The relationship of E-selectin singlenucleotide polymorphisms with breast cancer in Iraqi Arab women

Breast cancer (BC) is a significant threat to female health, with both modifiable andnon-modifiable risk factors. It is essential to monitor patients regularly and to raise population awareness. Increasing research also suggests that E-selectin (SELE) may increase tumor angiogenesis and the development of cancer. This study investigated SELE single-nucleotide polymorphisms (SNPs) in the following positions: rs5367T/C, rs5368C/T, rs5362T/G,and rs5362T/C. Using polymerase chain reaction, significant differences in allele and genotype frequencies were found between BC patients and controls. Position rs5368 was associated with an increased risk of BC for the CT and TT genotypes, with odds ratios (ORs) of16.3 and 6.90 (Fisher probability = 0.0001, p = 0.005). Women with the T allele had a 19.3-fold higher incidence of BC, while allele C may be a protective allele against BC (OR, 0.05).Heterozygous genotypes at rs5367, rs5362, and rs5362 were significantly more common inBC patients, with ORs of 5.70, 4.50, and 3.80, respectively. These SNPs may be associatedwith the risk of BC, because the frequency of mutant alleles was significantly higher in patients (OR: 4.26, 3.83, and 4.30, respectively) than in controls (OR: 0.23, 0.30, and 0.20, respectively). These SNPs may be considered a common genotype in the Iraqi population,with the wild-type allele having a protective fraction and the mutant allele having an environmental fraction. The results also revealed a 2-fold increase in gene expression in BCpatients compared to controls, with a significant effect (p = 0.017). This study's findingsconfirm the importance of SELE polymorphisms in cancer risk prediction.

Associations between single-nucleotide polymorphisms of the interleukin-18 gene and breast cancer in Iraqi women

According to long-term projections, by 2030, the world’s population is predicted to reach 7.5 billion individuals, and there will be roughly 27 million new cancer cases diagnosed. The global burden of breast cancer (BC) is expected to rise. According to the Ministry of Health-Iraqi Cancer Registry, cancer is the second largest cause of death after cardiovascular disease. This study investigated the interleukin-18 (IL18) single-nucleotide polymorphisms (SNPs) –607C/A rs1946518 and –137G/C rs187238 using the sequence-specific amplification-polymerase chain reaction approach. Regarding the position –607C/A, there was a highly significant difference between the observed and expected frequencies in patients and controls (χ 2 = 3.16 and χ 2 = 16.5), respectively. The AA and CA genotypes were associated with significantly increased BC risk (odds ratio [OR], 3.68; p = 0.004 and OR, 2.83; p = 0.04, respectively). Women with the A allele had a 5.03-fold increased susceptibility to BC. The C allele may be a protective allele against BC (OR, 0.19). Although position –137G/C showed no significant differences in the CC genotype distribution (p = 0.18), the frequency of the CC genotype was significantly higher in patients than in controls. In contrast, patients had a significantly higher frequency of GC genotypes than controls (p = 0.04), which was associated with an increased risk of developing BC (OR, 2.63). The G allele frequency was significantly lower in patients than in controls (55.0% vs. 76.2%, respectively). This SNP may be considered a common genotype in the Iraqi population, with the wild-type G allele having a protective function (OR, 0.19) and the mutant C allele having an environmental effect (OR, 2.63).

Preventing nerve damage during total thyroidectomy or total lobectomy surgeries

Background and objective: Thyroidectomy is an operation that involves surgical removal of all or part of the thyroid gland. The main postoperative complications of thyroidectomy are hypoparathyroidism and recurrent laryngeal nerve injury. This study aimed to find out the main postoperative complications particularly nerve damage during total thyroidectomy or total lobectomy

Methods: The medical records of patients who were diagnosed with thyroid disease and underwent surgery between January 2[nd], 2013 and December 30[th], 2014 in Teaching, Shar, Soma and Zhian hospitals in Sulaimaniyah were retrospectively reviewed

Results: All patients who underwent total thyroidectomy or total lobectomy surgeries were discharged within 24 hours of the operation. During the average follow-up of 24 months, no case of permanent recurrent laryngeal nerve injury was registered. Vocal cord paralysis was considered to be present, when there was absent or markedly reduced movement of the affected vocal cord

Conclusions: Meticulous hemostasis and a delicate technique are required to prevent nerve injury. We recommend dissection and division of all the vessels flush with the thyroid capsule at the anterior and peripheral aspect of the gland. Separate ligation of anterior and posterior branched of the superior thyroid artery will preserve the external branch of the superior laryngeal nerves

Effect of tactile kinesthetic stimulation on preterm infants' weight and length of hospital stay in Khartoum, Sudan

To determine the effect of 7 days tactile kinesthetic stimulation [TKS] on preterm infants' weight and hospital stays in Khartoum State, Sudan. This is a quasi-experimental study, it was conducted in 4 hospitals between January and June 2013, Khartoum, Sudan, and it involved 160 preterm infants randomly assigned into the case and control groups [80 neonates in each]. Preterm infants in the control groupreceived routine nursing care, while preterm infants in the case group received TKS for 3 periods, 15 minute per day for 7 constitutive days, in addition to routine care. Data was collected using a structured self-designed and validated questionnaire, checklist, and weighting scale. Weight gain and hospital stay were compared between the 2 groups. Over the constitutive 7 days, the case group gained significantly more weight [1071gm versus 1104gm] compared with the control group [1077gm versus 1084gm] [1084.55 +/- 90.74] who gained only 6.9gm within the same 7 days without TKS treatment. The mean difference in weight gain was significant [p=0.00]. The hospital stay for preterm infants in the case group was significantly shorter [18.05 +/- 9.36 versus 25.47 +/- 10.25; p=0.00]. Tactile kinesthetic stimulation for preterm infants has a beneficial effect on weight gain and earlier discharge from hospital, which are sequentially efficient and cost effective

Benign acute childhood myositis in the eastern region of Kingdom of Saudi Arabia; a 5-year experience

To assess the epidemiological, clinical and laboratory characteristics, and outcomes of BACM in children diagnosed at a teaching hospital in the eastern province of the KSA. A retrospective study of 28 patients admitted to the hospital with the diagnosis of BACM was carried out at King Fahd Hospital of the University, AlKhobar, Kingdom of Saudi Arabia [KSA], from January 2008 to December 2012. Demographics, clinical characteristics, laboratory findings and patients' responses were analyzed. Thirty episodes were reported over 5 years with incidence of 3.17 per 100,000. The male to female ratio was 6:1. The mean age was 6 years. A seasonal peak during the winter months was observed. The major symptoms were fever, inability to walk in all the patients [100%] and symptoms of upper respiratory tract infections found in 70%. Major clinical findings were the normal deep tendon reflex and calf muscle tenderness in 76.6% and 100% respectively. The prominent laboratory findings were the high creatine phosphokinase [CPK] and leukopenia in 100% and 60%, respectively. Our findings showed that the clinical and epidemiological features associated with BACM, in the KSA, have the similar pattern of other studies from different regions in the world. A nationwide survey, however, is necessary to investigate the overall incidence, risk factors and the outcome of BACM in the KSA

Iraqi parents' views of barriers to childhood immunization

Deficiencies in knowledge about immunization among parents often leads to poor uptake or errors in immunization dosage and timing. The aims of this study were to determine Iraqi parents'views of barriers to immunization and beliefs about ways to promote immunization. A questionnaire survey was carried out among 528 Iraqi parents with children who had incomplete immunization status. The main barriers to immunization agreed by the parents were lack of vaccine availability [51.5% of parents] and parents' lack of education [42.4%], while 88.4% of parents thought that lack of funding was not an important barrier. More than 60% of the parents suggested promoting childhood immunization via the media, and 77.5% thought that an increase in funding would not remove barriers to childhood immunization. Better vaccine availability in public health clinics and improving parents' literacy might enhance immunization uptake in Iraq

Patterns of meningococcal infection in Sudan with emergence of Neisseria meningitidis serogroup W135

This study was conducted during the 2004-2006 epidemic of meningitis in Sudan to follow-up the frequency of disease outbreak or endemic waves and to evaluate the new quadrivalent vaccine for actual application. Samples were collected from Darfur, El Gedaref, Kassala and Khartoum States and transported to the National Health Central Laboratory in Khartoum. Of 196 patients with clinical symptoms and signs of meningitis, conventional culture identified Neisseria meningitidis in 37 [18.9%], confirmed by polymerase chain reaction. N. meningitidis type A was identified in 29 [78.4%] patients, type C in 3 [8.1%] and N. meningitidis W135 in 5 [15.5%]. The serotyping and molecular diagnosis patterns of N. meningitidis showed the emergence of the new strain,W 135, in patients from the borders of Sudan, 3 from the West Darfur, and 1 each from El Gedaref and Kassala. These could be related to the movement of pilgrims through the borders to Saudi Arabia in the Hajj season. Serious consideration may be needed for quadrivalent vaccination to prevent seasonal and Hajj season outbreaks

First insight into the genetic diversity of Mycobacterium tuberculosis strains from patients in Duhok, Iraq

The aim of this study was to evaluate the genotypic diversity of Mycobacterium tuberculosis strains using IS6110 RFLP, spoligotyping and MIRU-VNTR typing. Between June 2008 and June 2009, all smear positive pulmonary specimens were collected prospectively at the national tuberculosis program [NTP] center of Duhok province. The specimens were processed for culture by modified Petroff's method and were inoculated into two tubes of L?wenstein-Jensen [LJ] media. The isolates were identified asM. tuberculosis by using biochemical tests and growth rate. Molecular fingerprinting of all M. tuberculosis strains was performed by IS6110 RFLP, spoligotyping and MIRU-VNTR. M. tuberculosis strains were isolated from 53 Iraqi patients with pulmonary TB. Spoligotyping of M. tuberculosis isolates showed T family [30%] as the predominant genotype. By using the three molecular techniques, there were four spoligotyping clusters of strains ["3540 and 3516", "3565 and 3563", "3605 and 3618" and "865, 877 and 13811"]. Complete concordance with RFLP was observed in one cluster of spoligotyping, but no concordance with MIRU-VNTR profile [234426153433 and 236424183433]. Molecular fingerprinting methods are vital for differentiating a reactivation of latent infection from a recent transmission; however, it should be coupled with clinical epidemiological investigation. The low clustering rate in this study suggests that either reactivation of latent infections may be the main driving force for the endemic situation of the disease in Duhok, or it may indicate that a big circle of TB transmission is missed in the community, which means effective control measures have not been achieved yet in Duhok

Adverse drug reactions of Intermittent chemotherapy compared to daily regimen in Sudanese patients with pulmonary Tuberculosis

The World Health Organization [WHO] declared Tuberculosis a global health emergency in 1993 as it remains a major cause of mortality in developing countries. The World Health Organization's Directly Observed Treatment Short course [DOTs] strategy achieve 87% success rate in the areas where it is implemented, usually with five drugs, lasts for 6months. Till 1998 Sudan was classified as one of the slowly moving countries in implementation of the DOTS strategy and making no progress against tuberculosis. A prospective comparative, randomized clinical trial, hospital based study carried out at Kosti Teaching Hospital using directly observed treatment short course [DOTS], to assess the adverse drug reactions of intermittent chemotherapy compared to the currently adopted short course therapy. Patients with smear positive new cases of tuberculosis were enrolled and randomized in to two groups, intermittent treatment group [A] and daily regimen group [B] .The raw data were introduced into SPSS program, the data comparison was carried out by Pearson Chi square and pair independent sample student T-test. The level of significance [P<0.05]. A total of 275 were studied, significant initial [pre-interventional] elevated means of aspartate aminotransferase [AST] was detected in the two groups and significantly in the intermittent regimen after two and four months, but the decrease was significant only after two months in the daily group. Liver injury following antituberculous treatment was minimal and the adverse drug reactions were tolerable concerning the majority of the patients completing the course of the treatment

Infection with Helicobacter pylori strains carrying babA2 and cagA is associated with an increased risk of peptic ulcer disease development in Iraq

Several genes of Helicobacter pylori, such as vacA, cagA, iceA and babA, have been reported to significantly increase the risk of gastrointestinal diseases. The aim of this study was to study the relationship between H. pylori virulence factors and clinical outcomes and identify the independent markers of peptic ulcer disease in Iraq. DNA was extracted from specimens taken from 154 unselected H. Pylori positive Iraqi patients. Genotyping was performed by the polymerase chain reaction [PCR] using specific primers for cagA, vacA [s, m], iceA and babA2 genes. A total of 56 [82%] peptic ulcer disease [PUD] patients carried cagA+ strains, significantly more than the 56 [65%] non-ulcer disease [NUD] patients [p = 0.017]. The difference in the prevalence ofbabA2 positivity was significant between patients with NUD [33.7%] and PUD [58.8%] [p = 0.002]. In addition, babA2 was associated as an independent factor, with PUD [p = 0.005; odds ratio [OR] = 0.4; confidence interval [CI] = 0.18-0.68] followed by cagA [p = 0.05; OR = 0.4; CI = 0.18-0.85]. Forty-five isolates [29%] were typed as 'triple positive' strains, and their presence was significantly associated with PUD [p = 0.001]. The cagA and babA2 genotypes might be considered as useful markers for PUD patients. However, iceAl and iceA2 seem not to be good markers for the disease. The presence of H. pylori strains with triple-positive status is of high clinical relevance to H. pylori-associated diseases

First paternity case resolved by conventional and DNA typing method in Iraq :a case report

In Iraq, DNA Typing Profile has been added to the routine work of disputed paternity cases as a powerful tool of investigation in Forensic in 2007. The old conventional investigation based on blood antigen systems like variable blood groups, HLA Tissue Typing was no more used in such sensitive cases because of the limitation or invariability of loci analyzed. We report here the first case of paternity test done for a trios [Alleged father, mother and child] rebated by two old and new techniques. The alleged father has been excluded from being a biological father according to the mismatch in ABO, MN blood group and 5 genetic markers in DNA profile between the alleged father and son

First insight into the drug resistance pattern of mycobacterium tuberculosis in Dohuk, Iraq: using spoligotyping and MIRU-VNTR to characterize multidrug resistant strains

The objectives of this study were to determine drug resistance pattern in new and previously treated tuberculosis [TB] patients, to assess function of TB control program, and to characterize multidrug resistant TB [MDR-TB] by molecular fingerprinting methods. Anti-micorbial susceptibility testing [AST] to the first line anti-TB drugs was performed on L?wenstein-Jensen [middlebrook 7H10] medium according to the proportion method. Molecular fingerprinting of all MDR strains was performed by spoligotyping and MIRU-VNTR. Mycobacterium tuberculosis strains were isolated from 53 Iraqi patients with pulmonary TB. Thirty eight patients [71.7%] tested cases, and 15 [28.3%] were previously treated. Four of the 38 new cases [10.5%] had resistant, of which 3 [7.9%] were MDR. Eight [53.3%] of the 15 previously treated patients had resistant strains, of which 7 [46.7%] were MDR. Spoligotyping of MDR strains showed CAS family [40%] as the predominant genotype. Using MIRU-VNTR typing, all isolates had a unique profile. MDR-TB prevalence is higher among previously treated patients than among the new cases. The many drug resistant strains, in absence of evidence of recent transmission and in combination with the many previously treated cases, highlight the need for an improved control program, coupled with a need to improve detection rate and early diagnosis of MDR-TB

Time trends and geographical distribution of childhood leukaemia in Basrah, Iraq, from 2004 to 2009

This study aimed to assess the incidence and trend of childhood leukaemia in Basrah. This was a hospital-based cancer registry study carried out at the Pediatric Oncology Ward, Maternity and Children's Hospital and other institutes in Basrah, Iraq. All children with leukaemia, aged 0 to 14 years diagnosed and registered in Basrah from January 2004 to December 2009 were included in the study. Their records were retrieved and studied. The pattern of childhood leukaemia by year of diagnosis, age at diagnosis, morphological subtypes, and geographical distribution was analysed. Rates of childhood leukaemia over time were calculated for six years using standard linear regression. The total number of cases of childhood leukaemia was 181. The number of cases ranged from 21 in year 1, to 31 in the final year reaching a peak of 39 in 2006. Leukaemia rates did not change over the study period [test fro trend was not significant, P =0.81]. The trend line shows a shift towards younger children [less than 5 years]. The commonest types of leukaemia were acute lymphoblastic leukaemia [ALL], then acute myeloid leukaemia [AML] and finally chronic myeloid leukaemia [CML]. Annual rates of childhood leukaemia in Basrah were similar to those in other countries with a trend towards younger children. This raises the question about the effect of environmental catastrophes in the alteration of some specific rates of childhood leukaemia, rather than the overall incidence rate. There is a need for further epidemiological studies to understand the aetiology of childhood leukaemia in Basrah

Reliability of agglutination test to detect alloantibodies in patients with repeated blood transfusion

Blood transfusion is an integral part in the management of sickle cell disease patients. Allogeneic blood transfusion is a form of temporary transplantation. A recipient often mounts an immune response to the donor antigens resulting in various clinical consequences including delayed hemolytic transfusion reactions. Delayed reaction is often seen in individuals who have received repeated transfusion of ABO compatible blood that incompatible for other blood group antigens because of minor allelic difference stimulate the production of IgG antibodies. In the patients who have sickle cell disease the majority of tests may have low sensitivity and in turn may fail to show the autoantibodies. This study has been conducted for detection of allo-antibodies in patient with sickle cell anaemia and hemophilia who received repeated blood transfusions using newly introduced test system; the DiaMed-Immuno-Diffusion microtyping system. Samples were collected randomly from 60 patients with repeated blood transfusions. Micro column gel test as well as agglutination method were performed for all samples. All the results were analyzed using Statistical Packages of Social Sciences [SPSS]. This test provides clear and stable reactions that improve result interpretation. It proved to be more sensitive than the conventional tube agglutination technique as it captures agglutinate in a semi solid medium and on the other hand it has the capacity to detect unexpected antibodies. This in turn enhances visibility of agglutination compared to the traditional Tube techniques

Comparative study of current antimicrobial resistance patterns of uropathogens: evaluation of empirical treatment

Urinary tract infection is a common disease in the community. There is a huge problem in management of these cases in general practice, which mainly attributed to misdiagnosis and misuse of empirical therapy. The aim of this study is to determine the distribution of uropathogens in Northern Iraq together with their in vitro susceptibility profiles to antimicrobial agents. The study included urine samples submitted for culture and antibiotic susceptibility examination for inpatient and outpatient cases. Mosul samples were from inpatient admitted to Al-Salam teaching hospital for a one year period of 2005. Duhok samples were from outpatients sent to the Laboratory of one of the two main private hospital in the city for a one year period of 2006. All samples were tested microbiologically by standard procedures and cultured quantitatively. Colony count was estimated after overnight incubation at 35 C. A total of 1692 and 842 samples were sent for urine culture for inpatient and out patient cases of which 31% and 60.6% of them showed a significant bacteruria respectively. Escherichia coli was the commonest bacteria isolated represented above 40% of total isolates in both groups. The other main bacterial isolates from inpatients were Klebsiella spp 18.9%, Staphylococcus. aureus 8.6%, Psendomonas aeruginosa 7.0% and Proteus spp 6.5%. while in out patients were; according to frequency, Proteus spp. 30.7%, Enterococcus, fecalis 7.8% and Staphylococcus saprophyticus 7.4%. The study showed a high emerging resistance for most commonly used antibiotics in general practice; with overall increase in antibiotic resistance profile mainly among inpatients. Empirical treatment was chosen as a general guideline for treating urinary tract infections in the North of Iraq. The data provide much needed information on the prevalence of antimicrobial resistance amongst pathogens currently causing UTI in hospitals and community in the North of Iraq

Rockall score of the acute upper gastrointestinal bleeding patients the experience in Sudan

Innovation of scoring systems helps to rectify personal experience based on subjective evaluation of outcome of patient treatment. To predict the morbidity and mortality in patients presenting with acute upper gastrointestinal bleeding at Ibn-Sina Hospital using the Rockall score. Prospective hospital-based study conducted from June 2007 through December 2007 at the Ibn-Sina Hospital Bleeding Centre. Demographic, data of history and physical examination and results of laboratory investigations of 238 patients were collected and allotted a Rockall score, Child-Pugh class and fed to Statistical Package of Social Sciences [SPSS] to calculate means and find the levels of statistical differences and define the predicted and observed mortality rates. The mean [ +/- SD] age 44.6 [ +/- 15.31] range [8-85] years. There were 190 [79%] males. Patients with oesophageal varices, peptic ulcer, and upper GI tumours were 215 [90.3%], 18 [7.6%], and 5 [2.1%], respectively. The mean/predicted mortality was 3.8% while the actual observed mortality 3.8%. The mortality in cases of oesophageal varices was 8[3.4%], while that of bleeding peptic ulcers was one [0.4%]. Rockall score is feasible, accurate, effective system for predicting outcome in patients with upper GI bleeding. The risk factor for mortality are Rockall score>3, age>70 and rebleeding

Influence of the biological and chemical pesticides and foliar fertilization in controlling the appearance of citrus trees deterioration at Rashidiya

Application of the bio-agent fungi Trichoderma harzianum and Paecilomyces lilacinus to the naturally infested soil with citrus root nematode Tylenchulus semipenetrans and pathogenic fungi during autumn season 1999, revealed a significant decrease in their population densities compared with untreated [control] trees after two years of application. Application of Cadusafus [Rugby] and Agrifos together confirmed their high efficacy in controlling the nematode-fungi disease complex and significantly decreased their population densities. Besides the growth parameters and the yield/tree, significantly improved and increased up to 78.3, 75.6 and 71.4% of the treated trees with P. lilacinus, T. harzianum and Rugby + Agrifos, respectively two years after soil application. When foliar fertilizers sprayed to the trees regularly for 6 months [May -October] at two weeks intervals in each year, the yield/tree improved and increased more up to 80.3, 78.2 and 78.2%, respectively

Deletion mutatios in the dystrophin gene of Saudi patients with Duchenne and Becker muscular dystrophy

The deletion in the dystrophin gene has been reported for many ethnic groups, but until now the mutations in this gene have not been thoroughly investigated in Saudi patients with Duchenne muscular dystrophy [DMD] and Becker muscular dystrophy [BMD]. We examined the deletion pattern in the dystrophin gene of the Saudi patients applying multiplex-polymerase chain reaction [PCR]. The aim of this study is to describe the outcome of our initial effort to identify mutations in the dystrophin gene in a representative group of Saudi patients with DMD and BMD. Genomic deoxyribose nucleic acid was isolated from 41 patients with DMD and BMD [27 patients confirmed by muscle biopsy and 14 patients with clinical suspicion], 3 patients with limb girdle muscular dystrophy, 12 male relatives of the patients, and 5 healthy Saudi volunteers. A total of 25 exons around the deletion prone regions [hot spots] of the dystrophin gene were amplified. The study was carried out at the King Fahad National Guard Hospital, Riyadh, Kingdom of Saudi Arabia between 2000 and 2002. The deletion of one or more exons was found in 21 of 27 DMD and BMD patients confirmed by muscle biopsy. The deletion in the gene was detected in 5 of 14 patients with DMD diagnosis, but not confirmed by dystrophin staining of muscle biopsy. No deletion in the dystrophin gene was detected in control Saudi volunteers, the limb girdle dystrophy patients, and the relatives of patients, as expected. The present study suggests that intragenic dystrophin gene deletions occur with the same frequency in Saudi patients compared with other ethnic groups. The PCR-based deletion analysis provides a reasonable first step in the diagnostic care of Saudi patients who may be afflicted with DMD and BMD

Polymethyl methacrylate [Perspex] line pattern phantom: a new gamma camera test pattern for assessment of extrinsic resolution and linearity

To evaluate the newly designed polymethyl methacrylate [Perspex] line pattern phantom [PLPP] for testing extrinsic resolution and linearity of gamma camera. The phantom was made of 10 mm thick Perspex in which tubes of 1 mm external diameter and 0.5 mm internal diameter were inserted in 1 mm deep grooves, which had been machined in a particular pattern. The final arrangement of lines divided the phantom into four similar quadrants, which encompassed the whole surface of the gamma camera head. Such an arrangement permitted full detection of any change in the linearity and resolution. The tube was filled with technetium-99m [99mTc]. Tests were performed on the only two single-headed gamma cameras available in Oman. It was possible to resolve two lines as close as 6 mm. Using the line spread function [LSF] facility, the estimated full width half maximum height [FWHM] value was 4.1 mm. In addition, any distortion in the shape of the lines, used to measure linearity, could be easily detected over the entire surface of the camera head. Data obtained from the PLPP are in agreement with those obtained using the conventional four-quadrant bar pattern phantom [FQBP]. The generally accepted relationship that the line profile FWHM is equal to approximately twice the minimal resolvable bar spacing does not apply to the PLPP. However, PLPP gives multi-direction linearity in any one quadrant. In addition, it does not need a flood source for imaging, thus minimizing the test cost

Practical proof of the validity of the Target Theory by simulating cellular targets

To practically prove the validity of the target theory as a mathematical model to describe and understand themechanisms involved in cell killing by ionising radiation. Experimental validation of the target theory was attempted using Bacillus megaterium spores. Sets of 100 vials containing averages of 1, 2, 5, 50 and 500 spores per vial was exposed to varying gamma radiation doses in presence [oxic] and absence [anoxic] of oxygen [O2]. The percentage of the vials that exhibited bacterial growth after 6 days of incubation was taken as containing one spore or more, which survived a given dose. For the purpose of simulation each vial was consideredto represent one living cell, as a unit, containing a given number of targets [spores] each of which needed a single hit to be inactivated. The need for single hit was assumed depending on the shape of the dose ln-survival curve of B. megaterium spores, which has a nonzero slope at zero dose. The dose ln-survival curves derived from these radiation experiments are characterized by a shoulder followed by an exponential part. The size of the shoulder increases with increasing number of spores per vial. However, the slope of the exponential parts stays the same. Despite some assumptions imposed to easily manipulate the simulation process, the data obtained from the present study correlate well with those calculated using the multitarget single hit [MTSH] equation: P = 1 - [1 - e-KD]N where P is the surviving fraction, K is the radiation inactivation constant, D is the radiation dose and N is the number of target. This proves the validity of the target theory model as a tool to provide a better understanding of the observed notorious effects of radiation