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Eleven cases of monomorphic adenoma of the salivary glands are interpreted as variants of pleomorphic adenomas (mixed tumors) that lack chondroid or myxomatous components. Nine of these tumors were in the parotid gland and two were on the hard palate. Monomorphic adenomas are usually encapsulated and frequently are partially cystic. Their histologic pattern may be confused with that of adenoid cystic carcinoma, but they grow in an expansile fashion and usually are monolobular. Histologically, they may be divided into trabecular-tubular, canalicular, and basaloid variants. Morphologically, they bear a resemblance to basaloid sweat-gland tumors (eccrine spiradenoma and cylindroma).

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The response to oral clonidine hydrochloride loading in 36 severely hypertensive patients is presented. Each patient initially received 0.2 mg of clonidine hydrochloride, followed by 0.1 mg each hour until a dose of 0.7 mg had been given, or the diastolic blood pressure (BP) reached a predetermined goal (110 mm Hg or total fall of at least 20 mm Hg). Only two patients (6%) failed to reach this goal. Supine BP in the group fell from 212 +/- 22 (SD)/139 +/- 11 (SD) mm Hg to 151 +/- 21 (SD) mm Hg at six hours. The average dose of clonidine required was 0.45 mg and control was maximized at five hours. The response to oral clonidine loading in the individual patient was not predictive of the eventual dose of clonidine necessary to achieve acceptable BP control at two weeks. Oral clonidine loading is safe and effective in the management of "hypertensive urgencies" and offers several advantages over parenteral antihypertensive agents in this clinical situation.

To elucidate the mechanism of action of prazosin in lowering the blood pressure, we studied the vascular pressor responsiveness to the infusion of norepinephrine and angiotensin II before and after prazosin in patients with essential hypertension. After prazosin, the pressor response to the alpha agonist norepinephrine was markedly attenuated, but the vascular reactivity to angiotensin II was unchanged. There was a threefold increment in the dose of norepinephrine required to elicit a 20 mm Hg rise in diastolic blood pressure after prazosin therapy. These results confirm that prazosin induces significant alpha adrenergic blockade during the treatment of essential hypertension. Clinical Pharmacology and Therapeutics (1981) 29, 719–722; doi: