الفهرس 
AcknowledgmentsOnly 14 pages are availabe for public view
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Abstract
Genotoxicity is a serious problem with a high morbidity to human population. It is responsible for occurrence of the majority of birth defects and spontaneous abortions. Moreover, it is involved in the basic mechanism of cancer development . Therefore, it is advisable screen compounds for potential genotoxic effects. In the present work, the possible genotoxicity of inhalation anesthetics (isoflurane and sevoflurane) were studied in patients who exposed to surgical operations for the first time and in subjects who work in operating rooms using RAPD analysis. Randomly amplified polymorphic DNA technique is a simple, sensitive and reliable method that utilizes molecular biology knowledge to assess genotoxicity.
A prospective, cohort, controlled study was conducted .The aim of the present work was to:
Study the possible genotoxicity of inhalation anesthetics by Random Amplified Polymorphic DNA (RAPD) method.
Evaluate the genotoxic effects of inhalation anesthetics after single and repeated exposure;
- Single exposure included patients admitted to Sohag University Hospitals for different surgical indications and were exposed to inhalation anesthetics for the first time .They were classified according to the period of exposure during the operation .
- Repeated exposure included health working persons (anesthesiologists, surgeons, nurses and workers) were classified into groups according to the period of exposure to inhalation anesthetics.
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Two hundreds individuals were enrolled in the present study, their ages ranged from 18 to 50 years. They were classified into:
Control groups (group A1 and group A2):
group A1: 50 non medical healthy persons who were not exposed to inhalation anesthetics.
group A 2: 50 medical field subjects but don’t work in the field of anesthesia.
group B (single exposure): 50 patients admitted to Sohag University Hospitals for different surgical indications and were exposed to inhalation anesthetics (isoflurane or sevoflurane) for the first time.
group C (repeated exposure): 50 medical field subjects who work in the field of anesthesia . The present study had strict exclusion criteria to minimize the influence of possible confounding factors. Two inhalation anesthetics were used in the present study; isoflurane and sevoflurane to detect the primary DNA changes following single exposure to these frequently used inhalation anesthetics. The patients subjected to ENT and neurosurgical operations. The control samples were taken before induction of inhalation anesthesia and the second samples were collected after the end of operation. The current study revealed that: There was no significant statistical difference in the mean value of the age of group B compared with control groups (A1& A2) and group C. There was no significant statistical difference as regard the gender of the cases in group B compared with control groups (A1 & A2) and group C .
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The band loss was associated with older age and band gain was associated with younger age. But there was non significant statistical difference. The females were more vulnerable to DNA changes . However there was non significant statistical relation between DNA changes and the gender of patients exposed to inhalation anesthesia . The least duration for DNA changes to occur in the present study was recorded at one hour . Changes observed in RAPD profiles were scored by identifying the appearance and disappearance of bands compared to the control. Band changes were significantly related to the operation period; the shorter the operation period, the likely to show ”no band changes”. Also, the maximum mean value of operation period was seen among those having band loss ( 2.59 hours) followed by band gain (2.14 hours) then combined band loss and gain (1.56 hours) and lastly no change (1.30 hours). The majority of patients suffered band gain (48%); followed by band loss (38%); then decreased band intensity (32%) and lastly increased band intensity (16%). The obtained results revealed that exposure to inhalation anesthetics led to DNA changes observed as a difference in the RAPD PCR pattern of the patient before and after exposure to the anesthetic. Eighty percent of patients exposed to inhalation anesthesia for the first time had a change in the RAPD PCR pattern in the form of band gain, increased band intensity, band loss, or decreased band intensity. Isoflurane was less mutagenic than sevoflurane. Studying the DNA lesions showed that band changes were significantly different between the patients receiving isoflurane and those receiving sevoflurane . The
vast majority of those received sevoflurane had combined band loss and gain (81.8%) compared to only 23.1% among those received isoflurane . As regard the repeated exposure group, the current study recorded that: There was no significant statistical difference in the mean value of the age of group C as compared with the control group A1 and A2. There was no significant statistical difference as regard the gender of the cases in repeated exposure group compared with control groups (A1 & A2) . The females had higher mean band number compared to males with a significant statistical difference. The majority of repeated exposure cases had four bands (70%) as compared with the control subjects (Groups A1 and A2) among whome no cases had four bands. The difference was highly significant statistically with a p value less than 0.001. The primers generated strong and similar banding patterns in the majority of samples tested due to repeated exposure to inhalation anesthetic . These banding patterns were different and distinctive and can be distinguished from patterns obtained from non exposed persons . This indicated that repeated exposure to inhalation anesthetic created polymorphic regions in the exposed genome. The occupational period was positively related to the mean value of band number. There was no significant statistical difference . The weekly working days was significantly and positively related to the mean value of band number.
There was significant statistical difference as regard the mean value of band number compared with the age of cases among group C.
High significant statistical difference in the mean value of band number among repeatedly exposed cases that was much higher than non exposed subjects (groups A1 and A2).
The mean value of band number was directly related to the age of cases in repeated exposure group. Significant statistical difference was detected. However, this relation was weak as the pearson correlation coefficient was less than 0.4 .
Significant statistical difference in the mean value of band number as regard the gender . It was higher in females than males.
Occupational period was positively related to the mean value of band number. Non-significant statistical difference was detected.
The weekly working days showed significant statistical difference and positive relation to the mean value of band number
The daily working hours showed negative relation to the mean band number (P value = - 0.031).
Comparison between single and repeated exposure as regards the mean value of band number was studied. It was found that the mean value of band number was higher in repeated exposure group (3.56 ± 0.733) as compared to single exposure group (2.34 ± 1.002). High significant statistical difference was detected . To our knowledge, this was the first study investigating the DNA damage in occupational exposed persons to inhalation anesthetics by RAPD profiles. The main limitation of the present study was the lack of data for repeated exposure to these agents by this type of analysis and lack of samples before exposure .
Conclusion The findings of the present study concluded that inhalation anesthetic exposure induced DNA changes in patients who exposed for the first time and in repeatedly exposed persons . It can be taken as an indication that these individuals have increased cancer risk.
The present study showed that isoflurane was less mutagenic than sevoflurane .
The current study revealed that females were more vulnerable to DNA changes .
The least duration for DNA change to occur in the present study was recorded at one hour.
Recommendations
It is recommended to develop sensitive methods and biomarkers at DNA level speak in favour of conducting assessments of the adverse effects of substances which are in regular clinical use. In the case of sevoflurane and isoflurane, it is recommended to extend the research, since the results of the existing studies are rather controversial.
It is recommended to examine patients after a period of exposure to inhalation anesthesia to indicate whether the DNA changes are temporary or permanent.
It is recommended to investigate the oxidative stress mechanism and extend the study to involve other commonly used inhalation anesthetics.
It is recommended to do RAPD analysis for all staff in the anesthesia department before receiving the work for comparison after that.
It is recommended to do biomonitoring studies to detect early changes caused by inhalation anesthetics in exposed personnel, favoring environment intervention by implanting effective scavenging systems in operating rooms and individual intervention by education and protocols that ensure the use of anesthetic techniques to reduce ambient air pollution.
It is recommended to limit the work of women inside the operating room, or at least to perform a periodic examination for them, while preventing pregnant women from entering the operating rooms.
It is recommended to minimize the use of sevoflurane and replace it with isoflurane as much as possible.
It is recommended to implement appropriate legislation in our country regarding the limit of occupational exposure to inhalation anesthetics. It is advisable to have knowledge of anesthetic measurements in
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operating rooms.
The best prevention for inhalation anesthetics exposure is the application of loco-regional or total intravenous anesthesia protocols where applicable but, overall the best prevention is the use of effective scavenger systems. Two questions in this topic still remain open and need further studies: the impact of exposure duration and inter-individual sensitivity related to significance of genetic factors.