Title Page
 Table of Contents
 List of Tables
 List of Figures
 Literature review
 Materials and methods
 Results and discussion
 Summary and conclusions
 Biographical sketch

Title: Whole-body retention and excretion of magnesium in humans
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00089543/00001
 Material Information
Title: Whole-body retention and excretion of magnesium in humans : I. Biological Half-life in normals and selected disease states; II. Radiation dosimetry.
Alternate Title: Magnesium in humans.
Physical Description: xi, 173 leaves. illus. 28 cm.
Creator: Roessler, Genevieve Schleret ( Dissertant )
Dunavant, Billy G. ( Thesis advisor )
Bolch, W. Emmet ( Reviewer )
Williams, Clyde M. ( Reviewer )
Putnam, Hugh ( Reviewer )
Whig, Robert E. ( Degree grantor )
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 1972
Subjects / Keywords: Environmental Engineering Sciences thesis Ph. D.
Dissertations, Academic -- UF -- Environmental Engineering Sciences
Magnesium -- Physiological effect
Abstract: Thirty-one whole-body retention and excretion measurements were made on 13 normal subjects and 12 patients with selected disease conditions to determine as accurately as possible the biological half-lives from a single intravenous administration of 28Mg int he form of MgCl2. the prime objective of this research was to contribute information to the currently sparse knowledge on magnesium metabolism in humans. Calculation of radiation dose based on the determined half-lives was an important aspect of the research since the experimental use of 28Mg is increasing rapidly and o dose estimates have been established. the feasibility of this measurement technique for studying abnormalities in disease conditions was also explored. A high specific activity (200-300 microcuries per milligram magnesium) preparation of the radioactive isotope 28Mg (21.3-hour physical half-life) was used in conjunction with the sensitive 4-pi liquid scintillation whole-body counting technique for retention measurements. A NaI(Tl) crystal whole-body counter was employed to measure localization of the magnesium in the body and appropriate low-level counting systems were used for measurement of the isotope in excreta. Whole-body retention data from the determinations of normal subjects were fit to a sum of two exponentials model. The coefficients of the resultant equation are 8.5 and 91.5 and represent the quantities in per cent involved in the turnover of the two compartments. Biological half-lives of 5.4 +/- 2.2 hours for the first compartment and 540 +/- 35 hours for the second compartment were calculated from the rate constants in the exponents of the fitted equation. The radiation dose from this single administration of the 28Mg was calculated to be 2.0 mrad/microcurie. In the normal subjects, excretion measurements on the average accounted for the amount of the 28Mg not retained in the body. Cumulative urinary excretion averaged 3 per cent per day while fecal excretion was approximately 0.5 per cent per day. Whole-body retention values for amyotrophic lateral sclerosis and sub-total gastrectomy patients were significantly lower than normal, while several subjects, one of whom was known to have been on diuretics, had higher than normal retention of the isotope. Repaired gastrectomy patients had retention patterns within the normal range. In the majority of the patients studied, the abnormal retention of the 28Mg was accounted for by amounts int he excreta. However, in several patients, excretion did not account for the total amount of the isotope not retained in the body, resulting in a deficit int he total-measure 28Mg. localization of the isotope in the body as measured by NaI(Tl) crystal whole-body counting showed consistent patterns between results of the normal subjects. An atypical build-up of the isotope was found in the abdominal region of the amyotrophic lateral sclerosis patient who previously exhibited an apparent precipitous whole-body loss of 28Mg. Based on published investigations to date, it is concluded that this turnover study is currently the most accurate. the use of a true tracer dose of 10 microcuries or less of high specific activity 28Mg and the sensitive whole-body counting system allowed administration of a dose which would not upset the physio-chemical balance of the body. also, this procedure permitted measurements up tot six times longer than previously reported studies. The amount of 28Mg to be administered in future investigations with this isotope should be guided by the 2.0 mrad/microcurie dose calculated from the data obtained in this study. Based on the consistent, significantly abnormal retention and excretion patterns shown by certain disease-state measurements in this study, it is concluded that this turnover procedure could serve as a valuable adjunct to other diagnostic techniques.
Additional Physical Form: Also available on World Wide Web
General Note: Typescript.
General Note: Vita.
Thesis: Thesis -- University of Florida.
Bibliography: Bibliography: leaves 158-172.
 Record Information
Bibliographic ID: UF00089543
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 13987388
alephbibnum - 000577531

Table of Contents
    Title Page
        Page i
        Page ii
        Page iii
    Table of Contents
        Page iv
        Page v
    List of Tables
        Page vi
    List of Figures
        Page vii
        Page viii
        Page ix
        Page x
        Page xi
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
    Literature review
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
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        Page 27
        Page 28
        Page 29
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        Page 32
    Materials and methods
        Page 33
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    Results and discussion
        Page 61
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    Summary and conclusions
        Page 113
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    Biographical sketch
        Page 173
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