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Coast JR, Clifford PS, Henrich TW, Stray-Gundersen J, Johnson RL. Maximal inspiratory pressure following maximal exercise in trained and untrained subjects. Med Sci Sports Exerc 1990; 22:811-5. [PMID: 2287259 DOI: 10.1249/00005768-199012000-00013] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Previous investigators have demonstrated that 5-10 min of fatiguing exercise would lead to respiratory muscle fatigue in normal subjects. The purpose of this study was to determine if there was a differential inspiratory pressure response to maximal cycle ergometer exercise in trained and untrained subjects. Six highly trained cross country skiers and five untrained college students were studied prior to and 10, 60, and 120 s postexercise (incremental VO2max to exhaustion). On each occasion, maximal inspiratory pressure (MIP) was measured at the mouth from residual volume. Prior to exercise, the two groups had similar MIP values. After exercise, the sedentary subjects experienced significant decreases in MIP compared to the preexercise values. These decreases averaged 10%, 17%, and 13% at 10, 60, and 120 s postexercise, respectively. The skiers, on the other hand, showed no evidence of a decrease in MIP postexercise, with the postexercise values being slightly, but not significantly, higher than the preexercise values. From these results, we conclude that maximal exercise results in inspiratory muscle dysfunction in normal subjects but not in athletes training at or near elite levels. Thus, it appears that endurance exercise training induces an adaptive change in the inspiratory muscles that protects them from the acute loss of strength seen following exercise in normal subjects.
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252
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Johnson RL. Networking: the era of the '90s. COMPUTERS IN HEALTHCARE 1990; 11:33. [PMID: 10108206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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253
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Feidenhans'l R, Grey F, Nielsen M, Besenbacher F, Jensen F, Laegsgaard E, Stensgaard I, Jacobsen KW, Norskov JK, Johnson RL. Oxygen chemisorption on Cu(110): A model for the c(6 x 2) structure. PHYSICAL REVIEW LETTERS 1990; 65:2027-2030. [PMID: 10042428 DOI: 10.1103/physrevlett.65.2027] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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254
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Subasinghe N, Schulte M, Chan MY, Roon RJ, Koerner JF, Johnson RL. Synthesis of acyclic and dehydroaspartic acid analogues of Ac-Asp-Glu-OH and their inhibition of rat brain N-acetylated alpha-linked acidic dipeptidase (NAALA dipeptidase). J Med Chem 1990; 33:2734-44. [PMID: 2213826 DOI: 10.1021/jm00172a009] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The following structural and conformationally constrained analogues of Ac-Asp-Glu-OH (1) were synthesized: Ac-Glu-Glu-OH (2), Ac-D-Asp-Glu-OH (3), Ac-Glu-Asp-OH (4), Ac-Asp-Asp-OH (5), Ac-Asp-3-aminohexanedioic acid (6), Ac-3-amino-3-(carboxymethyl)propanoyl-Glu-OH (7), N-succinyl-Glu-OH (8), N-maleyl-Glu-OH (9), N-fumaryl-Glu-OH (10), and Ac-delta ZAsp-Glu-OH (11). These analogues were evaluated for their ability to inhibit the hydrolysis of Ac-Asp-[3,4-3H]-Glu-OH by N-acetylated alpha-linked acidic dipeptidase (NAALA dipeptidase) in order to gain some insight into the structural requirements for the inhibition of this enzyme. Analogues 4-6 and 9 were very weak inhibitors of NAALA dipeptidase (Ki greater than 40 microM), while 2, 3, and 7 with Ki values ranging from 3.2-8.5 microM showed intermediate inhibitory activity. The most active inhibitors of NAALA dipeptidase were compounds 8, 10, and 11 with Ki values of 0.9, 0.4, and 1.4 microM, respectively. These results suggest that the relative spacing between the side chain carboxyl and the alpha-carboxyl group of the C-terminal residue may be important for binding to the active site of the enzyme. They also indicate that the chi 1 torsional angle for the aspartyl residue is in the vicinity of 0 degrees.
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255
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Perelman AH, Johnson RL, Clemons RD, Finberg HJ, Clewell WH, Trujillo L. Intrauterine diagnosis and treatment of fetal goitrous hypothyroidism. J Clin Endocrinol Metab 1990; 71:618-21. [PMID: 2203798 DOI: 10.1210/jcem-71-3-618] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Newborn screening programs for the detection of congenital hypothyroidism have dramatically shortened the time before treatment is begun. However, concern still exists about central nervous system sequelae which may persist due to a period of untreated intrauterine hypothyroidism. Presence of polyhydramnios led to the ultrasound diagnosis of a fetal goiter. Hypothyroidism was confirmed at 34 weeks gestation by percutaneous fetal blood sampling, which revealed an elevated TSH (186 mU/L) and a low T4 (19.3 nmol/L). Intraamniotic fluid injections of 500 micrograms levothyroxine sodium (T4) every 10-14 days increased fetal serum T4 (59.2 nmol/L), decreased fetal serum TSH (14 mU/L), decreased amniotic fluid TSH, and decreased the size of the fetal goiter. The infant was born at term without perinatal complications. Thyroid function studies on cord blood were normal (T4, 109.4 nmol/L; TSH, 1.3 mU/L), and the infant was discharged on oral T4. Follow-up examination at age 6 weeks revealed that the infant was developmentally normal and clinically and chemically euthyroid. Intrauterine T4 therapy can suppress fetal TSH and treat fetal hypothyroidism despite hypothyroid levels of serum T3. Highly sensitive TSH assays may allow the use of amniotic fluid TSH as a marker for fetal hypothyroidism.
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256
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Grant JW, Taubman MB, Church SL, Johnson RL, Nadal-Ginard B. Mammalian nonsarcomeric myosin regulatory light chains are encoded by two differentially regulated and linked genes. J Biophys Biochem Cytol 1990; 111:1127-35. [PMID: 2391362 PMCID: PMC2116279 DOI: 10.1083/jcb.111.3.1127] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The myosin 20,000-D regulatory light chain (RLC) has a central role in smooth muscle contraction. Previous work has suggested either the presence of two RLC isoforms, one specific for nonmuscle and one specific for smooth muscle, or the absence of a true smooth muscle-specific isoform, in which instance smooth muscle cells would use nonmuscle isoforms. To address this issue directly, we have isolated rat RLC cDNAs and corresponding genomic sequences of two smooth muscle RLC based on homology to the amino acid sequence of the chicken gizzard RLC. These cDNAs are highly homologous in their amino acid coding regions and contain unique 3'-untranslated regions. RNA analyses of rat tissue using these unique 3'-untranslated regions revealed that their expression is differentially regulated. However, one cDNA (RLC-B), predominantly a nonmuscle isoform, based on abundant expression in nonmuscle tissues including brain, spleen, and lung, is easily detected in smooth muscle tissues. The other cDNA (RLC-A; see Taubman, M., J. W. Grant, and B. Nadal-Ginard. 1987. J. Cell Biol. 104:1505-1513) was detected in a variety of nonmuscle, smooth muscle, and sarcomeric tissues. RNA analyses comparing expression of both RLC genes with the actin gene family and smooth muscle specific alpha-tropomyosin demonstrated that neither RLC gene was strictly smooth muscle specific. RNA analyses of cell lines demonstrated that both of the RLC genes are expressed in a variety of cell types. The complete genomic structure of RLC-A and close linkage to RLC-B is described.
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Taniguchi M, Johnson RL, Ghijsen J, Cardona M. Core excitons and conduction-band structures in orthorhombic GeS, GeSe, SnS, and SnSe single crystals. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:3634-3643. [PMID: 9995878 DOI: 10.1103/physrevb.42.3634] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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258
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Ghijsen J, Tjeng LH, Eskes H, Sawatzky GA, Johnson RL. Resonant photoemission study of the electronic structure of CuO and Cu2O. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:2268-2274. [PMID: 9995674 DOI: 10.1103/physrevb.42.2268] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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259
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Sparks PJ, Simon GE, Katon WJ, Altman LC, Ayars GH, Johnson RL. An outbreak of illness among aerospace workers. West J Med 1990; 153:28-33. [PMID: 2098006 PMCID: PMC1002462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A multispecialty panel of physicians evaluated a case series of 53 composite-materials workers in a large aircraft manufacturing facility who filed workers' compensation claims for illness labeled by the media as the "aerospace syndrome." Possible skin and respiratory tract exposures included formaldehyde, phenol, particulates, epoxy resins, and trace organic solvents, but measured concentrations were well below all regulatory and consensus standards. Most workers had histories of transient skin or respiratory tract irritation consistent with the known potential toxicity of these materials. None of the workers tested had immunoglobulin IgG or IgE antibodies to human serum albumin complexed with formaldehyde. A majority (74%) met DSM-III-R [Diagnostic and Statistical Manual of Mental Disorders, 3rd edition, revised] criteria for major depression, panic disorder, or both. Most of these psychiatric disorders were of a recent onset, correlating in time with the use of phenol- and formaldehyde-impregnated composite material. Psychosocial factors were thought to have played a major role in the high prevalence of illness in this group and should be evaluated directly in well-controlled epidemiologic studies of similar crisis-building situations in the future.
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260
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Hsia CC, Carlin JI, Cassidy SS, Ramanathan M, Johnson RL. Hemodynamic changes after pneumonectomy in the exercising foxhound. J Appl Physiol (1985) 1990; 69:51-7. [PMID: 2394663 DOI: 10.1152/jappl.1990.69.1.51] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Pulmonary arterial pressure is higher during exercise after pneumonectomy than before. Several factors may contribute to the elevation, e.g., loss of vascular bed, overinflation of the remaining lung, and active pulmonary vasoconstriction. We measured hemodynamic changes during graded exercise in conditioned foxhounds and compared pulmonary pressure-flow relationships before and after left pneumonectomy. Pulmonary arterial pressure-flow relationship in the remaining lung is not altered by pneumonectomy, suggesting that the increase in pulmonary vascular resistance post-pneumonectomy is largely the passive consequence of increased pulmonary blood flow to the remaining lung. The potential for chronic hyperinflation of the remaining lung to increase pulmonary resistance after pneumonectomy may have been counterbalanced by a concomitant reduction in lung elastic recoil. Unexpectedly, both mean systemic blood pressure and hematocrit were higher with respect to cardiac output after pneumonectomy. Cardiac output and stroke volume at any given work load were lower after pneumonectomy than before, and heart rate response was unaltered. This pattern of responses suggests that increases in left and right ventricular afterload may have contributed to the reduction in cardiac output.
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261
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Chapman DD, Hodgman JE, Johnson RL, Matlin NM. Replacing the work of pediatric residents: strategies and issues. Pediatrics 1990; 85:1109-11. [PMID: 2339034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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262
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Johnson RL, Bontems RJ, Yang KE, Mishra RK. Synthesis and biological evaluation of analogues of Pro-Leu-Gly-NH2 modified at the leucyl residue. J Med Chem 1990; 33:1828-32. [PMID: 1971310 DOI: 10.1021/jm00168a045] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A series of analogues of Pro-Leu-Gly-NH2 (PLG) in which the leucine residue has been replaced with the aliphatic amino acids L-isoleucine, L-2-aminohexanoic acid (Ahx), L-2-aminopentanoic acid, and L-2-aminobutanoic acid and the aromatic amino acids L-phenylalanine, L-phenylglycine, L- and D-2-amino-4-phenylbutanoic acid, L-O-methyltyrosine, and L-4-nitrophenylalanine have been synthesized. These analogues were tested for their ability to enhance the binding of the dopamine receptor agonist 2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (ADTN) to striatal dopamine receptors. Two of the above analogues, Pro-Ahx-Gly-NH2 (3) and Pro-Phe-Gly-NH2 (6), showed significant activity in this assay system. Pro-Ahx-Gly-NH2 produced a 16% enhancement of ADTN binding at 0.1 microM, while Pro-Phe-Gly-NH2 enhanced the binding of ADTN by 31% at a concentration of 1 microM.
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Mailänder L, Dosch H, Peisl J, Johnson RL. Near-surface critical x-ray scattering from Fe3Al. PHYSICAL REVIEW LETTERS 1990; 64:2527-2530. [PMID: 10041735 DOI: 10.1103/physrevlett.64.2527] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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264
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Grey F, Feidenhans'l R, Pedersen JS, Nielsen M, Johnson RL. Pb/Ge(111)1 x 1: An anisotropic two-dimensional liquid. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:9519-9522. [PMID: 9993303 DOI: 10.1103/physrevb.41.9519] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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265
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Good SS, Koble CS, Crouch R, Johnson RL, Rideout JL, de Miranda P. Isolation and characterization of an ether glucuronide of zidovudine, a major metabolite in monkeys and humans. Drug Metab Dispos 1990; 18:321-6. [PMID: 1974193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A major metabolite of zidovudine (3'-azido-3'-deoxythymidine, AZT), which previously had not been observed in a variety of experimental animals, was identified in samples of plasma and urine from cynomolgus monkeys and a patient treated with AZT. The urinary recoveries of metabolite from the monkeys and the patient were, respectively, 1.5- and 6.9-fold higher than the recoveries of unchanged drug. The metabolite was purified in gram quantities from the urines of the monkeys and the patient and was identified enzymatically, using beta-glucuronidase and a specific inhibitor of the enzyme, as a glucuronide conjugate of AZT. The metabolite was formed in vitro by incubating AZT with preparations of human liver in the presence of UDP-glucuronic acid. In addition, the metabolite was prepared synthetically and physical characterizations--including microanalysis and UV, IR, NMR and mass spectra--of compound from all three sources were identical and confirmed the metabolite to be the 5'-O-beta-D-glucuronide of AZT.
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266
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Shaulsky G, Johnson RL, Shockcor JP, Taylor LC, Stark AA. Properties of aflatoxin-DNA adducts formed by photoactivation and characterization of the major photoadduct as aflatoxin-N7-guanine. Carcinogenesis 1990; 11:519-27. [PMID: 2108817 DOI: 10.1093/carcin/11.4.519] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Aflatoxin-DNA adducts were formed by microsomal and photoactivation, using nick-translated DNA labelled with 14C in each of the DNA bases [3H]AFB1 and [3H]AFB2. DNA adducts were analysed by HPLC of DNA hydrolysates, and were characterized as double labelled peaks with specific retention times. The only AF-DNA adducts which were detected in significant amounts were guanine adducts, irrespective of the type of aflatoxin used or the mode of its activation. No stable adduct with adenine, cytosine or thymine was detected. UV spectra, proton NMR spectroscopy and mass spectrometry are consistent with the notion that the major AFB1-DNA photoadduct is the N7-guanine adduct. This report provides direct evidence for the existence of aflatoxin photoadducts formed on DNA.
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267
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Blankenhorn DH, Johnson RL, Mack WJ, el Zein HA, Vailas LI. The influence of diet on the appearance of new lesions in human coronary arteries. JAMA 1990; 263:1646-52. [PMID: 2407875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The Cholesterol Lowering Atherosclerosis Study, a randomized, placebo-controlled trial of blood lipid lowering, demonstrated significant benefit in 2-year coronary angiograms. Using angiograms of subjects in the Cholesterol Lowering Atherosclerosis Study who received a placebo and 24-hour dietary recall data, we performed an epidemiologic study of risk factors for formation of new atherosclerotic lesions. Age and baseline plus on-trial lipid levels, blood pressure levels, and diet variables were included. Significant dietary energy sources were protein, carbohydrate, alcohol, total fat, and polyunsaturated fat. Each quartile of increased consumption of total fat and polyunsaturated fat was associated with a significant increase in risk of new lesions. Increased intake of lauric, oleic, and linoleic acids significantly increased risk. Subjects in the Cholesterol Lowering Atherosclerosis Study in whom new lesions did not develop increased dietary protein to compensate for reduced intake of fat by substituting low-fat meats and dairy products for high-fat meats and dairy products. These results indicate that when total and saturated fat intakes are reduced to levels recommended by the National Cholesterol Education Program, protein and carbohydrate are preferred substitutes for fat calories, rather than monounsaturated or polyunsaturated fat.
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268
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Feidenhans'l R, Grey F, Johnson RL, Mochrie SG, Bohr J, Nielsen M. Oxygen chemisorption on Cu(110): A structural determination by x-ray diffraction. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:5420-5423. [PMID: 9994413 DOI: 10.1103/physrevb.41.5420] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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269
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Tjeng LH, Meinders MB, Ghijsen J, Sawatzky GA, Johnson RL. Electronic structure of Ag2O. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:3190-3199. [PMID: 9994097 DOI: 10.1103/physrevb.41.3190] [Citation(s) in RCA: 317] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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270
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Barth J, Johnson RL, Cardona M, Fuchs D, Bradshaw AM. Dielectric function of CaF2 between 10 and 35 eV. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:3291-3294. [PMID: 9994120 DOI: 10.1103/physrevb.41.3291] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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271
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Hsia CC, Carlin JI, Wagner PD, Cassidy SS, Johnson RL. Gas exchange abnormalities after pneumonectomy in conditioned foxhounds. J Appl Physiol (1985) 1990; 68:94-104. [PMID: 2107172 DOI: 10.1152/jappl.1990.68.1.94] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Loss of a major portion of lung tissue has been associated with impaired exercise capacity, but the underlying mechanisms are not well defined. We studied the alterations in gas exchange during exercise before and after left pneumonectomy in three conditioned foxhounds. After pneumonectomy, minute ventilation and O2 consumption at comparable submaximal work loads were unchanged but arterial PCO2 at any work load was higher, implying that ventilatory response to CO2 was impaired. Arterial hypoxemia and an elevated alveolar-arterial O2 tension difference (AaDO2) developed during heavy exercise. Using the multiple inert gas elimination technique, we determined the distributions of ventilation-perfusion (VA/Q) ratios postpneumonectomy. Significant increase in VA/Q inequality developed during exercise while the foxhounds were breathing room air, accounting for an average of 42% of the total increase in AaDO2 while diffusion limitation accounted for 58%. While the animals were breathing hypoxic gas mixture, diffusion limitation accounted for an average of 88% of the total increase AaDO2. Cardiac output and O2 delivery were reduced at a given O2 consumption after pneumonectomy. After pneumonectomy, the animals reached O2 consumptions close to the maximum expected for normal dogs. Compensation for the impairment in O2 delivery post-pneumonectomy occurred mainly by an increase in hemoglobin concentration. Training probably played an important role in returning exercise capacity toward prepneumonectomy levels. We conclude that significant abnormalities in gas exchange develop during exercise after loss of 42% of lung tissue, but the animals demonstrate a remarkable ability to compensate for these changes.
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272
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Ongerth JE, Johnson RL, Macdonald SC, Frost F, Stibbs HH. Back-country water treatment to prevent giardiasis. Am J Public Health 1989; 79:1633-7. [PMID: 2817191 PMCID: PMC1349767 DOI: 10.2105/ajph.79.12.1633] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This study was conducted to provide current information on the effectiveness of water treatment chemicals and filters for control of Giardia cysts in areas where treated water is not available. Four filters and seven chemical treatments were evaluated for both clear and turbid water at 10 degrees C. Three contact disinfection devices were also tested for cyst inactivation. Filters were tested with 1-liter volumes of water seeded with 3 x 10(4) cysts of G. lamblia produced in gerbils inoculated with in vitro cultured trophozoites; the entire volume of filtrate was examined for cyst passage. Chemical treatments were evaluated at concentrations specified by the manufacturer and for contact times that might be expected of hikers (30 minutes) and campers (eight hours, i.e., overnight). Two of the four filter devices tested were 100 percent effective for Giardia cyst removal. Of the other two filters, one was 90 percent effective and the other considerably less effective. Among the seven disinfection treatments, the iodine-based chemicals were all significantly more effective than the chlorine-based chemicals. None of the chemical treatments achieved 99.9 percent cyst inactivation with only 30-minute contact. After an eight-hour contact each of the iodine but none of the chlorine preparations achieved at least 99.9 percent cyst inactivation. None of the contact disinfection devices provided appreciable cyst inactivation. Heating water to at least 70 degrees C for 10 minutes was an acceptable alternative treatment.
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273
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Anholm JD, Stray-Gundersen J, Ramanathan M, Johnson RL. Sustained maximal ventilation after endurance exercise in athletes. J Appl Physiol (1985) 1989; 67:1759-63. [PMID: 2600009 DOI: 10.1152/jappl.1989.67.5.1759] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Although impaired respiratory muscle performance that persists up to 5 min after exercise is stopped has been demonstrated during exhaustive exercise in normal young men, it is not known whether impaired respiratory muscle function follows endurance exercise to exhaustion in highly trained athletes. To study the effects of exercise on sustained maximal voluntary ventilation immediately after exercise, eight elite cross-country skiers performed a 4-min maximal sustained ventilation (MSV) test before and immediately after exhaustive exercise. Subjects were encouraged to maintain maximal ventilation (VE) throughout the MSV test. To encourage greater effort, rapid visual feedback of VE was provided on a computer terminal along with a target VE based on their 12-s maximum voluntary ventilation (MVV). The subjects (7 males, 1 female) were 18.5 +/- 0.9 yr old (mean +/- SD) and exercised for 62.5 +/- 16.7 min at 77 +/- 5% of their maximum oxygen consumption during which average VE was 106.7 +/- 24.2 l/min BTPS. The mean MVV was 196.0 +/- 29.9 l/min or 107% of their age- and height-predicted MVV. Before exercise the MSV was 86% of the MVV or 176.7 +/- 30.5 l/min, whereas after exercise the MSV was 90% of the MVV or 180.3 +/- 28.9 l/min (P = NS). The total volume of gas expired during the 4-min MSV was 706.7 +/- 121.9 liters before and 721.2 +/- 115.5 liters after exercise (P = NS). In this group of athletes, exhaustive exercise produced no deleterious effects on the ability to perform a 4-min MSV test immediately after exercise.
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274
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Johnson RL, Gill SL. U.S. needs a new vision of national health policy. HEALTH PROGRESS (SAINT LOUIS, MO.) 1989; 70:24-8. [PMID: 10293861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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275
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Johnson RL. A question of ethics. U.S. HEALTHCARE 1989; 6:27. [PMID: 10294238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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