RESUMO
BACKGROUND: The motor neuron degenerative disease spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality and is caused by mutations in the survival of motor neurons (SMN) gene that reduce the expression levels of the SMN protein. A major goal of current therapeutic approaches is to increase SMN levels in SMA patients. The purpose of this study was to develop a reliable assay to measure SMN protein levels from peripheral blood samples. METHODS: We developed a novel cell immunoassay to quantitatively measure SMN levels from peripheral blood mononuclear cells (PBMCs) using a single anti-SMN antibody. RESULTS: SMN levels determined by the cell immunoassay are comparable to levels determined by Western blot, but in contrast, the immunoassay does not involve cell lysis, requires a small amount of patient material, and can be done on a large number of samples simultaneously. SMN levels from PBMCs are not influenced by cell type heterogeneity. CONCLUSION: SMN levels measured from total PBMCs provide an important snapshot of SMN protein expression, which should be a useful aid in SMA diagnosis, and a surrogate marker of efficacy of treatment in SMA clinical trials.
Assuntos
Imunoensaio/métodos , Neurônios Motores/patologia , Ribonucleoproteínas Nucleares Pequenas/sangue , Atrofias Musculares Espinais da Infância/sangue , Atrofias Musculares Espinais da Infância/patologia , Autoantígenos , Western Blotting/métodos , Contagem de Células/métodos , Linhagem Celular , Sobrevivência Celular/fisiologia , Humanos , Lactente , Monócitos/metabolismo , Proteínas Centrais de snRNPRESUMO
Finding cancer at its earliest, most treatable stage gives patients the greatest chance of survival. For a number of cancers, screening tests allow for early detection and treatment, and thereby, reduce cancer-related mortality. However, many cancers are discovered by symptomatic presentation rather than screening. This article addresses several symptoms commonly reported in the primary care setting, including rectal bleeding, a breast lump, cough, lymphadenopathy, and weight loss, and offers an evidence-based approach to the consideration and possibly the diagnosis of cancer.