细胞技术

The unprecedented availability of genome sequences, coupled with user-friendly, web-enabled search and analysis tools allows practitioners to locate interesting genome features or sequence tracts with relative ease. Although many public model organism- and genome-mappi ...

Genetic association studies are increasingly used in the search for susceptibility variants for human traits. While many of the statistical tools available for such studies are well established, the field is advancing rapidly, as biological and technological developments allow i ...

Microarrays and related technologies have allowed investigators to ask biological questions in far greater detail than has previously been possible. Microarrays had a troubled beginning, but most of these problems resulted from the growing pains of this technology, which, like many n ...

In biomedical research, meaningful conclusions can only be drawn based on data collected from a valid scientific design using appropriate statistical methods. Therefore, the selection of an appropriate study design is important in order to provide an unbiased and scientific evalua ...

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 ...

This chapter concerns statistical concepts and procedures that are applicable to diagnostic testing performed in the clinical laboratory. Three important laboratory issues are addressed: the estimation of analytical imprecision, the design of an effective laboratory qual ...

Missing data frequently arise in the course of research studies. Understanding the mechanism that led to the missing data is important in order for investigators to be able to perform analyses that will lead to proper inference. This chapter will review different missing data mechanisms, in ...

In this chapter, we introduce the basics of Bayesian data analysis. The key ingredients to a Bayesian analysis are the likelihood function, which reflects information about the parameters contained in the data, and the prior distribution, which quantifies what is known about the paramete ...

This chapter introduces some fundamental results in survival analysis. We first describe what is censored failure time data and how to interpret the failure time distribution. Two nonparametric methods for estimating the survival curve, the life table estimator and the Kaplan-Meier e ...

The Medical Subject Headings (MeSH) thesaurus used by the National Library of Medicine defines logistic regression models as “statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, su ...

When the same subjects or laboratory animals are observed across a set of different conditions or over time, we are usually interested in studying change. In these study designs, each subject serves as its own control. In this chapter, we consider different ways to assess change over time, for exampl ...

Hematopoietic stem cells (HSCs) have been studied for decades in order to understand their stem cell biology and their potential as treatments in gene therapy, and those studies have resulted in tremendous advancement of understanding HSCs. However, most of the studies required the sacri ...

Bacterial artificial chromosome (BAC) recombineering is a novel technique for DNA manipulation. It starts from an original chromosomal gene locus that is modified to introduce a transgene under the expression control of the original gene locus. In most cases a cell type specific promoter ...

Stable transgene insertion into a host genome irrevocably and unambiguously marks individual cells and all their descendants, i.e., the respective cell clone. Based thereon, retroviral gene marking has become an important tool for investigating the in vivo fate of different cell types, ...

This chapter describes the methods we use to transduce mouse and human hematopoietic stem cells (HSCs) and human embryonic stem cells (hESCs). We provide detailed protocols for producing high-titer lentiviral supernatants by transient transfection and for measuring viral titers. ...

The benzodiazepines are a large, commonly prescribed family of psychoactive drugs. We describe a method permitting the simultaneous detection and quantification of 12 benzodiazepines in serum using ultra-performance liquid chromatography (UPLC) coupled with tandem mass sp ...

Busulfan is a chemotherapy drug widely used as part of conditioning regimens for patients undergoing bone marrow transplantation (BMT). Challenges of busulfan treatment include a narrow therapeutic window and wide inter- and intra-patient variability. Inappropriately low dr ...

Nonketotic hyperglycinemia (NKH), a metabolic disorder due to defects in the glycine cleavage system, leads to the accumulation of toxic levels of glycine. Glycine levels in these patients may be lowered by sodium benzoate treatment. Benzoic acid binds to glycine to form hippurate, which is s ...

Marijuana, which is made from crushing the leaves, flowers, and sometimes the stems of the plant Cannabis sativa, contains more than 30 cannabinoids. The major psychoactive cannabinoid is delta-9-tetrahydrocannabinol (THC). The major metabolite of THC, 11-nor-delta 9-carboxy-tet ...

Cocaine is a widely abused stimulant. Numerous methods exist for the identification of the drug, or more commonly, one of its metabolites in urine. Urine testing is useful for most cases, but it is necessary to use other matrices in forensic situations and when subjects are anuric. We describe a novel me ...