Gamma radiation-induced impairment of hippocampal neurogenesis, comparison of single and fractionated dose regimens Deterioro de la neurogénesis en el hipocampo inducida por radiación gamma, comparación de los regímenes de dosis única y fraccionada

Radiation therapy of the brain is associated with many consequences, including cognitive disorders. Pathogenesis of radiation induced cognitive disorder is not clear, but reduction of neurogenesis in hippocampus may be an underlying reason. 24 adult male rats entered to study. Radiation absorbed dose to midbrain was 10 Gy, delivered by routine cobalt radiotherapy machine which its output was measured 115.24 cGy/min. The rats were divided in four groups of sixes, including groups of control, single fraction 10 Gy, fractionated 10 Gy and finally anaesthesia sham group. Number of pyramidal nerve cells was counted in two regions of hippocampus formation (CA1 and CA3). The radiation could reduce the number of cells in two regions of hippocampus significantly (p=0.000). It seems fractionated 10 Gy irradiation to more efficient than single fraction, while role of anaesthesia drug should be cautiously assessed. Moreover the rate of neurogenesis reduction was determined the same in these regions of hippocampus meaning the same radiosensitivity of cells

A survey on the possibility of utilizing γH2AX as a biodosimeter in radiation workers

Introduction DNA damage is among the main consequences of radiation. Of many different classes of DNA damage, double-strand breaks are the most deleterious. Development of a sensitive biodosimetry method, which utilizes a detection material with a similar construction to the body, seems essential for monitoring radiation workers. In this study, histone H2AX protein was examined as a potential biodosimeter in radiation workers. Moreover, the presence of this protein after in vitro irradiation of blood samples was assessed simultaneously. Materials and Methods Blood samples from 46 radiation workers were analyzed in Golestan province, Iran. Meanwhile, two groups of blood samples (five blood samples in each group) were irradiated in vitro by doses of 1 to 0.2 Gy and 0.09 to 0.01 Gy from a 60Co source, respectively. γH2AX level in lymphocytes was measured, using Western blot technique. ANOVA and Tukey's tests were performed, using SPSS version 16. The significance level was considered to be 0.05. Results The results of Western blotting for the identification of γH2AX protein in radiation workers were negative. However, γH2AX level in lymphocytes of two in vitro irradiated groups showed a significant correlation with the radiation dose (P<0.0001). Conclusion The results showed that γH2AX was a good indicator for acute or local exposure to ionizing radiation, while in chronically exposed individuals, including radiation workers, this protein was useless at least in autoradiography detection method. Regarding the presence of γH2AX protein in blood samples, which were irradiated in vitro at low doses, it can be concluded that this protein has powerful repair mechanisms

The simultaneous effect of valproic acid and gamma radiation on telomerase activity and bax and Bcl-2 protein levels in MCF-7 breast cancer cell line

Background: Breast cancer is one of the most prevalent types of cancer. Factors such as ionizing radiation and chemotherapeutic agents can trigger apoptosis and cancer cell death. An anticonvulsant drug named Valproic acid is a histone deacetylase inhibitor that shows promising anti-tumor effects in a variety of cancers. Telomerase is a ribonucleoprotein enzyme that activated in cancer cells and lead to telomeres shortening inhibition and triggering the apoptosis. Objectives: The purpose of this research was to investigate the simultaneously effect of Valproic acid and gamma radiation on telomerase activity and bax and Bcl-2 protein level in MCF-7 breast cancer cell line. Materials and Methods: MCF-7 cells was treated with different dose of Valproic acid (0, 2, 8 and 16 mM/l) and single dose of gamma radiation (4 Gy/min. (cell toxicity was determined using neutral uptake test. Telomerase activity was determined using TRAP assay (PCR-ELISA) method. Bax and Bcl-2 protein level was determined by ELISA method, as well. Results: Combination of Valproic acid and gamma radiation increased significantly cell toxicity in a time and dose dependent manner compared with control (P < 0.0001). The ratio of Bax/Bcl-2 was increased in a dose dependent manner at 48 and 72 hour treatment (P < 0.0001). There was a decrease in Telomerase activity after 24, 48 and 72 hours treatment in a dose dependent manner (P < 0.0001). Conclusions: The increasing cell toxicity, apoptosis-inducing effects and decreasing telomerase activity may play an important role in the Valproic acid and radiation mechanism. The current survey suggested that it is likely beneficial to combine Valproic acid and gamma radiation to treat breast cancer. © 2015, School of Pharmacy, Ahvaz Jundishapur University of Medical Sciences

Radiation-induced lowered neurogenesis associated with shortened latency of inhibitory avoidance memory response

The neural system is less sensitive to radiation than other late-responding organs and tissues such as the kidney and lung. The generation of new neurons in the adult mammalian brain has been documented in several works. Many studies show that adult hippocampal neurogenesis relates to hippocampal function, in several ways. In this study, we assessed the effect of single and fractionated cobalt radiation on neurogenesis in the dentate gyrus of the hippocampal formation. The irradiation time for delivering 2 Gy (for fractionated dose radiation) and 10 Gy (for single dose radiation) at maximum depth were respectively 1.98 min and 9.92 min. To study the association with memory function we examined inhibitory avoidance memory using a step-through device. Brains were withdrawn and fixed, and then sections were stained with cresyl violet for neurons. We found that a 10 Gy dose can induce lower neurogenesis in the dentate gyrus of the hippocampus (p < 0.05), in such a way that a fractionated dose (5 fractions of 2 Gy) is more effective than a single dose (one fraction of 10 Gy). Moreover, a fractionated dose could reduce step-through latency corresponding to damaged inhibitory avoidance memory (p < 0.05). Synergic action of an anaesthetic drug may be the cause of more reduction of neurogenesis in fractionated irradiated rats. There was no significant difference in latency of the inhibitory avoidance memory response between the single 10 Gy group and the sham group, while fractionated 10 Gy could reduce latency. Different mechanisms of action in the two regimens of irradiation may be a reason

Quality assurance program for prototype stereotactic system developed for Neptun 10 PC linac

Background: A prototype stereotactic radiosurgery set was designed and constructed for a Neptun 10 PC linac that is currently being used at Imam Reza hospital in Mashhad. Materials and Methods: A complete qualit y assurance program was designed and performed for the constructed system including isocentric accuracy test, localization accuracy test, dose delivery accuracy test and leakage radiation test. Target simulator, control alignment device and plexiglass phantom which were parts of the developed hardware were used to fulfill quality assurance program. Results: The average isocentric shift resulted from the gantry rotation and couch turning were respectively obtained to be 1.4 and 2 mm. The average localization error in the three coordinates was found to be 2.2 mm. The total treatment uncertainty due to all of the probable errors in the system was equal to 4.32 mm. The dose delivery accuracy test was carried out, the result indicated a 3-7% difference between the given and measured dose. Conclusion: The quality assurance tests showed consistent performance of the constructed system within the accepted limits; however, some inconsistency might exist in certain cases. The safety of SRS method is increased when the overall uncertainty is minimized and the treatment of the lesions adjacent to critical organs is avoided

Development of head docking device for linac-based radiosurgery with a Neptun 10 PC linac

Stereotactic radiosurgery is a method for focused irradiation of intracranial lesions. Linac-based radiosurgery is currently performed by two techniques: couch mounted and pedestal mounted. In the first technique a device is required to affix the patient's head to the couch and moreover to translate it accurately. Structure of such a device constructed by the authors plus acceptance test performed for evaluation is described in the article. A head docking device has been designed and constructed according to geometry of linac's couch and also desired functions. The device is completely made from aluminum and consists of four major components: attachment bar, lower structure with four movements, upper structure with two movements equipped with a lock, two handles and a mounting ring for stereotactic frame. Translating accuracy, mechanical stability and isocentric accuracy were assessed in the frame of acceptance test. Translating accuracy, mechanical stability and isocentric accuracy were found to be respectively: 1 mm, 1.64 mm and 3.2 mm with accuracy of 95%. According to AAPM report no.54, a head docking device should translate head with an accuracy of 1 mm; this recommendation has been met. Moreover, we have demonstrated that the isocentric accuracy and mechanical stability of the device are sufficient that the device can confidently be used in stereotactic treatment

The Underlying Causes of Religious Superstition; A Qur’anic Perspective Focusing on Social Exegeses (Tafsīr-i Nimūni and Fī Ẓilāl al-Qurʾān)

Received: 2021/6/8  |   Correction: 2022/1/9   |   Accepted: 2022/1/9The purpose of this article, which is written under the descriptive-analytical method, is to study more closely the phenomenon of religious superstition, as well as to identify the affecting factors that cause it in some people, albeit from the perspective of the Qur’an. The most important are factors such as personal profiteering, defending one’s favorite religion, weakening various viewpoints of opponents, corruption in religion, as well as religious tyranny. Of course, some superstitions such as bidʿa (heresy), taḥrīf (distortion), qīās (analogy), following mutashābihāt (ambiguous similarities), and intentional or unintentional mistakes of the narrator or listener of Hadith are formed sometimes due to the weakness of people’s religious beliefs. Even extremism in matters such as rationalism, traditionalism, religious toleration, or committing ghuluww (exaggeration) for the benefit of making myths seem among the causes of religious superstitions. Anyhow, identifying the causes of superstition is undoubtedly one of the most fundamental steps towards the pathology of this inauspicious phenomenon. Such a crucial task can put preventive mechanisms in front of present religious communities to increase popular religious insight and not fall into the abyss of superstition and its consequences. It seems only by trusting on God and a sheer obedience to the resuscitative teachings of divine leaders on the one hand and relying on human reason and attempting to raise the level of knowledge on the other, this destructive phenomenon can be overcomed.Farahani, M; Khoobbin Khoshnazar, S.K; Taban, J. (2022) The Underlying Causes of Religious Superstition; A Qur’anic Perspective Focusing on Social Exegeses (Tafsīr-i Nimūni and Fī Ẓilāl al-Qurʾān). Biannual Journal of Comparative Exegetical Researches, 8 (15) 139-166. Doi: 10.22091/PTT.2022.6461.1907

The Caveats of Applying Lean in Knowledge-Intensive Services with Hierarchy: Evidence from an Emergency Department

These days better performance of health systems is a serious concern and different methods have been proposed to overcome the performance challenges. Emergency departments (EDs) are one the most crowded part of the health systems, treating patients in a wide range of conditions. Various patient flow management approaches have been tested to enhance system output. However, visiting patients by a medical doctor (MD) in a short time, patients waiting time, and length of stay in the system are still great challenges. In the past few decades, healthcare systems and institutions have begun to employ operations management techniques within the EDs to enhance flows, better organize work, and improve productivity. Globalization of the Toyota Production System has introduced modern manufacturing methods, which integrate waste reduction activities and quality into the production processes as they are performed. This combination of the management philosophy and activities, aiming to reduce waste and improve quality, is known as lean thinking. Moreover, these manufacturing and service improvement principles are being used in an increasing number of sectors including healthcare services. In this thesis, after introducing lean principles and different aspects of its implementation in the industry, its application in healthcare was summarized. In the continue, applying pull strategy, the fourth principle of lean thinking, instead of push strategy in the Mary Washington emergency department, was tested. In the suggested strategy, instead of bringing in the patient by the triage nurse or physician when a bed is empty, the bottleneck resource, which is usually the treatment nurse in this ED, pulls a patient in when they are ready. It provides an opportunity to examine in detail how the implementation of lean thinking changes the patient flow and why the resulting outputs and outcomes were achieved. Better performance of the system after the implementation of a pull strategy was expected. But the observations indicated that emergency departments are more complicated than that. The hierarchical structure of the hospital was the first barrier for achieving better performance. Physicians, having a higher rank in the hierarchical structure of healthcare, could not tolerate that treatment nurses be the decision makers. Therefore, they did not cooperate, and when a bed was empty, they wanted to use it as soon as possible regardless of treatment nurses' business. Usually, in these organizations, it is too difficult to change ways that physicians and nurses work among themselves. Therefore, instead of changing responsibilities that are effected by human behavior, altering system configuration was suggested. Pooling two teams in the triage step with a close emergency severity index was suggested as the other solution for improving system quality and decreasing patient waiting time. Significant reduction in patients’ average wait time to get a bed and length of stay after pooling two teams (team two and team three)was obtained

Correlated quasiskyrmions as alpha-particles

By replacing quasiparticles by quasiskyrmions, we calculate the binding energy of the alpha-particle using the cluster expansion method