University of Minnesota

About: University of Minnesota is a education organization based out in Minneapolis, Minnesota, United States. It is known for research contribution in the topics: Population & Transplantation. The organization has 117432 authors who have published 257986 publications receiving 11944239 citations. The organization is also known as: University of Minnesota, Twin Cities & University of Minnesota-Twin Cities.

Age-Dependent Changes in Brain, CSF, and Plasma Amyloid β Protein in the Tg2576 Transgenic Mouse Model of Alzheimer's Disease

Abstract: The accumulation of amyloid β protein (Aβ) in the Tg2576 mouse model of Alzheimer9s disease (AD) was evaluated by ELISA, immunoblotting, and immunocytochemistry. Changes in Aβ begin at 6–7 months as SDS-insoluble forms of Aβ42 and Aβ40 that require formic acid for solubilization appear. From 6 to 10 months, these insoluble forms increase exponentially. As insoluble Aβ appears, SDS-soluble Aβ decreases slightly, suggesting that it may be converting to an insoluble form. Our data indicate that it is full-length unmodified Aβ that accumulates initially in Tg2576 brain. SDS-resistant Aβ oligomers and most Aβ species that are N-terminally truncated or modified develop only in older Tg2576 mice, in which they are present at levels far lower than in human AD brain. Between 6 and 10 months, when SDS-insoluble Aβ42 and Aβ40 are easily detected in every animal, histopathology is minimal because only isolated Aβ cores can be identified. By 12 months, diffuse plaques are evident. From 12 to 23 months, diffuse plaques, neuritic plaques with amyloid cores, and biochemically extracted Aβ42 and Aβ40 increase to levels like those observed in AD brains. Coincident with the marked deposition of Aβ in brain, there is a decrease in CSF Aβ and a substantial, highly significant decrease in plasma Aβ. If a similar decline occurs in human plasma, it is possible that measurement of plasma Aβ may be useful as a premorbid biomarker for AD.

Phytoplankton Community Ecology: The Role of Limiting Nutrients

Abstract: This paper is a summary and synthesis of the role of nutrients and spatial and temporal fluctuations in controlling the species composition, diversity, and seasonal succession of planktonic algal communities. We do not review the full breadth and depth of the literature that has appeared since the seminal papers by Hutchinson (34) and Dugdale (19). Rather, we focus on some of the major questions and hypotheses, and evaluate these in light of their consistency with observation and experimentation. Because the combined net effect of limiting nutrients, major ions, pH, and other physical factors ultimately determines the reproductive rate of a local algal population, we first briefly review the data on the role of these factors in phytoplankton ecology. We then review the theory of resource competition and apply it to the questions of equilibrium versus nonequilibrium approaches, seasonal succession, and multitrophic level effects in phytoplankton com-

Reinterpreting comorbidity: a model-based approach to understanding and classifying psychopathology.

Abstract: Comorbidity has presented a persistent puzzle for psychopathology research. We review recent literature indicating that the puzzle of comorbidity is being solved by research fitting explicit quantitative models to data on comorbidity. We present a meta-analysis of a liability spectrum model of comorbidity, in which specific mental disorders are understood as manifestations of latent liability factors that explain comorbidity by virtue of their impact on multiple disorders. Nosological, structural, etiological, and psychological aspects of this liability spectrum approach to understanding comorbidity are discussed.

Genes, evolution, and personality.

Abstract: There is abundant evidence, some of it reviewed in this paper, that personality traits are substantially influenced by the genes. Much remains to be understood about how and why this is the case. We argue that placing the behavior genetics of personality in the context of epidemiology, evolutionary psychology, and neighboring psychological domains such as interests and attitudes should help lead to new insights. We suggest that important methodological advances, such as measuring traits from multiple viewpoints, using large samples, and analyzing data by modern multivariate techniques, have already led to major changes in our view of such perennial puzzles as the role of "unshared environment" in personality. In the long run, but not yet, approaches via molecular genetics and brain physiology may also make decisive contributions to understanding the heritability of personality traits. We conclude that the behavior genetics of personality is alive and flourishing but that there remains ample scope for new growth and that much social science research is seriously compromised if it does not incorporate genetic variation in its explanatory models.