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School Directory
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Arben
Santo, M.D., Ph.D.
Professor,
Discipline Chair of Pathology
Edward Via Virginia College of Osteopathic Medicine
2265 Kraft Drive, Blacksburg, VA 24060
Tele: 540-231-4867
Fax: 540-231-5252
Email: asanto@vcom.vt.edu |
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Discipline: |
Pathology |
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Education: |
| 1973 |
University
of Tirana School of Medicine, Albania |
M.D. |
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| 1984 |
University
of Tirana, Albania |
Ph.D. |
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Currently Teaching: |
Pathology |
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Current
Research
Interests
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Histological
diagnosis of early period of myocardial infarction |
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Sudden coronary death |
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Experimental atherosclerosis |
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Acute myocardial infarction kills many people every
year in the industrialized countries. To 25% of these death comes
suddenly, usually within one hour of the first clinical symptoms.
There is no time to establish a firm clinical diagnosis for these
sudden coronary deaths; the last chance to find out what really happened
is post-mortem examination. Stated in terms of general pathology,
the problem is to recognize an infarct that has occurred within a
very short time, of the order of one hour.
In
a preliminary research study, we have examined the myofibrils of
control and ischemic myocardial cells in a Jennings and Wartman
model of myocardial infarction. We occluded the left circumflex
coronary artery beneath the left auricular appendage in 25 open-chest,
anesthetized dogs. Animals were sacrificed after 40 and 60 minutes
of coronary artery occlusion: the heart was arrested by intravenous
KCl injection and rapidly excised. Anterior (control) and posterior
(ischemic) papillary muscles of the left ventricle were immersed
in buffered 10% formaldehyde solution after the completion of
rigor mortis. Paraffin sections of longitudinally oriented papillary
muscles were stained with H&E and myocardial cell myofibrils
were examined in polarized light microscope. Sarcomere length
was calculated using a calibrated micrometer.
Control papillary muscles demonstrated uniformly
contracted myocardial cells, with sarcomeres 1.3 to 1.5 micrometers
long. Myocardial
cells of the ischemic papillary muscles demonstrated elongated
sarcomeres, of the order of 1.9 to 2.04 micrometers. The stretching
of myocardial cells was observed regularly in all the ischemic
samples, and is due to a loss of ability of irreversibly injured
myocardial cells to develop rigor mortis. This is a very sensitive
stigma of irreversible ischemic injury and allowed us to recognize
the ischemic cells from the moment
of their biological death. With this approach, the histological
identification of myocardial infarction becomes very easy; it can
be done after at least 40 minutes of coronary artery occlusion
in dogs.
The examination of myofibrils by polarized light microscopy offers
an accurate, very sensitive and especially simple method to identify
the earliest stages of myocardial ischemia and infarction.
It is very interesting to pursue the research by examining forensic
cases of autopsies of sudden coronary death. The identification
of the nature of myocardial changes would elucidate the pathogenesis
of this syndrome, whose mechanisms remain still poorly understood. |
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