Biomedical subjects
Publications and source records attributed to S J Ryan.
In two siblings with olivopontocerebellar degeneration, the retinal pigment epithelium or the sensory retinal or both appeared to be damaged first. These layers were markedly involved before secondary changes in the choriocapillaris, the inner retinal layers, or the optic nerve occurred.
There are very few eyes with the ocular histoplasmosis syndrome that have been studied as such by the ophthalmic pathologist. Hoefnagels and Pijpers [6] were the first to demonstrate H. capsulatum in the human eye. However, this was a case of endophthalmitis and not the clinically observe syndrome. Klintworth et. al. [7] demonstrated the organism histologically in granulomatous choroiditis occurring in dissemiated histoplasmosis. The hot was compromised immunologically, and this again is somewhat different from the typical clinical situation. The histopathological material available for study was derived from the eyes of patients enucleated after the diagnosis of malanoma at the AFIP, nd from autopsy material from the Wilmer Institute. These five cases have a number of findings in common. The atrophic scars and punched-out sponts in the periphery and elsewhere correlate with an absence of the pigment epithelium. The degree of inflammation, usually lymphocyte infiltration, can be variable...
Regadless of the etiology of the disciform lesion in the presumed ocular histoplasmosis syndrome, and regardless of our ignorance as to whether the pathogenetic mechanism relates in part to hypersensitization, or can be explained solely on a mechanistic interpretation (that is, chronic vascular decompensation [9]), the question of therapy can be evaluated independently. However, our knowledge regarding the natural history of these lesions is similarly incomplete and thus, without a controlled study, e cannot compare any of the therapeutic modalities with the natural history. Therefore, we cannot make any definitive statements regarding the value of therapy, let alone compare the different modalities. For these reasons, conclusions as to the results of photocoagulation of the macular lesions in the ocular histoplasmosis syndrome must remain incomplete...
In order to compare the known morphological changes which occur during the postnatal development of the salivary glands in the rat with alterations in membrane function, we measured adenylate cyclase activity and its responses to sodium fluoride (NaF), norepinephrine, and isoproterenol in salivary gland membranes at various times after birth. In the parotid gland, basal enzyme activity did not change significantly during postnatal life, but fluoride-stimulated activity rose on day 15; A similar marked rise in activity stimulated by norepinephrine (0.02 mM) and isoproterenol (0.03 mM) was noted simultaneously. In the submandibular gland, basal adenylate cyclase activity was higher just after birth than at 25 days of life or in maturity. Fluoride-stimulated activity was 7 times higher than basal activity on day 1, greater than 10 times higher on day 25, and 30 times greater in the adult. The gland was as responsive to norepinephrine and isoproterenol on day 5 as it was on day 25 or in the mature animal, showing a two- to threefold increase over the basal enzyme value at each time point studied. Residual phosphodiesterase activity in the membranes was always negligible. The data demonstrate a time-dependent developmental change in the responsiveness of the parotid gland to norepinephrine and isoproterenol, which corresponds to the time when morphological maturation normally occurs. By contrast, in the submandibular gland, membrane-bound adenylate cyclase is fully developed at the time of birth.
The vitreous is felt to play a significant role in the development of advanced proliferative sickle retinopathy. This is particularly true in Stages 3 to 5 of the Goldberg classification. A comparison with the classification of proliferative diabetic retinopathy by Davis is presented. The role of vitrectomy in this disorder has been considered.
We employed pars plana vitrectomy for several different indications in 100 eyes. In 51 eyes, the operation was performed for complications of pholiferative diabetic retinopathy. Improved visual acuity was our only criterion of success, and this varied widely depending on the specific indication forsurgery. Vision improved in all eight eyes undergoing anterior segment reconstruction and in none of three eyes with preoperative retinal detachment complicated by massive vitreous retraction. There was a high incidence of retinal tears complicating the operations in the series (37%). These retinal breaks could usually be closed at the time of the initial operation, and retinal detachment that could not be successfully managed developed in only four eyes.
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