The loss of antigenicity in archival formalin-fixed paraffin-embedded (FFPE) tissue sections negatively affects both diagnostic histopathology and advanced molecular studies. The mechanisms underlying antigenicity loss in FFPE tissues remain unclear. The authors hypothesize that water is a crucial contributor to protein degradation and decrement of immunoreactivity in FFPE tissues. To test their hypothesis, they examined fixation time, processing time, and humidity of storage environment on protein integrity and antigenicity by immunohistochemistry, Western blotting, and protein extraction. This study revealed that inadequate tissue processing, resulting in retention of endogenous water in tissue sections, results in antigen degradation. Exposure to high humidity during storage results in significant protein degradation and reduced immunoreactivity, and the effects of storage humidity are temperature dependent. Slides stored under vacuum with desiccant do not protect against the effects of residual water from inadequate tissue processing. These results support that the presence of water, both endogenously and exogenously, plays a central role in antigenicity loss. Optimal tissue processing is essential. The parameters of optimal storage of unstained slides remain to be defined, as they are directly affected by preanalytic variables. Nevertheless, minimization of exposure to water is required for antigen preservation in FFPE tissue sections. This article contains online supplemental material at http://www.jhc.org . Please visit this article online to view these materials.
S U M M A R Y Formalin-fixed, paraffin-embedded (FFPE) tissue is the most common specimen available for molecular assays on tissue after diagnostic histopathological examination. RNA from FFPE tissue suffers from strand breakage and cross-linking. Despite excellent extraction methods, RNA quality from FFPE material remains variable. To address the RNA quality factors within FFPE tissues, we studied RNA quality, isolating individual elements of the tissue fixation and processing including length of fixation in formalin and the type of buffer incorporated in the fixative. We examined the impact of the length of the tissue processing cycle as well. The optimal fixation period of 12-24 hr in phosphatebuffered formalin resulted in better-quality RNA. Longer tissue processing times were associated with higher quality RNA. We determined that the middle region of gene suffers less damage by these processes as shown by real-time quantitative RT-PCR. These data provide key information for the development of methods of analysis of gene expression in archival FFPE tissues and contribute to the establishment of objective standards for the processing and handling of tissue in surgical pathology. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials. (J Histochem Cytochem 56:1033-1042, 2008
IntroductionEating in restaurants is associated with high caloric intake. This review summarizes and evaluates the evidence supporting community-based restaurant interventions.MethodsWe searched all years of PubMed and Web of Knowledge through January 2014 for original articles describing or evaluating community-based restaurant interventions to promote healthy eating. We extracted summary information and classified the interventions into 9 categories according to the strategies implemented. A scoring system was adapted to evaluate the evidence, assigning 0 to 3 points to each intervention for study design, public awareness, and effectiveness. The average values were summed and then multiplied by 1 to 3 points, according to the volume of research available for each category. These summary scores were used to determine the level of evidence (insufficient, sufficient, or strong) supporting the effectiveness of each category.ResultsThis review included 27 interventions described in 25 studies published since 1979. Most interventions took place in exclusively urban areas of the United States, either in the West or the South. The most common intervention categories were the use of point-of-purchase information with promotion and communication (n = 6), and point-of-purchase information with increased availability of healthy choices (n = 6). Only the latter category had sufficient evidence. The remaining 8 categories had insufficient evidence because of interventions showing no, minimal, or mixed findings; limited reporting of awareness and effectiveness; low volume of research; or weak study designs. No intervention reported an average negative impact on outcomes.ConclusionEvidence about effective community-based strategies to promote healthy eating in restaurants is limited, especially for interventions in rural areas. To expand the evidence base, more studies should be conducted using robust study designs, standardized evaluation methods, and measures of sales, behavior, and health outcomes.
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