Regulatory T cells expressing the transcription factor Foxp3 have a critical role in the maintenance of tolerance to both self and innocuous exogenous antigens. Humans and mice die from overwhelming autoimmunity in the absence of Foxp3+ Treg whilst administration of regulatory T cells has shown promise therapeutically in ameliorating autoimmunity in several animal models. Regulatory T cells arise naturally in the thymus (nTreg) but may also be induced from naïve Foxp3- cells in the presence of TGF-β (iTreg), both in vitro and in vivo. This thesis focuses on in vitro generated mouse iTreg, testing the hypothesis that they are able to effect bystander suppression; iTreg activated by a given antigen are able to suppress other responding cells with different antigen reactivities. Chapter 3 details an in vitro assay system using iTreg and responder cells recognising different antigens (TCR transgenic cells). Evidence for bystander suppression is presented and that did not require the presence of iTreg-relevant antigen but did require iTreg-relevant MHC Class II. The kinetics of iTreg suppression are discussed, with evidence presented that iTreg exert their effects early in co-culture. Chapter 4 identifies the production of three pro-inflammatory cytokines by iTreg - IFN-γ, GM-CSF, and TNF. These were not involved in the in vitro suppressive mechanism, but early abrogation of TGF-β signalling did inhibit suppression. Chapter 5 describes the in vivo function of iTreg under various experimental protocols. iTreg did not limit initial proliferation of naïve T cells in response to antigen but did limit the development of effector cells producing pro-inflammatory cytokines. Exposure to a pro-inflammatory environment in vivo led to iTreg producing IFN-γ and TNF, but not GM-CSF. This could be replicated in vitro by exposure to IL-6, IL-12 or IL-27. Finally, evidence for bystander suppression by iTreg in vivo is presented, with a reduction in effector cells producing pro-inflammatory cytokines shown in an allergic airways diease model.

Many stakeholders in American education are concerned about the frequency of reported bullying incidents within schools in general and middle schools in particular. This nationwide problem has manifested itself in many ways over the past few decades. These manifestations include, but are not limited to, increased gang violence, school shootings, and attendance problems due to student concerns over safety. The purpose of this quantitative study was to investigate the bullying behaviors of a single class of students as they progressed through E. B. Stanley Middle School in Abingdon, Virginia. Data were gathered over the course of three consecutive school years beginning in August 2002 and continuing through May 2005. Reported bullying incidents were analyzed based upon gender of students, grade level of students, frequency of bullying behaviors, types of bullying behaviors (verbal, physical, or emotional), and location of incidents (bus, classroom, hallway, or other). The study offers a valuable insight into the bullying incidents that occur within E. B. Stanley Middle School. It also offers a number of recommendations to combat this problem in middle level schools. Effective implementation of bullying prevention programs will need to involve all school stakeholders in order to be successful. Students have a right to feel safe at school as they grow and mature into adulthood. It is the duty of all schools to provide them that safe and secure atmosphere.

The negative impacts of discriminatory events to the physiological and psychological stress of the recipient has been thoroughly documented. However, there is little to no evidence about the impacts to bystanders of these events, particularly White bystanders. Psychological impacts may emerge through academic achievement, which has implications for educational institutions and their diversity initiatives. This study examined the impact of witnessing discriminatory events on academic achievement, biological markers of distress, and emotional distress. Academic achievement was negatively impacted for participants in the microaggression and blatant racism conditions when compared to a control condition. Study participants also experienced negative emotional impacts. These were evident through a decrease of positive emotion and an increase of negative emotion throughout the study. Counter to the stated hypothesis, biological markers of distress did not demonstrate a negative impact from the discriminatory event. Microaggressions, specifically, were not found to have negative impacts on academic achievement. There were also no differences in the relationship between biological markers of distress and academic achievement among the three conditions. These findings suggest that discriminatory behavior negatively impacts White bystanders emotional state and academic achievement.

Τα αποτελέσματα ποικίλων δόσεων ακτινών Χ στην κυτταρική απόπτωση, τον πολλαπλασιασμό, την έκφραση του υποδοχέα του επιδερμικού αυξητικού παράγοντα (EGFR) και των μεταλλοπρωτεϊνασών-2 (MMP-2), μελετήθηκαν σε δύο κυτταρικές σειρές ανθρώπινου γλοιοβλαστώματος. Μέθοδος: Οι κυτταρικές σειρές LN18 και M059K ακτινοβολήθηκαν σε θερμοκρασία δωματίου με δόσεις κυμαινόμενες από 0,5 έως 15 Gy με τη χρήση πηγής 6 MV. Η απόπτωση μελετήθηκε με τη μέθοδο annexin V, ο πολλαπλασιασμός με τη μέθοδο MTT (methyl tetrazolium) και η έκκριση των MMP-2 με ζυμογράφημα. H καταγραφή των επιπέδων του φωσφοριωμένου EGFR έγινε με ELISA. Αποτελέσματα: Ο κυτταρικός πολλαπλασιασμός ανεστάλη με δόσο-εξαρτώμενο τρόπο ενώ η απόπτωση αυξήθηκε σημαντικά μετά την ακτινοβολία. Σε δόσεις μικρότερες των 2 Gy δεν καταγράφηκε καμία μεταβολή στην απόπτωση και τον κυτταρικό πολλαπλασιασμό. Τα επίπεδα των MMP-2 αυξήθηκαν 48 ώρες μετά την ακτινοβόληση με δόσο-εξαρτώμενο τρόπο. Αντιθέτως, η έκφραση του EGFR αυξήθηκε σημαντικά 15 λεπτά μετά την ακτινοβόληση και κατά δόσο-εξαρτώμενο τρόπο. Συμπέρασμα: Η ιοντίζουσα ακτινοβολία επάγει την έκφραση του EGFR και αυξάνει την έκκριση των MMP-2 γεγονός που αιτιολογεί την διηθητική και κακοήθη συμπεριφορά των γλοιωμάτων καθώς και την ανταπόκριση τους στην ιοντίζουσα ακτινοβολία. / The effect of different doses of X(-)rays on apoptosis, proliferation, epidermal growth factor receptor (EGFR) and matrix metalloproteinase (MMP-2) expression was investigated in a human glioblastoma cell line. Materials and Methods: The cell line LN18 was irradiated at room temperature with doses ranging from 0.5 to 15 Gy using 6 MV X(-)rays. Apoptosis was assessed using the annexin V binding assay, proliferation by the methyl tetrazolium (MTT) assay and MMP-2 secretion with zymography. The levels of phosphorylated (pEGFR) were estimated using a commercially available ELISA kit. Results: Cell proliferation decreased in a dose-dependent manner, while apoptosis was increased after radiation. Doses below 2 Gy did not affect proliferation or apoptosis. MMP-2 levels were increased 48 h after radiation in a dose-dependent manner. In contrast, EGFR signaling was significantly activated 15 min after radiation in a dose-dependent manner. Conclusion: Ionizing radiation activates EGFR signalling and enhances MMP-2 secretion, suggesting that the molecular pathways involved may contribute to the invasiveness and malignant behaviour of glioma cells and help to explain the response of gliomas to ionizing radiation.

Low survival rates following out-of-hospital cardiac arrest (OHCA) remain a serious health concern internationally. Early bystander cardiopulmonary resuscitation (CPR) and rapid defibrillation can increase the chances of survival dramatically. However, the number of OHCA patients who receive these interventions remains low. This study sought to characterize Canadian public knowledge, attitudes and willingness to perform both traditional and chest-compression-only CPR using a two-phase, mixed methods approach. Twenty-one qualitative interviews were conducted, the results of which informed an online, scenario-based, Canada-wide survey. Significant knowledge gaps regarding recognition of cardiac arrest, the precise steps of CPR and perceived survival rate were identified and common to both phases. A larger proportion of survey respondents demonstrated a willingness to perform chest-compression-only CPR compared to traditional CPR in general, and specifically in situations involving strangers and unkempt individuals. Knowledge gaps and misconceptions seem to dominate the public perspective, leading to the recommendation for a tailored knowledge translation solution.

Low survival rates following out-of-hospital cardiac arrest (OHCA) remain a serious health concern internationally. Early bystander cardiopulmonary resuscitation (CPR) and rapid defibrillation can increase the chances of survival dramatically. However, the number of OHCA patients who receive these interventions remains low. This study sought to characterize Canadian public knowledge, attitudes and willingness to perform both traditional and chest-compression-only CPR using a two-phase, mixed methods approach. Twenty-one qualitative interviews were conducted, the results of which informed an online, scenario-based, Canada-wide survey. Significant knowledge gaps regarding recognition of cardiac arrest, the precise steps of CPR and perceived survival rate were identified and common to both phases. A larger proportion of survey respondents demonstrated a willingness to perform chest-compression-only CPR compared to traditional CPR in general, and specifically in situations involving strangers and unkempt individuals. Knowledge gaps and misconceptions seem to dominate the public perspective, leading to the recommendation for a tailored knowledge translation solution.

Arbetsplatsmobbning har omfattande konsekvenser för individer i arbetslivet och samhället. Observatören har en viktig roll i arbetet mot mobbning, då dennes ingripande kan influera andra att göra detsamma. Denna studie undersökte om observatörens kön, locus of control och erfarenhet av observerad mobbning har en påverkan på intentionen att ingripa vid en mobbningssituation. Detta prövades utifrån sex hypoteser och frågeställningen hur relationen ser ut mellan ovangivna variabler i förhållandet till intentionen att ingripa vid mobbning. 165 individer i arbetslivet, varav 114 kvinnor, besvarade en enkät vilken innehöll Rotters The internal-external scale, en justerad Negative Acts Questionnaire-Revised och ett instrument inspirerat av Hektner och Swensons påstående om intentionen att ingripa. Materialet anlyserades med hjälp av tvåvägs-ANOVA och Pearsons korrelationskoefficient. Studiens resultat var att erfarenhet av observerad mobbning, både enskilt och i kombination med kön och locus of control, påverkar intentionen att ingripa. Kön och locus of control visade inte på signifikanta huvudeffekter.

This study sought to examine two gaps in the field of bullying research – (1) the lack of clear cut theoretical underpinnings and frameworks for examining the process of bullying and (2) oversight of the parent context in studies on bullying. This two-study dissertation examined the role of parents in understanding bullying, victimization and bystander behaviors using Belsky’s parenting process model (1984) as a potential guiding framework. Study 1 relied on secondary analysis with three waves of longitudinal data from the NICHD Study of Early Child Care and Youth Development to test the indirect effect of maternal depressive symptoms on bullying and victimization through mother-child relationship quality. Findings indicated that there was a small direct effect of maternal depressive symptoms at grade 3 on peer victimization at grade 5, but not bullying. Mother–child relationship quality at grade 5 negatively predicted bullying behaviors at grade 6, but not peer victimization. There were also small effects of bullying behaviors at grade 5 on increased maternal depressive symptoms and decreased mother-child relationship quality at grade 6. There were no significant indirect effects. Study 2, a cross-sectional study of N = 143 fourth and fifth graders and their parents, hypothesized indirect effects of parent’s general and specific self-efficacy related to bullying, peer victimization and bystander behaviors through parental monitoring and supervision. Parents’ self-efficacy beliefs related to knowledge of their children being victimized, and what to do about the victimization reports was directly and negatively associated with a reduction in bullying and victimization behaviors. Efficacy to know what to do was also negatively associated with negative bystander behaviors but positively associated with victimization in school. There were no significant indirect effects. Findings from both studies suggest that the parent context may play a limited role in processes of bullying during upper-elementary school. Secondly, parent functioning (i.e., maternal depressive symptoms, parental self-efficacy related to bullying) may have direct effects on bullying, victimization and bystander behaviors rather than indirectly through parenting as emphasized by Belsky’s model. Other findings, limitations and suggestions for future research and interventions are discussed.

Ionising radiation can cause damage to DNA that can result in gene mutations contributing to carcinogenesis. Radiation-protection policy currently estimates cancer risks from exposures to radiation in terms of excess risk per unit dose. At very low radiation dose-rates, where not all cells are absorbing radiation energy, this formula carries the inherent assumption that risk is limited to those cells receiving direct energy depositions. Numerous studies have now called this assumption into question. Such low dose-rates are in the relevant range that the public receives from natural background and man-made sources, and, if this fundamental assumption proves unfounded, current estimations of radiation-induced cancer risk at low doses will be incorrect. Accurate predictions of stochastic cancer risks from low-dose radiation exposures are crucial to evaluating the safety of radiation-based technologies for industry, power generation and the increasing use of radiation for medical diagnostic and screening purposes. This thesis explores phenomena known as radiation-induced bystander effects. The term bystander effects, as used here, describes biological responses to ionising radiation (hitherto observed in vitro) in cells not directly traversed by an ionising track, due to intercellular signals received from neighbouring cells that did receive energy depositions. This study aimed to determine whether radiation effects are communicated between irradiated and unirradiated cells in vivo, and if so, whether this effect alters current estimations of cancer risk following low-dose radiation exposures. In order to answer these questions, an in vivo experimental system for studying bystander effects in mice was developed. The method was based on the adoptive transfer of irradiated splenocytes into unirradiated hosts with simultaneous identification of irradiated donor cells, and biological endpoints in unirradiated bystander cells in situ using fluorescence microscopy and image analysis. Splenocytes from donor mice were radiolabelled with 3H-thymidine or received an acute X-ray dose. The irradiated donor cells, labelled with a fluorescent probe, were then adoptively transferred into unirradiated recipient mice via the tail vein, whilst control mice received sham-irradiated donor cells. A proportion of the cells lodged in the recipient mouse spleens where they remained for a period before the tissues were cryopreserved. The locations of donor cells were identified in frozen spleen sections by the fluorescent probe, and the levels of apoptosis and proliferation were simultaneously evaluated in situ in the surrounding unirradiated bystander cells using fluorescence-based assays. Transgenic pKZ1 recipient mice were also used to quantify chromosomal inversions in bystander cells. Since three-dimensional spatial relationships were preserved, responses could be measured in the local area surrounding irradiated cells as well as further afield. Following the development of the irradiated-cell adoptive transfer protocol and validation of the sensitivity and reproducibility of the biological assays in situ, a series of experiments was performed. In the initial experiments, 500,000 radiolabelled cells (0.33 mBq.cell-1) were injected into recipient mice and the spleen tissues were isolated 22 h later. No changes in apoptosis or proliferation were detected in local bystander spleen cells or throughout the spleen, compared to mice receiving sham-radiolabelled donor cells. In subsequent experiments, the effects of a number of experimental conditions were explored including the injection of tenfold more donor cells, analysis of spleen tissues after three days lodging in vivo, radiolabelling of donor cells with 100-fold higher 3H dose-rate and irradiation of donor cells ex vivo with 0.1 or 1 Gy X-rays. In each case, no changes in apoptosis or proliferation were observed. The in vivo method described here was designed to simulate the conditions of a bystander scenario from low dose-rate exposures relevant to public radiation protection. Contrary to the many reports of bystander effects in vitro, experiments using this sensitive method for examining the in vivo responses of unirradiated cells to neighbouring low-dose irradiated cells, have so far shown no changes in bystander cells in the spleen. This adoptive transfer method is the first in vivo method for examining the effects of known irradiated cells exposed to low radiation doses at low dose-rates, on neighbouring cells in situ that are truly unirradiated. Both the irradiated and bystander cells are normal, non-transformed primary spleen cells functioning in their natural environment. This in vivo experimental system allows the examination of tens of thousands of bystander cells and has shown a remarkable sensitivity, with statistical power to rule out changes in apoptosis &lt10% from the control. The relevance of in vitro bystander findings is unclear. Many reported bystander effects are more analogous to the systemic communication of abscopal effects from highly irradiated tissues. Disagreement between experimental systems and difficulty in reproducing key results between laboratories further complicate the translation of bystander data in vitro to human risk-estimation. The radiation protection community has expressed its need for in vivo validation of the bystander phenomenon before it can be included into the appraisal of carcinogenic risk. This adoptive transfer method is now available to study a range of bystander endpoints and potential signalling mechanisms in vivo, and provides a way to translate the wealth of data previously collected in vitro into findings directly relevant to human risk-estimation.

Bakgrund och problemformulering: Tjänsten SMS-livräddnings syfte är att i händelse av hjärtstopp ta hjälp av frivilliga personer som kan påbörja livräddande insatser innan ambulansens ankomst. SMS-livräddning fyller en viktig funktion i samhället då tidig hjärt-lungräddning och tidig defibrillering ökar överlevnaden för patienten. SMS-livräddaren kan ses som en ny partner till ambulanssjuksköterskan och därför är det av stor vikt att undersöka hur samarbetet mellan ambulanssjuksköterskan och SMS-livräddaren fungerar samt hur ambulanssjuksköterskan upplever SMS- livräddarens roll. Syfte: Att undersöka hur ambulanssjuksköterskan upplever SMS-livräddarens roll samt hur samarbetet mellan dessa fungerar vid misstanke om hjärtstopp. Metod: Studien genomfördes med en elektronisk enkät. Enkäten skickades ut till 166 sjuksköterskor och specialistsjuksköterskor inom ambulanssjukvården Sahlgrenska Universitetssjukhuset. Svarsfrekvensen var 43 % varpå 44 respondenter hade varit på ett ärende med SMS-livräddare vid misstanke om hjärtstopp. Resultatet baseras på dessa 44 respondenter. Resultat: Majoriteten av respondenterna upplevde SMS-livräddarens roll som positiv och ansågs vara en stor tillgång i samband med hjärtstopp. Respondenterna ansåg att SMS-livräddaren kunde bidra med viktig information om hjärtstoppet och hjälpa till med kompressioner samt övriga praktiska saker. Oftast fungerade samarbetet mellan ambulanssjuksköterskan och SMS-livräddaren bra. De flesta respondenter trodde att patientens överlevnad kunde öka genom ett bra samarbete. Diskussion: Ett väl fungerande samarbete mellan SMS-livräddaren och ambulanssjuksköterskan ligger till grund för att förbättra utgången i händelse av hjärtstopp. Att utveckla samarbetet kan förbättra omhändertagandet av patienten.