Faculty Bibliography

OBJECTIVES: South Africa is reported to have one of the highest rates of sexual violence in the world, with adolescent girls between the ages of 12-17 being particularly at risk. Given that adolescence is considered a critical developmental period for establishing normative sexual behavior, this study explored multiple levels of risk influences that render adolescent girls vulnerable to becoming victims of sexual violence and adolescent boys vulnerable to becoming perpetrators of such abuse in one South African community. METHOD: A case study approach using qualitative rapid focused ethnographic methods was used. This involved 10 focus group interviews and 10 individual interviews with a volunteer convenience sample of adolescent boys and girls between the ages of 14 and 16 years. RESULTS: Inductive thematic analysis revealed that there were indeed multiple levels of risk influences for adolescent girls and boys becoming either victims or perpetrators of sexual violence. Using the Theory of Triadic Influence as a framework, influences at the distal socio-cultural/environmental level included traditional notions of masculinity and normalization of inter-personal violence as well as poverty and the commodification of sex leading to rape supportive attitudes. Influences at the proximal situation context/social normative level included high-risk social norms as well as a weak adult and community protective shield. Finally, influences at the intra-personal level included low self-esteem and self-efficacy as well as inter-personal affective anger. CONCLUSION: Given the multiple levels of risk influences that need to be addressed to protect youth from becoming either perpetrators or victims of sexual violence in the South African context, prevention programs should necessarily be comprehensive, developmentally timed, and community-based.

There has been little research done in South Africa that investigates how families nested within communities can be strengthened to support the prevention of HIV infection in youth. A focused ethnographic case-study approach was employed to better understand how families in a semi-rural area outside Durban, South Africa, could support youth to make healthy life choices, particularly with respect to HIV risk behaviour. This involved a volunteer convenience sample of parents or caregivers and key community members. A psychodynamic extension of social representational theory was applied to an interpretation of the data. The findings suggest that caregivers of youth feel disempowered and unsupported in a context of fractured and un-containing leadership structures, which works against social cohesion. In the context of social change and relatively new and threatening phenomena such as HIV/AIDS, we argue that strong unified leadership structures are necessary to assist with anchoring the unfamiliar and rendering it manageable, as well as to form the building blocks of social cohesion, a protective social environmental factor for youth. In addition, we suggest that programmes aimed at empowering parents or caregivers with knowledge about HIV/AIDS as well as renegotiating parental practices to promote greater parental authority, would be important interventions at a family level.

This article describes an intake questionnaire (Adquest) that was designed, tested, and implemented, and later employed in clinical data-mining studies, by practitioners in an adolescent mental health program. The instrument is primarily a practice-based, clinical information-gathering and client engagement device. Consequently, it differs in significant ways from more research-driven Rapid Assessment Instruments (RAIs). Despite these differences, when aggregated and analyzed, Adquest data provides valuable psychosocial information about hundreds of vulnerable urban youth seeking mental health services

Active contour segmentation and its robust implementation using level sets have been studied thoroughly in the medical image analysis literature. Despite the availability of these powerful methods, clinical research still largely relies on manual slice-by-slice outlining for anatomical structure segmentation. To bridge the gap between methodological advances and clinical routine, we developed ITK-SNAP: an open source application intended to make level set segmentation easily accessible to a wide range of users with various levels of mathematical expertise. We briefly describe this new tool and report the results of a validation study in which ITK-SNAP was compared to manual segmentation of the caudate in the context of an ongoing child neuroimaging autism study

RATIONALE AND OBJECTIVES: Malignancy provokes regional changes to vessel shape. Characteristic vessel tortuosity abnormalities appear early during tumor development, affect initially healthy vessels, spread beyond the confines of tumor margins, and do not simply mirror tissue perfusion. The ability to detect and quantify tortuosity abnormalities on high-resolution magnetic resonance angiography (MRA) images offers a new approach to the noninvasive diagnosis of malignancy. This report evaluates a computerized, statistical method of analyzing the shapes of vessels extracted from MRA in diagnosing cancer. MATERIALS AND METHODS: The regional vasculature of 34 healthy subjects was compared with the tumor-associated vasculature of 30 brain tumors before surgical resection. The operator performing the analysis was blinded to the diagnosis. Vessels were segmented from an MRA of each subject, a region of interest was defined in each tumor patient and was mapped to all healthy controls, and a statistical analysis of vessel shape measures was then performed over the region of interest. Many difficult cases were included, such as pinpoint, hemorrhagic, and irradiated tumors, as were hypervascular benign tumors. Tumors were identified as benign or malignant on the basis of histological evaluation. RESULTS: A discriminant analysis performed at the study's conclusion successfully classified all but one of the 30 tumors as benign or malignant on the basis of vessel tortuosity. CONCLUSIONS: Quantitative, statistical measures of vessel shape offer a new approach to the diagnosis and staging of disease. Although the methods developed under the current report must be tested against a new series of cases, initial results are promising.

A publicly available database of high-quality, multi-modal MR brain images of carefully screened healthy subjects, equally divided by sex, and with an equal number of subjects per age decade, would be of high value to investigators interested in the statistical study of disease. This report describes initial use of an accumulating healthy database currently comprising 50 subjects aged 20-72. We examine changes by age and sex to the volumes of gray matter, white matter and cerebrospinal fluid for subjects within the database. We conclude that traditional views of healthy aging should be revised. Significant atrophy does not appear in healthy subjects 60 or 70 years old. Gray matter loss is not restricted to senility, but begins in early adulthood and is progressive. The percentage of white matter increases with age. A carefully-designed healthy database should be useful in the statistical analysis of many age- and non-age-related diseases.