ARTICLES |
Tagliabue, A.; Cena, H.; Deurenberg, P.
Comparative study of the relationship between multi-frequency
impedance and body water compartments in two European
populations
British Journal of Nutrition
75
1
JAN
1996
11-19
A Tagliabue
Univ Pavia
Dept Human Nutr
Via Bassi 21
I-27100 Pavia, Italy
0007-1145
body composition; total body water; multi-frequency
bioimpedance
BIOELECTRICAL-IMPEDANCE; SEGMENTS
To investigate possible differences in the relationship
between multi-frequency impedance and body-water
compartments (total body water (TBW) and extracellular
water (ECW)) measured by dilution techniques in two
European populations, we studied forty Italian (twenty male
and twenty female) and forty-three Dutch (twenty-three male
and twenty female) healthy subjects aged 19-41 years. The
main differences in body build between the two groups were
height, trunk length and the two ratios TBW/height and
ECW/height. Population-specific prediction formulas for ECW
(at 1 kHz) and TBW (at 100 kHz) were developed. The
prediction errors for ECW and TBW were about 0.6 and 1.5 kg
respectively, (CV 4%) in both groups. Cross-validation
analysis showed no significant error in the prediction of
TBW but a slight error (range -4.9 to + 2.8 %) in the ECW
prediction. The biases in both TBW and ECW were correlated
with ECW/TBW (r -0.44, P < 0.0005 and r + 0.52, P < 0.0005
respectively) in the two groups; the biases in ECW were
also related to ECW/height (r 0.51, P < 0.001), TBW/height
(r 0.25, P < 0.05), trunk length (r 0.36, P < 0.001) and
Z(1)/Z(100) (r 0.32, P < 0.01). In conclusion, the water
distribution between the extra- and intracellular
compartments emerged in the present study as the major
cause of error in the prediction of body water, and in
particular of ECW from impedance measurements with a
population-specific equation. Moreover, body build,
expressed as TBW/height and ECW/height, had an impact on
the bias.
Tagliabue, A.; Cena, H.; Deurenberg, P.
Title Comparative study of the relationship between multi-frequency
impedance and body water
compartments in two European
populations
Journal British Journal of Nutrition
75
1
JAN
Year 1996
Page 11-19
Address A Tagliabue
Univ Pavia
Dept Human Nutr
Via Bassi 21
I-27100 Pavia, Italy
Serial# 0007-1145
Keys body composition; total body water; multi-frequency
bioimpedance
BIOELECTRICAL-IMPEDANCE;
SEGMENTS
Abs. To investigate possible differences in the relationship
between multi-frequency
impedance and body-water
compartments (total body
water (TBW) and extracellular
water (ECW)) measured by
dilution techniques in two
European populations, we
studied forty Italian (twenty male
and twenty female) and forty-three
Dutch (twenty-three male
and twenty female) healthy
subjects aged 19-41 years. The
main differences in body
build between the two groups were
height, trunk length and
the two ratios TBW/height and
ECW/height. Population-specific
prediction formulas for ECW
(at 1 kHz) and TBW (at 100
kHz) were developed. The
prediction errors for ECW
and TBW were about 0.6 and 1.5 kg
respectively, (CV 4%) in
both groups. Cross-validation
analysis showed no significant
error in the prediction of
TBW but a slight error (range
-4.9 to + 2.8 %) in the ECW
prediction. The biases in
both TBW and ECW were correlated
with ECW/TBW (r -0.44, P
< 0.0005 and r + 0.52, P < 0.0005
respectively) in the two
groups; the biases in ECW were
also related to ECW/height
(r 0.51, P < 0.001), TBW/height
(r 0.25, P < 0.05), trunk
length (r 0.36, P < 0.001) and
Z(1)/Z(100) (r 0.32, P <
0.01). In conclusion, the water
distribution between the
extra- and intracellular
compartments emerged in
the present study as the major
cause of error in the prediction
of body water, and in
particular of ECW from impedance
measurements with a
population-specific equation.
Moreover, body build,
expressed as TBW/height
and ECW/height, had an impact on
the bias.
Taktak, A.; Spencer, A.; Record, P.; Gadd, R.; Rolfe, P.
Title Feasibility of neonatal lung imaging using electrical
impedance tomography
Journal Early Human Development
44
2
FEB 23
Year 1996
Page 131-138
Address A Taktak
Keele Univ
N Staffordshire Hosp
Dept Biomed Engn & Med
Phys
Thornburrow Dr
Stoke on Trent ST4 7QB
Staffs, England
Serial# 0378-3782
Keys neonatal lung imaging; electrical impedance
tomography
BIRTH-WEIGHT INFANTS; RECONSTRUCTION
Abs. The feasibility of detecting the lungs in preterm
babies
using electrical impedance
tomography (EIT) was
investigated, A single frequency
instrument using 16
electrodes to apply current
and detect peripheral voltages
was constructed. The instrument
applied AC current of 1.5
mA peak-peak at a carrier
frequency of 20 kHz, Images were
reconstructed using a sensitivity
regions backprojection
method. A 9-day-old preterm
baby was tested and data were
collected at a speed of
10 frames/s, A dynamic image
showing the lungs at full
inspiration referenced to
expiration is illustrated
in this paper. Impedance
measurements taken across
the chest during the first 2 s
did not show a clear pattern
thus demonstrating irregular
breathing. Region of interest
analysis were carried out on
the reconstructed images
and tracked with time. Fourier
transforms were then performed
on these signals and a
fundamental frequency at
1 Hz, corresponding to normal
breathing rate of 60 breaths/min,
was detected. Harmonics
of the signal caused distortion
especially on the left lung
where the effects of cardiac
events were more dominant.
Tobin, B.W.; Finegood, D.T.
Title Estimation of rat body composition by means of
electromagnetic scanning
is altered by duration of anesthesia
Journal Journal of Nutrition
125
6
JUN
Year 1995
Page 1512-1520
Address BW Tobin
Mercer Univ
Sch Med
Div Basic Med Sci
Macon, GA 31207 USA
Serial# 0022-3166
Keys electromagnetic scanning; anesthesia; body composition;
rats
ELECTRICAL-CONDUCTIVITY;
VALIDATION; INSTRUMENT; TOBEC; BIRDS;
MASS; FAT
Abs. We determined the effect of anesthesia on estimation
of fat-
free mass and body fat in
rats using electromagnetic
scanning (EMS). Male Wistar
Furth rats (n = 7, similar to
226 g) were injected with
66 mg/kg ketamine hydrochloride
and 6.6 mg/kg xylazine intramuscular
anesthesia. EMS
measures were repeated every
4 min, up to 80 min post-
anesthesia injection. From
4 to 44 min post-injection, the
EMS signal and consequently
the estimation of fat-free mass
decreased from 198 +/- 5
to 180 +/- 5 g (mean +/- SD, P <
0.05). Conversely, the estimation
of body fat increased by
63% during this period of
anesthesia (12.9 +/- 2.9 vs. 21.1
+/- 2.6 g/100 g body wt,
P < 0.05). In cohort animals (n =
6), body temperature and
respiration rate declined
following anesthesia (P
< 0.05), and may have
correspondingly suppressed
EMS signal via reduced ion flux
and/or muscular activity.
In another study the effects of
food deprivation, tail position,
and anesthesia duration
were demonstrated to alter
estimation of fat-free mass (P =
0.0001), but these effects
were not interactive (P > 0.05).
Proximate analysis of body
composition in cohort rats
indicated that EMS predicted
fat-free mass with a 3.5%
error when estimated at
4 min post-anesthesia injection.
Taken together, these data
suggest that standardized EMS
protocols should be adopted
to account for effects of
anesthesia, animal position
and food deprivation: When
manufacturer's equations
are used, body composition should
be measured immediately
after induction of anesthesia.
However, laboratories that
choose to internally generate
EMS regression equations
with proximate analysis should
determine and utilize the
period of minimal variability in
EMS measures. Such precautions
would minimize
interlaboratory differences
in the reporting of EMS body
composition measures in
anesthetized animals.
Toogood, A.A.; Oneill, P.A.; Shalet, S.M.
Title Beyond the somatopause: Growth hormone deficiency
in adults
over the age of 60 years
Journal Journal of Clinical Endocrinology and Metabolism
81
2
FEB
Year 1996
Page 460-465
Address SM Shalet
Christie Hosp Natl Hlth
Serv Trust
Dept Endocrinol
Wilmslow Rd
Manchester M20 4BX
Lancs, England
Serial# 0021-972X
Keys GH-RELEASING HORMONE; BODY-COMPOSITION; SOMATOMEDIN-C;
MEN;
DEFICIENCY; SECRETION; INSULIN;
HYPOGLYCEMIA; INDIVIDUALS;
ADIPOSITY
Abs. GH secretion declines by 14%/decade of adult
Life, leading
to the suggestion that people
over the age of 60 yr are
functionally GH deficient.
If this is the case, one might
not be able to detect a
difference in GH secretion between
the elderly with documented
hypothalamic-pituitary disease
and an age-matched control
group. We studied GH secretion
in 24 patients with hypothalamic-pituitary
disease and 24
controls matched for body
mass index and age using 24-h GH
profiles, arginine stimulation
tests, and serum insulin-
like growth factor I (IGF-I)levels.
The median (raaha, S.; Williams,
P.A.
Title Comparison
[<9.6 (<9.6-20) us.
18.5 (10.7-74.4) mu g/L 24 h; P <
0.0001], the median stimulated
peak GH response to arginine
[<0.4 (<0.4-7.7) vs.
8.0 (1.6-37.0) mu g/L; P < 0.0001],
and the median serum IGF-I
concentration [102 (<14-162) us.
147 (65-255) ng/mL; P =
0.0002] were significantly lower in
the patients than in the
controls. Fifteen patients showed
no evidence of spontaneous
or stimulated GH secretion,
whereas all controls had
evidence of both. The area under
the GH curve in the 33 subjects
with demonstrable GH
secretion correlated significantly
with the peak GH
response to arginine (r
= 0.71; P < 0.0001), but not with
serum IGF-I concentration.
This study suggests that
organic GH deficiency in the
elderly is distinct from
the decline in GH secretion
associated with the aging
process. These patients may
benefit from GH replacement
therapy.
Toogood, A.A.; Adams, J.E.; Oneill, P.A.; Shalet, S.M.
Title Body composition in growth hormone deficient adults
over the
age of 60 years
Journal Clinical Endocrinology
45
4
OCT
Year 1996
Page 399-405
Address SM Shalet
Christie Hosp NHS Trust
Dept Endocrinol
Wilmslow Rd
Manchester M20 4BX
Lancs, England
Serial# 0300-0664
Keys X-RAY ABSORPTIOMETRY; CARDIOVASCULAR-DISEASE;
HYPOPITUITARY
ADULTS; BIOELECTRICAL-IMPEDANCE;
ADIPOSE-TISSUE; MEN; MASS;
RISK; FAT; GH
Abs. OBJECTIVE Elderly patients with hypothalamic-pituitary
disease exhibit a reduction
in GH secretion distinct from
the decline in GH secretion
related to age, GH deficiency
in young adults causes a
change in body composition, with
increased fat mass (FM)
and reduced fat free mass (FFM),
similar to that seen as
a result of the normal ageing
process. The aim of this
study was to determine whether
organic GH deficiency in
elderly patients may cause changes
in body composition beyond
those due to ageing.
SUBJECTS Twenty-one patients
(15 male) with documented
pituitary disease and 24
controls (17 male) matched for age,
height, weight and BMI,
all over the age of 60, in whom GH
status had been defined
by a 24-hour GH profile and an
arginine stimulation test.
MEASUREMENTS Serum was taken
for fasting IGF-I and IGFBP-1
estimations. Total and regional
FM and FFM were determined
using dual-energy X-ray
absorptiometry.
RESULTS FM (median (range))
was increased in the patients,
27.76 (19.25-50.24) vs 21.23
(8.81-49.15) kg in the
controls (P < 0.005).
FM was significantly increased in the
arms, legs and trunk in
the patients compared with the
controls. The proportion
of fat deposited centrally did not
differ significantly between
the two groups (57.0% (47.6-
65. 1) in the patients vs
55.3% (44.1-63.8) in the controls,
P = 0.25). There was an
inverse relation between total FM
and serum IGFBP-1 present
in the patients, rho=-0.632, P <
0.005, and in the controls
rho=-0.467, P < 0.05, but the
relation between total FM
and area under the On profile was
significant only in the
controls (rho=-0.651, P < 0.001)
and not in the patients.
FFM (51.19 (26.96-69.18)
kg in the patients vs 51.55 (32.35-
60.53) kg in the controls,
P=0.99) and serum IGFBP-1 levels
did not differ significantly
between the two groups.
CONCLUSION Organic growth
hormone deficiency causes changes
in body composition beyond
the changes associated with the
ageing process. These changes
differ from those seen in
younger On deficient adults
in that they are limited to an
increase in FM with no change
in FFM. These findings
indicate that even in the
elderly, in whom On secretion is
normally very tow, the additional
imposition of GH
deficiency due to organic
disease has significant
biological impact.