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Table Of Contents
Genistein, vascular disease and
atherosclerosis
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S. Kapiotis, M. Hermann, I. Held, C. Seelos, H.
Ehringer, B.M.K. Gmeiner Arteriosclerosis Thrombosis and
Vascular Biology, 1997, Vol 17, Iss 11, pp 2868-2874
There is now growing evidence that the oxidative
modification of LDL plays a potential role in
atherosclerosis. In this study, genistein, a compound
derived from soy with a flavonoid chemical structure, has
been evaluated for its ability to act as an LDL antioxidant
and a vascular cell protective agent against oxidized LDL.
Results showed that genistein was able to inhibit the
oxidation of LDL in the presence of copper ions or
superoxide/nitric oxide radicals. Human endothelial
cell-mediated LDL oxidation was also inhibited in the
presence of genistein. In addition to its antioxidative
potential during LDL oxidating processes, genistein
effectively protected vascular cells from damage by oxidized
lipoproteins. Genistein was found to block upregulation of
two tyrosine-phosphorylated proteins in endothelial cells
induced by oxidized LDL. These findings support the
suggested and documented beneficial action of soy in
preventing chronic vascular diseases and early atherogenic
events.
Genistein inhibits bone
loss
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M. Yamaguchi, Y.H. Gao, Biochemical Pharmacology, 1998,
Vol 55, Iss 1, pp 71-76
This study investigated the effect of genistein on bone
resorption (assimilation) in vitro. Bone tissues were
obtained from elderly female rats. The bone-resorbing
factors parathyroid hormone (PTH), prostaglandin (PGE), and
lipopolysaccharide caused a significant decrease in bone
calcium content. However, the decrease in bone calcium
content induced by these bone-resorbing factors was
inhibited completely by genistein. In addition, this
isoflavonoid completely inhibited the PTH or PGE-induced
increase in medium glucose consumption and lactic acid
production by bone tissues. Also, genistein blocked both
PTH-increased acid phosphatase and decreased alkaline
phosphatase activities of bone tissues. On the other hand,
Tamoxifen, an anti-estrogen reagent, clearly prevented the
inhibitory effect of genistein on PTH-stimulated bone
resorption. These findings indicate that genistein has a
direct inhibitory effect on bone resorption in tissue
culture.
Vitamin C in mammals
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W. Ficek. Biochemical Archives, 1997, Vol 13, Iss 4, pp
207-213
Vitamin C (ascorbic acid) is an essential component of
every living cell. In mammals that cannot synthesize vitamin
C, intake is of paramount importance to various stages of
physiological processes. Vitamin C (a) has a beneficial
effect on collagen synthesis, which is essential to cell
growth and regeneration, (b) facilitates the healing of
wounds via cell regeneration, (c) lowers the cholesterol
level by increasing the elimination of cholesterol from the
intestines via bile, thus preventing ischemic heart disease,
(d) enhances the absorption of iron in the digestive tract
and influences the production of erythrocytes, (e) prevents
scurvy, and (f) absorbs free radicals, which are responsible
for many diseases, including neoplastic and heart diseases
as well as the aging of cells and the body.
Vitamin C vs. newborn
malformation
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Diabetologia, 1997, Vol 40, Iss 12, pp 1416-1424
An excess of reactive oxygen species (free radicals) has
been associated with the increased rate of congenital
malformations in experimental diabetic pregnancy. Studies
have shown that antioxidants can protect the embryonic
development in a diabetic environment. The capacity of
vitamin C as an antioxidative agent and dietary supplement
in diabetic pregnancy was investigated. Vitamin C treatment
reduced the rates of late resorptions and malformations in
the diabetic groups in proportion to the dose administered.
Vitamin C treatment caused accumulation of ascorbic acid in
the placenta, and in maternal and fetal liver. Vitamin C
supplementation yielded increased alpha- tocopherol
concentration in the placenta and caused a reduction of the
high concentrations of thiobarbituric acid reactive
substances in the serum of pregnant diabetic rats. Thus,
vitamin C treatment reduced the rates of congenital
malformations and late resorptions, thereby supporting the
proposition that free radicals are involved in the embryonic
dysmorphogenesis (abnormal development of tissue) of
diabetic pregnancy.
Diminished GH secretion in aging
humans
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J.D. Veldhuis, A. Iranmanesh, A. Weltman, Endocrine,
1997, Vol 7, Iss 1, pp 41-48
Remarkable decreases in growth hormone (GH) secretion
accompany healthy aging. There are concurrent changes in
body composition (with increased fat), physiological
declines in estrogen and androgen concentrations,
differences in gender responses to aging, and alterations
not only in the quantity of GH secreted, but also in the
orderliness or regularity of the GH release process. In
addition, physical fitness or aerobic capacity also
positively modulates GH secretion. Variables such as altered
sleep patterns and nutritional state may contribute to
overall regulation of the GH axis in aging. Studies suggest
partial growth hormone-releasing hormone (GHRH) deficiency
in healthy older individuals, presumptively combined with
somatostatin excess, and disruption of the moment-to-moment
pattern of coordinated and orderly GH release. The full
article reviews these selected facets of recent experimental
evaluation of human GH insulin-like growth factor-I in aging
humans.
Sunscreen ingredients cause DNA
damage
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R. Dunford, A. Salinaro, L.Z. Cai, N. Serpone, S.
Horikoshi, H. Hidaka, J. Knowland FEBS Letters, 1997, Vol
418, Iss 1-2, pp 87-90
Titanium dioxide (TiO2) is a safe sunscreen because it
reflects and scatters UVB and UVA in sunlight. However, TiO2
absorbs about 70 percent of incident UV, and in aqueous
environments this leads to the generation of hydroxyl
radicals that can initiate oxidation. The full study shows
that all the sunscreen TiO2 samples tested cause the
photo-oxidation of a representative organic substrate
(phenol)and that sunlight-illuminated TiO2 causes DNA damage
both in vitro and in human cells.
Ginkgo extract prevents
mitochondrial aging
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J. Sastre, A. Millan, J.G. delaAsuncion, R. Pla, G.
Juan, F.V. Pallardo, E. O'Connor, J.A. Martin, M.T.
DroyLefaix, J. Vina, Free Radical Biology and Medicine,
1998, Vol 24, Iss 2, pp 298-304
This study found that mitochondrial DNA from the brains
and livers of older rats exhibited oxidative damage that was
significantly higher than that found in mitochondrial DNA
from young rats. Mitochondrial glutathione is also more
oxidized in old than in young rats, and peroxide formation
in mitochondria from old animals was higher than in those
from young ones. According to morphological parameters (size
and complexity), there are two populations of mitochondria.
One is large, highly complex mitochondria, and the other
population is smaller and less complex. Brains and livers
from old animals had a higher proportion of the large highly
complex mitochondria than from young animals. Treatment with
the Ginkgo biloba extract partially prevented these
morphological changes as well as the indices of oxidative
damage observed in brain and liver mitochondria from old
animals.
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