Biomedical subjects
Publications and source records attributed to S Raphael.
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Blau syndrome (MIM 186580), first described in a large, three-generation kindred, is an autosomal, dominantly inherited disease characterized by multiorgan, tissue-specific inflammation. Its clinical phenotype includes granulomatous arthritis, skin rash, and uveitis and probably represents a subtype of a group of clinical entities referred to as "familial granulomatosis." It is the sole human model with recognizably Mendelian inheritance for a variety of multisystem inflammatory diseases affecting a significant percentage of the population. A genomewide search for the Blau susceptibility locus was undertaken after karyotypic analysis revealed no abnormalities. Sixty-two of the 74-member pedigree were genotyped with dinucleotide-repeat markers. Linkage analysis was performed under a dominant model of inheritance with reduced penetrance. The marker D16S298 gave a maximum LOD score of 3.75 at theta = .04, with two-point analysis. LOD scores for flanking markers were consistent and placed the Blau susceptibility locus within the 16p12-q21 interval.
We have developed a new set of tests for evaluation of visual function through media opacities, based on vernier acuity measurements (hyperacuity). In this paper, results of one of these tests, the 'gap test', are compared in patients with posterior subcapsular (PSC) cataract versus nuclear cataract (NC). Patients with PSC cataract often report multiple images or significant 'star burst' effects. We hypothesized the presence of 'multi-prismatic' and/or high frequency spurious resolution phenomena due to PSC cataract characteristic substructure. We were able to minimize these effects by using a pinhole held close to the eye, a large (adapting) background field of white light superimposed on the vernier test targets, a low-pass spatial filter applied to the targets. When the particular problems associated with PSC cataract are not present or are adequately addressed and when patients are matched for visual acuity, the hyperacuity 'gap test' shows less functional effect due to the opacity for PSC cataract than NC in all the cases we have tested. These findings, moreover, indicate that visual acuity provides an insufficient description of the effects of intraocular scattering on image formation. The results emphasize the importance and the necessity of developing models that better clarify the specific effects of different types of ocular media opacities.
We have developed two related clinical tests that offer potential in better assessing visual function behind an ocular opacity. The tests are resistant to the effects of opacities because they utilize a localization task (vernier acuity) rather than a resolution task. In this paper we report the initial trials in which we apply the two tests together. Results from six case studies (some with actual opacities and some with simulated opacities) illustrate both the conduct of the tests and their potential capabilities in detecting even very modest retinal dysfunction in the presence of opacities. These techniques offer considerable potential in the separation of a given acuity loss observed in the presence of cataract into a portion due to the opacity and a portion due to retinal dysfunction.
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The effects of optically produced "noise" in the retinal luminance distribution of a vernier stimulus are demonstrated in two experiments. In the first, vernier performance with a bright, two-dot target is shown to improve upon the introduction of a luminous background field, relative to performance with a completely dark background. The brighter background probably acts as an adapting field, reducing the visibility of the retinal image "noise". The second experiment demonstrates that, under defocused conditions, introduction of a low-pass spatial filter that removes phase-reversed high spatial frequency components can enhance vernier performance. Thus, high spatial frequency information may interfere with the vernier response when phase information is disturbed by defocus.
The resistance of certain types of hyperacuity tasks (eg, vernier acuity) to optical degradation of the retinal image has been demonstrated previously. This suggests that such a task might provide a means of filling the clinical need for a reliable test of retinal function in the presence of cataracts and other ocular opacities. In the present study, we measure several aspects of vernier acuity performance in cataract patients. These data provide an early basis for the development of a vernier acuity test to detect retinal/neural visual loss prior to cataract surgery. We report the results of measurements in 15 cataract patients using a two-dot vernier acuity task with variable separation between the two dots (gap). The data indicate that the shape and mean level of the vernier threshold-versus-gap function co-vary with the functional severity of the opacity as corroborated by Snellen acuity measures. Furthermore, the optical effects of the cataracts we studied are very similar to the effects of degrading the visual stimulus by interposing ground glass for a normal observer. We conclude that the shape of the vernier threshold-versus-gap function is a good indicator of the functional severity of the cataract in patients with otherwise normal vision.
OBJECTIVES: This study reports findings from the first-ever systematic enumeration of homeless population size using data previously collected from administrative records of homeless services providers in nine US jurisdictions over a one year period. As such, it provides the basis for establishing an ongoing measure of the parameters of the homeless population and for tracking related trends on the use of homeless services over time. METHODS: Each participating jurisdiction collected data through its homeless services management information systems for persons and families who use emergency shelter and transitional housing. The jurisdictions organized the data by a standardized reporting format. These data form the basis for reporting homeless population size, both in raw numbers and as adjusted for each jurisdiction's overall population size, as well as the rate of turnover and average annual length of stay in emergency shelters and transitional housing. RESULTS: Individual jurisdictions had annual rates of sheltered homelessness ranging from 0.1% to 2.1% of their overall population, and 1.3% to 10.2% of their poverty population. Annual population size was 2.5 to 10.2 times greater than the point-prevalent population size. Results are broken down for adults and families. CONCLUSIONS: The prevalence of homelessness varies greatly among the jurisdictions included in this study, and possible factors for this diversity are discussed. Future reports of this nature will furnish similar series of homeless enumerations across a growing number of jurisdictions, thereby providing a basis for exploring the effects of different contextual factors on local prevalence rates of homelessness.