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Title
Nutritional factors that can favorably influence the glucose/insulin
system: vanadium.
Author
Verma S; Cam MC; McNeill JH
Address
Faculty of Pharmaceutical Sciences, University of British Columbia,
Vancouver, Canada.
Source
J Am Coll Nutr, 17(1):11-8 1998 Feb
Abstract
A growing body of experimental and clinical research indicates
that the
trace element, vanadium, exerts potent insulin-mimetic effects
in vitro
and in vivo when used in pharmacological doses. Since our first
demonstration of the anti-diabetic and cardioprotective effects
of
vanadium in vivo, impressive advances have been made in our
understanding of its mechanism of action, pharmacokinetics and
pharmacodynamics. A major advance in the use of vanadium as an
insulin-mimetic has been the development of organic vanadium
complexes
which are 2 to 3 times as potent as inorganic vanadium and have
been
extensively studied in our laboratory. There is an emerging role
for
the use of vanadium in human diabetes and the recently conducted
clinical trials support this contention. The present review summarizes
some of the key aspects of vanadium biology which exemplify the
potent
insulin-mimetic, anti-diabetic and antihypertensive effects of
this
intriguing trace element.
Title
Risk assessment of essential trace elements: new approaches to
setting
recommended dietary allowances and safety limits.
Author
Mertz W
Address
United States Department of Agriculture Human Nutrition Research
Center' Beltsville' MD' USA.
Source
Nutr Rev, 53(7):179-85 1995 Jul
Abstract
By definition' every essential trace element must have a range
of
intakes safe from toxicity but adequate enough to meet nutrition
requirements. That range is part of the total dose-response curve
and
its lower and upper limits are delineated on the basis of nutrition
and
toxicology data' respectively. Close coordination of activities
to set
these limits is necessary to avoid recommendations that are either
impractical (narrow zones of safe and adequate intakes) or
contradictory (overlapping limits' i.e.' no zones of safe and
adequate
intakes).
Title
Evidence for chromium acting as an essential trace element in
insulin-dependent glucose uptake in cultured mouse myotubes.
Author
Morris B; Gray T; MacNeil S
Address
Department of Clinical Chemistry' Northern General Hospital'
Sheffield'
UK.
Source
J Endocrinol, 144(1):135-41 1995 Jan
Abstract
Previous work from this and other laboratories has suggested
that the
trace element chromium plays some role in glucose homeostasis.
In this
study' we sought to characterise an in vitro cell culture model
in
which the effects of chromium on insulin-dependent glucose uptake
could
be studied. Mouse C2C12 myoblasts were differentiated to form
myotubes
in culture in chromium-replete or chromium-poor media. Chromium
levels
in standard media were 0.56 +/- 0.01 micrograms/l (mean +/- S.E.M.)
compared with 0.09 +/- 0.01 micrograms/l in chromium-poor media.
In
chromium-poor media' insulin-stimulated uptake of radiolabelled
glucose
was reduced by almost 50% compared with that found in chromium-replete
media. This decreased response could be restored by the addition
of
physiologically relevant (0.3 micrograms/l) concentrations of
inorganic
chromium (P < 0.001). The sensitivity of these cells to insulin
was
reduced dramatically by a reduction in the chromium content of
the
medium and was again increased (P < 0.001) by chromium addition.
The
concentrations of chromium required to restore the sensitivity
to
insulin were of the same order as those found physiologically;
much
higher concentrations of chromium could also stimulate glucose
uptake
in the absence of insulin but such concentrations were
supra-physiological.
Title
A reappraisal of the role of zinc in life and death decisions
of cells.
Author
Fraker PJ; Telford WG
Address
Department of Biochemistry' Michigan State University' East Lansing
48824' USA.
Source
Proc Soc Exp Biol Med, 215(3):229-36 1997 Jul
Abstract
There is a great deal of interest in chemicals and biochemicals
that
can modulate apoptosis. As will be discussed' zinc' an essential
trace
element' can induce as well as block apoptosis. High concentrations
of
extracellular zinc (500-1000 microM) have frequently been used
to block
apoptosis or programmed cell death in a variety of systems. Early
investigators provided evidence that this concentration of zinc
could
block DNA fragmentation that is often associated with apoptosis.
Since
zinc plays a role in many aspects of cell function' there are
probably
many sites in a death pathway that zinc could potentially modulate.
In
the case of glucocorticoid-mediated apoptotic death' new evidence
presented herein indicates that high zinc can also block the
binding of
steroids to the glucocorticoid receptor thereby inhibiting the
death
signal itself. In this case' zinc probably binds to the vicinal
cysteines in the receptor ligand binding site thereby blocking
binding
of glucocorticoid. Indeed' glucocorticoid-induced apoptosis in
thymocytes has become one of the most frequently studied systems
and is
a focal point of this review. Studies herein will show that unlike
zinc
other trace-like metals such as nickel' copper' cadmium' and
gold do
not afford thymocytes protection against the DNA fragmentation
induced
by glucocorticoid-mediated cell death. Interestingly' in attempting
to
determine if lower or more physiological concentrations of zinc
could
provide protection against apoptosis' it was found that 80-200
microM
zinc could actually induce death in 40% of CD4+ CD8+ alpha beta
TCR10CD3(10) thymocytes. From these experiments one might have
been
optimistic that zinc could' indeed' be a modulator of cell death.
However' this thought has been overshadowed by growing evidence
that
zinc does not provide long-term protection to so-called surviving
cells.
Title
Selenium protection against toxicity from cadmium and mercury
studied
at the cellular level.
Author
Lindh U; Danersund A; Lindvall A
Address
Division of Biomedical Radiation Sciences' Uppsala University'
Sweden.
Source
Cell Mol Biol (Noisy-le-grand), 42(1):39-48 1996 Feb
Abstract
Interaction between selenium and the heavy metals cadmium and
mercury
was studied in an experimental rat model (Sprague-Dawley). The
rats
were administered either one single trace element or combinations
of
selenium and cadmium as well as selenium and mercury. Salts of
these
trace elements were administered intraperitoneally daily during
thirty
days. Thereafter the animals were sacrificed and kidneys and
livers
excised rapidly. Thin sections were produced by a cryotome and
subsequently freeze-dried. Nuclear microscopy of the sections
showed
that in the combination groups there was a co-localization of
selenium
and the heavy metals. None of the expected pathological signs
of
cadmium and mercury toxicity were observed. The conclusion was
that
selenium exerted a protective effect against the toxicity of
cadmium
and mercury through mechanisms still to be unveiled.
Title
Lipid peroxidation products' and vitamin and trace element status
in
patients with cancer before and after chemotherapy' including
adriamycin. A preliminary study.
Author
Faber M; Coudray C; Hida H; Mousseau M; Favier A
Address
Laboratoire de Biochimie C' H^opital Albert Michallon' Grenoble'
France.
Source
Biol Trace Elem Res, 47(1-3):117-23 1995 Jan-Mar
Abstract
Adriamycin is a potent chemotherapeutic agent used in the treatment
of
human neoplastic diseases. A maJor side effect limiting the use
of this
drug is its toxic effect on the heart. Several hypotheses have
been
proposed to explain the cardiotoxicity of Adriamycin. However'
the most
plausible hypothesis seems to be the reduction of Adriamycin
and free
radical production' which induces lipid peroxidation and oxidative
damages in the heart. We have thus undertaken this preliminary
study to
investigate Adriamycin-induced lipid peroxidation by the measurement
of
plasma thiobarbituric acid reactant materials and antioxidant
systems'
namely glutathione content' glutathione peroxidase activity'
and
vitamin and trace element status' in patients with cancer before
and
after chemotherapy' including Adriamycin. The concentration of
thiobarbituric acid reactant materials in plasma of patients
with
cancer was higher than in controls and was further increased
after
chemotherapy. Blood glutathione and plasma glutathione peroxidase
activity' as well as plasma zinc and selenium in patients with
cancer'
were decreased' but not further modified by chemotherapy. However'
only
zinc and selenium levels reached a significant level. In contrast'
plasma vitamin E and beta-carotene levels were not significantly
increased in patients with cancer. Finally' plasma vitamin A
and copper
levels were not modified either in patients with cancer or by
chemotherapy.
Title
Effects of chromium supplementation on fasting insulin levels
and lipid
parameters in healthy' non-obese young subJects.
Author
Wilson BE; Gondy A
Address
Department of Internal Medicine' University of Nevada School
of
Medicine' Las Vegas 89102' USA.
Source
Diabetes Res Clin Pract, 28(3):179-84 1995 Jun
Abstract
Trivalent chromium is an essential trace element for normal
carbohydrate metabolism and insulin sensitivity. Because of this
biological activity' chromium supplementation has been studied
as a
potential therapy of insulin resistant states and dyslipidemias'
and
has been promoted as a health aid to the general population.
To
determine if there is a risk of subclinical chromium deficiency
in
young' otherwise healthy adults' we evaluated the effect of chromium
supplementation' versus placebo' on insulin levels and serum
lipids in
a double-blind' randomized trial in 26 young adults (mean age
36
years). Fasting levels of glucose' immunoreactive insulin (IRI)'
and
lipids (total cholesterol' HDL cholesterol' LDL cholesterol'
triglycerides) were measured before and after 90 days of daily
supplementation with a chromium (III)-nicotinate preparation'
containing 220 micrograms elemental chromium' or placebo. There
were no
statistically significant differences in the percentage change
of
fasting glucose' IRI or lipids between the chromium (n = 15)
and
placebo (n = 11) groups after 90 days of supplementation. However'
those individuals within the chromium group with initial fasting
IRI
levels greater than 35 pmol/l had a significant decrease in IRI
level
after supplementation (P < 0.03) despite no significant changes
in
serum lipids. These subJects may benefit from chromium supplementation
by improving insulin sensitivity and cardiovascular risk over
time.
Title
Trace element determination in humans. The use of blood and hair.
Author
Folin M; Contiero E; Vaselli GM
Address
Department of Biology, University of Padua, Italy.
Source
Biol Trace Elem Res, 31(2):147-58 1991 Nov
Abstract
With the present study, we intend to verify the utility of hair
as
diagnostic tool for trace element analysis, to substitute, perhaps,
conventional materials, such as blood serum. Blood and hair were
collected from male individuals (n = 107) aged 20-59 y. Determinations
of Cu and Zn concentrations were performed with atomic absorption
spectrometry. An influence of age on Zn in hair has been found,
with
significantly different values before and after age 30 y. There
is no
correlation between Cu concentrations in hair and in serum, and
a
positive one (r = 0.3554, p < 0.05) between Zn levels in hair
and in
serum. No association between Zn and Cu levels in hair has been
demonstrated; on the contrary, these elements have a moderate
positive
correlation in serum (r = 0.3586, p < 0.01). The data indicate
that
hair may represent an additional analytical material for Cu and
Zn to
complement blood serum.
Title
Some observations on the trace element concentrations in human
dental
enamel.
Author
Lane DW; Peach DF
Address
School of Engineering and Applied Science, Cranfield University,
RMCS,
Wiltshire, UK.
Source
Biol Trace Elem Res, 60(1-2):1-11 1997 Oct-Nov
Abstract
The concentration of trace elements has been measured for dental
enamel
from 86 healthy human teeth using particle-induced X-ray emission
(PIXE). The majority of the teeth (n = 70) were collected from
dentists
in the county of Oxfordshire in the United Kingdom, although
a smaller
group (n = 16) were collected from Cornwall. The elements K,
Ca, Mn,
Fe, Co, Ni, Cu, Zn, Sr, Pb, and Hg have been detected and statistically
analyzed by grouping according to sex, age, and geographical
location.
The concentrations of Fe and Cu were found to be lower in the
teeth
from female donors (P < 5%) and are believed to result from
the
continued burden of blood loss during menstruation. Strong positive
correlations (P < 0.1%) were found between Ca, Co, Ni, and
Zn for all
groups; these elements were also found to exhibit a negative
correlation (P < 1%) with age for teeth from female donors.
This is
believed to be related to decalcification during the menopause.
Pb was
found to exhibit a positive correlation (P < 5%) with age
for both
sexes, and is believed to substitute for Ca in the Ca hydroxy
apatite
(HAP) within the dental enamel.
Title
Effect of pantothenic acid and ascorbic acid supplementation
on human
skin wound healing process. A double-blind' prospective and randomized
trial.
Author
Vaxman F; Olender S; Lambert A; Nisand G; Aprahamian M; Bruch
JF;
Didier E; Volkmar P; Grenier JF
Address
INSERM U 61' Hospices Civils' Strasbourg' France.
Source
Eur Surg Res, 27(3):158-66 1995
Abstract
This study aimed at testing human skin wound healing improvement
by a
21-day supplementation of 1.0 g ascorbic acid (AA) and 0.2 g
pantothenic acid (PA). 49 patients undergoing surgery for tattoos'
by
the successive resections procedure' entered a double-blind'
prospective and randomized study. Tests performed on both skin
and
scars determined: hydroxyproline concentrations' number of fibroblasts'
trace element contents and mechanical properties. In the 18
supplemented patients' it was shown that in skin (day 8) Fe increased
(p < 0.05) and Mn decreased (p < 0.05); in scars (day 21)'
Cu (p =
0.07) and Mn (p < 0.01) decreased' and Mg (p < 0.05) increased;
the
mechanical properties of scars in group A were significantly
correlated
to their contents in Fe' Cu and Zn' whereas no correlation was
shown in
group B. In blood' AA increased after surgery with supplementation'
whereas it decreased in controls. Although no maJor improvement
of the
would healing process could be documented in this study' our
results
suggest that the benefit of AA and PA supplementation could be
due to
the variations of the trace elements' as they are correlated
to
mechanical properties of the scars.
Title
Importance and physiologic nutritional requirement of the selenium
trace element within the scope of parenteral nutrition (TPN)
Author
Gramm HJ; Kopf A; Br atter P
Address
HPN-Centrum, Klinikum Franklin, Freien Universit at Berlin.
gramm@zop_admin.ukbf.fu-berlin.de
Source
Med Klin, 92 Suppl 3():20-2 1997 Sep 15
Abstract
BASIS: Selenium-responsive clinical manifestations of selenium
deficiency and elucidation of the biochemical and molecular biological
basis of the essentiality of selenium give evidence for the biological
importance of the trace element in human nutrition. CONCLUSION:
The
dietary parenteral selenium requirement can be calculated on
the basis
of the maximal gene expression of the selenoprotein plasma glutathione
peroxidase (plGPx). In total parenteral nutrition a daily requirement
of 0.01 mumol/kg body weight for adults and 0.025 mumol/kg body
weight
for children can be seen as adequate and safe. |
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