Methods in molecular biology
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In this chapter, we discuss the concept of statistical power and show how the sample size can be chosen to ensure a desired power. Power is the probability of rejecting the null hypothesis when the null hypothesis is false, that is the probability of saying there is a difference when a difference actually exists. ⋯ An overpowered study has too large a sample size and wastes resources. We will show how the power and required sample size can be calculated for several common types of studies, mention software that can be used for the necessary calculations, and discuss additional considerations.
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The insufficiency of terminological standards in neuroscience is increasingly recognized as a serious obstacle to interoperability. Adoption of a controlled vocabulary is a successful solution for small numbers of groups that work closely together but is impractical for large numbers of groups who represent diverse areas of research, index information by various legitimate nomenclatures, or publish in different languages. Interoperability among such disparate databases requires a translation mechanism, or "mediator," to enable communication and data sharing among databases. ⋯ We have created in NeuroNames an ontology of 2500 neuroanatomical concepts referenced by 15,000 terms in seven languages. NeuroNames is the mediator for BrainInfo, a portal to neuroanatomy on the Web. We hope that a description of our experience in establishing interoperability between BrainInfo and other neuroscience Web sites may be useful to others engaged in the development of ontologies for neuroscience.
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Statistics is defined by the Medical Subject Headings (MeSH) thesaurus as the science and art of collecting, summarizing, and analyzing data that are subject to random variation. The two broad categories of summarizing and analyzing data are referred to as descriptive and inferential statistics. This chapter considers the science and art of summarizing data where descriptive statistics and graphics are used to display data. ⋯ For describing quantitative variables, measures of location and spread, for example the standard deviation, are presented along with graphical presentations. We also discuss distributions of statistics, for example the variance, as well as the use of transformations. The concepts in this chapter are useful for uncovering patterns within the data and for effectively presenting the results of a project.
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Antisense oligonucleotides (ASO) against specific molecular targets (e.g., Bcl-2 and Raf-1) are important reagents in cancer biology and therapy. Phosphorothioate modification of the ASO backbone has resulted in an increased stability of ASO in vivo without compromising, in general, their target selectivity. Although the power of antisense technology remains unsurpassed, dose-limiting side effects of modified ASO and inadequate penetration into the tumor tissue have necessitated further improvements in ASO chemistry and delivery systems. ⋯ Raf-1 expression is decreased in normal and tumor tissues of LErafAON-treated mice. Therapeutic benefit of a combination of LErafAON and radiation or an anticancer drug exceeds radiation or drug alone against human prostate, breast, and pancreatic tumors grown in athymic mice. Further improvements in ASO chemistry and nanoparticles are promising avenues in antisense therapy of cancer.
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Human embryonic stem cells (hESCs) are pluripotent stem cells derived from the inner cell mass of the blastocyst. Due to their unique properties, hESCs might be used for research fields such as self-renewal, specific lineage differentiation, human developmental biology, and teratology. hESCs also have outstanding potential to serve for clinical purposes as a source for cell-based therapies. ⋯ Future industrial and clinical implementation of hESCs will require the use of a defined medium and an animal-free culture method that will prevent their possible exposure to animal pathogens. This chapter discusses the advancements in the development of methods for the defined culture of hESCs and describes a simple method for animals serum-free and feeder layer-free culture of hESCs.