Search PubMed⌕ Search

Biomedical subjects

G A Fishman

Publications and source records attributed to G A Fishman.

At least 145 records · Page 8Linked to original sources
PubMed1986

Visual acuity loss in patients with Usher's syndrome.

Using a life-table analysis, visual acuity loss with age was determined for a population of 106 patients with type 1 (N = 35) and type 2 (N = 71) Usher's syndrome. The cumulative percentage of patients maintaining visual acuity of 6/12 (20/40) or better in at least one eye by age 29 years was 69% for type 1 patients and 94% for type 2 patients. The cumulative percentage maintaining visual acuity of 6/24 (20/80) or better at this age was 89% for type 1 and 98% for type 2 patients. Within each subtype, the cumulative percentage maintaining 6/60 (20/200) or better was similar to the percentage maintaining 6/24 (20/80) or better. Knowledge of these data provides an objective basis for counseling patients with Usher's syndrome about their probability of developing loss of central visual acuity with age.

Actuarial Analysis↗
PubMed1986

Rod influence on cone flicker detection: variation with retinal eccentricity.

Previous studies have shown that cone flicker thresholds are influenced by the adaptation state of the rod system. We have examined how the properties of this rod-cone flicker interaction differ with retinal eccentricity. The threshold for detecting 25 Hz flicker was measured in the dark-adapted eye, against a rod-saturating Ganzfeld background and following a Ganzfeld bleach. The magnitude of the interaction, defined as the difference between light- and dark-adapted flicker thresholds, covaries with changes in rod absolute threshold across the visual field. At a given eccentricity, the magnitude of the interaction is constant for test diameters ranging from 7' to 1.7 degrees, indicating that variations in magnitude with eccentricity do not result from changes in spatial summation properties. The measurement of cone flicker thresholds during bleaching recovery provides evidence that variations in the magnitude of the rod-cone flicker interaction with retinal eccentricity may result from differences in the channel capacity of the pathway carrying the threshold-elevating signal from rods.

Adaptation, Ocular↗
PubMed1986

Cone-rod dystrophy. A clinical and histopathologic report.

Clinical, histopathologic, and electron microscopic findings in two postmortem eyes from a 29-year-old black man and the clinical and electrophysiologic findings of his 33-year-old sister, both of whom had bilateral atrophic macular lesions, confirmed the diagnosis of cone-rod dystrophy in these two patients. Light microscopy revealed a loss of photoreceptor cells primarily in the peripheral retina and macula, with relative preservation of both rod and cone cells in the equatorial area. Electron microscopy showed abundant lipofuscin-like granules aggregated in the basal portion of the retinal pigment epithelial cells. In the macular area, many retinal pigment epithelial cells were atrophic. The phagocytic capacity of the retinal pigment epithelium appeared to remain intact. The accumulation of lipofuscin-like granules in the retinal pigment epithelium may be one of the significant pathologic changes of this dystrophy.

Adult↗
PubMed1986

Cellular immune function of patients with retinitis pigmentosa.

Although initial investigations of peripheral blood lymphocytes (PBL) from patients with retinitis pigmentosa (RP) demonstrated a reduced percentage of Leu-4 positive (pan-T) lymphocytes, the authors recently determined that the absolute number of Leu-4 positive cells per milliliter of blood is normal. This investigation studied the production of the lymphokines gamma-interferon (gamma-IFN) and interleukin-2 (IL-2) in cultures of concanavalin-A stimulated PBL. The difference in the mean production of gamma-IFN or IL-2 by PBL from 33 RP patients versus PBL from 16 controls did not achieve statistical significance at P less than 0.05. Overall, the data did not demonstrate significant cellular immune abnormalities in patients with RP.

Adolescent↗
PubMed1985

Electrophysiology and inherited retinal disorders.

An understanding of electrophysiologic procedures and their application is crucial for evaluating patients with inherited retinal disorders. This review emphasizes the value of electrophysiologic procedures in the differential diagnosis of clinically similar disorders, the evaluation of atypical presentations of known retinal disorders, and the determination of the extent of dysfunction in photoreceptor-retinal pigment epithelial disease. It is important for each investigator to assess quantitatively the short-term variability inherent in each electrophysiologic procedure so that meaningful data can be obtained on the natural history of the various inherited retinal disorders being monitored.

Diagnosis, Differential↗
PubMed1985

Rod-cone interaction in flicker perimetry: evidence for a distal retinal locus.

The luminance threshold for the detection of 25 Hz flicker was measured in nine patients with retinal disorders under stimulus conditions that have been shown previously to involve an interaction between rod and cone systems. The disorders studied included congenital stationary nightblindness, X-linked juvenile retinoschisis, hereditary dominant optic atrophy, optic atrophy found in association with neurofibromatosis, retinitis pigmentosa, choroideremia, and an acquired diffuse photoreceptor disorder, all of which involve pathologic changes that are presumed to occur primarily at specific levels of the retina. The results are consistent with a distal (outer) retinal locus for the rod-cone interaction.

Adolescent↗
PubMed1985

Lymphocyte subpopulations and S-antigen reactivity in retinitis pigmentosa.

The lymphocyte subpopulations in the peripheral blood of 37 patients with retinitis pigmentosa (RP) and 24 controls were analyzed with the Leu series of monoclonal antibodies in conjunction with fluorescence-activated cell-sorter analysis. The peripheral blood lymphocytes (PBLs) from all RP genetic types had a significantly reduced frequency of Leu-4-positive T lymphocytes than controls, and a small but significant reduction in the frequency of Leu-3a-positive T lymphocytes was seen in patients with RP with the dominant trait. The reduced T-cell population seemed to be associated with an increased frequency of Leu-11a-positive cells. The PBLs from patients with RP did not react to retinal S-antigen, as assessed by the lymphocyte transformation or interleukin-2 assays. We conclude that patients with RP, although not clinically immunologically compromised, have a significantly reduced frequency of T lymphocytes in their PBLs. Furthermore, our study did not demonstrate reactivity to retinal tissue in PBLs from patients with RP.

Adolescent↗
PubMed1985

Drusen of the optic nerve associated with retinitis pigmentosa.

Globular excrescences of the optic nerve associated with retinitis pigmentosa have been interpreted as drusen or as astrocytic hamartomas. The histopathologic and ultrastructural findings of globular excrescences of the peripapillary region of the optic nerve associated with retinitis pigmentosa were described in a 22-year-old patient who died in a car accident. From our findings we conclude that the globular excrescences of the optic nerve associated with retinitis pigmentosa are definitely drusen and not astrocytic hamartomas.

Adult↗
PubMed1985

Autosomal dominant retinitis pigmentosa. A method of classification.

Four types of autosomal dominant retinitis pigmentosa (RP) were discernible in 84 patients by clinical, electrophysiologic, and psychophysical criteria. Type 1 patients showed diffuse fundus pigmentary changes and nondetectable electroretinographic (ERG) cone and rod functions. Both type 2 and type 3 patients showed fundus pigmentary changes more apparent within the inferior retina. Type 2 patients showed marked loss in rod ERG function, with prolonged cone implicit times, whereas type 3 patients showed substantial rod function and normal cone implicit times. Type 4 patients had a funduscopically and functionally "delimited" disease, with substantial cone and rod ERG amplitudes and normal implicit times. The classification of dominantly inherited RP is important for studies of natural history in disease progression, for patient counseling, and for various laboratory investigations of patients with RP in which patient homogeneity should be maximized.

Adolescent↗
PubMed1985

Autosomal dominantly inherited retinitis pigmentosa. Visual acuity loss by subtype.

Sixty-eight patients with autosomal dominant retinitis pigmentosa were divided into two distinct subtypes and studied for visual function using a life-table analysis. Type 1 patients (n = 23) had diffuse pigmentation, concentric visual field loss, and no recordable electroretinogram. Type 2 patients (n = 45) as a group had regionalized pigmentation, sectorial field loss, and some recordable electroretinogram. The cumulative probability of maintaining a visual acuity of 6/12 (20/40) or better over each decade of life decreased rapidly in eyes of type 1 patients; for type 2 eyes, this probability remained above 90% through the fifth decade of life. The presence of an atrophic-appearing foveal lesion was associated with a reduction in visual acuity to 6/15 (20/50) or worse in a majority of patients. Data from this study indicate that investigators should look for subtypes within the major genetic groupings of retinitis pigmentosa for more accurate assessment of a patient's potential for maintaining good central visual acuity.

Adolescent↗
PubMed1985

Synthetic activities of cultured retinal pigment epithelial cells from a patient with retinitis pigmentosa.

We established cultures of retinal pigment epithelial (RPE) cells from four normal individuals and a 56-year-old male patient with autosomal-dominant retinitis pigmentosa (RP) and examined the synthetic activities of these cells via radiolabeling experiments. The uptake of radioactive precursors per milligram of cell protein by RPE cells from the patient with RP was significantly higher than that found in the normal control cells. It appears that the net synthetic activities of glycosaminoglycans and proteins in our patient's cells were enhanced and that the cell metabolism was altered. This finding suggests that malfunctioning of the RPE cells may play a role in the deterioration of photoreceptor functions seen in at least some patients with autosomal-dominant RP.

Adult↗
PubMed1985

Prevalence of posterior subcapsular lens opacities in patients with retinitis pigmentosa.

We clinically evaluated 338 patients with various genetic types of retinitis pigmentosa (RP) for the presence of posterior subscapsular (PSC) lens opacities. Of these, 180 (53%) had PSC lens changes or were bilaterally aphakic. Patients with X-linked recessive RP showed a greater prevalence and patients with autosomal dominant RP a lesser prevalence of PSC lens changes compared with autosomal recessive or isolated cases.

Adolescent↗
PubMed1984

Birdshot retinochoroidopathy.

Nine patients had birdshot retinochoroidopathy. Associated ophthalmologic findings included rhegmatogenous retinal detachment, rubeosis iridis, glaucoma, and a high incidence of disciform macular degeneration. Four patterns of birdshot spot distribution were noted on fundus examination. Immunologic studies showed a significantly elevated percentage of EA rosettes and an elevated C4 complement level. Electroretinograms showed b-wave amplitude reduction, with a disproportionate implicit time prolongation. The etiology of this syndrome remains unknown.

Adult↗
PubMed1984

Multiple evanescent white dot syndrome. I. Clinical findings.

We examined 11 young patients with unilateral ocular findings that included multiple white dots at the level of the retinal pigment epithelium (RPE) or the deep retina, vitreal cells, RPE granularity in the macula, reduced visual acuity, electroretinogram (ERG) and early receptor potential (ERP) amplitudes, and fluorescein leakage from disc capillaries and late staining of the RPE. Recovery of visual function included a dramatic improvement in ERG and ERP amplitudes over several weeks. The etiology of this syndrome remains uncertain; there is no definite evidence of systemic involvement.

Adolescent↗
PubMed1984

Multiple evanescent white dot syndrome. II. Electrophysiology of the photoreceptors during retinal pigment epithelial disease.

We performed electrophysiologic studies of photoreceptor function in three patients with multiple evanescent white dot syndrome. During the acute stage, while the visual acuity was impaired, the electroretinogram (ERG) a-wave and the early receptor potential (ERP) amplitudes were profoundly decreased. The ERP regeneration times, determined for one subject, were prolonged. These findings suggest that photoreceptor function was impaired (abnormal a-wave), the effective visual pigment optical density of the outer segments was markedly reduced (ERP amplitude), and visual pigment regeneration was abnormal (ERP regeneration kinetics). During the recovery stage, the ERG and ERP amplitudes and visual acuity returned to normal. Our patients' disease seemed to be primarily of the retinal pigment epithelium (RPE). The decreased visual pigment density and prolonged regeneration kinetics emphasize the physiologic dependence of the sensory retina on the RPE.

Acute Disease↗
PubMed1984

Transport of fluorescein in the ocular posterior segment in retinitis pigmentosa.

The function of the blood-retinal barrier was assessed by vitreous fluorophotometry in 12 patients with various genetic types of retinitis pigmentosa and in 11 normal subjects. The measurements were corrected to minimize the effect of artifacts. We evaluated the inward penetration of fluorescein sodium across the blood-retinal barrier and determined the outward permeability coefficient for fluorescein by interpreting the data with a pharmacokinetic computer model. Patients with retinitis pigmentosa had increased inward permeability and decreased outward permeability to fluorescein in comparison with values of normal subjects.

Adolescent↗