http://aladinrc.wrlc.org:80/handle/1961/3486 2013-06-20T05:44:38Z http://aladinrc.wrlc.org:80/handle/1961/5579 Assessing Leakage Workloads of Medical Linear Accelerators for IMRT and TBI Techniques Jordan, James Current estimates for leakage workloads are not well quantified for Intensity Modulated Radiation Therapy (IMRT) and Total Body Irradiation (TBI) treatments. When analyzed on a large scale, using a large sample, a well defined leakage workload may be established. A database of 17 cancer treatment centers and 73 linear accelerators were used to make the assessment. There were 374,003 total treatments, with 213,757 low energy (4 and 6 MV) treatments, 106,343 of which were IMRT and 149,730 high energy (15, 16, 18, and 20 MV) treatments, 64,138 of which were IMRT. There were 184 TBI treatments, with 98 being low energy and 86 being high energy. The numbers are too scant to make any statements about the contribution TBI makes to workload, there is more than enough data to estimate the IMRT contribution to leakage workload. An IMRT factor, CI, of 5.1 may be used for low energy photon calculations, and a CI of 4.4 may be used for high energy photon calculations, where CI is: CI=MUIMRT/MUconv. 2009-08-25T17:16:44Z http://aladinrc.wrlc.org:80/handle/1961/4238 Interracial Dating Attitudes, HIV Risks, Substance Use, and Depression in a Sample of Asian MSM in an Urban Setting Antonio, Albert There is an extensive body of behavioral and scientific research devoted to HIV/AIDS among Asian American and Pacific Islander (AAPI) communities with a specific focus on men who have sex with men (MSM). There is also a decent body of psychosocial literature devoted to Interracial Dating and Attitudes in MSM. There are very few investigations that have begun to bridge these two concepts and critically address how social, psychological, and behavioral factors contribute to the risk associated with what is posited as the next wave of the HIV/AIDS epidemic. Little is known about how attitudes of AAPI MSM affect their decision to engage in HIV risk behaviors and substance use. These behaviors and practices, also have correlations with the depressive symptoms exhibited in this population, the majority of which are foreign born. From a three-ring impact domain perspective, this study serves to understand the complexities of the AAPI MSM atmosphere. Dating preference scales (i.e. preferring Asian partners versus non- Asian) were created using preferential and attitudinal statements. They were unsuccessful in predicting specific behaviors. Findings suggest important specific differences between individuals from different nativities as well as ethnicities. Major correlated findings are consistent with previous literature, further suggesting that the many subgroups that fall under the AAPI umbrella, are actually distinct and different on many levels. HIV intervention and prevention campaigns should take these distinctions into consideration, to provide more effective, culturally sensitive and specific resources for this high risk, AAPI MSM population. Consistent with the hallmarks of a Georgetown education, this Honors Thesis in Human Science serves to promote the well-being of humankind via a commitment to addressing the complicated issues of at risk, minority populations. 2007-08-20T18:06:15Z http://aladinrc.wrlc.org:80/handle/1961/4237 The Role of the ErbB2/PI 3-K/Akt1 Pathway in the Development of Hormone Resistance in Breast Cancer Cesari, Whitney The presence of estrogen receptor α (ER-α) in breast tumors predicts the patient response to hormone therapy. The most common treatments are the antiestrogens 4- hydroxy tamoxifen (Tam) and fulvestrant (ICI 182,780). While Tam exhibits partial agonistic activities, ICI is a total antagonist. Most patients eventually develop resistance to antiestrogens. Identifying cellular pathways which enable hormone sensitive and hormone resistant breast cancer cells to continue growing will help determine the direction of future therapy. To study the acquired hormone resistance of MCF7 breast cancer cells during endocrine treatment, specifically the role of antiestrogens, epidermal growth factor receptor II (ErbB2), and the phosphoinositide 3-kinase/ serine/threonine protein kinase 1(PI 3-K/Akt1) pathway, I used three variants of MCF7 cells. Parental MCF7 cells are estrogen-dependent and responsive to antiestrogens, Tam and ICI 182,780. LCC1 cells grow independently of estrogen, but are sensitive to Tam and ICI 182,780. LCC2 and LCC9 cells were generated from LCC1 cells that underwent long- term treatment with antiestrogens, Tam and ICI 182,780, respectively. LCC2 and LCC9 grow estrogen-independently and are antiestrogen resistant. RNA was extracted from MCF7/LCC1, 2, and 9 cells under estradiol (E2) treatment in the presence or absence of antiestrogens, ErbB2 and/or PI 3-K inhibitors to determine the effect of these treatments on ER-α activity by real time RT-polymerase chain reaction (PCR). The mRNA induction was measured for the progesterone receptor (PGR), an estrogen-dependent gene, and compared to the internal control, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA induction. Results are compared in MCF7 cells versus LCC cells. In MCF7/LCC cells, PGR mRNA is induced upon E2 treatment. This effect is inhibited by both Tam and ICI 182,780 only in MCF7 and LCC1 cells. Tam and ICI 182,780 also increase PGR mRNA in LCC2 and LCC9 cells, respectively. The E2 effect and antiestrogen resistance was stably inhibited by both inhibitors of ErbB2, AG825, and PI 3-K, LY 294,002. The data support that activation of ErbB2 and PI 3-K/Akt1 signaling pathway can overcome the antiestrogenic effects of Tam and ICI 182,780. Results demonstrate the ability of the selective ErbB2 inhibitor, AG825, and the PI 3-K inhibitor, LY 294,002 to inhibit cell growth after breast cancer cells have developed resistance to antiestrogens, Tam and ICI 182,780. Further studies of the effects of the AG825 and LY 294,002 are needed to determine their reliability and the practical clinical use of these findings for those patients who have developed resistance to antiestrogens. 2007-08-20T17:59:39Z http://aladinrc.wrlc.org:80/handle/1961/4236 College Student Bereavement: University Responses, Programs and Policies, and Recommendations for Improvement Fajgenbaum, David The overall aim of this study was to conduct a comprehensive examination of bereavement among college students. There were three main objectives: (1) to assess the science behind the body’s physiological and psychological response to bereavement; (2) to evaluate the current practices used by colleges and universities to support bereaved students; and (3) to develop recommendations for future work in this area by synthesizing current policies and practices into programming that can be implemented across academic institutions. To address these objectives, the following research activities were conducted: an extensive review of the literature, a cross-sectional bereavement survey of 54 college and university administrators, and five in-depth interviews with expert informants. For the bereavement survey, counseling center directors, deans of students, and a “third administrator” at four-year, public, private, and geographically-diverse colleges and universities were asked about current practices, programs, and policies that were currently being implemented on their campuses to support bereaved college students. The data led to three major findings: (1) 100% of university administrators underestimate the prevalence of bereavement among college students; (2) administrators reported believing that bereaved students need support from friends more so than they do from counselors; however, only one institution has an established system in place to provide peer support; and (3) Deans of Students/Student Affairs report that programs that raise awareness and educate campus members about student bereavement are the most important new programs for universities to offer to the student body, faculty and administration; whereas, counseling center directors believe new academic policies and guidelines are most important. Recommendations are offered for use by members of the university community to improve the current practices, policies, and programs in place to reach and assist bereaved students. 2007-08-20T17:55:24Z http://aladinrc.wrlc.org:80/handle/1961/4235 Comparison of Drug Treatment Protocols for Children Infected with HIV in Washington, DC and Cape Town, South Africa in Relation to NIH Guidelines Marshall, Mariah A variety of clinical indicators including CD4 T-lymphocyte counts, HIV viral levels, symptoms of AIDS, and adherence to HIV drug therapies are utilized in selecting and modifying antiretroviral (ARV) drug treatment regimens in individuals infected with HIV. Although guidelines have been published by the National Institutes for Health (NIH) that suggest how these indicators should be used for the treatment of pediatric HIV/AIDS, these recommendations may overlook some of the complications associated with pediatric infection, such as poor adherence, drug intolerance, and inadequate human growth. In order to assess the extent to which published guidelines are used in clinical practice in hospitals located in Cape Town, South Africa and Washington, DC, clinicians responsible for the treatment of children at these hospitals were interviewed using original questionnaires. The results of the interviews were then evaluated and compared to the published guidelines to determine the points of agreement and divergence. Although the NIH recommendations suggest using CD4 counts, HIV RNA levels, and clinical symptoms as the major determinants when prescribing drug therapy, Victoria Hospital in Cape Town, South Africa uses adherence and general health of the child as the primary indicators for initiation and alteration of ARV therapy. The treatment methods of Children’s National Medical Center and Howard University Hospital in Washington, DC differ from the published guidelines in that physicians at these hospitals place all children under the age of one year on drug therapy regardless of any other clinical indicators. The differences that are seen in the application of the published guidelines at these hospitals can be attributed to the dynamics of the specific environments of Cape Town, South Africa and Washington, DC. Because antiretroviral drugs are easily available in the United States, clinicians here are able to treat HIV-infected children in the most aggressive ways. However, since South Africa is bound by financial limitations that limit access to ARVs, clinicians are forced to alter the published guidelines in order to best serve their pediatric population by using primary indicators other than those specifically recommended by the published guidelines. Thus, depending on the specific population, clinicians of these hospitals prescribe drug therapy differently in order to meet the needs of HIV-infected children within the confines of the specific healthcare system. 2007-08-20T17:49:22Z http://aladinrc.wrlc.org:80/handle/1961/3565 Smoking Cessation Strategies: Health Promotion and Disease Prevention Kasid, Natasha 2006-05-05T20:05:57Z http://aladinrc.wrlc.org:80/handle/1961/3564 Characterization of the Drosophila Ortholog of the Mammalian Anti-apoptotic Protein Aven Chang, Joy 2006-05-05T20:04:36Z http://aladinrc.wrlc.org:80/handle/1961/3563 Potential Anticonvulsant Properties of the Three Major Ketone Bodies Elevated During the Ketogenic Diet French, Amy 2006-05-05T20:02:55Z