published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Thesis (M. Med. Sc.)--University of Hong Kong, 2007.

Thesis (M.D.) -- Dept. of Surgery, University of Adelaide, 1981. / Typescript (photocopy).

Thesis (M.S.) -- University of Adelaide, Dept. of Surgery, 2000. / Corrigenda inside back cover. Bibliography: leaves 161-178.

a variety of South African Hospitals: a retrospective study Purpose: To examine the number of lymph nodes present in specimens submitted for histological examination from a variety of South African hospitals; the identification of factors that influence nodal yield and node positivity; determining whether oncological clearance is improved based on the number of nodes examined in high volume centers versus low volume centres; the establishment of guidelines on where surgery for colorectal cancer should ideally be performed. Patients and methods: Pathology reports of resected specimens of colorectal adenocarcinoma in the database of the National Health Laboratory Service Johannesburg laboratory from 2000 to 2005, were examined for patient demographics, referring hospital, tumour specific features of T-stage, degree of differentiation, lymphovascular invasion and adenocarcinoma subtype (mucinous versus non-mucinous), number of lymph nodes identified, number of nodes positive and whether preoperative radiotherapy was administered. Hospitals were grouped into four groups of Charlotte Maxeke Johannesburg Academic Hospital, Helen Joseph Hospital, private hospitals and non-academic public hospitals. Patients were grouped according to the number of lymph nodes retrieved into the following groups: not recorded, no nodes identified,1-7 nodes identified, 8-12 nodes, 13-18 nodes, and greater than 18 nodes identified. Additionally, patients were subdivided into those with nodal metastasis and those without, and into colon and rectal cancer respectively. Multivariate analysis was performed via StatSoft, Inc. (2008) STATISTICA (data analysis software system), version 8.0 on the different lymph node groups versus the abovementioned covariates. Results: Of the 365 patients identified, the mean number of lymph nodes examined per resected specimen was 8.9 (±6.2SD), with significant differences noted between the different resection subtypes (p < 0.001). No statistically significant difference in mean number of nodes identified could be seen between the various hospitals. Alarmingly, in the group of patients where no metastatic nodes could be identified, the recommendation of 12 or more nodes examined per specimen was upheld in only 29% of cases. Factors associated with positive lymph nodes in this study include T-stage, degree of differentiation and lymphovascular invasion by the tumour. No significant benefit in terms of finding metastasis nodes could be demonstrated by examining more than 18 nodes. Conclusions and recommendations: This study highlights a substandard nodal assessment in colorectal cancer specimens overall, including the academic hospitals. More than 70% of node negative patients in this series may have been understaged. Close liaison between the surgeon and examining pathologist is recommended. In the presence of the identified high risk factors for nodal involvement and a substandard nodal assessment, additional measures i.e. fat clearance and immunohistochemistry need employment. A prospective study assessing quality of surgery is necessary, as is the creation of a central database to improve overall quality of cancer care.

Introduction To measure the radiation exposure to the surgeon during axillary sentinel lymph node biopsy using the radioactive isotope technetium-99m. Method A prospective analysis of 36 patients undergoing axillary sentinel lymph node biopsy using technetium-99m, between 15th January 2013 to the 20th February 2013.. Results The exposure to the surgeon during axillary sentinel lymph node dissection was measured in 36 patients by placing a thermoluminescent dosimeter (TLD) on the surgeon’s finger. The TLDs recorded the total radiation exposure to the surgeon. The recommended occupational dose limit for non radiation workers extremity exposure is less than 500 μSv. The analysed and extrapolated data showed an average exposure dose to the surgeon per patient of 2.7 μSv. Conclusion One surgeon would need to perform more than 85 such procedures per year in order to exceed the advised annual extremity dose limit. The data also suggests that regular measurements of radiation exposure and radiation protective measures need not be undertaken in theatres where surgeons are working with radioactive isotope for axillary sentinel lymph node biopsies.

Typescript (photocopy) / 163 leaves, [8] leaves of plates : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (M.D.)--Dept. of Surgery, University of Adelaide, 1981

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 112-126).

Thesis (Ph.D.)--Boston University / The golden hamster, Mesocricetus auratus, is unique in that it frequently accepts not only homografts but even heterografts of normal and malignant tissues. One of the many theories a tterpting an explanation of this phenomenon, namely that lymphatic tissues that drain the sites of imphntation do not respond in a t;rpicol fashion, motivated this study. Thus, the weight changes ,and the c;'tolof'ical variations of the superficial cervical nodes in response to homologous and heterologous normal and malignant tissue transplants in the cheek pouch of the hamster were studied. The major objectives were: (1) to determine if there be any "defect" in the hamster's lymphatic tissue response to the various transplants; (2) to investigate the effects of the grafts on the large lymphoid cells of the cortex and on the plasma cells of the medulla; and ( 3) to investigate the feasibility of employing the histological picture of a regional node draining the site of a tumor heterotransplant as a base line for anti-tumor studies during the cortisone conditioning. [TRUNCATED]

Mechanisms for human memory T cell differentiation and maintenance have predominantly been inferred from studies of peripheral blood, though the majority of T cells reside in lymphoid and non-lymphoid sites. Studies in mice have shown that memory T cells in non-lymphoid sites provide superior protection to pathogens compared to those in blood, defining a subset known as tissue-resident memory T cells (TRM), with emerging roles in lymphoid sites. There are many key unknown aspects of TRM biology in human tissues including if TRM have superior functional abilities, the mechanisms for maintenance of TRM in lymphoid and non-lymphoid sites, and the relatedness of tissue and blood localized T cell subsets. Through a collaboration with the local organ procurement agency, we obtained samples from >15 tissue sites from healthy organ donors of all ages. We analyzed CD8+ T cells in diverse sites and found the majority of TRM cells in lymph nodes (LNs) display an increased proliferative capacity, increased expression of TCF-1, and decreased turnover compared to TRM and effector memory (TEM) cells in other sites including blood, bone marrow (BM), spleen and lung. Further, we identified that exposure to type 1 interferons results in increased downregulation of TCF-1 expression during cell divisions driven by T cell receptor (TCR) stimulation. We investigated the relatedness of CD4+ and CD8+ T cell subsets, including central memory (TCM), effector memory (TEM), TRM, and terminal effectors (TEMRA) by sequencing TCR rearrangements. From diversity analysis of TCR repertoires we found that effector and memory subsets are maintained in a hierarchy from most to least diverse (TCM > TEM and TRM > TEMRA) that is largely conserved across tissues and CD4+ and CD8+ T cell lineages. Overlap analysis revealed the low and high relatedness of TCM and TEMRA cells respectively and this was highly conserved across tissues; in contrast, we found the relatedness of TEM and TRM was more dynamic across tissues. Together, these findings have implications for immune monitoring and modulation, highlighting that lymph nodes may function as reservoirs for long-lived memory T cells with high functional capacity; additionally, we identify cell extrinsic signals that regulate tissue-specific maintenance of T cell memory in lymph node sites.