The Role of Tuft Cell Gustatory Signaling in Pancreaticobiliary Disease

Pancreaticobiliary tract diseases are common digestive disorders diagnosed by painful symptoms with minimal treatment options. Among these diagnoses, pancreatic ductal adenocarcinoma (PDA) is the third most common cause of cancer death in the United States with only a 10 percent 5-year survival rate. Pancreatic injury promotes acinar to ductal metaplasia (ADM), a wound healing process, which can be hijacked by mutant KRAS expression, leading to progressive dysplasia termed pancreatic intraepithelial neoplasia (PanIN), and carcinoma. Accompanying this process is a desmoplastic stromal response which aids progression through suppression of immune mediated cytotoxicity. Formation of ADM and PanIN lesions promotes epithelial cell heterogeneity and metaplastic tuft cell (MTC) formation, a cell found only in the common bile duct in the normal pancreas. Tuft cell function regulates immune cell recruitment and activation in many organs by use of canonical gustatory signaling pathways. Initiation of tuft cell signaling through G-protein coupled receptor (GPCR) activation promotes alpha-gustducin (GNAT3), the gustatory G alpha-protein, activation, ultimately leading to cell depolarization, through opening of TRPM5 cation channels, which releases signals to regulate immune function. MTC roles in the pancreaticobiliary tract remain unknown but expression of gustatory signaling and immune-regulatory proteins indicate a sensory role to also modify immune cell function. The aim of the research presented in this dissertation is to understand the role of MTC gustatory signaling following biliary dysfunction and pancreatic neoplastic progression. To explore the role of gustatory signaling in pancreatic neoplasia and progression, alpha-gustducin ablated (Gnat3-/-) mice were bred to models of pancreatic neoplasia. GNAT3 ablation in the neoplastic pancreas increased CXCL1 and CXCL2 expression in the pancreatic epithelium, studied in 3D culture and animal models, and increased immunosuppressive myeloid-derived suppressor cells (MDSC) in the stromal compartment. Exploration of tumorigenesis finds GNAT3 ablation promotes advanced PDA tumorigenesis and metastasis. Preliminary data suggest MTC function requires the use of canonical gustatory signaling to promote multiple signaling molecules, including ATP, acetylcholine or CXCL1. Preliminary work also indicates a role for other immune populations and fibroblasts in contribution to MTC function in PDA. Overall, these data indicate a tumor suppressive role for MTC function in PDA progression. The function of biliary MTCs gustatory signaling was studied in GNAT3 ablated biliary tract tissue expressing mutant KRAS. While expression of mutant KRAS promotes mild biliary dilation, additional loss of GNAT3 enhances immune cell presence, bile accumulation and biliary dilation with increased mortality of a small group of mice in a pilot study. No obvious histological blockages were found in the ampulla of Vater but the presence of apical vesicles suggests altered cholangiocyte secretion or absorption into the biliary tract. Advancement of this model with the addition of mutant TP53 did not progress to biliary cancer. These preliminary data suggest mutant KRAS expressing biliary tuft cells may play a role in the secretory function of cholangiocytes and bile homeostasis. These data indicate organ specific functions for MTC during disease progression. In the neoplastic pancreas, MTCs regulate tumor suppressive immunity, slowing PDA progression, and in the biliary tract, MTCs aid in homeostasis. Though further work is required to fully analyze the differential mechanisms behind MTC function, these results demonstrate neoplastic epithelial cell signaling can play a multifaceted role in the development of pancreaticobiliary disease.PHDMolecular and Integrative PhysiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/162977/1/mthoff_1.pd

A Comparative Assessment of How Rhesus Monkeys and 3- to 4-year-old Children Remember Self-Agency with Spatial, Temporal, and Contextual Features in Working Memory

Comparative research on event memory has typically focused on the binding of spatial and temporal information in memory, but much less is known about how animals remember information about the source of their memories (i.e., whether the event is something they performed themselves or whether they observed it). The purpose of the present study was to examine how rhesus monkeys (n = 8) and 3- to 4- year-old children (n = 20) remember this information along with other relevant event features (object identity, spatial location, temporal properties and contextual features) in working memory. In Experiment 1, rhesus monkeys completed five different delayed matching-to-sample tasks to assess independent encoding of these five event components. In Experiment 2, the monkeys either performed or observed an event and then had to respond to a randomly selected pair of memory tests used in the previous experiment. In Experiment 3, children were presented with the same memory task, but were given a brief demonstration to learn how to perform the task. Both children and monkeys responded to these tests using photos and shapes (for the identity and spatial tests) and icons (for the temporal, agency and context tests). The monkeys demonstrated significantly above-chance performance on the identity, spatial, temporal and agency tasks. The children were above chance on the one component the monkeys had difficulty with (context), but conversely demonstrated difficulty on the temporal memory test. There was evidence of feature integration in both monkeys and children. Specifically, the children were significantly more likely to respond correctly to the second memory test if they had also been correct on the first memory test. Two of five rhesus monkeys also showed this effect, indicating that for these individuals, the features were integrated in working memory. Implications of this research are discussed in relation to self-awareness and episodic memory research in children and nonhuman species

Career Development Interventions with Low Socioeconomic Status Students

Research has shown that students that are of low socioeconomic status (SES) are less likely to engage in deliberate and planful career development. This paper reviews group counseling in the high school setting, career development in the high school setting, career counseling in the group setting, issues associated with low SES, career development and SES and low SES and career development theories. Results of career development interventions in a group counseling setting are included

Communication of where an event occurred by a gorilla (gorilla gorilla gorilla)

Episodic-like memory for the where component of unique events was examined in an adult gorilla (Gorilla gorilla gorilla). The gorilla witnessed a unique event, performed by an experimenter (e.g. watching an experimenter blow bubbles) at one of three locations surrounding his enclosure. After a 4 to 17 minute retention interval, a tester presented the gorilla with photographs of the three locations, which were mounted on wooden cards, and asked the gorilla where the event had occurred. The gorilla communicated his choice by handing a card to the tester and was rewarded if correct. The gorilla was significantly above chance at identifying the event location. Results suggest that the gorilla was not responding on the basis of familiarity by choosing the most recently visited location, but choosing the location where the event occurred

The Substantial Weight Test: A Proposal to Resolve the Circuit's Disparate Interpretations of Materiality Under the False Claims Act

This is the published version

Memory for What , Where , and When Information by Rhesus Monkeys (Macaca Mulatta) and Adult Humans

The purpose for the present study was to examine working memory for what, where, and when information in rhesus monkeys (Macaca mulatta) and adult humans using a computerized task. In Experiment 1, monkeys and humans completed three delayed matching-to-sample (DMTS) tasks: 1) identity DMTS, 2) spatial DMTS, and 3) temporal DMTS. In Experiments 2, the identity and spatial tasks were combined so that monkeys had to report both what and where information about an event. In Experiment 3, the identity, spatial, and temporal tasks were combined in order to examine what-where-when memory integration. In Experiment 4, monkeys and humans were presented with two sequential events, and a memory cue indicated which event they were required to report. The rhesus monkeys and human participants were able to report all three components of the events and there was some evidence suggesting that these components were integrated in memory for the rhesus monkeys

Cooperative Federalism: Nevada’s Indigent Defense Crisis and the Role of Federal Courts in Protecting the Right to Counsel in Non-Capital Cases

In Martinez v. Ryan, the United States Supreme Court held the ineffective assistance of post-conviction counsel, or the lack of representation in a state post-conviction proceeding, provides cause to allow a federal habeas petitioner to overcome a procedural default on an ineffective assistance of trial counsel claim. This represented a radical shift in the criminal justice system. Prior to Martinez, state post-conviction proceedings—the typical mechanism for a criminal defendant to challenge the performance of his trial attorney—were not heavily scrutinized. It was understood and accepted that defendants did not have the right to counsel in these post-conviction proceedings. Whether a defendant represented himself in the state post-conviction proceedings or had counsel to assist him, federal review was strictly limited to those claims raised in that proceeding, regardless of how well they were investigated or presented. However, Martinez has now altered that calculus and, in doing so, shined a bright spotlight on whether these state post-convictions proceedings adequately protect a defendant’s right to the effective assistance of counsel. The Supreme Court explained why this is so important: “[T]he right to the effective assistance of counsel at trial is a bedrock principle in our justice system . . . . Indeed, the right to counsel is the foundation for our adversary system.” In light of Martinez, a criminal defendant now has a broader mechanism for protecting this fundamental constitutional right. A defendant can raise new challenges to his attorney’s performance in a federal habeas proceeding and argue that what occurred in the state post-conviction proceedings was inadequate. Martinez’s impact in non-capital cases in Nevada could be quite significant. The need for vigorous post-conviction review in Nevada is hard to deny. There have been systematic problems in the indigent defense system that continue to this day. Despite these nearly intractable issues, the Nevada Supreme Court refused to extend Martinez to its own state post-conviction process. Rather, the court chose to elevate the concept of finality of the conviction over rigorous protection of this invaluable constitutional right. It is this cramped vision of post-conviction review that Martinez was clearly meant to address

Women writing women : gender and representation in British 'Golden Age' crime fiction

In this thesis, I examine representations of women and gender in British ‘Golden Age’ crime fiction by writers including Margery Allingham, Christianna Brand, Agatha Christie, Ngaio Marsh, Dorothy L. Sayers, Josephine Tey and Patricia Wentworth. I argue that portrayals of women in these narratives are ambivalent, both advocating a modern, active model of femininity, while also displaying with their resolutions an emphasis on domesticity and on maintaining a heteronormative order, and that this ambivalence provides a means to deal with anxieties about women’s place in society. This thesis is divided thematically, beginning with a chapter on historical context which provides an overview of the period’s key social tensions. Chapter II explores depictions of women who do not conform to the heteronormative order, such as spinsters, lesbians and ‘fallen’ women. Chapter III looks at the ways in which the courtships and marriages of detective couples attempt to negotiate the ideal of companionate marriage and the pressures of a ‘cult of domesticity’. Chapter IV considers the ways in which depictions of women in schools, universities and the workplace are used to explore the tensions between an expanding role in the public sphere and the demand to inhabit traditionally domestic roles. The thesis concludes with a discussion of the image of female victims’ and female killers’ bodies and the ways in which such depictions can be seen to expose issues of gender, class and identity. Through its examination of a wide variety of texts and writers in the period 1920 to the late 1940s, this thesis investigates the ambivalent nature of modes of femininity depicted in Golden Age crime fiction written by women, and argues that seemingly conservative resolutions are often attempts to provide a ‘modern-yet-safe’ solution to the conflicts raised in the texts

Respiratory anatomy, physiology, and central CO₂ chemosensitivity of the Arctic air-breathing fish Dallia pectoralis

Thesis (M.S.) University of Alaska Fairbanks, 2010"Aerial respiration using a ancestral lung, central respiratory rhythm generation, and central CO₂ chemosensitivity arose early in vertebrate evolution prior to the divergence of sarcopterygian and actinopterygian fish. All vertebrate air breathing, however, is not homologous as this trait evolved independently several times among teleost fishes. Two long-standing questions in respiratory physiology are whether air breathing in fish is controlled by a central rhythm generator and whether air breathing and central CO₂ chemosensitivity co-evolved. One means to address these questions is to investigate control of breathing in the brainstem; therefore, we established an isolated brainstem preparation from the Alaska blackfish, Dallia pectoralis, a rare example of an arctic air-breathing fish. In blackfish, air breathing consists of gulping and swallowing an air bubble into the esophagus and holding it in place by closing off the esophagus from the buccal cavity with a sphincter. Gulping the air bubble is accomplished by the same opercular and mandibular muscles that draw water into the buccal cavity during gill ventilation. Activation of the opercular and mandibular muscles for ventilation is effected by a central rhythm generator in the brainstem that is spontaneously active in the absence of peripheral input. This central rhythm generator, however, is not modulated by central CO₂ chemosensitivity. Unless central CO₂ chemosensitivity was lost in blackfish, we might conclude that centrally controlled vertebrate air breathing can evolve independent of central CO₂ chemosensitivity"--Leaf iiiNational Institute o f Health- (NIH-NINDS) 2U54NS041069-06A1Chapter 1. General introduction -- Origins of vertebrate respiration -- Evolutionary pressure favoring aerial respiration -- Neural control of vertebrate respiration -- Respiratory chemosensitivity -- Air breathing in Alaska Blackfish -- References -- Figures -- Chapter 2. Respiratory anatomy, physiology, and central CO₂ chemosensitivity of the Arctic air-breathing fish Dallia pectoralis -- Abstract -- Introduction -- Methods -- Animals -- Characterization of air breathing in Dallia pectoralis -- Validation of the air-breathing organ by visual inspection -- Validation of air-breathing musculature by electromyostimulation and electromyography -- Validation of the neural correlates of air breathing in the semi-intact preparation -- Characterization of central rhythm generation for air breathing and CO₂ -- Chemosensitivity in Dallia pectoralis -- Isolated brainstem preparation challenged with high Pco₂ -- Intact Dallia pectoralis challenged with acetazolamide-induced acidosis -- Data analysis and statistics -- Validation -- Central CO₂ chemosensitivity -- Results -- Characterization of air breathing in Dallia pectoralis -- Validation of the air-breathing organ by visual inspection -- Validation of air-breathing musculature by electromyostimulation and electromyography -- Validation of the neural correlates of air breathing in the semi-intact preparation -- Characterization of central rhythm generation for air breathing and CO₂ chemosensitivity in Dallia pectoralis -- Isolated brainstem preparation challenged with high Pco₂ -- Intact Dallia pectoralis challenged with acetazolamide-induced acidosis -- Discussion -- Air breathing in Alaska blackfish -- Central CO₂ chemosensitivity -- Acknowledgements -- References -- Figures -- Tables -- Chapter 3. General discussion -- Respiration -- Validation of respiratory myo- and neurocorrelates -- Central CO₂ chemosensitivity -- General conclusion -- References