Injuries over exertion

Usually it is the skeletal or striated muscles that will require therapy for painful spasm or will need to be relaxed to allow the surgeon to gain access to the abdomen easily. Muscle spasm may be associated with a trauma or may be brought on by multiple sclerosis, cerebral palsy, stroke, or an injury to the spinal cord. Severe cold, an interruption of blood supply to a muscle, or over exertion of the muscle also can lead to spasms. A muscle spasm actually is an increase in muscle tone brought on by an abnormality in motor control by the spinal nerves. 

The manner in which the human body controls temperature is important not only under normal conditions but also during exercise, fever, and trauma induced by injury, bums, surgery, etc. Over longer periods of time, hormones, adaptation, and acclimatization can exert significant effects. Although the work reported here is limited to normal short-term regulation, it is possible that the other situations can be explained in terms of modifications of the basic mechanism. 

The scaffold acts like an extracellular matrix that anchors growing cells. New cells anchor to the artificial matrix rather than to the oi nism s own extracellular material, allowing engineers to exert control over the eventual size, shape, and function of the new tissue. In addition, scaffolds can aid in the diffusion of resources within the growing tissue and can help engineers direct the placement of functional cells, as the scaffold can be installed directly at the site of an injury. 

One form of cellular demise common to epithelial cells is detachment-initiated apoptosis, also referred to as anoikis (Frisch and Francis, 1994). Epidermal keratinocytes rely on signals derived from the surrounding extracellular matrix for survival. It is possible that loss of these signals plays a role in SM-induced epidermal cell injury, and that cell detachment from the basal lamina precedes cytotoxicity. Several lines of evidence support this possibility. First, SM can alter the dynamics of cytosolic proteins that exert control over the attachment of cells to the basement membrane. For example, SM can modify intracellular actin microfilaments and keratin intermediate filaments known to be important in maintaining epithelial cell connections with the basal lamina. Thus, Hinshaw et al. (1999) reported that SM causes changes in the actin microfilament architecture and morphology of human keratinocytes within 3h of... 

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