Analytical Biological Services Inc.

Wilmington, DE, United States

Analytical Biological Services Inc.

Wilmington, DE, United States
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D'Andrea M.,New Hill | Howanski R.,Analytical Biological Services Inc. | Saller C.,Analytical Biological Services Inc.
Biotechnic and Histochemistry | Year: 2017

Immunohistochemistry (IHC) is used to detect antibody-specific antigens in tissues; the results depend on the ability of the primary antibodies to bind to their antigens. Therefore, results depend on the quality of preservation of the specimen. Many investigators have overcome the deleterious effects of over-fixation on the binding of primary antibodies to specimen antigens using IHC, but if the specimen is under-fixed or fixation is delayed, false negative results could be obtained despite certified laboratory practices. Microtubule-associated protein 2 (MAP2) is an abundant microtubule-associate protein that participates in the outgrowth of neuronal processes and synaptic plasticity; it is localized primarily in cell bodies and dendrites of neurons. MAP2 immunolabeling has been reported to be absent in areas of the entorhinal cortex and hippocampus of Alzheimer’s disease brains that were co-localized with the dense-core type of amyloid plaques. It was hypothesized that the lack of MAP2 immunolabeling in these structures was due to the degradation of the MAP2 antigen by the neuronal proteases that were released as the neurons lysed leading to the formation of these plaques. Because MAP2 is sensitive to proteolysis, we hypothesized that changes in MAP2 immunolabeling may be correlated with the degree of fixation of central nervous system (CNS) tissues. We detected normal MAP2 immunolabeling in fixed rat brain tissues, but MAP2 immunolabeling was decreased or lost in unfixed and delayed-fixed rat brain tissues. By contrast, two ubiquitous CNS-specific markers, myelin basic protein and glial fibrillary acidic protein, were unaffected by the degree of fixation in the same tissues. Our observations suggest that preservation of various CNS-specific antigens differs with the degree of fixation and that the lack of MAP2 immunolabeling in the rat brain may indicate inadequate tissue fixation. We recommend applying MAP2 IHC for all CNS tissues as a pre-screen to assess the quality of the tissue preservation and to avoid potentially false negative IHC results. © 2017 The Biological Stain Commission


Tarvin K.A.,Analytical Biological Services Inc. | Sandusky G.E.,Indiana University
Expert Opinion on Drug Discovery | Year: 2014

The value of molecular profiled human tissue lies in its potential to improve the efficiency of drug discovery and development. The sequencing and profiling of human biospecimens across multiple omics dimensions provides layers of molecular information that can be used to enhance our knowledge of disease mechanisms to identify and prioritize novel drug targets and provide supportive biological evidence to support a therapeutic hypothesis. It is critical to control pre-analytical variables because the reproducibility and accuracy of molecular data generated by high-throughput technologies is dependent upon biospecimen quality. The scientific knowledge and technology developments gained in tissue banking research are transforming biospecimen collection and biostorage practices. These tissue banking advancements will improve specimen quality and utilization and, at the same time, reduce biobanking costs. Furthermore, well-annotated, high quality biospecimens will provide reliable, consistent gene expression data for target validation for drug discovery. Challenges in understanding the molecular signatures of biospecimens follow the challenges of human tissue acquisition. Sequencing and profiling high-throughput technologies generate heterogeneous, complex data sets that require sophisticated informatics tools for data storage and analysis. As tissue banking and informatics technologies improve and we gain deeper knowledge of the human genome and its functionality, we will see biomarker identification and target therapies brought about by the research performed on high quality biospecimens. © 2014 Informa UK, Ltd.

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