A sparse matrix approach to the solubilization of overexpressed proteins.

Many biophysical experiments depend on large amounts of pure, soluble protein. Indeed, the revolution in structural biology has depended on molecular biology's potential to make experiments possible by allowing the overexpression of normally rare proteins in a heterologous host. All too often, however, overexpressed proteins are poorly soluble in buffers that attempt to mimic physiological conditions. Often in such cases the overexpressed protein is assumed to be present in inclusion bodies and hopes of obtaining the desired sample from the overexpression vector are abandoned. We have developed a sparse matrix approach to the solubilization of such proteins that is often successful. This approach relies on well accepted theories of protein solubility and folding to build a sparse matrix that samples 'solubility space' effectively. The buffers of the sparse matrix are used to make crude extracts that are rapidly assayed for soluble protein using gel electrophoresis. We describe our approach and give examples of its application.

The effects of the pneumatic antishock garment on intracranial pressure in man: a prospective study of 12 patients with severe head injury.

Changes in intracranial pressure, mean arterial blood pressure, and cerebral perfusion pressure in response to sequential inflation of the pneumatic antishock garment were monitored in 12 patients with severe head injury and initial intracranial pressure less than 20 mm Hg. The small incremental increases in intracranial pressure that occurred with inflation of the pneumatic antishock garment were compensated for by improved hemodynamic stability and elevated mean arterial blood pressure which produced a simultaneous rise in cerebral perfusion pressure. The treatment of hypotension in traumatized patients with head injuries is paramount and sequential slow inflation of the pneumatic antishock garment can be used in such patients without apparent ill effect to the brain when the initial intracranial pressure is 20 mm Hg or below. Further study is needed to determine the safety of the device in head injured patients with elevated intracranial pressures.