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. We believe that measurement of aqueous ACE activity should be considered in patients with uveitis who have normal serum ACE activity and are suspected of having sarcoidosis.

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. 4-Methylumbelliferone, liberated under currently used conditions for enzyme activity in urine and fibroblasts, can be measured by this procedure because these materials contain no substances interfering with the 4-methylumbelliferone peak. Applied to lysosomal enzymatic activity analyses, this procedure eliminates substrate background fluorescence. Determinations of eight lysosomal enzymes in urine and fibroblasts are presented in bar graph form.

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.

Angiotensin-converting enzyme in sarcoid uveitis.

The diagnosis of ocular sarcoid is presumptive in the absence of systemic disease. The association of elevated serum angiotensin-converting enzyme (ACE) levels with active systemic sarcoid has been well described. With a sensitive fluorimetric assay for ACE, we found that five of ten chronic granulomatous uveitis patients without systemic sarcoid had elevated serum ACE levels. None of ten patients with uveitis of known etiology had elevated serum ACE levels. We believe that the association of an elevated serum ACE level with chronic granulomatous uveitis suggests the diagnosis of ocular sarcoid.

Glycosaminoglycan accumulation with partial deficiency of beta-glucuronidase in the C3H strain of mice.

Young (60--80 days) mice of the low beta-glucuronidase strain, C3H/HeJ, showed no differences in hepatic levels of glycosaminoglycans (GAGs) when compared to the randombred, "normal" Swiss-Webster mice of the same age. However, by 12 months of age hepatic GAG is nearly twice as high in C3H/HeJ mice as in Swiss-Webster mice. Studies of beta-glucuronidase, beta-galactosidase, and N-acetyl-beta-glucosaminidase in four tissues of the two types of mice at the two ages revealed that glucuronidase was the only enzyme with lower activity in the C3H/HeJ strain.

Gyrate atrophy of the retina: inborn error of L-ornithin:2-oxoacid aminotransferase.

Cultured fibroblasts from a patient with gyrate atrophy of the retina do not convert L-ornithine, uniformly labeled with carbon-14, to proline. This metabolic block is caused by deficient L-ornithine:2-oxoacid aminotransferase activity in the patient. Her heterozygote father has intermediate activity of this enzyme.

A new variant mucolipidosis: biochemical investigations on two siblings.

Biochemical studies are presented on two siblings with some features of Mucolipidosis III, but with distinctive clinical findings. Levels of beta-galatosidase, alpha-mannosidase, beta-glucuronidase, N-acetyl-beta-glucosaminidase and alpha-fucosidase found in serum from these patients ranged from 10 to 10 times higher than normal. The ratio of heat stable to heat labile serum isoenzymes of N-acetyl-beta-glucosaminidase is considerably greater than normal. An extremely low activity of beta-galactosidase was found in fibroblasts cultured from one patient. Levels of the remaining enzymes were in the low normal range. Similarly, beta-galactosidase levels were low in heart, kidney, liver, spleen and lung of one patient who died during the course of the study. Activities of the remaining enzymes were close to normal. No excessive excretion of mucopolysaccharide was noted, however, changes in distribution of several fractions were found. Mucopolysaccharide labeled with radioactive sulfate was degraded by cultured fibroblasts at a normal rate. In addition to clinical differences, the biochemical studies further demonstrate the uniqueness of these patients.

Nucleoside-phosphorylase deficiency in a child with severely defective T-cell immunity and normal B-cell immunity.

A 5-year-old girl with a history of recurrent infection and anaemia has no measurable purine nucleoside phosphorylase (N.P.) activity in her red blood-cells. Her serum-immunoglobulin levels are normal, as are her antibody responses to thymus dependent and independent antigens. However, she has severe lymphopenia, pronounced depression of lymphocyte response to mitogenic and allogeneic cell stimuli, and greatly decreased T-cell rosette formation. Her parents are second cousins; their red cells contain less than half the normal level of N.P. activity. They also share an unusual N.P. isozyme pattern indicative of molecular hybridisation between catalytically active and inactive subunits, which strongly supports the assumption that they are heterozygous and their daughter is homozygous for a "silent" allele at the N.P. gene locus. Inherited deficiency of adenosine deaminase, an enzyme catalysing a reaction only one metabolic step away from that of N.P., is known to cause immunodeficiency. It is therefore very likely that this patient's lack of demonstrable N.P. activity is responsible for her syndrome.