Medical Pharmacology and Physiology, College of Medicine, University of Missouri, Columbia, Missouri ; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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Simmons GH, Fieger SM, Wong BJ, Minson CT, Halliwill JR. No effect of systemic isocapnic hypoxia on α-adrenergic vasoconstrictor responsiveness in human skin. Acta Physiol (Oxf) 2011; 201:339-47. [PMID: 20946237 DOI: 10.1111/j.1748-1716.2010.02193.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [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: 01/15/2023]
Abstract
UNLABELLED Hypoxia impairs body temperature regulation and abolishes the decline in skin temperature associated with cold exposure, suggesting that cutaneous vasoconstriction is impaired. AIM The purpose of this study was to test the hypothesis that cutaneous vasoconstriction to intradermal tyramine, an index of post-junctional vasoconstrictor responsiveness, is reduced during hypoxia. METHODS Twelve subjects (six males, six females) had three microdialysis fibres placed in the ventral forearm. Fibres received either lactated ringers, 5 mm yohimbine (α-adrenergic blockade), or 10.5 μm BIBP-3226 (to antagonize neuropeptide Y Y(1) receptors). Skin blood flow was assessed at each site (laser-Doppler flowmetry) and cutaneous vascular conductance (CVC) was calculated (red blood cell flux/mean arterial pressure) and scaled to baseline. Vasoconstrictor responses to tyramine (173 μm) were tested during normoxia and steady-state isocapnic hypoxia (SaO(2) = 80%) in random order. RESULTS During normoxia, tyramine reduced CVC by 56.0±5.6 and 50.3±8.0% in control and BIBP-3226 sites (both P<0.05 vs. pre-tyramine; P=0.445 between sites) whereas CVC in the yohimbine site did not change (P=0.398 vs. pre-tyramine). During isocapnic hypoxia, tyramine reduced CVC by 55.9±5.1 and 54.2±5.4% in control and BIBP-3226 sites (both P<0.05 vs. pre-tyramine; P=0.814 between sites) whereas CVC was unchanged in the yohimbine site (P=0.732 vs. pre-tyramine). Isocapnic hypoxia did not affect vasoconstrictor responses at any site (all P>0.05 vs. normoxia). CONCLUSION We conclude that post-junctional α-adrenergic vasoconstrictor responsiveness is not affected by hypoxia in non-acral skin.
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Affiliation(s)
- G H Simmons
- Department of Human Physiology, University of Oregon, Eugene, OR 97403, USA
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Roustit M, Simmons GH, Carpentier P, Cracowski JL. Abnormal digital neurovascular response to local heating in systemic sclerosis. Rheumatology (Oxford) 2008; 47:860-4. [DOI: 10.1093/rheumatology/ken065] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Carson PL, Simmons GH, Bernal EA, Deye JA, Mishkin M. ACR survey results: diagnostic imaging scientists and engineers. Radiol Manage 1990; 12:31-8. [PMID: 10104178] [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
The American College of Radiology's Committee on Physics Resources of the Commission on Human Resources conducted a survey of diagnostic imaging scientists and engineers to assess who is providing radiologic physics and related services in diagnostic imaging departments. The survey forms were distributed through the members of the American Healthcare Radiology Administrators. Survey results showed a predominance of M.S. and Ph.D. degrees in physics and medical/radiological physics. Nearly all respondents had their time split between numerous categories of work, such as clinical and research, and between different modalities such as diagnostic x-ray, nuclear medicine and radiation oncology. To enhance physics services in important areas such as CT, which currently receive little time, support is needed for work prioritization, for training, and for positions for physics and physics-support personnel.
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Shih WJ, DeLand FH, Simmons GH, Coupal J, Domstad PA, Lee LY. 111In-chloride thorax scintigraphic study for demonstration of pulmonary edema: canine model. Eur J Nucl Med 1986; 11:498-501. [PMID: 3488217 DOI: 10.1007/bf00252797] [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] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Pulmonary edema induced by injections of oleic acid was demonstrated using 111In-chloride lung/heart image in five anesthetized dogs. The anesthetized dogs were positioned under a gamma camera interfaced to a computer. After 111In-chloride IV injections, dynamic data were recorded at 1 frame/min before and after induced pulmonary edema. The computer generated the curve of the lung-to-heart activity ratio; the ratio rose from 0.5-0.6 at baseline to 0.85-1.5 at the end of the study in the dogs. At the end of each study, the removed lungs demonstrated edematous fluid, and a few red blood cells were seen in the alveoli. The results indicating pulmonary edema exhibited in the 111In-chloride lung-to-heart ratio obtained from a computerized gamma camera were compatible with the pathological result. Since 111In-chloride instantly binds to plasma transferrin, an excellent intravascular imaging agent, leakage of this tracer into alveoli indicates loss of membranous wall competence. Pulmonary edema, as in the adult respiratory distress syndrome, is sometimes difficult to diagnose; and this 111In-chloride lung-to-heart imaging technique may be potentially useful.
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Shih WJ, Domstad PA, DeLand FH, Magoun SE, Simmons GH, Schacht RA. Demonstration of splenomegaly by gated cardiac blood pool imaging. Correlation with Tc-99m sulfur colloid scans and autopsy findings. Clin Nucl Med 1982; 7:568-9. [PMID: 7172540 DOI: 10.1097/00003072-198212000-00009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Abstract
The distribution and acute lethality of i.v. administered 3 micrometers latex spheres were determined in rats. The results extend previous studies demonstrating the similarity between dog and rat in the dynamics of microspheres in these species and the inverse relationship between sphere diameter and hemodynamic toxicity. The results suggest that 3 micrometers spheres may be safe imaging agents or drug delivery systems for spleen and liver when administered slowly. Acute hemodynamic toxicity appears to be a function of the total volume of the spheres injected.
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Slack JD, Kanke M, Simmons GH, DeLuca PP. Acute hemodynamic effects and blood pool kinetics of polystyrene microspheres following intravenous administration. J Pharm Sci 1981; 70:660-4. [PMID: 7252811 DOI: 10.1002/jps.2600700621] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The acute hemodynamic effect of intravenous administration of polystyrene microspheres was investigated and correlated with their distribution pattern and kinetics. Microspheres of three diameters (3.4, 7.4, and 11.6 micrometer) were administered. The 7.4- and 11.6-micrometer diameter microspheres were filtered by the pulmonary capillary network following intravenous administration, the majority during the first pass. There was no significant hemodynamic effect following administrations of the 7.4- and 11.6-micrometer diameter microspheres in doses as high as 3.0 X 10(9) and 6.1 X 10(8) respectively (total cross-sectional area of 1.3 X 10(11) and 6.4 X 10(10) micrometer2, respectively). Intravenous administration of 3.4-micrometer diameter microspheres produced significant dose-dependent systemic hypotension and depression of myocardial performance at dosages as slow as 1.0 X 10(10) (cross-sectional area of 9.1 X 10(10) micrometer2). These differences in acute hemodynamic effect from the 7.4- and 11.6-micrometer diameter microspheres may be due to the differences in distribution kinetics and fate of the 3.4-micrometer diameter microspheres, which readily pass through the lungs to the spleen. Although elimination of the smaller spheres from the blood during the first 6-8 min was rapid, i.e., t 1/2 = 1.62 and 1.72 min from the venous and arterial blood circulation, respectively, levels of 10(3) spheres/g of blood were present in the circulation for greater than 1 hr. These findings must be considered in the planning of intravenous administration of microspheres as a drug delivery system to target organs.
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Kanke M, Simmons GH, Weiss DL, Bivins BA, DeLuca PP. Clearance of 141C3-labeled microspheres from blood and distribution in specific organs following intravenous and intraarterial administration in beagle dogs. J Pharm Sci 1980; 69:755-62. [PMID: 7391933 DOI: 10.1002/jps.2600690703] [Citation(s) in RCA: 118] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Schroeder HG, Simmons GH, DeLuca PP. Distribution of radiolabeled subvisible microspheres after intravenous administration to beagle dogs. J Pharm Sci 1978; 67:504-7. [PMID: 641758 DOI: 10.1002/jps.2600670417] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Abstract
A new method for optimizing the design of multi-aperture parallel-hole collimators for the gamma scintillation camera is presented. The method takes into account the frequency spectrum of a plane source object distribution as well as the energy of the radiation. A frequency dependent statistical figure of merit is calculated and combined with a weighted object distribution frequency spectrum to obtain an objective function which, when maximized, yields the optimum collimator design according to the chosen criteria. The optimization is performed by means of a sequential pattern search technique. The results show a positive correlation between te objective function and an experimental performance index evaluated for existing collimators. The optimal designs obtained by maximizing the objective function, under the assumption of no scatter within the source, exhibit somewhat higher sensitivity and lower resolution than the commercial low energy collimators tested. It is concluded that much of the resolution capability of very high resolution collimators is unused because of the limitation imposed by the intrinsic resolution of the detector assembly.
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Sear R, Dean PM, Simmons GH, Kereiakes JG. Unidirectional versus bidirectional scanning. J Nucl Med 1971; 12:768-9. [PMID: 5113646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Simmons GH, Kereiakes JG, Wellman HN. Educational program in nuclear medicine technology. JAMA 1971; 217:1082-4. [PMID: 4398003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Sear R, Dean PM, Simmons GH, Kereiakes JG. A digital ratemeter system for rectilinear scanning. J Nucl Med 1971; 12:320-1. [PMID: 5580855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Simmons GH, Hunkar DE, Kereiakes JG. A digital ratemeter system for rectilinear scanning. J Nucl Med 1970; 11:610-2. [PMID: 5506345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Simmons GH, Hunkar D, Kereiakes JG. A digital ratemeter system for medical radioisotope scanning. Phys Med Biol 1969; 14:334. [PMID: 5777114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Galvin JM, Simmons GH, Kereiakes JG. A comparison of radioisotope imaging devices using plane-source distributions. Phys Med Biol 1969; 14:335. [PMID: 5777116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Miller MS, Simmons GH. Optimization of timing and positioning of the technetium brain scan. J Nucl Med 1968; 9:429-35. [PMID: 5713651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Simmons GH. Proprietary Medicines: Some General Considerations. Cal State J Med 1906; 4:195-200. [PMID: 18733881 PMCID: PMC1651523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Cushny AR, Diehl CL, Hallberg CS, Hatcher RA, Kebler LF, Long JH, Novy FG, Puckner WA, Sadtler SP, Schlotterbeck JO, Simmons GH, Sollmann T, Stieglitz J, Wilbert MI, Wiley HW. A. M. A. Council on Pharmacy and Chemistry. Cal State J Med 1905; 3:103-104. [PMID: 18733430 PMCID: PMC1650471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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