细胞技术

Transdifferentiation is defined as the conversion of one cell type to another. One well-documented example of transdifferentiation is the conversion of pancreatic cells to hepatocytes. Here we describe a robust in vitro model to study pancreas to liver transdifferentiation. It is bas ...

Regenerative medicine aims at producing new cells for repair or replacement of diseased and damaged tissues. Embryonic and adult stem cells have been suggested as attractive sources of cells for generating the new cells needed. The leading dogma was that adult cells in mammals, once committ ...

Cellular reprogramming is an interplay between the original starting cell’s plasticity and the (epi)genetic mechanisms used to drive this cell towards a new fate. Our capacity to reprogram mature cells into progenitors thus greatly depends on the inherent physiological plasticity ...

Reprogramming of committed cells from one lineage to another is possible in the hematopoietic system using enforced expression of transcription factors. Here we describe methods to convert committed B and T progenitors into macrophages. In order to obtain a labeled population of start ...

Induction of pluripotent stem cells from somatic cells by defined factors was shown to be possible only recently, but already several laboratories have made tremendous strive toward improving and understanding the process. Originally, Oct4, Sox2, Klf4, and cMyc were identified as being ...

This chapter describes the methods we use to derive and characterize human induced pluripotent stem (iPS) cells. We describe in order, first our culture techniques for the starting fibroblast populations and methods for retrovirus preparation and concentration. Subsequently, a de ...

Genomic reprogramming can be accomplished by five different types of methods: nuclear transfer, cell fusion, in vitro culture, introduction of egg extract, and transduction of transcription factors. We have shown that fusion-induced reprogramming is an efficient method for repro ...

Somatic cell nuclear transfer (SCNT) is a technique by which the nucleus of a differentiated cell is introduced into an oocyte from which its genetic material has been removed by a process called enucleation. In mammals, the reconstructed embryo is artificially induced to initiate embryon ...

This chapter is primarily devoted to experiments that compare 2 treatments with respect to an outcome measure. Six design scenarios are discussed: (a) completely randomized designs (treatments are assigned completely at random); (b) randomized block designs (experimental units a ...

Statistical models provide a framework in which to describe the biological process giving rise to the data of interest. The construction of this model requires balancing adequate representation of the process with simplicity. Experiments involving multiple (correlated) obser ...

This chapter presents the general linear model as an extension to the two-sample t-test, analysis of variance (ANOVA), and linear regression. We illustrate the general linear model using two-way ANOVA as a prime example. The underlying principle of ANOVA, which is based on the decomposition of t ...

This chapter describes multiple linear regression, a statistical approach used to describe the simultaneous associations of several variables with one continuous outcome. Important steps in using this approach include estimation and inference, variable selection in model b ...

This chapter highlights important steps in using correlation and simple linear regression to address scientific questions about the association of two continuous variables with each other. These steps include estimation and inference, assessing model fit, the connection betw ...

This chapter describes statistical methods to test for differences between means or other measures of central tendency of 2 or more populations. Parametric tests and nonparametric tests are included. Methods for pairwise comparisons when more than 2 groups are being compared are inclu ...

Diagnostic tests, medical tests, screening tests, biomarkers, and prediction rules are all types of classifiers. This chapter introduces methods for classifier development and evaluation. We first introduce measures of classification performance including sensitivity, ...

Categorical data are data that capture a characteristic of an experimental unit (such as a tissue specimen) rather than a numerical value. In this chapter, we first describe types of categorical data (nominal and ordinal) and how these types of data are distributed (binomial, multinomial, and i ...

In this chapter, we discuss the fundamental principles behind two of the most frequently used statistical inference procedures: confidence interval estimation and hypothesis testing. both procedures are constructed on the sampling distributions that we have learned in previo ...

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 sta ...

Much can be learned about a process by observing changes over time or by comparing two different processes under different conditions. This chapter introduces the major types of observational study designs: the longitudinal or cohort study, the comparative or case-control study, and so ...

This chapter presents some guidelines for working with a statistician, beginning with when and why you should consult one. We emphasize the importance of good communication between the statistician and the client and the need for clearly defined tasks and a timetable. Other consideratio ...