Basic requirements to establish a neuromuscular laboratory

Histopathological analysis of muscle biopsy is a prerequisite in the evaluation of neuromuscular disorders, particularly inflammatory myopathies, metabolic myopathies, congenital myopathies, muscular dystrophies and differentiating myopathies and neurogenic disorders with overlapping clinically features. It not only provides useful information that helps in the diagnosis but also treatment and management. Fundamental skills and basic knowledge regarding handling, processing and analyzing a muscle biopsy are required in any specialized or a general pathology lab supporting neuromuscular clinical services. Care during transport of the muscle biopsy, sample receipt in the laboratory and grossing is very important. Standard operating procedure should be followed for the preanalytical steps (freezing and cryomicrotomy), routine and special staining (enzyme and non enzymatic) and immunohistochemistry. A well organized neuromuscular laboratory with good quality management system is necessary for the practice of myopathology. This article gives an overview of establishing such a laboratory.

Impact of Freezing Delay Time on Tissue Samples for Metabolomic Studies

Introduction

Metabolic profiling of intact tumor tissue by high-resolution magic angle spinning (HR MAS) MR spectroscopy (MRS) provides important biological information possibly useful for clinical diagnosis and development of novel treatment strategies. However, generation of high-quality data requires that sample handling from surgical resection until analysis is performed using systematically validated procedures. In this study, we investigated the effect of postsurgical freezing delay time on global metabolic profiles and stability of individual metabolites in intact tumor tissue.

Materials and methods

Tumor tissue samples collected from two patient-derived breast cancer xenograft models (n = 3 for each model) were divided into pieces that were snap-frozen in liquid nitrogen at 0, 15, 30, 60, 90, and 120 min after surgical removal. In addition, one sample was analyzed immediately, representing the metabolic profile of fresh tissue exposed neither to liquid nitrogen nor to room temperature. We also evaluated the metabolic effect of prolonged spinning during the HR MAS experiments in biopsies from breast cancer patients (n = 14). All samples were analyzed by proton HR MAS MRS on a Bruker Avance DRX600 spectrometer, and changes in metabolic profiles were evaluated using multivariate analysis and linear mixed modeling.

Results

Multivariate analysis showed that the metabolic differences between the two breast cancer models were more prominent than variation caused by freezing delay time. No significant changes in levels of individual metabolites were observed in samples frozen within 30 min of resection. After this time point, levels of choline increased, whereas ascorbate, creatine, and glutathione (GS) levels decreased. Freezing had a significant effect on several metabolites but is an essential procedure for research and biobank purposes. Furthermore, four metabolites (glucose, glycine, glycerophosphocholine, and choline) were affected by prolonged HR MAS experiment time possibly caused by physical release of metabolites caused by spinning or due to structural degradation processes.

Conclusion

The MR metabolic profiles of tumor samples are reproducible and robust to variation in postsurgical freezing delay up to 30 min.

Beyond laser microdissection technology: follow the yellow brick road for cancer research

Normal biological tissues harbour different populations of cells with intricate spacial distribution patterns resulting in heterogeneity of their overall cellular composition. Laser microdissection involving direct viewing and expertise by a pathologist, enables access to defined cell populations or specific region on any type of tissue sample, thus selecting near-pure populations of targeted cells. It opens the way for molecular methods directed towards well-defined populations, and provides also a powerful tool in studies focused on a limited number of cells. Laser microdissection has wide applications in oncology (diagnosis and research), cellular and molecular biology, biochemistry and forensics for tissue selection, but other areas have been gradually opened up to these new methodological approaches, such as cell cultures and cytogenetics. In clinical oncology trials, molecular profiling of microdissected samples can yield global "omics" information which, together, with the morphological analysis of cells, can provide the basis for diagnosis, prognosis and patient-tailored treatments. This remarkable technology has brought new insights in the understanding of DNA, RNA, and the biological functions and regulation of proteins to identify molecular disease signatures. We review herein the different applications of laser microdissection in a variety of fields, and we particularly focus attention on the pre-analytical steps that are crucial to successfully perform molecular-level investigations.