Biological Dosimetry-Cytogenetics Findings At Persons Occupationally Exposed To Ionizing Radiation

A large number of physical and chemical agents are capable to course chromosomal aberrations. Ionizing radiation is frequent and well known course of chromosomal aberrations. If deoxyribonucleic acid (DNA) is irradiated before synthesis chromosomal – type aberrations are caused. Chromatid – type aberrations are results of DNA damages occurred during or after synthesis. Some of these changes could exist at patients several years after exposition. Biological dosymetry – cytogenetics analysis of persons occupational exposed to ionizing radiation in Federation of Bosnia and Herzegovina have been carried out in "Center for Human Genetics" of Medical Faculty in Sarajevo. In this study we have evaluated cytogenetics fi ndings of persons employed in a zone of radiation. Cytogenetics fi ndings have been demonstrated in allowed limit in  (,) examinees, and cytogenetics fi ndings were out of normal values in  (,) examinees. Th e majorities who have been employed in a zone of ionizing radiation were in age group - (,) and age group - (,). Radiological technicians (,) were exposed the most to ionizing radiation, than clinical nurse specialists (,), radiologists (,), physicians (,) machines technicians (,), pneumologist (,), orthopedists (,) and scrub nurses (,). Biological dosimetry – cytogenetics analysis have been carried out at  (,) male and  (,) female examinees. Th e most frequent aberration have been presented with , in the form of acentric fragments, than chromatid fragments with ,, dicentric chromosomes with ,, gaps with ,, minutes with , and interarm interchanges with ,.


Introduction
Th e chromosomal damages, chromosomal aberrations can be detected by cytogenetics analysis.Chromosomal aberrations are mutations on chromosomal level that course irregularities in the number or structure of chromosome of one species.Numerical irregularities with changed number of chromosomes in cell are coursed by disturbance in separation and moving of chromosomes or chromatids during cell division.Structural irregularities are coursed by breakages (transversal breakages of chromatids or chromosomes with reunion of segments or without reunion); the results can be balance or unbalance chromosomal rearrangements.Th ese irregularities can occur during meiosis (reductional or gametic cell division) and mitosis (equal or somatic division).Irregularities happened during mitosis are connected with aging process and cell cancer transformation, and irregularities happened during meiosis are responsible for changed genetics materials of off spring ().A large number of chemical and physical agents could induce mutation of genetics material.Ionizing radiations is major mutagen agent.Hermann Joseph Muller, the father of radiation genetics, studded mutations in fruit flies Drosophila melanogaster) and artifi cially increased the mutation rate by means of X ray ().For this discovery he was awarded the  Nobel Prize in Physiology and Medicine.Radiation is frequent and good known course of chromosomal aberrations in the peripheral lymphocytes and myeloid cells of bone marrow.If deoxyribonucleic acid (DNA) is irradiated before synthesis chromosomal -type aberrations are caused.Chromatid -type aberrations are results of DNA damages occurred after synthesis.Some of these changes could exist at patients several years after exposition.Th e relationship between these changes and possible biological eff ects is not well known.Irregularities in the number or structure of chromosome can be detected by means of the microscope analysis.Bender and Gooch were fi rst who suggested analysis of chromosomal aberrations in human lymphocytes to detect and quantify radiation exposures ().In its conventional form, chromosome analysis is largely based on the scoring of uniformly stained dicentrics in metaphase preparations of peripheral lymphocytes ().Dicentric chromosomes as a consequence of irradiation can be found in the organism up to  years after time of irradiation, which is actually the life span of lymphocytes ().Th e basic goal of this study is to evaluate biological dosimetry -cytogenetics fi ndings in persons employed in a zone of ionizing radiation and establish frequency of chromosomal aberrations.

Subjects and Methods
Cytogenetics studies are carried out in medical surveillance of persons employed in a zone of ionizing radiation.Chromosomal aberrations of peripheral lymphocytes are analyzed.Th e peripheral lymphocyte population, which is normally non-cycling, is precious, chip and simple source of chromosomal preparation because of short time taken in setting up a culture and sample is obtained easily.Th e culturing method is based on mitogenically stimulation of phytohaemagglutinin (PHA), so called mitotic vitamin.Under the influence of PHA the lymphocytes are transformed into blastoid cells after  hours.Th e procedure is to add , ml of whole blood and , ml of PHA to a vessel containing ml of medium and ml of serum and than incubate.Colcemid is used three hours before harvesting.After hypotonic treatment with KCl (, M) for  minutes the lymphocytes are fi xed in a mixture of methanol and icy acetic acid in ratio : and than material is dropped onto glass slides.Only clearly well spread complete metaphases are analyzed ().In our study we have evaluated cytogenetics fi ndings of  examinees employed in a zone of ionizing radiation during .

Results
By means of biological dosimetry it was determined that cytogenetics state was in standard allowed limits in  (,) examinees, and cytogenetics fi ndings were out of normal values in  (,) examinees (Graph ).Th e majority who have been employed in a zone of ionizing radiation were in age group - (,), then age group - (,), age group - (,), age group - (,), and further as showed by Graph .Analyses of examinees by occupation pointed that radiological technicians (,) were exposed the most to ionizing radiation, than clinical nurse specialists (,), radiologists (,), physicians (,) machines technicians (,), pneumologist (,), orthopedists (,), scrub nurses (,) and further as shown by Table .Structure of examinees (persons who employed in a zone of ionizing radiation) by sex is showed in Table .Biological dosimetry -cytogenetics analysis have been carried out at  (,) male and  (,) female examinees (persons who employed in a zone of ionizing radiation in ).Multiple chromosomal aberrations have been detected at  (,) examinees -persons, who employed in a zone of ionizing radiation in  in Faderation of Bosnia and Herzegovina (Graph ).At  (,) examinees -persons who employed in a zone of ionizing radiation acentric fragments have been presented with ,, chromatid fragments with ,, dicentric chromosome with ,, gaps with ,, minutes with , and interarm interchanges with ,.

Discussion
Workers in the nuclear industry and those who work with medical X-rays may be designated as "classified workers" and have their occupational radiation exposure monitored and recorded.The best method for biomonitoring is chromosomal aberration assay.Th e increased frequencies of chromosomal aberrations in radiation workers indicate the cumulative eff ect of low-level chronic exposure to ionizing radiation ().Analysis of chromosomes aberration ought to be done: ) in medical surveillance before starting with job in a zone in ionizing radiation, ) every three years after previous medical surveillance, ) if employer has been radiated with single dose higher than  mSv, ) if employers are exposed to doze radiation higher than  mSv during work in a zone of ionizing radiation.Frequency and type of chromosomal aberrations are out of control values for general population if there have been found in  analyzed metaphases: -fi ve or more acentric fragments, -total number of acentric fragments and dicentric chromosomes is equal to fi ve or higher, Frequency and type of chromosomal aberrations are on the top of control values for general population if there have been found in  analyzed metaphases: -total number of acentric fragments is equal to four.Th e fi nding is out of standard allowed values if there have been found more than three binuclear lymphocytes on . lymphocytes.Th e fi nding is out of standard allowed limit if there have been found marker chromosome occurred by reciprocal translocation or pericentrical inversion.If frequency and type of chromosomal aberrations are out of control values for general population examinee is not capable for work in a zone of ionizing radiation and control analysis should be done in  days.If frequency and type of chromosomal aberrations are on the top of limit of control values for general population examinee is capable for work in a zone of ionizing radiation but control analysis should be done in  days.Very high levels of ionizing radiation, such as that from a nuclear explosion, will course severe cell damage or cell death.Th is may lead to immediate death of individual as a result of acute exposure, or to longer-term consequences as a result of damage to the reproductive cells.It is more diffi cult to predict the eff ects of low-level doses of ionizing radiation such as cosmic radiation or medical X-rays because of individual variability in the body's selfrepair process ().Th e comparison of dosimetric date obtained by fi lm-badge measurements and the frequency of dicentric chromosomes in some study revealed no correlation between the two observed parameters (,).

Conclusion
It was determined that cytogenetics state was in standard allowed limits in  (,) examinees, and cytogenetics fi ndings were out of normal values in  (,) examinees using the method of biological dosimetry.Th e majorities who have been employed in a zone of ionizing radiation were in age group - (,) and age group - (,).Radiological technicians (,) were exposed the most to ionizing radiation, than clinical nurse specialists (,), radiologists (,), physicians (,) machines technicians (,), pneumologist (,), orthopedists (,) and scrub nurses (,).Biological dosimetries, in its conventional form of cytogenetics analysis, have been carried out at  (,) male and  (,) female examinees.Multiple chromosomal aberrations have been detected at  (,) examinees -persons who employed in a zone of ionizing radiation in  in Federation of Bosnia and Herzegovina.Th e most frequent aberration have been presented with , in the form of acentric fragments, than chromatid fragments with ,, dicentric chromosomes with ,, gaps with ,, minutes with , and interarm interchanges with ,.