الفهرس 
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Abstract
The exposure of human beings to ionizing radiation take the most consideration during medical practice. Exposure to low dose of ionizing radiation is one of the most definite risk factors for cancer development .
Many cardiac diagnostic or therapeutic testing, such as cardiac catheterization involve considerable exposure to ionizing radiation. A contemporary cardiac patient is exposed to a significant cumulative effective dose, resulting in deleterious clinical implications which can affect not only the personnel involved, but also their progeny.
Radiation cytogenetics has benefited from recent developments in genetics and molecular biology to develop biomarkers and methods for radiation dose assessment.
On the other hand , evidence have shown cardio vascular risk factors closely correlated with endothelial progenitor stem
cells numbers and functions .The circulating form of endothelial progenitors cells (EPCs) are derivated from bone marrow (BM)-derived hematopoietic stem cells (HSCs).
Ionizing radiation is highly efficient in producing chromosome aberrations as a consequence of miss rejoining of induced DNA double-strand breaks .
The current study was designed to identification of circulating endothelial progenitor stem cell (CD133+ , CD34+, CD133+ CD34+ and SDF-1 ) by flow cytometry in cardiac catheterization patients, to investigate the effect of ionizing radiation on circulating endothelial progenitor stem cell (CD133+ , CD34+, CD133+ CD34+ and SDF-1 ) before and after 24 hours from cardiac catheterization and to study chromosomal aberration before and after the effect of ionizing radiation on catheterization patients.
The study included 40 patient , whose ages were ranged between (40-65) year and divided into patients above 50 year and patients below 50 year and underwent a cardiac catheterization. 10 ml blood was drawn before and after 24 hours from cardiac catheterization procedure. The control group included 10 healthy men. Patients were recruited from National Heart Institute between July 2009 and May 2010.
The present study revealed that mean of (CD34+) ( after cardiac catheterization , before cardiac catheterization and control) was (38.9 , 37.1 and 48.6 ) , the mean of (CD133+) after cardiac catheterization , before cardiac catheterization and control was (39.25 , 38.5 and 54.2 ) and the mean of (CD34+ CD133+) after cardiac catheterization , before cardiac catheterization and control was (20 , 20.3 and 25.4) .
There was a significant decrease in the number of EPCs (CD34+, CD133+ and CD34+CD133+) patients before and after cardiac catheterization (P<0.0001,P<0.001,P<0.05) when compared to control groups . It may be the results of ionizing radiation or increasing the age of patients.
On the other hand we divided the patients into two groups , a group above the age of 50 years and a group below the age of 50 years .
In the patients above the age of 50 years : the mean of (CD34+) after cardiac catheterization ,before cardiac catheterization and control was (37.6, 29.8 and 48.6 ) , the mean of (CD133+) after cardiac catheterization , before cardiac catheterization and control was (40.25 , 34.5 and 54.2 ) and the mean of (CD34+ CD133+) after cardiac catheterization , before cardiac catheterization and control was (19.5 , 16.2 and 25.4) .
In the patients below the age of 50 years : the mean of (CD34+) after cardiac catheterization ,before cardiac catheterization and control was (40.2, 44.5 and 48.6 ) , the mean of (CD133+) after cardiac catheterization , before cardiac catheterization and control was (38.25, 43.5 and 54.2 ) and the mean of (CD34+ CD133+) after cardiac catheterization , before cardiac catheterization and control was (20.5 , 24 and 25.4) .
The present data showed that mean of EPCs (CD34+, CD133+,CD34+CD133+) was significantly increase in patients below the age of 50 years after cardiac catheterization compared to patients before cardiac catheterization, but still (CD34+, CD133+,CD34+CD133+) significant decrease in patients when compared to control groups .
SDF-1 is considered as a part of host defense processes that protect stem cells from DNA-damaging agents including ionizing radiation and a pivotal regulator of trafficking of various types of stem cells in the body necessary for organ/tissue regeneration. We found a significant increase in the number of SDF-1in patients below the age of 50 years after cardiac catheterization compared to control groups and patients before cardiac catheterization it may be due to the ionizing radiation increases stem cell active mobilization factors through the expression of SDF-1
Cytogenetic analysis was performed through standard and G/T banded chromosomal analysis , also structural and numerical chromosomal aberration was determined.
The present study explained that the structural chromosomal aberrations were significant increase in patients after cardiac catheterization (16.56%) which represented in (centric fusion ,chromosome fusion, gap , isochromatid gap , chromatid fusion , Dicentric , deletion , break , diradial , chromatid exchange) compared to before cardiac catheterization (4.63%) which represented in (centromeric separation , centric fusion chromosome fusion, isochromatid gap , chromatid fusion , Dicentric deletion , break , diradial ,chromatid exchange) when compared to control groups (3.8%) .
The numerical chromosomal aberrations were significant increase in patients after cardiac catheterization (4.5%) which represented in (aneuploidy, polyploidy and endroduplication) compared to before cardiac catheterization (1.31%) which represented in (endroduplication and aneuploidy) when compared to control groups (1%). The increase of the percentage of chromosomal aberration after cardiac catheterization may be due to the doses of radiation which used during cardiac catheterization or increase the age of patients.
It is important to mention that , the karyotyping in all cases found that, the percentage of monosomy in chromosome 20 in patients before cardiac catheterization represented (15%) which found in 3 cases and the percentage increased after cardiac catheterization to (40%) which found in 8 cases . It may be related to any cardiac disease or specific genes in chromosome 20 related to this disease .
Also through G/T banding in patients after catheterization found trisomy in chromosome 3 in one case, it may be due to the doses of radiation which used during cardiac catheterization .
The present data found that an inverse correlation between endothelial progenitor stem cells and chromosomal aberrations by increased in the number of progenitor stem cells, the number of structural and numerical chromosomal aberrations was decreased and vice versa .
In conclusion, This study clearly showed that a significant decrease in the number of circulating endothelial cell in patients with coronary artery disease and a significant increase in chromosomal aberration after cardiac catheterization .
The present study suggested that prolonged exposure of man to X-rays may result in genetic damage it is obligatory on the part of hospital management to take appropriate steps to minimize exposure to X-rays at the workplace.