Angiotensin-converting enzyme activity in human aqueous humor.

We measured aqueous angiotensin-converting enzyme (ACE) activity in 37 patients. Patients with granulomatous uveitis and probable sarcoidosis (based on increased serum ACE activity or characteristic radiologic findings) had a significant increase in aqueous ACE activity compared with normal subjects. Aqueous ACE activity was also significantly elevated in patients with sarcoid who had normal serum ACE activity.

Determination of 4-methylumbelliferone after separation from its conjugates by high-performance liquid chromatography. Application to lysosomal enzyme activity assays.

A high-performance liquid chromatographic method is described for the separation and estimation of 4-methylumbelliferone in the presence of its conjugates. The technique utilizes a simple, isocratic eluent and fluorometric detection. Percentages of 4-methylumbelliferone in the conjugates and fluorescences of the conjugates are reported.

Gyrate atrophy of the retina and choroid. Two methods for prenatal diagnosis.

We report two methods for prenatal diagnosis of gyrate atrophy of the retina and choroid caused by an inborn error of ornithine aminotransferase activity. A high pressure liquid chromatography assay measures ornithine aminotransferase accurately and directly in cultured amniotic fluid cells. The differential incorporation of 14C-ornithine and 3H-leucine into cell protein measures OAT directly but rapidly and simply.

Measurement of pilocarpine and its degradation products by high-performance liquid chromatography.

An assay method for pilocarpine using reversed-phase high-performance liquid chromatography is presented. This method also measures isopilocarpine, the stereoisomer of pilocarpine, and the degradation products pilocarpic acid and isopilocarpic acid. Maximum sensitivity was obtained with optical absorbance at 216 nm.