Proteomic heterogeneity of glial cells of the central nervous system

Mammalian brain and retina, both part of the central nervous system (CNS), contain a multitude of distinct glial cell populations. On a rough scale they can be categorized for example as oligodendrocytes, microglia and astroglia. While oligodendroglia are mostly absent from the eye, astrocytes line the inner surface of the retina and microglia reside between its nuclear layers. Most importantly, the retina has its own kind of specialized glial cells: Müller glia. These long cells are evenly distributed, span the whole thickness of the retina and fulfil similar homeostatic functions as astrocytes in the brain. As the CNS is divided in functional and anatomical subunits that additionally differ by species, the respective glia are also thought to vary in their duties. In this work I addressed the question which cellular functions are shared between, and which are specific for astroglial cells from different brain regions and retina. Additionally, Müller cell heterogeneity was under special scrutiny focusing on cells from the macular and peripheral human retina. As glial cells constitute only a subpopulation of all CNS cells, it was necessary to enrich our cells of interest to make the following analysis as precise as possible. We achieved this by magnetic bead associated cell sorting. These cell fractions were then subjected to tandem mass spectrometry and served as the basis of the subsequent work. To extract the information hidden in such complex datasets, I used various bioinformatics tools to break them down into smaller protein lists that allowed conclusions on their role in glial biology. Furthermore, I selected individual proteins for in-depth validation and functional examination. I identified transcription factors of the nuclear factor 1 family to be expressed across glial cells of all contemplated regions and species, which corroborated their reported role in gliogenesis of brain and retina. Several of the pathways with interregional differential expression, including candidate proteins SLMAP and ZEB1, converged onto Hippo pathway signaling and alternative splicing. Furthermore, Müller cells of the human macula displayed an increased expression of proteins of the extracellular matrix, cell adhesion and exosomal pathways hinting towards a shift in the extracellular milieu. In this context, I showed how EPPK1 might play a role in establishing the intricate Müller cell morphology, their biomechanical properties and the secretion of extracellular vesicles. Finally, the proteomic datasets generated as part of my thesis have expanded our understanding of the biology of glia in different regions of the CNS and the retina specifically. The present findings will help to better understand the regional adaptions of astrocytes and Müller cells allowing the development of better tools or treatments targeting the desired subpopulations and translate insights between them

The electro deposition of lead in sugar and acetate solutions

The experiments, while hardly sufficiently numerous, seemed to indicate that sugars do not have a good effect on cathodic lead deposits --Conclusion, page 14

Consumer Prices for Surgical Management of Ankle Arthritis: Limited Availability and Wide Variability.

Background: Healthcare costs for the surgical management of ankle arthritis continue to rise. Patients are generally unaware of the prices of the services they use. Understanding the costs associated with surgical management of ankle arthritis is an important facet of patient care. The purposes of this study were to (1) determine the access to the surgical cost of total ankle arthroplasty (TAAs) and ankle arthrodesis and (2) the variability of the price between the two procedures. Methods: Fifty foot and ankle centers (25 academic, 25 private) that perform TAAs and ankle arthrodeses were contacted using a standardized patient script. The described patient was a 63-year-old man who had failed conservative treatment of ankle arthritis. Each institution was contacted up to three times in an attempt to obtain a full-bundled surgical quote for a TAA and an ankle arthrodesis. Results: Twenty-one centers (42%, 14 academic, 7 private) were able to provide a quote for a TAA and an ankle arthrodesis. The mean bundled price for a TAA was $50,332 (SD ±$25,744), with the mean academic and private center quote being $56,529 and$37,937, respectively. The mean bundled price for an ankle arthrodesis was $41,756 (SD ±$26,033), with the mean academic and private center quote being $48,116 and$29,037, respectively. No statistically significant difference was found between the bundled prices for TAA and ankle arthrodesis. Discussion: This study demonstrated limited availability of consumer prices for TAA and ankle arthrodesis. When comparing different institutions for surgical management of ankle arthritis, there was a wide range of quotes for both TAA and ankle arthrodesis. When comparing the choice of surgical management for ankle arthritis, no statistically significant difference was observed in price between TAA and ankle arthrodesis

Effect of Free Treatment and Surveillance on HIV-Infected Persons Who Have Tuberculosis, Taiwan, 1993–2006

In 1997, Taiwan made highly active antiretroviral therapy (HAART) available without cost to HIV-infected persons; in 2001, a national web-based surveillance system was implemented. Healthcare workers use the system to monitor patients' conditions and can intervene when necessary. Free HAART, coupled with the surveillance system, appears to have increased survival rates of HIV-infected persons with tuberculosis in Taiwan

Retinal regions shape human and murine Müller cell proteome profile and functionality

The human macula is a highly specialized retinal region with pit‐like morphology and rich in cones. How Müller cells, the principal glial cell type in the retina, are adapted to this environment is still poorly understood. We compared proteomic data from cone‐ and rod‐rich retinae from human and mice and identified different expression profiles of cone‐ and rod‐associated Müller cells that converged on pathways representing extracellular matrix and cell adhesion. In particular, epiplakin (EPPK1), which is thought to play a role in intermediate filament organization, was highly expressed in macular Müller cells. Furthermore, EPPK1 knockout in a human Müller cell‐derived cell line led to a decrease in traction forces as well as to changes in cell size, shape, and filopodia characteristics. We here identified EPPK1 as a central molecular player in the region‐specific architecture of the human retina, which likely enables specific functions under the immense mechanical loads in vivo

Two Epidemiologic Patterns of Norovirus Outbreaks: Surveillance in England and Wales, 1992–2000

In the period 1992–2000, the Public Health Laboratory Service Communicable Disease Surveillance Centre collected standardized epidemiologic data on 1,877 general outbreaks of Norovirus (formerly “Norwalk-like virus”) infection in England and Wales. Seventy-nine percent of general outbreaks occurred in health-care institutions, i.e., hospitals (40%) and residential-care facilities (39%). When compared with outbreaks in other settings, those in health-care institutions were unique in exhibiting a winter peak (p<0.0001); these outbreaks were also associated with significantly higher death rates and prolonged duration but were smaller in size and less likely to be foodborne. These data suggest that Norovirus infection has considerable impact on the health service and the vulnerable populations residing in institutions such as hospitals and residential homes. A distinct outbreak pattern in health-care institutions suggests a combination of host, virologic, and environmental factors that mediate these divergent epidemiologic patterns

As in Real Estate, Location Matters: Cellular Expression of Complement Varies Between Macular and Peripheral Regions of the Retina and Supporting Tissues.

The cellular events that dictate the initiation of the complement pathway in ocular degeneration, such as age-related macular degeneration (AMD), is poorly understood. Using gene expression analysis (single cell and bulk), mass spectrometry, and immunohistochemistry, we dissected the role of multiple retinal and choroidal cell types in determining the complement homeostasis. Our scRNA-seq data show that the cellular response to early AMD is more robust in the choroid, particularly in fibroblasts, pericytes and endothelial cells. In late AMD, complement changes were more prominent in the retina especially with the expression of the classical pathway initiators. Notably, we found a spatial preference for these differences. Overall, this study provides insights into the heterogeneity of cellular responses for complement expression and the cooperation of neighboring cells to complete the pathway in healthy and AMD eyes. Further, our findings provide new cellular targets for therapies directed at complement

Natural history of human Calicivirus infection: A prospective cohort study

We investigated the natural history of human Calicivirus infection in the community. Clinical information was obtained from 99 subjects infected with Norwalk-like viruses (NLV) and 40 subjects infected with Sapporo-like viruses (SLV) in a prospective, community-based cohort study. NLV infection was common in all age groups, whereas SLV infection was mainly restricted to children aged 75% for NLV and >67% for SLV). Overall, NLV was detected in 26% of patients up to 3 weeks after the onset of illness. This proportion was highest (38%) for children aged <1 year. SLV shedding subsided after 14 days. These data show that the durations of disease and viral shedding of caliciviruses are longer than has been described elsewhere. Therefore, the impact of these infections may have been underestimated