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LE Magazine September
2002
Studies
from throughout the world that can help you live
longer
September 2002 Table of
Contents
1. Element of
timing in breast cancer treatment
Approximately 200,000 American women develop breast cancer
every year. Typically, chemotherapy and tamoxifen are used
simultaneously after surgery. However, new research shows that
when tamoxifen is given after chemotherapy, breast cancer is
less likely to resurface. Tamoxifen (an anti-estrogen) is a
drug that prevents breast tumor growth by blocking estrogen. A
study was conducted with 1,477 postmenopausal women with
early-stage breast cancer that had spread to the lymph nodes.
Patients were divided into three groups: A) those treated with
chemotherapy and tamoxifen simultaneously, B) those given
chemotherapy followed by tamoxifen or C) tamoxifen alone. The
results after eight years were encouraging. For those in group
A, 67% remained free of breast cancer, compared to 62% in
group B and 55% in group C. The women in group B were 18% more
likely to remain disease-free than those in the other two
groups. These results demonstrate the importance of starting
tamoxifen after chemotherapy.
Initial results from 2002 INTERGROUP
TRIAL, Loyola University Medical Center, IL
2. Calcium
supplementation affects HDL levels
A new study shows that calcium supplementation significantly
increases HDL cholesterol levels in postmenopausal women. The
study consisted of 223 women (avg. age 72) who had not
received prior treatment for hyperlipidemia or osteoporosis.
The women were administered either calcium (1 g/day) or
placebo for one year. The results showed that among women
taking calcium supplements, HDL cholesterol levels and HDL:LDL
ratio increased (7%) more than in the placebo group. In
addition, LDL cholesterol was decreased by 6%. The
concentrations of triglycerides showed no significant change.
The results show the benefits of calcium intake on lipid
levels, and encourage the use of calcium supplementation in
postmenopausal women.
AMERICAN JOURNAL OF MEDICINE
2002;112:343-347
3. Sudden
cardiac death linked to inflammatory protein
A study showed that levels of a protein in the blood called
C-reactive protein (CRP), can predict the risk of sudden death
due to heart disease. Inflammation is believed to play a key
role in atherosclerosis (hardening and narrowing of arteries)
that can lead to heart attack and stroke. Elevated CRP is a
known indicator of inflammation. The immune system is
activated during an infection and blood CRP levels rise
significantly as CRP circulates through the body. A link has
been found between chronic elevations of CRP and the increased
risk of heart disease. The study analyzed blood from the
arteries of 144 people who died due to sudden cardiac death.
Approximately half of them had blocked arteries caused by
plaque rupture or erosion. The placebo group died of causes
unrelated to heart disease, and did not have any condition
that would have raised their CRP levels. The results showed a
modest elevation of blood levels of CRP in all those who died
suddenly of heart-related causes. The study shows that an
elevated level of CRP is a risk factor for sudden death and of
vascular disease from atherosclerosis. High levels of CRP may
be controlled by changes in lifestyle and with drugs like
statins and aspirin.
JOURNAL OF THE AMERICAN HEART
ASSOCIATION 2002;105
4. Vitamin C,
E and arteriosclerosis in heart transplants
A recent study showed that supplementation with vitamins C
and E slows the progression of arteriosclerosis in patients
who have received heart transplants. Arteriosclerosis develops
within three years in 70% of these patients. In this study,
vitamins C (500 mg) and E (400 IU) were given twice daily for
one year to a total of 40 patients who had heart transplants
within the last two years. The results showed that after one
year, the thickness of the coronary artery had increased by 8%
in the group not given the vitamins. However, in the vitamin
group, the artery thickness did not change significantly
(0.8%). Vitamins C and E improved upon the benefits achieved
with statin therapy. The results showed that the growth of
plaque in the artery had been inhibited. The study
demonstrates that vitamins C and E can reduce arteriosclerosis
after a heart transplant. Since antioxidants slow
arteriosclerosis in the hearts of people who have not had
heart transplants, the results of this study are expected.
LANCET 2002 Mar
30;359(9312):1108-13
5. Coenzyme
Q10 and kidney failure
Coenzyme Q10 (CoQ10, ubiquinone) is an essential antioxidant
that is highly efficient in protecting cell membranes from
free radicals. CoQ10 also helps convert food into energy.
CoQ10 is produced naturally in the body. However, a deficiency
of CoQ10 occurs in heart failure, cardiomyopathies,
gingivitis, hypertension, muscular dystrophy, AIDS and kidney
problems. In older people, low levels of CoQ10 are more
common. In a recent study, 11 patients with chronic kidney
failure were given 60 mg of CoQ10, 3x/day. In the CoQ10 group,
there were significantly fewer people (36.2%) on dialysis,
compared to the placebo group (90.0%). Blood levels of
vitamins A, E, C and beta-carotene rose significantly, and
stress indicators were reduced considerably. Thus, CoQ10
supplementation improves the functioning of the kidneys and
reduces free radicals in those with kidney failure.
JOURNAL OF NUTRITIONAL AND
ENVIRONMENTAL MEDICINE, 2000;10:281-8
6. Preconditioning the heart with
resveratrol
Resveratrol is a grape-derived polyphenolic antioxidant that
has been found to protect the heart from ischemic-reperfusion
injury. A study looked at the mechanism of heart protection by
investigating the ability of resveratrol to precondition the
heart. Preconditioning of the heart with resveratrol provided
protection, as evidenced by improved heart functional recovery
(developed pressure and aortic flow), and reduced size of
heart attacks and death of heart cells. The results
demonstrate that resveratrol can pharmacologically
precondition the heart.
AMERICAN JOURNAL OF PHYSIOLOGY-HEART
AND CIRCULATORY PHYSIOLOGY, 2002;282(6):H1988-H1995
7. Vitamin C,
vasoconstriction and vasodilation
High tension in arteries due to blood oxygen increases
vascular resistance. This is possibly related to an
interaction between oxygen free radicals and vasoactive
factors derived from the endothelium (layer of cells of
membranous tissue lining the heart and vessels of the
circulatory system). Vitamin C is a potent antioxidant capable
of reversing dysfunction of the endothelium caused by
increased oxidant free radical stress. A study determined
whether vasoconstriction (decrease in diameter of blood
vessels) due to hyperoxia (excess oxygen) would be prevented
by vitamin C, and whether vasodilation (increase in diameter),
mediated by acetylcholine (transmits nerve impulses to
excitable membranes), would be blunted by hyperoxia and then
restored by vitamin C. The participants were 11 healthy
subjects and 15 congestive heart failure (CHF) patients. The
CHF group was characterized by endothelial dysfunction and
oxidative stress. Vitamin C prevented the hyperoxia-mediated
increases in forearm vascular resistance in both healthy
subjects and CHF patients. Vitamin C also prevented the
impairment by hyperoxia of acetylcholine-mediated increase in
forearm blood flow in healthy subjects. The addition of
vitamin C during hyperoxia augmented forearm blood flow
responses to acetylcholine. Thus, it was shown that vitamin C
prevents the effects of hyperoxia. The results also suggest
that vasoconstriction due to hyperoxia is mediated by free
radical oxidative stress, and that hyperoxia impairs
acetylcholine-mediated vasodilation in normal cell
function.
AMERICAN JOURNAL OF PHYSIOLOGY-HEART
AND CIRCULATORY PHYSIOLOGY 2002; 282(6):H2414-H2421
8. Potassium
level and risk of CVD
A study sought to determine the association between blood
potassium concentration and cardiovascular disease (CVD) risk
in 3,151 participants (avg. age 43; 48% men). They were free
of CVD, were not taking medications affecting potassium
homeostasis, and had blood potassium levels measured
(1979-1983). After 16 years, there were 313 CVD events,
including 46 CVD-related deaths. The results show that blood
potassium level was not significantly associated with the risk
of CVD or disease-related death. Thus, in a community-based
sample of individuals free of CVD, blood potassium level was
not associated with risk of cardiovascular disease.
ARCHIVES OF INTERNAL MEDICINE
2002;162(9):1007-12
9. New
water-soluble vitamin E inhibits atherosclerosis
A new form of vitamin E that is water soluble,
2-(alpha-D-glucopranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol
(TMG), was evaluated for its ability to inhibit the
development of atherosclerosis in hyperlipidemic (high lipid
levels) or cholesterol-loaded rabbits. The results showed that
although TMG rapidly entered the circulation blood after oral
administration, the blood TMG concentration remained low,
while neither TMG nor its metabolites appeared in the
low-density lipoprotein (LDL) fraction. TMG did not decrease
total blood cholesterol, VLDL or HDL. However, TMG did reduce
the blood concentration of thiobarbituric acid-reactive
substances (TBARS; an indicator of lipid peroxidation) in
cholesterol-loaded rabbits but not in the hyperlipidemic
rabbits. Nonetheless, TMG did inhibit atherosclerosis of the
aorta as effectively as probucol (a lipid lowering drug). The
results indicate that TMG opposes the progression of
atherosclerosis by preventing oxidation of LDL, and by
presently unknown mechanisms. Thus, even an antioxidant that
is not fat soluble, and thus not absorbed by LDL, apparently
can inhibit development of atherosclerosis despite a very low
blood concentration.
ATHEROSCLEROSIS 2002;162(1):111-7
10. Green
tea protects against alcohol-induced liver injury
A study examined the antioxidant polyphenolic extract of
green tea against early alcohol-induced liver injury. Rats
were fed high-fat liquid diets with or without alcohol and
green tea (300 mg kg/day) continuously for four weeks. After
four weeks, the blood ALT (sign of liver damage) levels were
increased significantly from 35 to 114 (four-fold over placebo
group values). However, the inclusion of green tea extract in
the diet significantly blunted the increase to 65. The alcohol
also caused severe fatty accumulation, mild inflammation and
tissue death in the liver. However, with green tea extract,
the increase in tissue death caused by alcohol were
significantly reduced, while not affecting fat accumulation or
inflammation. Alcohol also significantly increased the
accumulation of protein adducts (products of lipid
peroxidation and an indication of oxidative stress). However,
green tea extract blocked this effect almost completely. Green
tea extract also blunted the increase of TNFalpha (causes
inflammation) protein levels in the liver by alcohol. The
results indicate that dietary antioxidants, such as those
found in green tea, prevent early alcohol-induced liver
injury, most likely by preventing free radical stress.
BIOLOGICAL CHEMISTRY
2002;383(3-4):663-70
11. Effect
of multivitamins on immune system
A study looked at the effect of regular intake of low doses
of a multivitamin on the free-radical-producing activity of
peritoneal (membrane of abdomen) macrophages under conditions
resembling a possible infection in vitro. (Macrophages are
long-lived cells that engulf bacteria, protozoa, and tumor
cells, and stimulate other cells of the immune system.) For
two weeks mice were fed a basic diet, with or without
supplementation of a multivitamin. Multivitamin
supplementation increased the number and activity of
macrophages. This effect persisted for two weeks after higher
doses of supplementation were stopped. Multivitamin
supplementation lowered the steady-state free radical
concentrations of the liver and spleen and increased their
antioxidant reactivity. Thus, when taken regularly, low doses
of multivitamin supplementation may have a beneficial effect
on the body's immune system.
BRITISH JOURNAL OF NUTRITION
2002;87(5):501-8
12. Effects
of Chinese herbal extracts on lung cancer
A study examined lung cancer cells treated with four extracts
of Chinese herbal medicines taken by many cancer patients.
They exposed normal cells, drug-sensitive cells, and
multidrug-resistant lung cells to extracts from two plants
used in Chinese herbal medicine for lung cancer: 1)
Glycorrhiza glabra (GLYC) and 2) Olenandria diffusa (OLEN).
The cells were also exposed to extracts of two commercially
available combinations of Chinese herbal medicines, 3) SPES
(15 herbs) and 4) PC-SPES (8 herbs). Cell toxicity was
measured in terms of the inhibition of cell growth. The
results showed that the four herbal extracts were equally
cytotoxic to all the drug-sensitive cells tested. All four
extracts induced DNA fragmentation in the lung cancer cells.
The cancer cells treated with OLEN, SPES and PC-SPES showed
increased expression of several genes involved in the normal
cell death cascade. Therefore, the Chinese herbal medicine
extracts OLEN, SPES and PC-SPES are cytotoxic to both
drug-resistant and drug-sensitive lung cancer cells. The
extracts show some tumor cell specificity (interaction with
tumors only) compared to their effect on normal cells. Thus,
the herbal extracts help initiate apoptosis, as measured by
DNA breaks and gene expression. The reaction of the tumor
cells to these herbal extracts was similar to their reaction
to conventional chemotherapeutic drugs.
CANCER CHEMOTHERAPY AND PHARMACOLOGY
2002;49(4):261-26
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