Stem cells play a critical role in tissue regeneration and repair, maintenance and turnover and the control of haematopoiesis in the various tissues. These cells have an incredible ability to differentiate into specific cell types like osteoblasts, chondrocytes or myocytes and to develop bone, cartilage or muscle tissues. Now it is believed that the cells do not differentiate by themselves but rather the secretion of the bioactive (trophic) factors which are responsible for the functional outcome of the tissue. Stem cells reside in complicated and dynamic three-dimensional (3D) microenvironments in vivo known as stem cell niches. The niches are composed of extracellular matrix (ECM), soluble and tethered proteins and supporting cells, which have a profound influence on the functionality of the cells, including differentiation and trophic factor release. In this chapter, we review and emphasize the influence of stem cell microenvironment on the secretion of trophic factors and their perspective application for bone regeneration.
Part of the book: Advanced Techniques in Bone Regeneration
Spinal epidural haematomas (SEH) occur from extra-dural bleeding, most commonly after trauma, epidural anaesthesia or operative intervention. However, these also occur in arterio-vascular malformations or spontaneously without an obvious inciting event. Spontaneous spinal epidural haematomas (SSEH) are rare, with a quoted incidence of 0.1 cases per 100,000 population annually. However, these haematomas carry a significant risk of spinal cord or nerve root compression potentially resulting in permanent neurological dysfunction or death. This chapter reviews the presentation, diagnosis and treatment of SSEH in adults, pregnancy and children in order to provide clinicians with an understanding of their typical presentation, required investigations and treatment algorithms.
Part of the book: Vascular Malformations of the Central Nervous System