Methods in molecular biology
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Normal and tumor stem cells are present in rare quantities in tissues and this has historically represented a major hurdle to in-depth investigations of their biology. In the case of the mammary gland, the relative promiscuity of the immunophenotypical markers described in several studies for the isolation of human and mouse mammary stem cells limits their usefulness, in particular when highly purified mammary stem cell fractions are required for an in-depth molecular and functional characterization (Stingl et al. Nature 439:993-997, 2006; Shackleton et al. ⋯ Cell 138:1083-1095, 2009). Following mammosphere dissociation, the differential degree of PKH26 epifluorescence displayed by stem cells compared to precursor cells is exploited for their purification by FACS sorting. As a result, the scarcely represented PKH26-labeled mammary stem cells are purified to near homogeneity and can be used for further molecular and biological studies.
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Spinal cord injury-induced pain is a common clinical problem affecting adversely the quality of daily lives of spinal cord injured patients. Management with current pain medications can only lead to partial pain relief in some spinal cord injured patients, which is usually associated with unfavorable side effects. ⋯ We describe here the generation of a spinal cord contusion injury model that mimics the etiology and phenotypes of chronic pain states in spinal cord injured patients. Therefore, this model can be a useful tool for studying spinal cord injury mechanisms, functional recovery, research, and development of new medications for better functional and symptomatic improvements, including pain management.
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The spared nerve injury (SNI) model mimics human neuropathic pain related to peripheral nerve injury and is based upon an invasive but simple surgical procedure. Since its first description in 2000, it has displayed a remarkable development. ⋯ Besides, variants of the SNI model have been developed in rats, mice and neonatal/young rodents, resulting in several possible angles of analysis. Therefore, the purpose of this chapter is to provide a detailed guidance regarding the SNI model and its variants, highlighting its surgical and behavioural testing specificities.
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Many genetic mutations result in the disruption of (alternative) splicing. Prime examples are the SMN1 and SMN2 genes: a silent mutation in SMN2 leads to the skipping of the constitutive exon 7 in the majority of SMN2 transcripts, while this exon is generally included in SMN1 transcripts. ⋯ There are proteins and drugs that can chance alternative splicing events, e.g. increase the inclusion of exon 7 in SMN2. This chapter describes mini-genes and methods that can be employed to screen for candidate proteins and drugs.
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Astrocytes produce numerous mediators under conditions of inflammation in the central nervous system. One such mediator is nitric oxide (NO) derived from nitric oxide synthase-2 (NOS-2), the high output, inducible NOS isoform. Expression of NOS-2 and production of NO can be stimulated in astrocyte cultures by combinations of cytokines and lipopolysaccharide, a gram-negative bacterial endotoxin. This chapter details methods to induce and analyze NOS-2 expression and NO production in astrocyte cultures.