The kidneys filter blood plasma across a specialized structure, called the glomerulus, that is permeable to small molecules (water, salts, glucose, etc.) but not to proteins. Suppose that the protein concentration in blood is 70 mg/mL, and the average molecular weight of plasma protein is 70 kDa. In severe hypotension (low blood pressure), urine output drops to essentially zero, a condition called oligouria. Calculate the minimum blood pressure required to avoid oligouria.