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Title
manganese metabolism is impaired in the Belgrade laboratory rat.
Author
Chua AC; Morgan EH
Address
Department of Physiology' University of Western Australia' Nedlands'
Australia.
Source
J Comp Physiol [B , 167(5):361-9 1997 Jul
Abstract
Homozygous Belgrade rats have a hypochromic anaemia due to impaired
iron transport across the cell membrane of immature erythroid
cells.
This study aimed at investigating whether there are also abnormalities
of Mn metabolism in erythroid and other types of cells. The experiments
were performed with homozygous (b/b) and heterozygous (+/b) Belgrade
rats and Wistar rats and included measurements of Mn uptake by
reticulocytes in vitro' Mn absorption from in situ closed loops
of the
duodenum' and plasma clearance and uptake by several organs after
intravenous inJection of radioactive Mn bound to transferrin
(Tf) or
mixed with serum. Similar measurements were made with 59Fe-labelled
Fe
in several of the experiments. Mn uptake by reticulocytes and
absorption from the duodenum was impaired in b/b rats compared
with +/b
or Wistar rats. The plasma clearance of Mn-Tf was much slower
than
Mn-serum' but both were faster than the clearance of Fe-Tf. Uptake
of
54Mn by the kidneys' brain and femurs was less in b/b than Wistar
or
/+b rats' but uptake by the liver was greater in b/n rats. Similar
differences were found for 59Fe uptake by kidneys' brain and
femurs but
is concluded that the genetic abnormality present in b/b rats
affects
Mn metabolism as well as Fe metabolism and that Mn and Fe share
similar
transport mechanisms in the cells of erythroid tissue' duodenal
mucosa'
kidney and blood-brain barrier.
Title
The effect of manganese supply on thyroid hormone metabolism
in the
offspring of manganese-depleted dams.
Author
Eder K; Kralik A; Kirchgessner M
Address
Institute of Nutrition Physiology' Technical University Munich'
Freising' Germany.
Source
Biol Trace Elem Res, 55(1-2):137-45 1996 Oct-Nov
Abstract
The present study was performed to investigate the effect of
manganese
(Mn) supply on metabolism of thyroid hormones in the rat. A study
with
rats was carried out over two generations. Female rats were raised
with
a Mn-deficient diet (0.1 mg Mn/kg)' and mated to produce a second
generation. The male rats of the second generation were used
as
subJects for the investigation. They were divided into five groups
and
fed diets with Mn concentrations of 0.1' 0.5' 2.2' 10' and 46
mg/kg for
40 d. For assessment of thyroid hormone metabolism' concentrations
of
thyroid hormones in serum and activity of hepatic type I 5`deiodinase
(5`D-1) were measured. Feeding diets with 0.1 mg Mn/kg impaired
growth
and food conversion' influenced parameters of thyroid hormone
metabolism' and changed some clinical-chemical parameters' such
as
concentrations of total protein' albumin' calcium (Ca) and magnesium
(Mg) as well as activity of alkaline phosphatase in serum. Regarding
the thyroid hormone metabolism' rats fed the diet with a Mn level
of
0.1 mg/kg had a higher 5`D-I activity in liver' and consequently
a
higher concentration of triiodothyronine in serum than the rats
fed the
other diets. In contrast' the concentrations of total and free
thyroxine were not influenced by the Mn intake. Growth'
clinical-chemical parameters' concentrations of thyroid hormones
in
serum' and activity of hepatic 5`D-I were similar in the rats
fed diets
with Mn concentrations between 0.5 and 64 mg/kg. The present
study
shows that feeding a diet with a very low Mn concentration affects
growth and thyroid hormone metabolism and that a dietary level
of 0.5
mg Mn/kg is adequate for growth and thyroid hormone metabolism
in the
offspring of Mn-depleted dams.
Title
The effect of heavy metals on neutrophils
Author
Hrycek A; Misiewicz A
Address
II Katedry i Kliniki Chor]ob Wewn,etrznych' Sl,askieJ Akademii
MedyczneJ w Katowicach.
Source
Wiad Lek, 49(7-12):107-11 1996
Abstract
The influences of some heavy metals i.e. of mercury' zinc' copper'
manganese' nickel and cobalt on metabolic activity and functional
states of human neutrophils were presented. Simultaneously the
pathomechanisms of the observed disturbances were described.
Title
Effect of metal ions on calcifying growth plate cartilage chondrocytes.
Author
Litchfield TM; Ishikawa Y; Wu LNY; Wuthier RE; Sauer GR
Address
University of South Carolina, Department of Chemistry and Biochemistry,
Columbia, South Carolina 29208, USA.
Source
Calcif Tissue Int, 62(4):341-9 1998 Apr
Abstract
The effects of the trace metals zinc (Zn), manganese (Mn), and
cadmium
(Cd) on the metabolism of growth plate chondrocytes was examined
using
a mineralizing culture system. Supplementation of serum-free
primary
cultures of growth plate chondrocytes with 10-100 mu m Zn resulted
in
an increase in cell protein and greatly increased alkaline phosphatase
(AP) activity; however, above 25 mu m Zn mineralization of the
cultures
was reduced. The effects of Zn on cellular protein and AP activity
were
enhanced by the addition of the albumin to the culture media.
Removal
of Zn from basal culture media resulted in recoverable reductions
in
cellular protein and AP activities. Cadmium was acutely toxic
to
chondrocyte cell cultures at concentrations above 5 mu m. Even
at very
low concentrations (0.25 mu m) Cd caused significant reductions
in DNA,
cellular protein, and matrix protein synthesis. In contrast,
Cd had
negligible effects on AP activity or culture mineralization.
manganese
treatment (50 mu m) resulted in reduced levels of proteoglycan,
cell
protein, DNA synthesis, and collagen synthesis, although AP specific
activity did not change. At 10 mu m, Mn significantly reduced
mineralization but had only minor influence on other culture
parameters. Both Zn (200 mu m) and Cd (0.1 mu m), but not Mn,
induced
the synthesis of metallothionein. The physiological and biochemical
effects of specific metal ions is largely dependent on their
physicochemical properties, especially their ligand affinities.
Knowledge of these properties allows predictions to be made regarding
whether the organic or the mineral phase are most likely to be
affected
in a mineralized tissue.
Title
Ultrastructure of retina of manganese-deficient rats.
Author
Gong H; Amemiya T
Address
Department of Ophthalmology' Nagasaki University School of Medicine'
Japan.
Source
Invest Ophthalmol Vis Sci, 37(10):1967-74 1996 Sep
Abstract
PURPOSE: To elucidate some biologic functions of manganese in
the
retina. METHODS: Three-week-old weanling Wistar Kyoto rats were
used.
manganese-deficient rats were fed a manganese-deficient solid
diet
containing 0.23 mg manganese/100 g diet and all other nutrients.
Control rats were fed a solid diet with 2.9 mg manganese/100
g diet.
The retinas were examined by electron microscopy in the 12th'
18th' and
30th months of experimentation. RESULTS: There was a statistically
significant decrease in the plasma manganese levels in
manganese-deficient animals compared to controls. In rats fed
a
manganese-deficient diet for 12 months' photoreceptor cells showed
karyopyknosis-like changes of nuclei and a decrease in size and
number
of outer segments. Rats fed a manganese-deficient diet for 18
months
showed a complete loss of photoreceptor cells' and the inner
nuclear
layer nuclei came in direct contact with the retinal pigment
epithelium. Rats with manganese deficiency of 30 months showed
invasion
by capillaries and processes of M uller-like cells from the sensory
retina into the retinal pigment epithelium. In the sensory retina'
M
uller-like cells proliferated' and neural cells disappeared.
CONCLUSIONS: Because manganese is related to Mn superoxide in
the
mitochondrial matrix and to protein and glycogen metabolism'
manganese
deficiency may disturb the renewal of photoreceptor outer segment
discs' and the decrease in antioxidant action caused by a lower
level
of Mn superoxide dismutase may accelerate the damage to photoreceptor
cells. After neural cell loss' M uller-like cells may proliferate.
manganese appears to be essential for maintaining photoreceptor
cells.
Title
Effect of essential trace metal on bone metabolism in the
femoral-metaphyseal tissues of rats with skeletal unloading:
comparison
with zinc-chelating dipeptide.
Author
Yamaguchi M; Ehara Y
Address
Laboratory of Endocrinology and Molecular Metabolism' Graduate
School
of Nutritional Sciences' University of Shizuoka' 52-1 Yada' Shizuoka
City 422' Japan.
Source
Calcif Tissue Int, 59(1):27-32 1996 Jul
Abstract
The effect of essential trace metals on bone metabolism was
investigated in the femoral-metaphyseal tissues obtained from
skeletal-unloaded rats. Skeletal unloading was designed by using
the
model of hindlimb suspension in rats; the animals were fed for
4 days
with the unloading. Femoral-metaphyseal tissues were cultured
for 24
hours in a medium containing either vehicle (control)' nickel'
manganese' cobalt' copper' zinc' or zinc-chelating dipeptide
(beta-alanyl-L-histidinato zinc; AHZ) in the concentration range
of
10(-6) to 10(-4) M. Bone biochemical components (alkaline phosphatase
activity' glucose consumption' and DNA content) were significantly
decreased by skeletal unloading. The presence of zinc sulfate
or AHZ
(10(-5) and 10(-4) M) caused a significant increase of alkaline
phosphatase activity in the bone tissues from unloaded rats.
This
effect was not seen by nickel' manganese' cobalt and copper (10(-6)
to
10(-4) M). The culture medium glucose was clearly consumed by
the bone
tissues. This consumption was inhibited by nickel' manganese'
or copper
(10(-5) and 10(-4) M)' while cobalt' zinc' and AHZ had no effect.
DNA
content in the bone tissues from unloaded rats was significantly
increased by all metal compounds (10(-5) M). The effect of AHZ
on bone
components was greater than zinc sulfate. The AHZ (10(-5) M)-increased
alkaline phosphatase activity in the bone tissues from unloaded
rats
was clearly blocked by the presence of cycloheximide (10(-6)
M)'
staurosporine (10(-7) M)' dibucaine (10(-4) M)' or okadaic acid
(10(-7)
M). The present study demonstrates that' of various essential
trace
metals' zinc compounds have an unique anabolic effect on bone
metabolism in the femoral-metaphyseal tissues of rats with skeletal
unloading. Zinc-chelating dipeptide may stimulate bone protein
synthesis through the mechanism that is involved in protein kinases.
Title
Mutations in PMR1 suppress oxidative damage in yeast cells lacking
superoxide dismutase.
Author
Lapinskas PJ; Cunningham KW; Liu XF; Fink GR; Culotta VC
Address
Department of Environmental Health Sciences' Johns Hopkins University
School of Hygiene and Public Health' Baltimore' Maryland 21205.
Source
Mol Cell Biol, 15(3):1382-8 1995 Mar
Abstract
Mutants of Saccharomyces cerevisiae lacking a functional SOD1
gene
encoding Cu/Zn superoxide dismutase (SOD) are sensitive to atmospheric
levels of oxygen and are auxotrophic for lysine and methionine
when
grown in air. We have previously shown that these defects of
SOD-deficient yeast cells can be overcome through mutations in
either
the BSD1 or BSD2 (bypass SOD defects) gene. In this study' the
wild-type allele of BSD1 was cloned by functional complementation
and
was physically mapped to the left arm of chromosome VII. BSD1
is
identical to PMR1' encoding a member of the P-type ATPase family
that
localizes to the Golgi apparatus. PMR1 is thought to function
in
calcium metabolism' and we provide evidence that PMR1 also participates
in the homeostasis of manganese ions. Cells lacking a functional
PMR1
gene accumulate elevated levels of intracellular manganese and
are also
extremely sensitive to manganese ion toxicity. We demonstrate
that
mutations in PMR1 bypass SOD deficiency through a mechanism that
depends on extracellular manganese. Collectively' these findings
indicate that oxidative damage in a eukaryotic cell can be prevented
through alterations in manganese homeostasis.
Title
Resonance Raman spectral properties and stability of manganese
protoporphyrin IX cytochrome b5.
Author
Gruenke LD; Sun J; Loehr TM; Waskell L
Address
Department of Anesthesia and the Liver Center' University of
California' and the Veterans Administration Medical Center' San
Francisco 94121' USA.
Source
Biochemistry, 36(23):7114-25 1997 Jun 10
Abstract
The structure and stability of cytochrome b5 reconstituted with
manganese protoporphyrin IX instead of iron protoporphyrin IX
has been
investigated by resonance Raman spectroscopy and stopped-flow
visible
spectroscopy. The resonance Raman spectrum of MnIII cytochrome
b5 was
consistent with a high-spin hexacoordinate MnIII protoporphyrin
IX
structure that converted to a high-spin pentacoordinate structure
at
higher laser power. The resonance Raman spectrum of MnII cytochrome
b5
indicated a high-spin pentacoordinate structure which was independent
of laser power. Studies of the binding of MnIII protoporphyrin
IX to
apocytochrome b5 indicated that the MnIII-containing porphyrin
bound
much less tightly to the protein than did heme. Although the
second-order rate constant at 20 degrees C for the association
of heme
with apocytochrome b5 (4.5 x 10(7) M(-1) s(-1)) was estimated
to be
only 1 order of magnitude higher than that with Mn protoporphyrin
IX
(3.3 x 10(6) M(-1) s(-1))' the dissociation of manganese substituted
cytochrome b5 into the apoprotein and free Mn protoporphyrin
IX occurs
with a first-order rate constant of 1.2 x 10(-2) s(-1) at 20
degrees C
while the dissociation of heme from cytochrome b5 at room temperature
occurs 3 orders of magnitude more slowly with a first-order rate
constant of 1.67 x 10(-5) s(-1) [Vergeres' G.' Chen' D. Y.' Wu'
F.F.' &
Waskell' L. (1993) Arch. Biochem. Biophys. 305' 231-241 . The
equilibrium dissociation constant for manganese-substituted cytochrome
b5 increased with temperature from 4 nM at 20 degrees C to 14
nM at 37
degrees C. These results suggest that' in the reconstituted cytochrome
P450 metabolizing system' especially in studies done with low
protein
concentrations (0.1 microM)' and at elevated temperatures (37
degrees
C)' as much as 30% of the manganese-substituted cytochrome b5
may
dissociate to free Mn-protoporphyrin IX and apocytochrome b5.
Title
Pathogenic mechanisms of the acute porphyric attack: speculative
roles
of manganese associated enzymes.
Author
Thunell S; Floderus Y; Harper P; Henrichson A; Lindh U; Marklund
S
Address
Porphyria Centre Sweden' S:t G oran Hospital' Stockholm' Sweden.
Source
Cell Mol Biol (Noisy-le-grand), 43(1):1-8 1997 Feb
Abstract
The significantly increased concentrations of granulocyte manganese
in
subJects with AIP may be an indication of overexpression of
manganese-associated enzymes. In this study we present further
observations related to this phenomenon and speculate that this
may
provide a rational basis for hypotheses attempting to explain
the
pathogenesis of the acute attack of porphyria. Such hypotheses
are
advanced with regard to pyruvate carboxylase' mitochondrial superoxide
dismutase and glutamine synthetase' three manganese-dependent
enzymes
associated with either ALA-generating or ALA-dependent processes.
The
metabolic impacts in acute porphyria of these enzymes would be
functions of the current energy charge of the organism' and would
thus
explain the protecting and ameliorating effects of glucose in
these
conditions. Although granulocytes from AIP subJects have elevated
manganese concentrations' this did not appear to be associated
with
increased activities of two enzymes assayed' pyruvate carboxylase
or
mitochondrial superoxide dismutase. However' enzyme activities
in white
blood cells do not necessarily represent the levels of catalytic
activity in cell types involved in the phenotypic expression
of
porphyria. Thus it proposed that hypotheses along these new lines
of
thinking are not flawed by the apparently missing correlations'
and
should not be therefore discarded. The possible roles of
manganese-associated enzymes in the mechanisms behind the acute
porphyric attack are discussed in some detail in the paper.
Title
Changes in blood manganese levels during pregnancy in iron supplemented
and non supplemented women.
Author
Tholin K; Sandstr om B; Palm R; Hallmans G
Address
Department of Medicine' Ostersund Hospital' Sweden.
Source
J Trace Elem Med Biol, 9(1):13-7 1995 Mar
Abstract
Blood manganese levels and iron status indices were determined
each
trimester in 66 healthy pregnant women. Twenty-five were randomly
assigned to iron supplementation' 19 to placebo and 22 received
dietary
advise aimed at increasing their dietary intake of fibre. Iron
supplemented women had significantly higher levels of blood haemoglobin
compared to the levels of the two other groups' and higher serum
ferritin levels compared to the placebo group. No significant
difference in blood manganese levels was observed among the three
groups of women. There was a significant increase in blood manganese
levels from one trimester to the next' which was slightly more
pronounced in non supplemented women. The median values in the
three
trimesters were 154 (range 79-360) nmol/L' 190 (range 98-408)
nmol/L'
and 230 (range 133-481) nmol/L' respectively. Pregnancy seems
to change
manganese status or otherwise influence manganese metabolism
irrespective of iron status and iron supplementation.
Title
Serum and urinary manganese levels in patients with Parkinson`s
disease.
Author
Jim]enez-Jim]enez FJ; Molina JA; Aguilar MV; Arrieta FJ;
Jorge-Santamar]ia A; Cabrera-Valdivia F; Ayuso-Peralta L; Rabasa
M;
V]azquez A; Garc]ia-Albea E; et al
Address
Department of Neurology of Hospital Pr]incipe de Asturias' Alcal]a
de
Henares' Madrid' Spain.
Source
Acta Neurol Scand, 91(5):317-20 1995 May
Abstract
To elucidate the possible role of manganese in the risk of developing
Parkinson`s disease (PD)' we compared serum levels of manganese'
and
24-h manganese excretion by urine in 29 PD patients and in 27
matched
controls. We also measured chromium and cobalt in the same samples.
All
these values did not differ significantly between the groups'
they were
not influenced by antiparkinsonian drugs' and they did not correlate
with age' age at onset and duration of the PD' scores of the
Unified PD
Rating Scale or the Hoehn & Yahr staging in the PD group.
These results
might suggest that serum levels and urinary excretion of manganese
are
apparently unrelated to the risk of developing PD. |
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