Studies of human dendritic cells in the skin after antigen exposure

Dendritic cells (DCs) act at the interface of innate and adaptive immunity. They are capable of inducing strong effector immune responses to invading pathogens, but also exert important functions in the maintenance of tolerance. The DCs of the skin are strategically located to be amongst the first cells to react to exposure to foreign substances and initiate immune responses, and increased understanding of these cells is critical for the development of new treatments of infections, allergic reactions and autoimmune disorders, as well as of new vaccine delivery strategies, targeting the skin. Studies of skin DC subsets are held back by technical difficulties in isolating the cells. In paper I of this thesis, we therefore aimed to develop a new DC purification method, using a skin graft mesher. This device is used clinically for expansion of skin graft tissue for transplantation. We found that by using the skin graft mesher the processing of skin was significantly accelerated, which had both practical and biological advantages. The DCs isolated from epidermis consisted of a uniform CD1a+ Langerin+ Langerhans cell population with high antigen uptake capacity. The DCs from dermis showed varied antigen uptake capacity and could be divided into three distinct populations based on CD1a expression. In addition, a skin explant model to study antigen uptake by DC subsets in situ was developed. We found that antigen injected into the skin explants was rapidly taken up, mainly by DCs in the dermis. This model can be a useful tool to study immediate responses to antigen exposure. However, since no recruitment of new cells into the tissue can occur, skin explants cannot illustrate all the components of innate immune responses. This prompted for the studies in paper II and III, where we took the approach to study infiltration of DCs to sites of antigen exposure in the skin in vivo. By using skin punch biopsies collected from standard skin antigen test sites like the tuberculin skin test (TST), we quantified recruited immune cells by immunohistochemical stainings of cryosections. We found that several DC subsets including plasmacytoid DCs (pDCs) accumulated in the dermis in the indurations induced in individuals with positive TSTs. In contrast, donor-matched saline injected skin did not show any DC recruitment, nor did TST sites of individuals lacking induration. The positive TST induration tissue was also associated with cell death and high expression of the antimicrobial peptide LL37, which together can provide a means for pDC activation and IFN! production. In line with this, IFN-inducible MxA was highly induced at the positive TST sites. By in vitro experiments, we found that pDCs were not as efficient as myeloid DC subsets to take up the TST antigens. Further, IFN! containing supernatants from pDC activated with LL37-DNA complexes reduced antigen uptake in myeloid DCs as well as decreased their capacity to activate T cells. Infiltrating pDCs in the TST reaction may thus have a regulatory effect upon the antigen processing and presentation functions of surrounding DC subsets, to limit potentially detrimental and excessive immune stimulation. TST and other antigen skin tests are used to monitor the integrity of the cellular immune system in HIV-1 infected individuals. To evaluate whether mobilization of DCs in response to antigen skin tests was impaired in HIV-1 infected individuals, we analyzed skin punch biopsies from skin test sites using mumps virus, Candida albicans or TST. Control skin biopsies showed that there was no difference in the number of skin-resident DCs between healthy and HIV-1 infected individuals. Also, multiple DC subsets infiltrated the dermis in response to injection with all antigens. However, the levels of DC infiltration correlated with the generally lower levels of memory T cells that accumulated at the antigen sites. A depleted or deficient T cell compartment could therefore lead to compromised DC recruitment and insufficient antigen presentation to T cells. Taken together, these studies contribute with new methods and data on the function and phenotypes of skin DCs, and their response to antigen administration in the skin in health and HIV-1 infection

Modeling the Performance Improvement Process: A Case Study of a Federally Qualified Health Center

The city of Gary, Indiana, has experienced an economic downturn in recent years that has led to an unemployment rate that is 2.5 times higher than the national average. In addition, Lake County, which includes the city of Gary, is currently one of the two unhealthiest counties in the state of Indiana. Documented poor health behaviors in this area highlight the need to change how at-risk communities access health care. Community HealthNet (CHN) is a federally funded clinic with five locations in Lake County and a vision to provide accessible, affordable, and quality medical services. Since 1998, CHN has made efforts to create a continuum of care and a stabilized medical experience for patients in their jurisdiction. CHN also targets services to specific needs, such as prenatal care and education to address the high infant mortality rate in this area. A case study of this particular federally qualified health center has shown a need for sufficient information technology infrastructure and a database so that the clinic can be constantly aware of patient needs and can allocate resources effectively. Purdue researchers and I have worked closely with CHN staff to establish this database and have examined the clinic’s internal process to create and measure strategies for performance improvement. CHN shows increased efficiency in meeting funding requirements and utilizing resources. This improvement of CHN’s process will translate to improved access to affordable and high-quality health care for the Gary community

The relationship between biodiversity and ecosystem functioning across space and time

Recent empirical studies conducted in disparate ecosystems have shown that greater species diversity has positive effects on ecosystem functioning; however, other studies have found neutral or sometimes negative results. It is still unclear why the relationship between biodiversity and functioning varies among studies, but perhaps, investigating this relationship across spatial and temporal scales will lead to further understanding. One theory predicts that local niche complementarity among species (the partitioning of species based upon niche differentiation) is predicted to positively affect local ecosystem functioning at the local spatial scale. However, more recent theory predicts that greater local diversity may hinder local ecosystem functioning when diversity is enhanced through regional processes. I suggest community assembly as a way to incorporate both the local and regional processes that determine biodiversity and its consequent effects on ecosystem functioning. From this, I propose a hump-shaped relationship between diversity and ecosystem functioning at local spatial scales, but a linear increase of functioning with diversity at regional spatial scales. Thus, species diversity may have different effects on ecosystem functioning across different spatial scales. Species diversity may affect ecosystem functioning differently across time as environmental conditions shift. Through integrating recent theoretical models in ecosystem ecology and empirical examples of food-webs in community ecology, the effects of herbivore diversity on ecosystem functioning (grazing of primary producers) were examined under unchanged (no nutrients added) and changed (nutrients added) environmental conditions. I found that communities with higher species richness and diversity did not significantly differ from lower diversity communities in grazing intensity in the unchanged environments. However, higher diversity communities did have a significant effect on the biomass of primary producers in the nutrient enriched environments, while lower diversity communities did not. This empirical study showed that the functioning of local communities is dependent on the environmental conditions present in the habitat. Overall, this investigation found that the relationship between species diversity and ecosystem functioning may be dependent on spatial scale and environmental changes over time

Voluntary temporary abstinence from alcohol during “Dry January” and subsequent alcohol use

Objective: Temporary abstinence from alcohol may convey physiological benefits and enhance well-being. The aim of this study was to address a lack of information about: (1) correlates of successful completion of a planned period of abstinence, and (2) how success or failure in planned abstinence affects subsequent alcohol consumption. Methods: 857 British adults (249 men, 608 women) participating in the “Dry January” alcohol abstinence challenge completed a baseline questionnaire, a one-month follow-up questionnaire, and a 6-month follow-up questionnaire. Key variables assessed at baseline included measures of alcohol consumption and drink refusal self-efficacy (DRSE). Results: In bivariate analysis, success during Dry January was predicted by measures of more moderate alcohol consumption and greater social DRSE. Multivariate analyses revealed that success during Dry January was best predicted by a lower frequency of drunkenness in the month prior to Dry January. Structural Equation Modelling revealed that participation in Dry January was related to reductions in alcohol consumption and increases in DRSE among all respondents at 6-month follow-up, regardless of success, but these changes were more likely among people who successfully completed the challenge. Conclusions: The findings suggest that participation in abstinence challenges such as “Dry January” may be associated with changes toward healthier drinking and greater DRSE, and is unlikely to result in undesirable “rebound effects”: very few people reported increased alcohol consumption following a period of voluntary abstinence

The Cost of Uncertainty: Navigating the Boundary Between Legal Information and Legal Services in the Access to Justice Sector

The self-regulatory bodies that oversee legal professionals in Canada maintain strict control on the delivery of legal services, and access to justice projects must therefore always be conscious of activities that would violate certain restrictions. Careful adherence to these parameters is made difficult, however, by the lack of clarity about where the relevant boundaries are drawn. Using a project that provides legal assistance for refugees as a case study, this article highlights the challenges that the unclear distinction between “legal information” and “legal services” creates for access to justice initiatives. We conclude that the uncertainty can carry a variety of significant costs—including financial expense, human resource burdens, and unnecessary limits on program innovation—in a sector where affordable and creative solutions are desperately needed as a result of a persistent access to justice crisis. Ultimately, it is not merely the under-resourced access to justice sector that bears these costs, but rather disadvantaged individuals and society as a whole

Cannulation for Cardiopulmonary Bypass

Cardiac surgery has made significant progress since the advent of cardiopulmonary bypass. Arterial cannulation for bypass is a cornerstone to most cardiac procedures. Choosing an ideal cannulation site, employing peri- and intraoperative imaging, selecting an appropriate cannula, and avoiding complications are vital to success. These, along with the steps to arterial cannulation, are discussed in this chapter

The Cost of Uncertainty: Navigating the Boundary Between Legal Information and Legal Services in the Access to Justice Sector

The self-regulatory bodies that oversee legal professionals in Canada maintain strict control on the delivery of legal services, and access to justice projects must therefore always be conscious of activities that would violate certain restrictions. Careful adherence to these parameters is made difficult, however, by the lack of clarity about where the relevant boundaries are drawn. Using a project that provides legal assistance for refugees as a case study, this article highlights the challenges that the unclear distinction between “legal information” and “legal services” creates for access to justice initiatives. We conclude that the uncertainty can carry a variety of significant costs—including financial expense, human resource burdens, and unnecessary limits on program innovation—in a sector where affordable and creative solutions are desperately needed as a result of a persistent access to justice crisis. Ultimately, it is not merely the under-resourced access to justice sector that bears these costs, but rather disadvantaged individuals and society as a whole

Enhancement of latent fingerprints on fabric using the cyanoacrylate fuming method followed by infrared spectral mapping

A method has been developed for the visualization of latent fingerprints on fabrics, which is based upon cyanoacrylate (superglue) fuming followed by imaging using an infrared microscope. Results show that imaging on smooth, shiny fabrics such as polyester, silk, nylon and acetate of different colors and patterns can give an improvement over existing enhancement methods. Results for cotton and polycotton were less successful and it is thought this may be due a combination of the presence of the carbonyl functional group in these fabrics as well as their absorbency to fingerprint sweat. The carbonyl peak (1700 cm-1) provided the optimum spectroscopic feature to map and image a fingerprint. Comparisons between infrared mapping at a specific frequency range and principal component analysis showed that improved imaging was obtained with principal component analysis

Criers, Impresarios, and Sextons: Disreputable Occupations in the Roman World

Roman law stigmatized not only the individual but also the collective for dishonorable acts. Numerous professions incurred varying degrees of disrepute that carried legal and civic disabilities. Professionals in the sex and entertainment trades who incurred the legal stigma of infamia have been investigated by modern scholarship; yet, those people who worked in the disreputable occupations of praeco (crier), dissignator (event coordinator), libitinarius (funeral director), and in the mortuary trade have not been fully discussed in terms of either the reasons for their disrepute or their significance within social, economic, administrative, and religious networks. To counteract this void of literature, I analyze the status and role of these professionals from the Republic to Late Antiquity. Through this research, I show the origins of social perceptions of disrepute and their codification into legal statute in the first century BCE, and illustrate the creation of a marginal society that was placed outside the civic realm in Roman cities. I argue that these professionals were crucial negotiators between the civic and marginal society. Moreover, my use of predominantly epigraphic remains such as dedications and epitaphs allows me to investigate the identities and associative relationships formulated by these professionals, as well as the shifts in their status related to broad administrative and religious changes in the Roman world. The elevation of groups of funeral workers in Late Antiquity--fossores, copiatae, decani, and lecticarii--and their use within the minor orders of some early Christian churches illustrates this status shift. Though disreputable, these professionals did have a level of social and economic mobility and served as vital cultural mediators within Roman society