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Clinical practice guidelines are systematically developed statements to assist practitioners and patients reach appropriate health care decisions. If developed properly, clinical practice guidelines assimilate and translate an abundance of evidence published on a dai ...

The pressure for health care systems to provide more resource-intensive health care and newer, more costly therapies is significant, despite limited health care budgets. It is not surprising, then, that demonstration that a new therapy is effective is no longer sufficient to ensure that it can ...

A systematic review uses an explicitly defined process to comprehensively identify all studies pertaining to a specific focused question, appraise the methods of the studies, summarize the results, identify reasons for different findings across studies, and cite limitations of cu ...

This chapter has been written to specifically address the usefulness of qualitative research for the practice of clinical epidemiology. The methods of grounded theory to facilitate understanding of human behavior and construction of monitoring scales for use in quantitative stu ...

Genetic factors play a substantive role in the susceptibility to common diseases. Due to recent advancements in the characterization of genetic variants and large-scale genotyping platforms, multiple genes have now been identified for common, complex diseases. As a result, there is an i ...

Clinical epidemiological research in genetic diseases entails the assessment of phenotypes, the burden and etiology of disease, and the efficacy of preventive measures or treatments in populations. In all areas, the main focus is to describe the relationship between exposure and outc ...

The study of patient-reported outcomes, now common in clinical research, had its origins in social and scientific developments during the latter 20th century. Patient-reported outcomes comprise functional and health status, health-related quality of life, and quality of life. The t ...

Biomarkers are defined as anatomic, physiologic, biochemical, molecular, or genetic parameters associated with the presence, absence, or severity of a disease process. As such, biomarkers may be useful as prognostic and diagnostic tests. Establishing the utility of a given biomarker ...

As technology advances, diagnostic tests continue to improve, and each year, we are presented with new alternatives to the standard procedures. Given the plethora of diagnostic alternatives, diagnostic tests must be evaluated to determine their place in the diagnostic armamentari ...

When analyzing the results of a trial, the primary outcome variable must be kept in clear focus. In the analysis plan, consideration must be given to comparing the characteristics of the subjects, taking account of differences in these characteristics; intention-to-treat analysis; inte ...

In longitudinal studies, the relationship between exposure and disease can be measured once or multiple times while participants are monitored over time. Traditional regression techniques are used to model outcome data when each epidemiological unit is observed once. These models ...

The primary model systems used for studying the role of regulated gene expression in senescence and the effects that genetic variations have on this process have been to date either mammalian cells in vitro or invertebrate systems such as yeast, C. elegans, and Drosophila. Both types of model syst ...

The popularity of the dietary restriction (DR) paradigm (often used interchangeably with calorie restriction) among gerontologists is primarily based on the research finding of the last two decades. Originally discovered by McCay’s group in the 1930s, this paradigm showed that anim ...

The major histocompatibility complex (MHC) is located in the region 9p216pter on the short arm of chromosome 6 and encompasses approx 4000 kilobases of genomic DNA. Contained within this complex are numerous genes with immune-related functions: notably the class I and class II human leukoc ...

Human natural killer (NK) cells represent a heterogeneous lymphoid population involved in the recognition and lysis of tumor and virally infected cells. NK cells are defined by the expression of the IgG Fc receptor CD16 (FcγRIIIA) and/or CD56. NK cells do not rearrange immunoglobulin (Ig) or T- ...

Dendritic cells (DCs) are powerful antigen-presenting cells that have the unique capacity to stimulate naive T-cells (1, 2). DCs are identified by a triad of criteria: Morphologically, they exhibit pronounced cytoplasmic veils that are mobile and can easily be observed under a phase-cont ...

Certain immunological activities, particularly cell-mediated immunity, decline with advancing age. Gaining insight into the underlying mechanism(s) is complicated by the fact that human T-cells comprise several functionally and phenotypically distinct populations a ...

Since the first demonstration that mutations of the mitochondrial genome were associated with human disease, more than 100 pathological mitochondrial DNA (mtDNA) defects have been characterized in patients with a broad spectrum of clinical manifestations (1). Single-point mut ...

Although the precise mechanisms of the aging process remain poorly understood, a plausible theory for cellular dysfunction and deterioration during aging involves mitochondria (1, 2). The major function of mitochondria is to generate energy for cellular processes in the form of ATP by ox ...

A rapidly increasing amount of data supports the view that progressive bioenergetic loss caused by injury of the main energy-producing subcellular organelles, that is, the mitochondria, plays a key role in aging. A link between senescence and energy loss is already implied in Harman’s (1) free ...