Jewish World Review June 7, 2002 / 27 Sivan, 5762
By Robert A. Wascher, M.D., F.A.C.S.
http://www.NewsAndOpinion.com |
In the past, people with clinically significant narrowing of their main
coronary arteries all required open heart surgery and coronary bypass
grafting to restore blood flow to the heart. More recently, however,
coronary artery stents (expandable mesh tubes that resembles those paper
"Chinese handcuffs" you played with when you were a kid) have made it
possible for many patients to avoid going under the surgeon's knife.
These
diminutive vascular conduits are threaded-up through an artery in the leg or
arm, and are then passed through the area of blockage in the affected
coronary artery. These internal bypass devices have a very high rate of
success in restoring coronary artery blood flow but, in 25 to 40 percent of
cases, the body responds to the device by gradually narrowing the stented
artery again. A number of approaches have been taken to reduce the
incidence of restenosis in stented arteries.
In this week's New England
Journal of Medicine is a study that looked at rapamycin-impregnated stents
as a novel way of reducing the restenosis rate. Rapamycin is often used as
an anti-rejection medication in transplant patients, as the drug inhibits
certain immune cells from dividing and attacking the transplanted organs.
The researchers coated coronary artery stents with rapamycin, and then
randomized 238 patients to receive either a rapamycin-coated stent or a
non-coated stent. The patients were then followed for at least one year
after stenting. The patients who had the rapamycin-coated stents implanted
were found to have significantly less restenosis than patients receiving the
conventional stents.
After being observed for 12 months, fully 27 percent
of the patients with conventional stents developed at least a 50 percent
reduction in the diameter of the stented artery, while none of the patients
with the rapamycin-coated stents experienced a comparable degree of
reduction in arterial diameter. Most importantly, 29 percent of the
standard-stent group experienced a heart attack, death, or the need for
emergent bypass during the 12 month follow-up period, while only 6 percent
of the rapamycin-coated stent group experienced any of these severe
complications of coronary artery restenosis.
This study convincingly
demonstrated a dramatic reduction in the most common complication associated
with coronary artery stents, and along with other similarly successful
interventions, further advances the state of the art of non-surgical
coronary artery disease treatment.
POSSIBLE CAUSE OF PARKINSON'S DISEASE IDENTIFIED
The area in the brain that is affected by the disease
is known as the substantia nigra, and is thought to be an important relay
system for nerve cell impulses involved in movement. For reasons that have
eluded scientists since it was first described in 1817 by the British
physician James Parkinson, dopamine-secreting neurons in this area of the
brain die off, causing the symptoms of PD.
However, a new study, just
reported in Nature Medicine, has identified at least one possible cause of
Parkinson's Disease. A brain protein called alpha-synuclein is known to be
elevated in the substantia nigra of most patients with PD. In this study,
the scientists added alpha-synuclein to healthy substantia nigra neurons
growing in a culture dish, and observed that this protein actually appeared
to convert the dopamine secreted by substantia nigra neurons into a toxic
compound which then, in turn, killed the neurons. Ironically,
alpha-synuclein appears to have a protective effect on neurons that do not
secrete dopamine in other parts of the brain.
Most spontaneous cases PD
have long been suspected to arise from exposure to unknown environmental
toxins. It is, therefore, especially intriguing that this Nature Medicine
study concluded that alpha-synuclein converts dopamine into a neurotoxin by
way of oxygen free radicals, which are byproducts of normal metabolism, and
the metabolism of numerous drugs and toxins as well. If alpha-synuclein
does in fact cause or mediate the onset of PD, this knowledge could serve as
a critical starting point for the development of drugs that target this
protein, or the free radicals that also appear to be involved. PD might
then be prevented in many cases or, at least, more effectively treated than
is possible at the present time.
BRIEFLY...
A Duke University team has studied pregnancy and birth rates among unmarried
teenagers in Texas. They found that conception rates dipped during the
summer months, and then dramatically increased again when school started in
the fall. Their conclusion, not surprisingly, was that most teens meet
their sexual partners at school....
When breast cancers spread, their favorite target is the skeletal system.
Traditionally, a nuclear medicine bone scan is utilized to evaluate breast
cancer patients for possible spread of their cancer to their bones. The
nuclear medicine bone scan has been around for decades, and is very
sensitive to any disruption of the bone caused by inflammation, injury or
tumors.
Unfortunately, arthritis, relatively minor injuries and infections
can all cause a positive bone scan result, making this test rather
nonspecific as a cancer detection tool. PET scans, on the other hand, are
both very sensitive and very specific for tumors. In the Journal of Cancer
Research & Clinical Oncology, a new study has compared the two types of
scans, and has found PET to be as sensitive as bone scans in detecting
metastatic breast cancer lesions in the bone.
However, unlike bone scans,
PET was also found to be highly specific for metastatic bone tumors. In
another words, bone scans picked up even subtle abnormalities in the
skeleton, irrespective of whether cancer metastases were present or not. An
abnormal PET scan, however, was far more likely to represent a true
metastasis of breast cancer to the bone than an abnormal nuclear medicine
bone scan.
JWR contributor Dr. Robert A. Wascher is a senior research fellow in molecular & surgical oncology at
the John Wayne Cancer Institute in Santa Monica, CA.
Comment by clicking here.
New coronary artery stent reduces risk of restenosis
Parkinson's Disease (PD), which affects about 1.5 million Americans, is a
neurological syndrome that causes tremors, difficulties in starting and
stopping movements, a peculiar stiffness of the body, depression and, in
some cases, dementia.
Bioflavanoids are in the news a great deal these days. Antioxidant
flavanoids contained in tea and other natural sources are thought to have a
variety of beneficial effects, including the elimination of potentially
harmful free radicals that have been linked to an increased risk of heart
disease and some cancers. The journal Cancer Research is reporting that
silibinin, a flavanoid found in the milk thistle plant, is capable of
significantly inhibiting the growth of human prostate cancer cells implanted
in mice. Silibinin reduced tumor volume in these mice by 53 to 64 percent,
and appeared to have virtually no observable toxicity. Human studies using
this compound are currently being planned.
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05/24/02: Molecular detection of tumor cells in the blood & prognosis; Cox-2 & breast/lung cancers; BRCA2 gene mutations & the risk of breast cancer; breast density & the risk of breast cancer
05/19/02: Moderate alcohol intake and blood sugar levels; more good news for tea drinkers; blood potassium levels & the risk of cardiovascular disease; ethnic differences in diabetic complications
05/10/02: Tea drinkers and the risk of death following heart attack; duration of breastfeeding & adult intelligence; abdominal aortic aneurysms: surgery or observation?
05/03/02: Risk of adverse drug reactions from newly released medications; preoperative beta-blockers may reduce heart bypass deaths; shape-shifting plastics may alter surgical practice; weight loss
supplement may cause liver damage
04/26/02: Angry young men & risk of premature cardiovascular disease; stay-at-home dads & risk of
cardiovascular disease; more on the effects of statins; dairy consumption and the risk of
pre-diabetes; smallpox vaccine: good to the last drop?
04/19/02: Change your sex by drinking water?; Anti-inflammatory RXs may reduce growth of breast cancer cells; radiation treatment reduces repeat narrowing of bypass grafts
04/05/02: Fish & Omega-3 fatty acid consumption and cardiac health; news briefs
04/05/02: Can coffee reduce your risk of tooth decay?; exercise & blood pressure; a single high-fat meal reduces coronary artery function
04/01/02: Pre-diabetes: a newly defined category of
health risk; teen television viewing and subsequent
aggressive behavior; the benefits of strength training
in the elderly; more ...
03/22/02: Bacteria, antibiotics & heart disease; mammograms: the debate continues; calcium & the risk of colon cancer ... and more
03/15/02: Mammography debate continues; statins & fracture risk; physical fitness & the risk of death; other intriguing findings
03/08/02: Blows to the chest & sudden cardiac death; air quality & the risk of lung cancer; tomatoes and your prostate
03/01/02: Diet & the risk of ovarian cancer; lifetime risk of developing high blood pressure; Osteoporosis prevention with a once-a-year injection?
02/26/02: The continuing controversy regarding screening mammography
02/22/02: Lowering body temperature after heart attack improves outcome; A silver lining for the chronically sleep-deprived?
02/15/02: Hormone replacement therapy & the risk of breast cancer; use it or lose it: Alzheimer's disease
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02/08/02: Possible breakthrough in early cancer diagnosis; mammography: the controversy continues; CPR techniques revisited
02/01/02: Antibiotics in livestock feed & human disease; genetic detection of early colon cancer in the stool; genetic analysis of breast cancers may help decide treatment
01/25/02: Drug increases lifespan (if you're a fly...); workplace attitudes and smoking cessation; effects
of inadequate sleep on surgeons
01/18/02: Lifelong effects of premature birth; smokers under the knife; aspirin and cardiovascular health
01/11/02: Estrogen levels in the blood & breast cancer risk; Heart attack: sex and survival; dangerous lettuce invaders
01/09/02: Cancer & aging: Two sides of the same coin?
01/04/02: Vitamin a & the risk of hip fracture in postmenopausal women; ovarian cancer risk and oral contraceptives
12/28/01:
Magnetic Resonance Imaging (MRI) detects
coronary artery disease; new development in
obesity research; adverse childhood experiences &
the risk of suicide attempts
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12/14/01: Chernobyl and the Risk of Thyroid Cancer in hildren; children & obesity; gastroesophageal reflux disease update
12/07/01: Update on school shootings; new implantable heart-assist device approved for further evaluation; prevention of fungal infections in pre-term babies
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11/21/01: Modified smallpox vaccine may reduce risk of cervical cancer; New approach to breast cancer diagnosis; New non-invasive prenatal diagnostic test for down's syndrome
11/16/01: Cholesterol-lowering drugs reduce risk of heart attack; supplemental radiation therapy reduces risk of breast cancer recurrence; brains of women may answer age-old questions
11/09/01: Bio-warfare (redux); my gray matter is bigger than yours; mad elk disease?
11/02/01: Making sense of bio-warfare
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10/19/01: New insights into autism; the wiley appendix
10/12/01: More bad news about obesity links to other diseases…Hey dad, can I borrow the car keys?
10/05/01: California leads nation in reduction of tobacco-related disease; exercise as an antidepressant?
09/25/01: Advances in the detection of breast cancer; primary care physician awareness of peripheral arterial disease; arsenic in the water
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09/05/01: English milk cows prefer Beethoven and Simon & Garfunkel over
Bananarama; new prostate cancer prevention study: looking for a few good men; exercise & diet can help prevent diabetes
08/28/01: Arthritis drugs may be linked with increased risk of heart disease; errors in blood clotting tests can be fatal; infant soy formula not associated with reproductive side effects