BioImpedance Analysis

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Authors - M

Madden, R.H.; Gilmour, A.
Title   Impedance as an alternative to MPN enumeration of coliforms
        in pasteurized milks
Journal Letters in Applied Microbiology
        21
        6
        DEC
Year    1995
Page    387-388
Address RH Madden
        Queens Univ Belfast
        Dept Agr No Ireland
        Newforge Lane
        Belfast BT9 5PX
        Antrim, North Ireland
Serial# 0266-8254
Keys    ANIMAL PROTEIN; SALMONELLA
Abs.    Samples (900) of pasteurized whole, semi-skimmed and
        skimmed milk were subjected to conventional enumeration of
        coliforms bf a nine-tube most probable number (MPN)
        technique, and impedance enumeration, in parallel.
        Regression analysis of the positive samples (98) showed
        that impedance enumeration was at least as accurate as the
        MPN method but results were obtained faster, with all
        testing being completed in 20 h, rather than 48 h.
        Consumable requirements, and staffing levels, were also
        much less with the impedance system. The impedance method
        could therefore beneficially replace the conventional
        method.

Maggiore, Q.; Nigrelli, S.; Ciccarelli, C.; Grimaldi, C.;
        Rossi, G.A.; Michelassi, C.
Title   Nutritional and prognostic correlates of bioimpedance indexes
        in hemodialysis patients
Journal Kidney International
        50
        6
        DEC
Year    1996
Page    2103-2108
Address Q Maggiore
        S Maria Annunnziata Hosp
        Dialysis & Nephrol Unit
        Usl 10
        I-50011 Florence, Italy
Serial# 0085-2538
Keys    BIOELECTRICAL-IMPEDANCE ANALYSIS; TOTAL-BODY WATER;
        SUBJECTIVE GLOBAL ASSESSMENT; DIALYSIS PATIENTS; MASS
        ESTIMATION; PREDICTOR; KINETICS
Abs.    We carried out a cross sectional and longitudinal study to
        assess whether bioimpedance indexes (resistance, Rz;
        reactance, Xc; phase angle, PA) reflect the nutritional
        status of hemodialysis (HD) patients, and bear a
        significant association with their long-term survival. The
        bioimpedance data of 131 patients on chronic HD treatment
        were compared with those of 272 healthy controls matched
        for age and sex. Nutritional status was assessed by
        anthropometric variables, serum albumin (SA), normalized
        protein catabolic rate (nPCR), and subjective global
        assessment (SGA). All three bioimpedance indexes varied
        significantly with HD treatment, however, with the
        exception of Xc in post-HD, they were on average
        significantly (P <0.016) different from controls either pre-
        and post-HD. Post-HD PA appeared to be the best index of
        nutritional status, being significantly correlated with SA,
        age, mid arm muscle circumference (MAMC), SGA, and nPCR
        (R(2)=0.44; P <0.01). However, depending on the cut-off
        levels, PA failed to detect clinically overt malnutrition
        in one to two thirds of the 12 patients with the worst SGA
        score. During the follow-up the changes in bioimpedance
        indexes reflected poorly the changes in dry body weight,
        only the Delta Rz bore a significant correlation (r=-0.29;
        P <0.01) with Delta body wt. Patients having baseline phase
        angle values within the lower quartile had a significantly
        lower two-year survival rate than patients having higher
        values (59.3% vs. 91.3%; P <0.01). Cox's analysis
        proportional hazard model) showed that phase angle as a
        predictor of death outweighed all other parameters included
        in the model (age, SG nPCR, MAMC, SGA), with a relative
        risk of 2.6 (95% CI=1.6 to 4.2). Bioimpedance indexes do
        not appear to be reliable in detecting clinically overt
        depletion of lean body mass. However, the strong
        association of PA with patient survival suggests that this
        bioimpedance index reflects some dimension of the illness,
        which is not fully identifiable with the deranged
        nutritional status.

Author Mannix, E.T.; Farber, M.O.; Aronoff, G.R.; Brier, M.E.;
        Weinberger, M.H.; Palange, P.; Manfredi, F.
Title   Hemodynamic, renal, and hormonal responses to lower body
        positive pressure in human subjects
Journal Journal of Laboratory and Clinical Medicine
        128
        6
        DEC
Year    1996
Page    585-593
Address ET Mannix
        Indiana Univ
        Sch Med
        Dept Med
        Vet ADM Med Ctr 151
        1481 W 10TH St
        Indianapolis, IN 46202 USA
Serial# 0022-2143
Keys    ATRIAL NATRIURETIC FACTOR; G SUIT INFLATION; OBSTRUCTIVE LUNG-
        DISEASE; ANTI-SHOCK TROUSERS; IMPEDANCE CARDIOGRAPHY; WATER-
        EXCRETION; KIDNEY-FUNCTION; BLOOD-PRESSURE; RENIN RELEASE;
        PLASMA
Abs.    Studies in healthy human subjects subjected to lower body
        positive pressure (LBPP) have failed to elucidate many of
        the physiologic effects of this maneuver. In 7 healthy,
        well-hydrated men we studied the following responses to
        LBPP (35 mm Hg, 1 hour, supine position): systemic and
        renal hemodynamics; urine volume (UV), urine osmolality
        (Uosm), and urine sodium level (UNaV); free water (CH20)
        and osmolar (Cosm) clearances; plasma renin activity (PRA);
        levels of aldosterone (PA), cortisol (CORT), norepinephrine
        (NE), atrial natriuretic peptide (ANP), and vasopressin
        (AVP); osmolality (Posm); and serum sodium revel. Subjects
        were restudied on a control day with zero trouser pressure.
        The recorded changes (p < 0.05) when comparing the LBPP day
        with the control day were as follows: fractional Na+
        reabsorption increased (98.7% +/- 0.2% to 99.3% +/- 0.1%)
        and UNaV decreased (0.19 +/- 0.03 mEq/min to 0.10 +/- 0.01
        mEq/min), with concomitant increases in PRA (1.7 +/- 0.2
        ng/ml/90 min to 4.5 +/- 1.8 ng/ml/90 min), PA (7.7 +/- 0.7
        ng/dl to 9.3 +/- 1.5 ng/dl), and CORT (13.0 +/- 2.6 mg/dl
        to 19.2 +/- 3 mg/dl); the increase in blood pressure with
        LBPP (96 +/- 3 mm Hg to 112 +/- 4 mm Hg) was greater than
        that during control conditions. Renal plasma flow tended to
        display an interactive pattern across days, with ct slight
        decline during LBPP (5%) and a slight elevation under
        control conditions (9%). On the LBPP day only, filtered Na+
        declined (15 +/- 1 mEq/min to 12 +/- 1 mEq/min) as a
        function of reduced glomerular filtration rate (112 +/- 5
        ml/min to 91 +/- 7 ml/min), blood volume decreased (by 2.7%
        +/- 0.7%), CO decreased (5.5 +/- 0.3 L/min to 4.7 +/- 0.3
        L/min), and stroke volume declined (101 +/- 6 ml to 84 +/-
        3 ml). On both days, NE increased (control, 221 +/- 23
        pg/ml to 340 +/- 33 pg/ml; L8PP, 236 +/- 17 pg/ml to 369 +/-
        31 pg/mD and ANP increased (control, 47 +/- 7 pg/ml to 97
        +/- 21 pg/ml; LBPP, 49 +/- 10 pg/ml to 104 +/- 30 pg/ml).
        We concluded that LBPP reduces renal sodium excretion. The
        mechanism for this reduction is not known, although it did
        occur in association with an increase in plasma renin
        activity, which in turn results from mechanical reduction
        of renal perfusion, stress-related CORT stimulation, a
        reflex-based elevation in peripheral vascular resistance
        leading to a reflex increase in plasma renin activity, or a
        combination of these.

Martinsen, O.G.; Grimnes, S.; Karlsen, J.
Title   Electrical methods for skin moisture assessment
Journal Skin Pharmacology
        8
        5
        SEP-OCT
Year    1995
Page    237-245
Address OG Martinsen
        Univ Oslo
        Dept Phys
        POB 1048
        N-0316 Oslo, Norway
Serial# 1011-0283
Keys    moisture, skin; hydration, skin; three-electrode system;
        electrical admittance
        IMPEDANCE; ELECTRODES; HYDRATION; MOISTURIZATION; ADMITTANCE
Abs.    Skin sites on 8 test subjects were treated with
        moisturizers, and different electrical measuring methods
        were compared regarding their quality in the assessment of
        the induced changes in the stratum corneum hydration level.
        Low frequency susceptance measurements were found
        preferable to high frequency admittance measurements, and
        the advantages of monopolar measurements with the three-
        electrode system are described.

Matthie, J.R.; Withers, P.O.
Title   Segmental vs whole body multifrequency bioimpedance
        measurements
Journal Journal of Applied Physiology
        79
        6
        DEC
Year    1995
Page    2177-2178
Address JR Matthie
        Xitron Technol Inc
        San Diego, CA 92121 USA
Serial# 8750-7587

Matthie, J.R.; Withers, P.O.
Title   The ambiguities of predicting total body water and body cell
        mass with a single frequency (50KHz) measurement of
        bioimpedance
Journal Journal of the American Society of Nephrology
        6
        6
        DEC
Year    1995
Page    1682-1685
Address JR Matthie
        Xitron Technol Inc
        6296 Ferris Sq
        Suite D
        San Diego, CA 92121 USA
Serial# 1046-6673
Keys    IMPEDANCE

Marven, S.S.; Hampshire, A.R.; Smallwood, R.H.; Brown, B.H.;
        Primhak, R.A.
Title   Reproducibility of electrical impedance tomographic
        spectroscopy (EITS) parametric images of neonatal lungs
Journal Physiological Measurement
        17
         Suppl. 4A
        NOV
Year    1996
Page    A205-A212
Address SS Marven
        Univ Sheffield
        Sheffield Childrens Hosp
        Dept Paediat
        Stephenson Bldg
        Sheffield S10 2TN
        S Yorkshire, England
Serial# 0967-3334
Keys    MULTIFREQUENCY
Abs.    The reproducibility of electrical impedance tomographic
        spectroscopy (EITS) images of neonatal lungs have been
        investigated in 11 clinically stable babies. We have used
        the Sheffield Mark IIIa EITS system. An average inspiration
        frame was generated from the data frames associated with
        maximum inspiration. Frequency images were reconstructed
        from these frames. The frequency images were analysed to
        locate the pixel with the maximum change in the right lung
        field. The change was defined as the 614 kHz measurement
        relative to 9.6 kHz. A 3 x 3 pixel region of interest was
        centred at this point. The changes in impedance with
        frequency for this region of interest show good overall
        reproducibility between electrode applications for eight
        frequencies (95% limits of agreement +/-28%). This
        reproducibility is improved (95% limits of agreement +/-
        13%) by omitting the highest frequency (1.2 MHz) which is
        most subject to system noise. The parameters for the Cole
        model derived from data with the highest frequency omitted
        are less reproducible between electrode applications (95%
        limits of agreement, R/S +/- 0.83, f(c) +/- 81.6, RC +/-
        0.52, SC +/- 0.39). We suspect that the parametric model
        used may have an effect on this. The signals recorded at
        the highest frequency (1.2 MHz) are a major source of
        variability. The reproducibility results are improved by
        omitting this frequency from the analysis.

Mazariegos, M.; Valdez, C.; Kraaij, S.; Vansetten, C.;
        Luirink, C.; Breuer, K.; Haskell, M.; Mendoza, I.;
        Solomons, N.W.; Deurenberg, P.
Title   Comparative body composition estimates for institutionalized
        and free-living elderly in metropolitan areas of the Republic
        of Guatemala
Journal Nutrition Research
        16
        3
        MAR
Year    1996
Page    443-457
Address M Mazariegos
        Hosp Ojos & Oidos Dr Rodolfo Robles
        Cessiam
        Diagonal 21
        19-19 Zona 11
        Guatemala City 01011, Guatemala
Serial# 0271-5317
Keys    aging and nutrition; body composition; anthropometry;
        bioelectrical impedance; Guatemala
        BIOELECTRICAL IMPEDANCE ANALYSIS; DEVELOPING-COUNTRIES;
        NUTRITIONAL-STATUS; CROSS-VALIDATION; MASS; FAT
Abs.    Elderly populations from developing countries represent two-
        thirds of the whole world's elderly population; however
        very little is known respect their health and nutritional
        status. Guatemala has a population of almost 10 million
        inhabitants, and approximately 6% is composed of persons
        over 60 y. The objectives of the present study were to
        evaluate the nutritional status and the body composition
        profile in a group of 234 Guatemalan elderly subjects; and
        to document any differences between institutionalized (I)
        (n=174) and ambulatory free-living elderly subjects (FL)
        (n=60). A total of 108 were male and 126 female. The mean
        (+/- SD) ages of male and female were respectively, 78 +/-
        7 and 77 +/- 8 y; the I group tended to be older than to FL:
        79 +/- 8 vs 74 +/- 8 y. Anthropometric measurements
        included weight, height, mid-arm circumference and four
        skinfolds (triceps, biceps, subscapular and suprailiac);
        these were complemented with bioelectrical impedance
        analysis indices: resistance and reactance. The overall
        means (+/- SD) in terms of height, weight and BMI For males
        and females, respectively were 156.4 +/- 8.0 and 144 +/- 7
        cm; 54.5 +/- 9.4 and 49.4 +/- 10.6 kg; and 22.2 +/- 2.9 and
        23.8 +/- 4.3 kg/m(2). As it was expected males were taller
        and heavier compared to women. After adjusting for age, sex
        and setting, I younger elderly were fattier than their
        counterparts (FL); however, older FL groups differed only
        in having more weight and greater mid-arm muscle area
        compared to I. An age effect was observed principally in
        older I women, showing less weight and fat than younger
        groups, while free-living older groups had more weight and
        greater BIA-body fat compared to younger FL. In conclusion,
        I and FL differed in terms of body composition, and the
        differences were age dependent. BIA and anthropometry
        showed high correspondence and to be sensitive to
        demonstrate the findings in the expected direction. Due to
        the high specificity of the published BIA-equations,
        attention should be paid when estimating body composition
        in elderly populations of developing countries.

Mcadams, E.T.; Jossinet, J.
Title   Tissue impedance: A historical overview
Journal Physiological Measurement
        16
         Suppl. 3A
        AUG
Year    1995
Page    A1-A13
Address ET Mcadams
        Univ Ulster
        No Ireland Bioengn Ctr
        Jordanstown BT37 0QB
        Antrim, North Ireland
Serial# 0967-3334
Abs.    Over the past 150 years the study of the electrical
        properties of various biological tissues has been
        undertaken by researchers from a wide variety of scientific
        backgrounds. This has, unfortunately, led to the existing
        range of confusing and misunderstood terminology/concepts.
        Some of the most important are presented and explained.

Mcadams, E.T.; Jossinet, J.
Title   Problems in equivalent circuit modelling of the electrical
        properties of biological tissues
Journal Bioelectrochemistry and Bioenergetics
        40
        2
        AUG
Year    1996
Page    147-152
Address ET Mcadams
        Univ Ulster
        No Ireland Bioengn Ctr
        Jordanstown BT37 0QB
        Antrim, North Ireland
Serial# 0302-4598
Keys    biological tissues; electrical properties; equivalent circuit
        modelling
        IMPEDANCE
Abs.    There has been a noticeable increase in the recent
        literature in the use of empirical ''constant phase angle''
        impedances to model the observed a.c. impedances of a wide
        range of materials and interfaces (including biological
        tissues and electrode-tissue interfaces), thus highlighting
        the basic similarities in their electrical characteristics.
        Unfortunately, a range of basic mistakes, misnomers and
        naiveties appear to have become accepted as part of the
        established science associated with this potentially
        attractive technique. There is a disconcerting lack of a
        clear understanding of the limitations inherent in the use
        of a.c. impedance spectroscopy, especially when employed in
        tandem with equivalent circuit modelling. It seems that the
        importance of choosing an appropriate model, testing its
        validity and limitations and comparing experimental and
        theoretical data on optimal plots is not widely
        appreciated.
        It is to be regretted Bat the relevance of a large amount
        of otherwise good work presented in the literature is open
        to question. Some of the common problem areas are briefly
        reviewed in this paper.

Author Mcadams, E.T.; Jossinet, J.; Lackermeier, A.; Risacher, F.
Title   Factors affecting electrode-gel-skin interface impedance in
        electrical impedance tomography
Journal Medical & Biological Engineering & Computing
        34
        6
        NOV
Year    1996
Page    397-408
Address ET Mcadams
        Univ Ulster
        No Ireland Bioengn Ctr
        Jordanstown BT37 0QB
        Antrim, North Ireland
Serial# 0140-0118
Keys    EIT; electrodes; electro-osmosis; electroporation;
        penetration enhancers; skin preparation; temperature
        TRANSDERMAL DRUG-DELIVERY; PHYSICAL INTERPRETATION; MAMMALIAN
        SKIN; ELECTROPORATION; LINEARITY; SYSTEMS; FLOW
Abs.    The magnitude, mismatch and temporal variations of the
        electrode-gel-skin interface impedance can cause problems
        in electrical impedance tomography (EIT) measurement. It is
        shown that at the high frequencies generally encountered in
        EIT the capacitive properties of the electrode interface,
        and especially those of the skin, are of primary
        importance. A wide range of techniques are reviewed that
        could possibly be used to minimise these problems. These
        techniques include the use of skin preparation, penetration
        enhancers, temperature and electrical impulses. Although
        several of these techniques appear very attractive, they
        are not without serious potential drawbacks. A combination
        of some of these techniques may well hold the key to
        success.

Author   - McRae DA
Author   - Esrick MA
Author   - Mueller SC
Title    - Non-invasive, in-vivo electrical impedance of EMT-6
           tumours during hyperthermia: Correlation with morphology
           and tumour-growth-delay.
         - English
         - Article
         - McRae DA, Georgetown Univ, Dept Radiat Med, Washington,DC
           20057 USA
         - The electrical impedance at frequencies from 100Hz to
           40MHz of EMT-6 tumours was measured non-invasively, in
           vivo, during hyperthermia using an apparatus constructed
           for this purpose. Histology and morphometry were performed
           on tumours harvested periodically during the heating. A
           ratio of conductivities at two frequencies
           (sigma(10MHz)/sigma(10KHz)), which minimizes the tissue
           temperature-coefficient effects, was used to correlate
           impedance changes with the histopathological changes. The
           bulk of the cell population followed a necrotic cell death
           sequence during the heating. Initial increase of the sigma-
           ratio correlated with cell swelling, and a reversal of the
           rate of this increase correlated with the appearance of
           small membrane breaks and evidence of mitochondrial
           damage. A continued, slowing sigma-ratio increase to a
           maximum correlated with continued cell swelling
           accompanied by increasing membrane disruption. The
           subsequent decrease in sigma-ratio correlated with
           continued general cell lysing. Between the appearance of
           the first membrane breaks (sigma-ratio rate peak) and the
           evidence of general lysing (sigma-ratio peak), the tumour-
           growth-delay increased non-linearly. Because the sigma-
           ratio consistently discerned these events, these
           measurements were able to predict the fate of this cell
           population when subjected to hyperthermia. Knowledge of
           temperature or time of heating was not required.
Journal - Int J Hyperthermia 1997 JAN-FEB;13(1):1-20

Meeson, S.; Blott, B.H.; Killingback, A.L.T.
Title   EIT data noise evaluation in the clinical environment
Journal Physiological Measurement
        17
         Suppl. 4A
        NOV
Year    1996
Page    A33-A38
Address S Meeson
        Univ Southampton
        Dept Phys
        Southampton SO17 1BJ
        Hants, England
Serial# 0967-3334
Keys    SPECTRAL EXPANSION
Abs.    In the clinical environment the reliable interpretation of
        EIT images depends on the quality of the data. In the
        electrically noisy hospital environment the system
        performance needs to be assessed for each clinical
        investigation. From the model of noise presented, a figure
        of merit for comparisons of system performance with a known
        standard, or with previous studies, can be generated. The
        method depends on calculating the variances of the
        differences in reciprocity measurements as a function of
        the distance between the current drive electrodes and the
        receive voltage electrodes. These measurements fit the
        noise model, with minimal interference from physiological
        variability, and permit a figure of merit to be calculated
        which is a representation of the noise at the input to the
        system. Typical figures of merit are 7.36 +/- 0.03 mu V for
        a test card and 10.50 +/- 0.16 mu V for subject data.

Meeson, S.; Killingback, A.L.T.; Blott, B.H.; Mitchell, C.;
        Evans, D.F.; Milla, P.J.
Title   Optimal filtering of EIT data in spectral expansion analysis
Journal Physiological Measurement
        17
         Suppl. 4A
        NOV
Year    1996
Page    A85-A90
Address S Meeson
        Univ Southampton
        Dept Phys
        Southampton SO17 1BJ
        Hants, England
Serial# 0967-3334
Abs.    The signal-to-noise ratios for some EIT measurements are
        very low, and for in vivo EIT measurements these ate
        dependent on the electrode positioning and the distance
        from the current drive. The effect of removing noisy
        measurements to produce higher-fidelity images was
        investigated for the case of gastric emptying data. A
        consequence of this filtering was the reduction in the size
        of the sensitivity matrix and its subsequent singular-value
        decomposition. Several different filters were tested and
        for each of these the spectral expansion regularization
        filter was optimized using a chi(2) test. Filtering out the
        measurements made by the spinal electrode, where the spinal
        bone barrier lies directly in the current path to the
        stomach, produced improved images by reducing the artefact
        content in the spinal sector of the conductivity map. For
        stomach imaging little useful information is produced by
        the spinal electrode, and the benefits of filtering
        dominate. However artefact images may be generated. In
        contrast consistent small improvements were produced by
        filtering out some of the weakest signals.

Metherall, P.; Barber, D.C.; Smallwood, R.H.; Brown, B.H.
TI Three-dimensional electrical impedance tomography
SO Nature
VL 380
IS 6574
DA APR 11
YR 1996
PG 509-512
AF P Metherall
   Univ Sheffield
   Royal Hallamshire Hosp
   Dept Med Phys & Clin Engn
   Glossup Rd
   Sheffield S10 2JF
   S Yorkshire, England
SN 0028-0836
KW APPLIED POTENTIAL TOMOGRAPHY
NO THE electrical resistivity of mammalian tissues varies
   widely(1-5) and is correlated with physiological function(6-
   8). Electrical impedance tomography (EIT) can be used to
   probe such variations in vivo, and offers a non-invasive
   means of imaging the internal conductivity distribution of
   the human body(9-11). But the computational complexity of
   EIT has severe practical limitations, and previous work has
   been restricted to considering image reconstruction as an
   essentially two-dimensional problem(10,12). This
   simplification can limit significantly the imaging
   capabilities of EIT, as the electric currents used to
   determine the conductivity variations will not in general
   be confined to a two-dimensional plane(13), A few studies
   have attempted three-dimensional EIT image
   reconstruction(14,15), but have not yet succeeded in
   generating images of a quality suitable for clinical
   applications. Here we report the development of a three-
   dimensional EIT system with greatly improved imaging
   capabilities, which combines our 64-electrode data-
   collection apparatus(16) with customized matrix inversion
   techniques. Our results demonstrate the practical potential
   of EIT for clinical applications, such as lung or brain
   imaging and diagnostic screenings.

Mitchell, I.M.; Davies, P.S.W.; Pollock, J.C.S.;
        Jamieson, M.P.G.
Title   Total body water in children with congenital heart disease,
        before and after cardiac surgery
Journal Journal of Thoracic and Cardiovascular Surgery
        110
        3
        SEP
Year    1995
Page    633-640
Address IM Mitchell
        City Hosp Nottingham
        Dept Cardiothorac Surg
        Hucknall Rd
        Nottingham NG5 1PB, England
Serial# 0022-5223
Keys    DOUBLY-LABELED-WATER; BIOELECTRICAL IMPEDANCE; INFANTS;
        OPERATIONS; VALIDATION
Abs.    The aim of this study was to measure total body water in
        children with congenital heart disease before and after
        cardiac surgery and to compare the results of deuterium and
        (18)oxygen dilution methods, Seventeen children (aged 4 to
        33 months) were given aliquots of isotopically labeled
        water 1 week before and 6 hours after cardiac surgery,
        Isotope equilibration and analysis of the declining
        enrichment of daily urine samples allowed calculation of
        the total body water content, Before operation, total body
        water was significantly elevated (p < 0.001, Wilcoxon test);
        after operation it fell to approximately normal values.
        This finding is in contrast to those of previous reports,
        but may be explained in that the method used for
        calculation depended on measurements taken over a 7-day
        period rather than on a single measurement of isotope
        dilution as used elsewhere, Nevertheless, these results do
        suggest that surgery can correct the preoperative fluid
        overload, Comparison of deuterium and (18)oxygen dilution
        methods showed a 2% to 2.5% overestimation of the total
        body water content with deuterium sampling.

Mizobata-Y; Rounds-J-D; Prechek-D; Derosa-E; Wilmore-D-W; Jacobs-D-O
31P magnetic resonance spectroscopy demonstrates expansion of the
extracellular space in the skeletal muscle of starved rats.
Journal of Surgical Research 56(6): 491-499
1994
English
Starvation significantly alters the distribution of body water. To
study the effects of starvation on cellular energetics and water
distribution in skeletal muscle, a novel 31P magnetic resonance
technique (31P MRS) was developed to measure water compartments.
After 31P MRS-visible water space markers which distribute in
total body water (dimethyl methylphosphonate, DMMP) and
extracellular water (phenylphosphonate, PPA) were infused
intravenously, 31P MRS spectra were obtained from the
gastrocnemius muscle of male virus-free Wistar rats at baseline
and after starvation or ad libitum feeding for 4 days. Muscle
water spaces were also measured using the chloride method and
Nernst's equation. Muscle water contents as determined by drying
were equivalent in the two groups. In vivo measurements of changes
in DMMP relative to all of the MRS visible phosphates also
demonstrated that the total water space was similar in control and
starved rats. However, starvation significantly increased the
ratio of PPA/DMMP (0.67 +- 0.05 vs 0.87 +- 0.04, Control vs
Starvation; P lt 0.001), and therefore the ratio of extracellular
water to total water in the gastrocnemius. Furthermore, because
muscle water contents were comparable between the groups, this
expansion of the extracellular space was accompanied by
contraction of the intracellular compartment in starved animals.
Equivalent changes were detected in vitro using the chloride
method. Lastly, phosphocreatine/ATP ratios, which measured changes
in high-energy phosphate stores, decreased after starvation (4.09
+- 0.06 vs 3.61 +- 0.06; P lt 0.001) and were inversely related to
changes in PPA/DMMP (r = -0.61; P lt 0.001). We conclude that
starvation alters the distribution of water within skeletal muscle
and these changes are related to the depletion of energy stores.
These phenomena can be studied simultaneously in a noninvasive
fashion using in vivo 31P MRS and MRS-visible water space markers.

Mizobata-Y; Rounds-J-D; Prechek-D; Derosa-E; Wilmore-D-W; Jacobs-D-O
31P magnetic resonance spectroscopy demonstrates expansion of the
extracellular space in the skeletal muscle of starved rats.
Journal of Surgical Research 56(6): 491-499
1994
English
Starvation significantly alters the distribution of body water. To
study the effects of starvation on cellular energetics and water
distribution in skeletal muscle, a novel 31P magnetic resonance
technique (31P MRS) was developed to measure water compartments.
After 31P MRS-visible water space markers which distribute in
total body water (dimethyl methylphosphonate, DMMP) and
extracellular water (phenylphosphonate, PPA) were infused
intravenously, 31P MRS spectra were obtained from the
gastrocnemius muscle of male virus-free Wistar rats at baseline
and after starvation or ad libitum feeding for 4 days. Muscle
water spaces were also measured using the chloride method and
Nernst's equation. Muscle water contents as determined by drying
were equivalent in the two groups. In vivo measurements of changes
in DMMP relative to all of the MRS visible phosphates also
demonstrated that the total water space was similar in control and
starved rats. However, starvation significantly increased the
ratio of PPA/DMMP (0.67 +- 0.05 vs 0.87 +- 0.04, Control vs
Starvation; P lt 0.001), and therefore the ratio of extracellular
water to total water in the gastrocnemius. Furthermore, because
muscle water contents were comparable between the groups, this
expansion of the extracellular space was accompanied by
contraction of the intracellular compartment in starved animals.
Equivalent changes were detected in vitro using the chloride
method. Lastly, phosphocreatine/ATP ratios, which measured changes
in high-energy phosphate stores, decreased after starvation (4.09
+- 0.06 vs 3.61 +- 0.06; P lt 0.001) and were inversely related to
changes in PPA/DMMP (r = -0.61; P lt 0.001). We conclude that
starvation alters the distribution of water within skeletal muscle
and these changes are related to the depletion of energy stores.
These phenomena can be studied simultaneously in a noninvasive
fashion using in vivo 31P MRS and MRS-visible water space markers.

Moller, J.; Jorgensen, J.O.L.; Frandsen, E.; Laursen, T.; Christiansen, J.S.
Title   Body fluids, circadian blood pressure and plasma renin during
        growth hormone administration: A placebo-controlled study
        with two growth hormone doses in healthy adults
Journal Scandinavian Journal of Clinical & Laboratory Investigation
        55
        8
        DEC
Year    1995
Page    663-669
Address J Moller
        Aarhus Kommune Hosp
        Med Dept M
        DK-8000 Aarhus C, Denmark
Serial# 0036-5513
Keys    diurnal blood pressure; extracellular volume; growth hormone;
        plasma volume; renin; total body water
        ANGIOTENSIN-ALDOSTERONE SYSTEM; DEFICIENT ADULTS;
        EXTRACELLULAR VOLUME; THYROID-FUNCTION; SODIUM; STIMULATION;
        METABOLISM; EXPANSION; CHILDREN; THERAPY
Abs.    Side effects that can be related to fluid retention are
        common during the initial phases of growth hormone (GH)
        administration. The aim of this study was to examine the
        changes in body fluid compartments, diurnal blood pressure
        and plasma renin concentration during GH administration
        with two different dosages in healthy adults. Eight healthy
        male subjects aged 24-32 years were examined during three 2-
        week study periods in a double-blind placebo controlled
        study. They received, in random order, GH (3 or 6 IU m(-2)
        daily) or placebo during 2 weeks. Bio-impedance was
        measured every 2nd day, and extracellular volume (ECV) and
        plasma volume (PV) were isotopically determined at day 6.
        Blood samples were obtained regularly. Diurnal blood
        pressure was recorded and 24-h urinary samples were
        collected at days 0, 6 and 14. ECV (1) was increased by GH
        (placebo, 19.58 +/- 0.82; 3 IU m(-2), 20.77 +/- 1.22; 6 IU
        m(-2), 20.65 +/- 0.94; p<0.01), whereas PV (1) was
        unaffected (placebo, 3.91 +/- 0.20; 3 IU m(-2) 4.04 +/-
        0.22; 6 IU m(-2), 3.90 +/- 0.27). Total body water (1)
        increased significantly during GH administration (placebo,
        50.8 +/- 2.6; 3 IU m(-2), 52.6 +/- 2.3; 6 IU m(-2) 53.9 +/-
        1.8, p<0.05). After 6 days of treatment a significant
        increase in renin (p=0.03) was observed. Mean diurnal blood
        pressure levels remained unchanged, whereas mean diurnal
        heart rate (min(-1)) increased significantly (placebo, 75
        +/- 3.6; 3 IU m(-2), 79 +/- 3.2; 6 IU m(-2), 79 +/- 3.7;
        p<0.01). In conclusion, GH administration induces an
        elevation in total body water which may involve a
        stimulation of plasma renin and an increased ECV without
        any changes in PV or diurnal blood pressure.

Morucci, J.P.; Granie, M.; Lei, M.; Chabert, M.; Marsili, P.M.
Title   3D reconstruction in electrical impedance imaging using a
        direct sensitivity matrix approach
Journal Physiological Measurement
        16
         Suppl. 3A
        AUG
Year    1995
Page    A123-A128
Address JP Morucci
        Univ Toulouse 3
        Hotel Dieu
        Inserm
        U305
        F-31052 Toulouse, France
Serial# 0967-3334
Abs.    This paper presents a reconstruction algorithm using a
        direct sensitivity matrix (DSM) approach for fast 3D image