Axon Death Prevented: Wld\u3csup\u3es\u3c/sup\u3e and Other Neuroprotective Molecules: A Dissertation

A common feature of many neuropathies is axon degeneration. While the reasons for degeneration differ greatly, the process of degeneration itself is similar in most cases. Axon degeneration after axotomy is termed ‘Wallerian degeneration,’ whereby injured axons rapidly fragment and disappear after a short period of latency (Waller, 1850). Wallerian degeneration was thought to be a passive process until the discovery of the Wallerian degeneration slow (Wlds) mouse mutant. In these mice, axons survive and function for weeks after nerve transection. Furthermore, when the full-length protein is inserted into mouse models of disease with an axon degeneration phenotype (such as progressive motor neuronopathy), Wlds is able to delay disease onset (for a review, see Coleman, 2005). Wlds has been cloned and was found to be a fusion event of two neighboring genes: Ube4b, which encodes an ubiquitinating enzyme, and NMNAT-1 (nicotinamide mononucleotide adenylyltransferase-1), which encodes a key factor in NAD (nicotinamide adenine dinucleotide) biosynthesis, joined by a 54 nucleotide linker span (Mack et al., 2001). To address the role of Wlds domains in axon protection and to characterize the subcellular localization of Wlds in neurons, our lab developed a novel method to study Wallerian degeneration in Drosophila in vivo (MacDonald et al., 2006). Using this method, we have discovered that mouse Wlds can also protect Drosophila axons for weeks after acute injury, indicating that the molecular mechanisms of Wallerian degeneration are well conserved between mouse and Drosophila. This observation allows us to use an easily manipulated genetic model to move the Wlds field forward; we can readily identify what Wlds domains give the greatest protection after injury and where in the neuron protection occurs. In chapter two of this thesis, I identify the minimal domains of Wlds that are needed for protection of severed Drosophila axons: the first 16 amino acids of Ube4b fused to Nmnat1. Although Nmnat1 and Wlds are nuclear proteins, we find evidence of a non-nuclear role in axonal protection in that a mitochondrial protein, Nmnat3, protects axons as well as Wlds. In chapter 3, I further explore a role for mitochondria in Wlds-mediated severed axon protection and find the first cell biological changes seen in a Wlds-expressing neuron. The mitochondria of Wlds- and Nmnat3-expressing neurons are more motile before injury. We find this motility is necessary for protection as suppressing the motility with miro heterozygous alleles suppresses Wldsmediated axon protection. We also find that Wlds- and Nmnat3- expressing neurons show a decrease in calcium fluorescent reporter, gCaMP3, signal after axotomy. We propose a model whereby Wlds, through production of NAD in the mitochondria, leads to an increase in calcium buffering capacity, which would decrease the amount of calcium in the cytosol, allowing for more motile mitochondria. In the case of injury, the high calcium signal is buffered more quickly and so cannot signal for the axon to die. Finally, in chapter 4 of my thesis, I identify a gene in an EMS-based forward genetic screen which can suppress Wallerian degeneration. This mutant is a loss of function, which, for the first time, definitively demonstrates that Wallerian degeneration is an active process. The mammalian homologue of the gene encodes a mitochondrial protein, which in light of the rest of the work in this thesis, highlights the importance of mitochondria in neuronal health and disease. In conclusion, the work presented in this thesis highlights a role for mitochondria in both Wlds-mediated axon protection and Wallerian degeneration itself. I identified the first cell biological changes seen in Wlds-expressing neurons and show that at least one of these is necessary for its protection of severed axons. I also helped find the first Wallerian degeneration loss-of-function mutant, showing Wallerian degeneration is an active process, mediated by a molecularly distinct axonal degeneration pathway. The future of the axon degeneration field should focus on the mitochondria as a potential therapeutic target

Unweighted regression models perform better than weighted regression techniques for respondent-driven sampling data: results from a simulation study

Background: It is unclear whether weighted or unweighted regression is preferred in the analysis of data derived from respondent driven sampling. Our objective was to evaluate the validity of various regression models, with and without weights and with various controls for clustering in the estimation of the risk of group membership from data collected using respondent-driven sampling (RDS). Methods: Twelve networked populations, with varying levels of homophily and prevalence, based on a known distribution of a continuous predictor were simulated using 1000 RDS samples from each population. Weighted and unweighted binomial and Poisson general linear models, with and without various clustering controls and standard error adjustments were modelled for each sample and evaluated with respect to validity, bias and coverage rate. Population prevalence was also estimated. Results: In the regression analysis, the unweighted log-link (Poisson) models maintained the nominal type-I error rate across all populations. Bias was substantial and type-I error rates unacceptably high for weighted binomial regression. Coverage rates for the estimation of prevalence were highest using RDS-weighted logistic regression, except at low prevalence (10%) where unweighted models are recommended. Conclusions: Caution is warranted when undertaking regression analysis of RDS data. Even when reported degree is accurate, low reported degree can unduly influence regression estimates. Unweighted Poisson regression is therefore recommended.York University Librarie

Hospital Community Benefits After the ACA: Building on State Experience

Analyzes hospitals' requirements to conduct community health needs assessments, financial assistance and billing and collection policies, and community benefit reporting and oversight strategies. Notes implications for federal and state law and practice

What we are like when we are at our best: Appreciative stories of staff in a community mental health center

Appreciative Inquiry is an organizational change methodology that discovers what works well in an organization and then pursues strategies to enhance those factors. The initial discovery process itself provides data ripe for qualitative analysis. Narratives were collected from 27 community mental health staff about times when they were at their best. An emergent, consensus-based analysis was used to understand the stories and exemplary work -- with competent, caring staff and elements needed to support them. Findings are discussed in light of self-determination theory that people are at their best with a sense of mastery, connection, and autonomy

Appreciative Inquiry as Organizational Change in a Community Mental Health Setting

poster abstractAppreciative Inquiry (AI) is an approach to organizational change that focuses on the strengths of an organization – discovering what is working well, and generating ideas within the organization for building on those strengths. AI has been applied in a variety of contexts including education, social work, health care, and academia. Little to no research, however, has applied AI to mental health contexts. The current study reports themes from staff member interviews conducted in the early phases of AI applied in a community mental health center (CMHC); these themes paint a picture of this CMHC “at its best” and will be fed-back to employees to lay the foundation for change and enhancing morale among staff. Interviews were conducted by 11 staff who volunteered from various departments and were trained by research staff at an all-day training. Appreciative Interviews first involved asking staff to describe a time they were at their best at this organization. Next, participants were asked to share what it was about themselves, others, and the setting that contributed to this experience. Additionally, interviewees were asked to “dream into the future” and to describe what they wish to see for this organization. Interviews were audio recorded, transcribed, and de-identified. Iterative, consensus-based coding was conducted by a multidisciplinary team that included CMHC staff. Several consistent themes emerged among participants’ stories. Staff at their best frequently reported feeling effective and seeing success in working with consumers. Other themes included working as a team, communicating well, and trusting one another. Stories also involved feeling valued and supported by their supervisors and coworkers. A foundational aspect involved believing in and caring about consumers with whom they work. Themes from participants’ interviews reflect perceptions of this community mental health center at its best and are consistent with tenets self-determination theory and future study

Closing the gap in surveillance and audit of invasive mold diseases for antifungal stewardship using machine learning

Clinical audit of invasive mold disease (IMD) in hematology patients is inefficient due to the difficulties of case finding. This results in antifungal stewardship (AFS) programs preferentially reporting drug cost and consumption rather than measures that actually reflect quality of care. We used machine learning-based natural language processing (NLP) to non-selectively screen chest tomography (CT) reports for pulmonary IMD, verified by clinical review against international definitions and benchmarked against key AFS measures. NLP screened 3014 reports from 1 September 2008 to 31 December 2017, generating 784 positives that after review, identified 205 IMD episodes (44% probable-proven) in 185 patients from 50,303 admissions. Breakthrough-probable/proven-IMD on antifungal prophylaxis accounted for 60% of episodes with serum monitoring of voriconazole or posaconazole in the 2 weeks prior performed in only 53% and 69% of episodes, respectively. Fiberoptic bronchoscopy within 2 days of CT scan occurred in only 54% of episodes. The average turnaround of send-away bronchoalveolar galactomannan of 12 days (range 7-22) was associated with high empiric liposomal amphotericin consumption. A random audit of 10% negative reports revealed two clinically significant misses (0.9%, 2/223). This is the first successful use of applied machine learning for institutional IMD surveillance across an entire hematology population describing process and outcome measures relevant to AFS. Compared to current methods of clinical audit, semi-automated surveillance using NLP is more efficient and inclusive by avoiding restrictions based on any underlying hematologic condition, and has the added advantage of being potentially scalable

Clinical characteristics of persistent frequent attenders in primary care: case–control study

Background. Most frequent attendance in primary care is temporary, but persistent frequent attendance is expensive and may be suitable for psychological intervention. To plan appropriate intervention and service delivery, there is a need for research involving standardized psychiatric interviews with assessment of physical health and health status. Objective. To compare the mental and physical health characteristics and health status of persistent frequent attenders (FAs) in primary care, currently and over the preceding 2 years, with normal attenders (NAs) matched by age, gender and general practice. Methods. Case–control study of 71 FAs (30 or more GP or practice nurse consultations in 2 years) and 71 NAs, drawn from five primary care practices, employing standardized psychiatric interview, quality of life, health anxiety and primary care electronic record review over the preceding 2 years. Results. Compared to NAs, FAs were more likely to report a lower quality of life (P < 0.001), be unmarried (P = 0.03) and have no educational qualifications (P = 0.009) but did not differ in employment status. FAs experienced greater health anxiety (P < 0.001), morbid obesity (P = 0.02), pain (P < 0.001) and long-term pathological and ill-defined physical conditions (P < 0.001). FAs had more depression including dysthymia, anxiety and somatoform disorders (all P < 0.001). Conclusions. Persistent frequent attendance in primary care was associated with poor quality of life and high clinical complexity characterized by diverse and often persistent physical and mental multimorbidity. A brokerage model with GPs working in close liaison with skilled psychological therapists is required to manage such persistent complexity

Cognitive behaviour therapy for long-term frequent attenders in primary care: a feasibility case series and treatment development study

Background: Most frequent attendance in primary care is temporary. Long-term frequent attendance may be suitable for psychological intervention to address health management and service use. Aim: To explore the feasibility and acceptability of cognitive-behaviour therapy (CBT) for long-term frequent attendance in primary care and obtain preliminary evidence regarding clinical and cost-effectiveness. Design and Setting: A CBT case series was carried out in five GP practices. Method: Frequent attenders (FAs) were identified from case notes and invited by their practice for assessment, then offered CBT. Feasibility and acceptability were assessed by CBT session attendance and thematic analysis of semi-structured questionnaires. Clinical and cost effectiveness was assessed by primary care use and clinically important change on a range of health and quality of life instruments. Results: Of 462 FAs invited to interview, 87 (19%) consented to assessment. Thirty-two (7%) undertook CBT over median three months. Twenty-four (75%) attended > 6 sessions. Eighteen FAs (86%, n=21) reported overall satisfaction with treatment. Patients reported valuing listening without judgement alongside support to develop coping strategies. Thirteen (55%, n=24) achieved clinically important improvement on the SF-36 Mental-Component Scale at six month follow-up and improved quality of life, but no improvement on other outcomes. Primary care use reduced from median eight contacts in three months at baseline (n=32) to three contacts in three months at one year (n=18). Conclusion: CBT appears feasible and acceptable to a sub-set of long-term FAs in primary care who halved their primary care use. With improved recruitment strategies, this approach might contribute to decreasing GP workload and merits larger-scale evaluation

Platelet zinc status regulates prostaglandin-induced signaling, altering thrombus formation

Background: Approximately 17.3% of the global population exhibits an element of zinc (Zn2+) deficiency. One symptom of Zn2+ deficiency is increased bleeding through impaired hemostasis. Platelets are crucial to hemostasis and are inhibited by endothelial-derived prostacyclin (prostaglandin I2 [PGI2]), which signals via adenylyl cyclase (AC) and cyclic adenosine monophosphate signaling. In other cell types, Zn2+ modulates cyclic adenosine monophosphate concentrations by changing AC and/or phosphodiesterase activity. Objectives: To investigate if Zn2+ can modulate platelet PGI2 signaling. Methods: Platelet aggregation, spreading, and western blotting assays with Zn2+ chelators and cyclic nucleotide elevating agents were performed in washed platelets and platelet-rich plasma conditions. In vitro thrombus formation with various Zn2+ chelators and PGI2 was assessed in whole blood. Results: Incubation of whole blood or washed platelets with Zn2+ chelators caused either embolization of preformed thrombi or reversal of platelet spreading, respectively. To understand this effect, we analyzed resting platelets and identified that incubation with Zn2+ chelators elevated pVASPser157, a marker of PGI2 signaling. In agreement that Zn2+ affects PGI2 signaling, addition of the AC inhibitor SQ22536 blocked Zn2+ chelation–induced platelet spreading reversal, while addition of Zn2+ blocked PGI2-mediated platelet reversal. Moreover, Zn2+ specifically blocked forskolin-mediated AC reversal of platelet spreading. Finally, PGI2 inhibition of platelet aggregation and in vitro thrombus formation was potentiated in the presence of low doses of Zn2+ chelators, increasing its effectiveness in inducing platelet inhibition. Conclusion: Zn2+ chelation potentiates platelet PGI2 signaling, elevating PGI2’s ability to prevent effective platelet activation, aggregation, and thrombus formation

The Impact of the COVID-19 Pandemic on the Food Security of UK Adults Aged 20–65 Years (COVID-19 Food Security and Dietary Assessment Study)

The first UK lockdown greatly impacted the food security status of UK adults. This study set out to establish if food procurement was adapted differently for different income groups and if this impacted dietary intakes disproportionately. Adults (n=515) aged 20-65 years participated in an online survey with 56 completing a 3-4 day diet diary. Food availability was a significant factor in the experience of food insecurity. Similar proportions of food secure and food insecure adapted food spend during lockdown, spending similar amounts. Food insecure (n = 85, 18.3%) had a 10.5% lower income and the money spent on food required a greater proportion of income. Access to food was the biggest driver of food insecurity but monetary constraint was a factor for the lowest income group. The relative risk of food insecurity increased by 0.07-fold for every 1% increase in the proportion of income spent on food above 10%. Micronutrient intakes were low compared to the reference nutrient intake (RNI) for most females, with riboflavin being 36% lower in food insecure groups (P=0.03), whilst vitamin B12 was 56% lower (p = 0.057) and iodine 53.6% lower (p = 0.257) these were not significant. Coping strategies adopted by food insecure groups included altering the quantity and variety of fruit and vegetables which may have contributed to the differences in micronutrients