Experimental approaches to study cerebral amyloidosis in a transgenic mouse model of Alzheimer's disease

Misfolding, aggregation and the accumulation of proteins in the brain are common characteristics of diverse age-related neurodegenerative diseases. Each of these neurodegenerative diseases is associated with abnormalities in the folding of a different protein leading to protein aggregation and finally to neuronal death. Alzheimer’s disease (AD) is one of these protein conformational diseases characterized by two major neuropathological features: extracellular accumulation of amyloid-b (Ab) peptide in the form of plaques and intracellular tangles consisting of hyperphosphorylated tau protein. Although the majority of AD cases are sporadic, three genes have been described whose mutations cause early-onset familial AD (FAD). The identification of mutations in these genes has provided new opportunities to explore pathogenic mechanisms using transgenic approaches. Based on the finding that mutations in these genes all lead to elevated levels of Ab, new anti-amyloid therapies have been developed to either lower the production of Ab or to clear the amyloid peptides. In the past few years, several groups have generated transgenic mouse models of cerebral amyloidosis that exhibit age related Ab deposition similar to AD patients through expression of mutated human amyloid precursor protein (APP). The studies presented herein were done using such a transgenic mouse model, the APP23 mouse, that overexpresses human APP with the Swedish mutation under the control of a neuron specific Thy-1 promotor. APP23 transgenic mice develop cerebral amyloidosis in an age- and region-dependent manner. Plaque formation starts early at 6 months of age and is associated with the typical AD-like pathology including cerebral amyloid angiopathy, neuron loss, glial activation and cognitive impairment. The purpose of this thesis was to study the mechanism and initiation of amyloid formation as well as the spread of cerebral amyloidosis in vivo. The first series of studies were conducted to define the role and contribution of extracellular versus intracellular b-amyloid in plaque formation. To this end, we transplanted embryonic wildtype (wt) and APP23 transgenic (tg) brain tissue into the hippocampus and cortex of both APP23 and wt mice. We observed that APP23 grafts into wt hosts did not develop amyloid deposits up to 20 moths post-grafting. In contrast, both tg and wt grafts into APP23 hosts developed amyloid plaques already 3 months post-grafting. The amyloid deposits in wt grafts were surrounded by neuritic changes and gliosis similar to the amyloid-associated pathology described in APP23 mice as well as in AD patients. These results suggest that the phenotype of the transplanted tissue is strongly influenced by the properties of the host. Moreover, these results provide evidence that diffusion of Ab in the extracellular space is important for the spread of Ab pathology, that amyloid formation starts extracellularly and that it is the extracellular amyloid that causes neurodegeneration. The second set of experiments were performed to study the initiation of amyloid deposition and to clarify which factors are involved in the seeding process in vivo. Since seeded polymerization of Ab has already been demonstrated in vitro and in vivo, we replicated and advanced these findings by intracerebral injection of diluted brain extract from AD patients and brain extracts from aged APP23 transgenic mice into young predepositing APP23 mice. AD and APP23 brain homogenate induced a similar amount of seeded Ab deposits in the brain parenchyma and vessel walls four month post-infusion. This seeding was time- and concentration-dependent. In contrast, no seeding was observed when PBS was injected or when the same extract was injected into wt mice. To address whether Ab itself is the seeding agent we injected synthetic Ab into young APP23 mice. These synthetic Ab injections resulted in limited Ab deposition compared to that obtained with Ab-rich brain extract. Our findings suggest that Ab-containing human and mouse brain extracts can induce cerebral amyloidosis in vivo, and that Ab, in combination with additional factors, initiates amyloid formation. The third part of the work presented here follows up on our previous finding that diffusion of Ab in the extracellular space plays an important role in the spread of cerebral amyloidosis. Therefore, we came up with the hypothesis that amyloid deposition and the accompanied pathophysiology could influence extracellular space (ECS) volume and interstitial fluid (ISF) diffusion properties. By using diffusion weighted magnetic resonance imaging (DWI), we determined the diffusion properties in the brains of young and aged APP23 transgenic mice and control littermates. Our results indicate that fibrillar amyloid formation and the associated gliosis are accompanied by a decrease in the apparent diffusion coefficient (ADC), suggesting that both build a barrier for interstitial fluid diffusion. Thus, in elderly people, ADC measurements and the assessment of diffusion properties in the ECS could serve as a biomarker to detect pathological events in the brain of AD patients. In summary, the studies presented herein have increased our understanding of the mechanisms leading to protein aggregation and finally to neurodegeneration in a transgenic mouse model. We have shown that factors other than local Ab production, such as diffusion in the extracellular space, are important in determining whether amyloid pathology will occur. Moreover, the results highlight the relevance of extracellular Ab to the pathogenesis of the disease. It still remains an open question whether Ab itself is sufficient to initiate plaque formation, and if so, what conformational form of Ab is required. Together, these studies provide insights into the mechanisms and disease pathways which may lead to AD

The impact of globalisation on higher education : achieving a balance between local and global needs and realities.

The business world has changed dramatically over the last decade to address the reality of globalisation in the sphere of business. However, most universities have remained intact as local universities servicing local needs of citizens studying at their closest universities. For instance, a small number of universities have managed to attract students from other provinces, countries and regions. The question arises: to what extent have universities in South Africa embraced to the reality of globalisation? Are higher education institutions preparing students to work globally, or do they still function as institutions operating with a local mindset for a local market? Although South African universities have been widely criticised for not producing graduates meeting the needs of the local economy, these institutions are now challenged to prepare students for global markets. Only one local university achieved a ranking in the top hundred universities in the world according to the latest international ranking of universities. This reality poses several challenges for universities, for example, globalising curriculum to meet global needs and realities, as well as sourcing more academics from different parts of the world to infuse a global focus in the development and delivery of a global curriculum. Similarly, local universities are expected to play a key role in the socio-economic transformation of South Africa, while being challenged to meet international standards. This dichotomy places severe strain on the resources of universities, of which many may not be ready to compete globally, especially in the light of the rapid growth of private higher education, and big business, resorting to corporate universities to meet their needs. This paper seeks to determine the impact of globalisation on higher education with specific recommendations for achieving a balance between global and local higher education needs and realities

Customer Communication of Regional Quality Efforts: A Case From the Grain Sector

Usually, marketing communication efforts in the agrifood sector address the end consumers and concentrate on products that are processed and ready for consumption, thus quality efforts often concentrate on the final product. Moreover, there’s a widespread view that agricultural commodities like wheat aren’t suitable neither for product focused marketing nor branding. However, recent developments in the in agrifood sector challenge this view. The increasing use of biotechnology, the globalisation of markets and changing consumer demands for quality, food safety and process attributes require improved communication concepts and information sharing along whole production chains. This paper considers the development of a quality communication system to support a regional wheat brand and prerequisites for quality management efforts

BRCA1/2 mutation screening and LOH analysis of lung adenocarcinoma tissue in a multiple-cancer patient with a strong family history of breast cancer

BACKGROUND: Germline mutations in BRCA1/2 greatly elevate risks of breast and ovarian cancers, but the role of these genes in tumourigenesis of other cancer types is still being investigated. OBJECTIVE: We report on an investigation of BRCA1/2 mutations and their loss of heterozygosity (LOH) in a patient with a strong family history of breast cancer who was diagnosed with consecutive primary cervical, ovarian and lung carcinomas. METHODS AND RESULTS: BRCA1/2 mutation screening of the proband revealed a common familial breast- and ovarian cancer-associated germline BRCA2 mutation (3034del4bp). We then performed LOH analysis for BRCA2 in lung adenocarcinoma tissue of the patient. Using the laser-capture microdissection (LCM) technique, we obtained pure populations of neoplastic cells from which DNA could be extracted. Mutation analysis by denaturing high-performance liquid chromatography (DHPLC) and direct sequencing revealed loss of the mutant allele in the adenocarcinoma tumour tissue. CONCLUSION: To our knowledge, this is the first report of investigation for LOH for BRCA2 in primary lung adenocarcinoma tissue of a patient with multiple primary tumours related to a familial germline BRCA2 mutation. Interestingly, it was the mutant, not the wild-type, allele which was lost in the lung adenocarcinoma tissue

The Effects of Financial Literacy on Patient Engagement

Health care reform has caused consumers to learn more about what it means to have health insurance and its costs. Patient engagement, a critical component of health care reform, reflects provider and consumer attention to shared decision making between patient and physician. The problem addressed in this study is that although researchers have studied patient engagement, there has been insufficient exploration of the relationship between financial literacy and patient engagement, which could negatively impact health outcomes not only for patients or consumers but for society as a whole. The purpose of this quantitative research was to determine if a relationship exists between patient financial literacy and patient engagement, as measured by the patient activation measure. The potential effects of increased patient financial responsibility due to high deductible health plans, measured via an item inquiring about participants\u27 deductible, as well as shared decision making between physician and patient were also evaluated as potential moderators between financial literacy and patient engagement. Theories used to provide conceptual context include Shim\u27s cultural health capital theory and Bourbeau\u27s (2008) self-management model. Two hierarchical linear multiple regression models were used to test the research hypotheses. While the research did not find a significant relationship between patient financial literacy and patient engagement, it did confirm the importance of mental health status and patient-physician shared decision making as important predictors of patient engagement. These findings provide a better understanding of financial literacy and specific financial behaviors in the context of healthcare environment today

Species-Specific Differences in the Susceptibility of Fungi to the Antifungal Protein AFP Depend on C-3 Saturation of Glycosylceramides

AFP is an antimicrobial peptide (AMP) produced by the filamentous fungus Aspergillus giganteus and is a very potent inhibitor of fungal growth that does not affect the viability of bacteria, plant, or mammalian cells. It targets chitin synthesis and causes plasma membrane permeabilization in many human- and plant-pathogenic fungi, but its exact mode of action is not known. After adoption of the “damage-response framework of microbial pathogenesis” regarding the analysis of interactions between AMPs and microorganisms, we have recently proposed that the cytotoxic capacity of a given AMP depends not only on the presence/absence of its target(s) in the host and the AMP concentration applied but also on other variables, such as microbial survival strategies. We show here using the examples of three filamentous fungi (Aspergillus niger, Aspergillus fumigatus, and Fusarium graminearum) and two yeasts (Saccharomyces cerevisiae and Pichia pastoris) that the important parameters defining the AFP susceptibilities of these fungi are (i) the presence/absence of glycosylceramides, (ii) the presence/absence of Δ3(E) desaturation of the fatty acid chain therein, and (iii) the (dis)ability of these fungi to respond to AFP inhibitory effects with the fortification of their cell walls via increased chitin and β-(1,3)-glucan synthesis. These observations support the idea of the adoption of the damage-response framework to holistically understand the outcome of AFP inhibitory effects.TU Berlin, Open-Access-Mittel - 201

New Trends, Resources, and Applications | The Future of Nebraska\u27s Data

Many Nebraska organizations are doing excellent work in the field of data visualization and improving access to data. This session will highlight some of this work, including portals and dashboards that present data quickly and easily. See live demonstrations of various useful products from: Nebraska Department of Labor, Omaha Community Foundation, Nebraska Children and Families Foundation, Nebraska Coordinating Commission for Postsecondary Education, and our own Center for Public Affairs Research