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Purpose: To develop computer algorithms for reconstructing 24-bit color, wide-angle composite retinal fundus images from a set of adjacent 45 degrees fundus slides. The authors present the description, technical details, and results of the image reconstruction technique., Methods: Patients with retinal degeneration underwent fundus photography with a 45 degrees field-of-view fundus camera. Individual photographic slides were digitized for creating fundus montages. Background variations in individual 45 degrees images were modeled to first- or second-order two-dimensional polynomial functions to generate a background image. The background image was subtracted from the original image to obtain background corrected image. Background corrected images were registered and spatially transformed using a first- or second-order two-dimensional polynomial warp model to reconstruct a composite retinal fundus montage., Results: The authors successfully reconstructed 24-bit color, 100 degrees field-of-view, composite retinal fundus images. The computer-reconstructed montages are an improvement over manually generated montages because computer analysis can be performed on the computer-based montages. In addition, background variations and discontinuities between individual photographs observed in manually generated montages are reduced greatly in computer-generated montages. Most important, the computer-generated montages are better aligned than the manually generated photomontages., Conclusions: This method of reconstructing a wide-angle composite retinal fundus image from a set of adjacent small- and wide-angle fundus slides is a new tool for creating montages as large as 100 degrees field of view. The computer-generated montages may be used for documenting and quantifying retinal findings. This can greatly assist studies of retinal manifestations of diseases, such as gyrate atrophy, retinitis pigmentosa, sickle cell disease, and acquired immune deficiency syndrome.

This study examined the ultrastructural morphology and posttranslationally modified alpha-tubulin isoforms in the sperm flagella of a patient presenting with infertility and retinal degeneration. Clinical evaluation showed impaired motility and gross morphological abnormalities of the sperm and a rod-dominant retinal degeneration with midperipheral pigment clumping and scattered bone spicules. Other neurological indications included delayed neuroelectric transmission in the auditory brainstem and a temporal lobe seizure disorder. Ultrastructural analysis showed that 46% of sperm axonemes had missing and/or misplaced doublets compared with 10% to 12% in control subjects. ELISA analysis showed hypoacetylation of alpha-tubulin (30% of control) but normal levels of alpha-tubulin tyrosination. Tubulin acetyl-transferase specific activity was also 30% of control activity. These characteristics may be indicative of microtubule instability leading to the pathological consequences described.

We examined three affected members of a Chinese-American family with Bietti's crystalline retinopathy. The clinical characteristics of a 24-year-old proband are contrasted to the clinical findings of her grandmother, for whom we have 26 years of follow-up data. Lymphocytes and fibroblasts from a skin biopsy of the grandmother contained crystalline lysosomal material, which supports the diagnosis. Biochemical studies of the crystalline lysosomal material failed to identify the stored compounds but did not show them to be cholesterol or cholesterol ester. Finally, histopathologic studies performed for this condition demonstrated advanced panchorioretinal atrophy, with crystals and complex lipid inclusions seen in choroidal fibroblasts.

Gyrate atrophy of the choroid and retina is an autosomal recessive, chorioretinal dystrophy that begins in childhood and leads to blindness in the fourth to seventh decade of life. The primary defect is deficiency of ornithine-delta-amino-transferase, which results in accumulation of ornithine. We examined six pairs of affected siblings to determine if intrafamilial variability in the phenotype was less than interfamilial, and to determine if long-term (5- to 7-year) reduction of ornithine with an arginine-restricted diet had an effect on the progression of the chorioretinal degeneration. All but one set of siblings underwent periodic ophthalmologic examinations. The clinical diagnosis was confirmed with the demonstration of hyperornithinemia and deficiency of ornithine-delta-aminotransferase. The molecular defects in their ornithine-delta-amino-transferase genes also were determined. The two younger pairs of siblings were given an arginine-restricted diet and followed up for 5 to 7 years. We found strikingly similar phenotypes in affected members of the same pair of siblings. In the young patients receiving the diet, there was substantial reduction of ornithine levels. These children had only modest progression of their ocular disease during this period. Furthermore, a comparison of the outcome of the younger with their older siblings at an equivalent age showed that the younger siblings, who started receiving the diet at an earlier age, had much less ocular disease. We conclude that intrafamilial phenotypic variation in gyrate atrophy is less than interfamilial and, therefore, that genetic heterogeneity plays a role in the phenotypic variability of gyrate atrophy. Furthermore, we conclude that chronic reduction of ornithine with an arginine-restricted diet dramatically slows the progression of the chorioretinal dystrophy.

Two patients had milder variants of the usual form of gyrate atrophy. Although the appearance of the chorioretinal degeneration was identical, the progression of the clinical signs and symptoms were slower with night blindness, cataracts, and decreased vision occurring at an older age. Additionally, the level of hyperornithinemia, although still increased above normal, was lower than that usually found in such patients (between 448 and 676 microM). Additionally, one of our patients responded to high dosage vitamin B6 with a 27% reduction in plasma ornithine. The difference in the quantitation of the increase in plasma ornithine, the difference in responsiveness to vitamin B6, and the difference in the clinical consequences of this underlying biochemical abnormality, indicated a variant form of gyrate atrophy, suggesting the presence of genetic heterogeneity.

Visual function has been serially assessed in two gyrate atrophy patients who have had long-term reduction of plasma ornithine concentrations by a low-arginine diet. One patient demonstrated subjective and objective improvement after 15 months of treatment. In addition to improvements in dark adaptation thresholds, enlargement of visual fields, and a more normal electroretinogram, there was marked improvement in cone function as measured by color vision. There has been no change noted in the second patient. These results suggest that reduction of plasma ornithine may be beneficial in gyrate atrophy patients and that the high ornithine concentrations characteristic of this disorder play some role in the pathophysiology.

To establish the enzyme defect in gyrate atrophy, we measured the activity of ornithine aminotransferase in phytohemagglutinin stimulated lymphocytes in a patient with gyrate atrophy, her daughter, and three normal controls. The patient's cells had no detectable ornithine aminotransferase activity and the daughter's cells had 44% of control activity. This intermediate value is characteristic of an obligate heterozygote. These results are the first demonstration of an enzyme defect in gyrate atrophy.

Ornithine-delta-aminotransferase deficiency is the primary biochemical defect in gyrate atrophy of the choroid and retina and results in the characteristic accumulation of ornithine. An additional consequence of this inborn error is that arginine, the precursor of ornithine, becomes an essential amino acid. Therefore, to reduce the accumulated ornithine, we placed nine gyrate atrophy patients on an arginine-restricted diet. Plasma ornithine decreased by 50 to 85% within one month. Orally administered, alpha-aminoisobutyric acid facilitated the reduction in ornithine by augmenting renal losses. Over the long term, three patients have maintained near normal plasma ornithine concentrations from 4 to 32 months. Two patients have maintained less striking reductions in ornithine, and four have either been poorly controlled or have terminated the diet. Urinary losses of arginine and ornithine in gyrate atrophy patients with high or low plasma ornithine concentrations are less than 50% of the estimated arginine intake. This observation suggests that the bulk of ingested arginine is somehow metabolized despite the severe reduction in ornithine-delta-aminotransferase activity.

Intravitreal injection of L-ornithine hydrochloride in physiologic saline solution caused marked edema specifically in the pigment epithelium of Sprague-Dawley strain albino and Evans black hooded rats and rhesus and cynomologus monkeys. Swelling of the pigment epithelial cells, which was most prominent four hours after the injection, disappeared by 24 hours. However, many pigment epithelial cells gradually degenerated resulting in patches of denuded areas. The photoreceptor cells overlying the damaged pigment epithelium degenerated secondarily.

Gyrate atrophy of the choroid and retina is an inherited form of chorioretinal degeneration associated with hyperornithinemia. We measured the activity of ornithine aminotransferase (L-ornithine:2-oxo-acid aminotransferase, EC 2.6.1.13) in phytohemagglutinin-stimulated lymphocytes of a patient with gyrate atrophy and her daughter. The patient's cells had no detectable ornithine aminotransferase activity, and the activity in the heterozygote's cells was 44% of normal values. Measurements of [3H]thymidine incorporation and other transformation-affected enzymes verified that the patient's cells were transformed. These results demonstrate an enzyme deficiency in gyrate atrophy.

In a patient with gyrate atrophy of the choroid and retina, an arginine-deficient diet has reduced plasma ornithine concentration fivefold during the past 20 months. Subjective improvement in her visual function was noted approximately 15 months after institution of her diet. This has been documented by improvements in the electroretinogram, dark-adaptation, and color vision. The improvement involves rod and, to a lesser extent, cone function. The results, although preliminary and limited to a single patient, suggest that reduction of plasma ornithine with a low arginine diet is beneficial in this disease.

In ten patients with gyrate atrophy (GA) and hyperornithinemia, the head hair was fine, straight, and sparse. On microscopic examination, both scalp and pubic hair contained intermittent dark cores within the medullary zone, which was not a deposit, but appeared to be due to the unusual refractive properties of loosely formed macrofilaments amidst wide spaces containing a structureless electron lucent but compact substance, which was insoluble in both water and solvents. Seven of the ten patients had abnormal wave forms on electroencephalography. Three of the five patients who underwent muscle biopsy had tubular aggregates. Of particular interest was the toxicity of exogenous ornithine added to muscle cell culture from GA patients as compared with the lack of toxicity in muscle from control patients. What specific role the hyperornithinemia and absence of OAT is playing in the histopathology of hair and muscle and the EEG changes awaits further biochemical investigation.