Evaluation of phenotypic similarities between Stargardt flavimaculatus and retinal pigment epithelial pattern dystrophies.
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Adolescent↗
Biomedical subjects
D P Han
Publications and source records attributed to D P Han.
Internal limiting membrane wrinkling after argon and krypton laser photocoagulation of choroidal neovascularization.
A retrospective study was performed to determine the prevalence and risk factors for internal limiting membrane (ILM) wrinkling following successful argon and krypton laser photocoagulation of choroidal neovascular membranes. The study included 139 eyes with presumed ocular histoplasmosis syndrome (POHS) and age-related macular degeneration (AMD). Argon treated eyes with POHS had a significantly higher prevalence of ILM wrinkling (30/63, 47.6%) than those with AMD (6/40, 15%, P = 0.0007). Krypton treated eyes also demonstrated a higher prevalence of ILM wrinkling in eyes with POHS (3/12, 25%) than in eyes with AMD (2/19, 10.5%) but this difference was not significant. In general, argon-treated eyes had a greater prevalence of ILM wrinkling than krypton treated eyes (35.0% vs 16.1%, P = 0.046). Factors which appeared to increase the risk of ILM wrinkling included intensity of treatment, area of the neovascular membrane, and the presence of subretinal blood.
Adult↗
Differentiation between recently resolved optic neuritis and central serous retinopathy. Use of tests of visual function.
A test battery was performed on 13 patients with resolved central serous retinopathy and on 13 patients with resolved optic neuritis to see whether the tests would help to distinguish between the two conditions. We found that the most useful discriminators were the relative afferent pupillary defect, followed by the visual evoked potential latency and the critical flicker frequency. The total error score on the Farnsworth-Munsell 100-Hue Test and the nature of the color vision defect were not helpful in separating the two diseases.
Adult↗
Visual function abnormalities in central serous retinopathy.
Eighteen patients with central serous retinopathy (CSR) underwent a battery of visual function tests when first seen and after resolution of the subretinal fluid. Eyes with CSR had minimal relative afferent pupillary defects, reduced critical flicker-fusion thresholds, prolonged visual evoked potential (VEP) latencies, increased errors on the Farnsworth-Munsell 100-hue (FM 100) test, and depressed central visual fields (Octopus). The afferent pupillary defect and critical flicker-fusion thresholds were the first to improve after resolution of the subretinal fluid. Next in rate of improvement were the visual acuity, the VEP latency, and the FM 100 test results. The threshold of the central Octopus at fixation improved the slowest and was still abnormal during long-term follow-up, indicating a prolonged depression in the threshold of central field sensitivity after resolution of the CSR. Many of these abnormalities are also seen in patients with optic nerve disease.
Adult↗
Nomograms for the assessment of Farnsworth-Munsell 100-hue test scores.
Although the Farnsworth-Munsell 100-hue test is a sensitive means of evaluating congenital and acquired color vision deficiencies, using the data it provides involves complex calculations. We have developed two nomograms that permit the clinician to determine quickly and easily whether a given score is normal for the patient's age and whether the difference between fellow eyes is within the normal range.
Adult↗
Asynchronous switching of flagellar motors on a single bacterial cell.
Salmonella possesses several flagella, each capable of counterclockwise and clockwise rotation. Counterclockwise rotation produces swimming, clockwise rotation produces tumbling. Switching between senses occurs stochastically. The rotational sense of individual flagella on a single cell could be monitored under special conditions (partially de-energized cells of cheC and cheZ mutants). Switching was totally asynchronous, indicating that the stochastic process operates at the level of the individual organelle. Coordinated rotation in the flagellar bundle during swimming may therefore derive simply from a high counterclockwise probability enhanced by mechanical interactions, and not from a synchronizing switch mechanism. Different flagella on a given cell had different switching probabilities, on a time scale (greater than 2 min) spanning many switching events. This heterogeneity may reflect permanent structural differences, or slow fluctuations in some regulatory process.
Bacterial Proteins↗
Technical aspects of the Staphylococcus aureus teichoic acid antibody assay: gel diffusion and counterimmunoelecrophoretic assays, antigen preparation, antigen selection, concentration effects, and cross-reactions with other organisms.
Because variable results are being reported from laboratories performing the teichoic acid antibody assay in patients with serious infections due to Staphylococcus aureus, we have thoroughly reviewed all technical aspects of the test. This paper reports on the importance of agar and antigen preparation in standardizing results of the assay and reducing the prevalence of false-negative and -positive tests. Once standardized, the counterimmunoelectrophoretic method is as accurate as the gel diffusion method for both initial screening and generating titers; practically, however, unless numerous tests are to be performed, the gel diffusion technique will suffice for most purposes. The cell wall of the Lafferty strain of S. aureus was used as the standard antigen in assays for serum antibodies. We studied whether it is an appropriate antigen and found that antibody titers obtained with the Lafferty strain antigen were, in three patients with endocarditis, the same as those obtained with antigens from the individual blood stream isolates. We have also confirmed that pooled human gamma globulin can be used, by back titration against newly prepared lots of antigen, to select optimal antigen concentration and is as good as more specific, higher titer serum specimens for that purpose. Finally, cell wall antigens from Staphylococcus epidermidis and a variety of streptococci may react with normal human sera, but such antigens are distinct by immunoprecipitation from those from S. aureus.
Antibodies, Bacterial↗
Cranial nerve injuries following carotid endarterectomy: an analysis of 336 procedures.
Cranial nerve injuries may result from carotid endarterectomy. From January 1984 to December 1987, a total of 336 carotid endarterectomies were performed at University Hospitals of Cleveland and Cleveland Veterans Administration Hospital. Forty-five cranial nerve injuries were documented (13.5%). Twenty patients (6%) had documented unilateral vocal cord paralysis, 16 (4.8%) had hypoglossal injuries, 8 (2.4%) had facial nerve paresis, and 1 (0.3%) had an injury to the spinal accessory nerve. Although most injuries were due to either retraction or edema of cranial nerves, long-term follow-up regarding recovery of function is very important. We feel that proper clinical evaluation of these patients should be routinely done preoperatively in order to document possible preexisting cranial nerve deficits. Postoperatively, if symptoms of possible cranial nerve abnormalities occur, these patients should have a thorough head and neck evaluation in order to identify possible lesions and institute further treatment to improve their quality of life.
Accessory Nerve Injuries↗
Late ophthalmic manifestations of the shaken baby syndrome.
We examined six children between 12 and 55 months after an initial shaking injury to determine whether visually significant retinal abnormalities persisted, despite clearing of intraocular hemorrhage. In two children (age 21 months and 6.7 years at follow-up), visual acuity was reduced due to macular folds occurring in the region of previous large subhyaloid hemorrhages. A third child (age 3.2 years) had a midperipheral lacunar defect of the retinal pigment epithelium which was not visually significant. Cerebral injury was responsible for an apparent profound visual loss in three children. Our findings indicate that both macular folds and cortical injury are functionally significant complications of the shaken baby syndrome.
Blindness↗
Collagen shield delivery of tissue plasminogen activator: functional and pharmacokinetic studies of anterior segment delivery.
BACKGROUND: Postoperative fibrin formation remains a major complication associated with intraocular surgery, especially after vitreoretinal surgery for proliferative vitreoretinopathy, proliferative diabetic retinopathy, trauma, or endophthalmitis. Tissue plasminogen activator (tPA) has been shown, both in experimental studies and clinical trials, to specifically dissolve formed intraocular fibrin after intracameral or intravitreal injection. We studied collagen shield delivery of tPA to the anterior segment and vitreous of rabbit eyes to evaluate a noninvasive delivery modality. METHODS: Anterior segment fibrin clots were formed in rabbit eyes by injecting citrated rabbit plasma. The tPA hydrated collagen shields, or control shields, were then placed on the rabbit corneas and the extent of fibrin clot was followed. In other rabbit eyes, tPA hydrated collagen shields were placed on the rabbit corneas and an enzyme-linked immunosorbent assay (ELISA) was utilized to determine aqueous, vitreous, and blood levels of tPA over time. RESULTS: Collagen shield tPA delivery shortened the time to fibrin clot lysis by 50% (mean clearance time = 49 +/- 23 hours; P less than .05). ELISA for tPA levels noted measurable vitreous levels by 2 hours after tPA hydrated collagen shield application with a peak at 24 hours. Aqueous tPA levels were not measurable until 18 hours after tPA collagen shield application and peaked at 36 hours. Vitreous tPA levels were greater than aqueous tPA levels at all time points (P less than .05). No evidence of corneal edema or opacification, hemorrhage, or cataract was seen. CONCLUSIONS: These results document the efficacy and safety of tPA delivery to the aqueous and vitreous via a hydrated collagen shield in this animal model.
Absorption↗