Mr. Jessup, a 55-year-old man, is operated on for a cerebral tumor. About one month later, he complains that he is excessively thirsty and that he has been voiding almost continuously. A urine sample is collected, and its specific gravity is 1.001. What is your diagnosis of Mr. Jessup's problem, and how might it be related to his previous surgery?

Raymond is hypertensive and was recently diagnosed with impaired kidney function based on urinalysis and a blood test for creatinine. What sorts of test results would you expect, and how is hypertension related to kidney function?