Blood
transfusion may up death risk for patients with heart attack
A meta-analysis of 10 studies conducted by
researchers, including an Indian origin, has found that receipt of a blood
transfusion among patients with myocardial infarction (heart attack) was
associated with increased all-cause mortality compared with not receiving a
blood transfusion during heart attack.
Therapeutic measures including anticoagulation
and antiplatelet drugs have “revolutionized” the approach to acute coronary
syndrome and improved clinical outcomes.
However, some of these therapies may also
increase the risk for bleeding, which can lead to patients developing anemia
during their hospital stay and requiring blood transfusion, according to the
study background.
Saurav Chatterjee, MD, of Brown University and
Providence Veterans Affairs Medical Center, Rhode Island, and colleagues
conducted a review of studies published between January 1966 and March 2012.
Ten studies, including 203,665 participants, were
selected for analysis. Only one study was a randomised trial, while the others
were observational studies.
“Analyses of blood transfusion in myocardial
infarction revealed increased all-cause mortality associated with a strategy of
blood transfusion vs. no blood transfusion during myocardial infarction (18.2%
vs. 10.2%), with a weighted absolute risk increase of 12%,” the researchers
said.
Other statistical analyses suggest that blood
transfusion was associated with a higher risk for mortality independent of
baseline hemoglobin level, nadir hemoglobin level and change in hemoglobin
level during the hospital stay. Blood transfusion also appeared to be
associated with a higher risk for subsequent myocardial infarction (risk ratio,
2.04), according to the study results.
“In conclusion, this meta-analysis provides
evidence that rates of all-cause mortality and subsequent myocardial infarction
are significantly higher in patients with acute myocardial infarction receiving
blood transfusion. Additional outcomes data are needed from randomised clinical
trials that investigate important outcomes with adequate sample size and with
low risk for bias," the researchers concluded.
The finding was published Online First by
Archives of Internal Medicine, a JAMA Network publication.
27.12.2012
Cholesterol important for development and function of brain
Two molecules that play
an important role in the survival and production of nerve cells in the brain,
including nerve cells that produce dopamine, have been identified by scientists
at Karolinska Institutet in Sweden. The discovery may be significant in the
long term for the treatment of several diseases, such as Parkinson’s disease.
The same scientists
have previously shown that receptors known as “liver X receptors” or LXR, are
necessary for the production of different types of nerve cells, or neurons, in
the developing ventral midbrain. One of these types, the midbrain
dopamine-producing neurons plays an important role in a number of diseases,
such as Parkinson’s disease.
What was not known,
however, was which molecules stimulate LXR in the midbrain, such that the
production of new nerve cells could be initiated. The scientists have used mass
spectrometry and systematic experiments on zebrafish and mice to identify two
molecules that bind to LXR and activate it. These two molecules are named
cholic acid and 24,25-EC, and are bile acid and a derivate of cholesterol,
respectively.
The first molecule,
cholic acid, influences the production and survival of neurons in what is known
as the “red nucleus”, which is important for incoming signals from other parts
of the brain. The other molecule, 24,25-EC, influences the generation of new
dopamine-producing nerve cells, which are important in controlling movement.
One important
conclusion of the study is that 24,25-EC can be used to turn stem cells into
midbrain dopamine-producing neurons, the cell type that dies in Parkinson’s
disease. This finding opens the possibility of using cholesterol derivates in
future regenerative medicine, since new dopamine-producing cells created in the
laboratory could be used for transplantation to patients with Parkinson’s
disease.
“We are familiar with
the idea of cholesterol as a fuel for cells, and we know that it is harmful for
humans to consume too much cholesterol,” said Ernest Arenas, Professor of Stem
Cell Neurobiology at the Department of Medical Biochemistry and Biophysics at
Karolinska Institutet, who led the study.
“What we have shown now
is that cholesterol has several functions, and that it is involved in extremely
important decisions for neurons. Derivatives of cholesterol control the
production of new neurons in the developing brain. When such a decision has
been taken, cholesterol aids in the construction of these new cells, and in
their survival. Thus cholesterol is extremely important for the body, and in
particular for the development and function of the brain.
The study has been
published in the journal Nature Chemical Biology.
27.12.2012
He
only is exempt from failures who makes no efforts
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