Biomedical subjects
Publications and source records attributed to J L George.
Quality control exposures of commercial alpha-track radon monitors have been conducted approximately weekly at the U.S. Department of Energy (DOE) Grand Junction Projects Office since early 1987 in support of DOE remedial action programs. The results of these exposures provide a historical record of the comparative performances of these radon monitors.
Two grafting methods were devised to transplant heterotopically human corneas to nude mice. Half of them were secured on the mesenterium, enclosed in a small intestine ring; the others were stitched to the anterior abdominal muscles after removal of a muscular disc. We used theses procedures to implant 13 human corneas: 7 according to the first technique and 6 tho the second one. Most of the corneas observed from Day 3 to Day 90 remained transparent along the whole grafting period. The grafts were surgically removed from Day 3 to Day 90 and submitted to an histological examination. It was not observed any morphological changes, versus normal human cornea and especially none neovascularization. These observations are fully in agreement with the persistent transparency of the corneas. With this model, many experimental studies in vivo on human corneas can be planed and conducted without any ethical restriction.
A personal series of 10 patients with post surgical bacterial endophthalmitis is reviewed. Clinical signs, risk factors and diagnostic modalities are analysed and compared to other reports in literature. The role of intraocular lens is discussed. While it does not seem to be a risk factor in acute endophthalmitis, it plays a major role in chronic bacterial endophthalmitis. Endophthalmitis remains a rare but serious complication after cataract surgery and prevention modalities, especially using prophylactic antibiotherapy, have still to be evaluated.
Junction scotoma is a classic field defect initially described by Traquair in 1917. Sparse cases have been reported until today. The authors report a silent pituitary adenoma in a 58 year-old female revealed by a junction scotoma. The field defects secondary to insult of chiasma from pituitary tumors besides usual bitemporal hemianopsia are reviewed by the authors. The possibility of minor ophthalmologic symptoms despite voluminous tumor has to be emphasized.
The accuracy and precision of indoor 222Rn measurements obtained with the use of diffusion barrier charcoal canisters (DBCC) under actual field conditions were determined by comparing the integrated average of 26 successive 7-d exposures of DBCC in each of 16 occupied residences over a 6-mo period with simultaneous measurements using four types of commercially available alpha-track monitors (ATM) and one type of scintillation chamber continuous 222Rn monitor. The results suggest that properly calibrated DBCCs provide very good estimates of the integrated 222Rn concentrations in residential structures over the standard 1-wk exposure period despite the occurrence of large diurnal variations in the actual 222Rn concentrations. The results also suggest that a relatively small number of 1-wk DBCC measurements at selected times throughout the calendar year would provide estimates of the annual average indoor 222Rn concentrations that compare favorably with single long-term ATM measurements.
Annual average indoor 222Rn concentrations in 40 residences in and around Grand Junction, CO, have been measured repeatedly since 1984 using commercial alpha-track monitors (ATM) deployed for successive 12-mo time periods. Data obtained provide a quantitative measure of the year-to-year variations in the annual average Rn concentrations in these structures over this 6-y period. A mean coefficient of variation of 25% was observed for the year-to-year variability of the measurements at 25 sampling stations for which complete data were available. Individual coefficients of variation at the various stations ranged from a low of 7.7% to a high of 51%. The observed mean coefficient of variation includes contributions due to the variability in detector response as well as the true year-to-year variation in the annual average Rn concentrations. Factoring out the contributions from the measured variability in the response of the detectors used, the actual year-to-year variability of the annual average Rn concentrations was approximately 22%.
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Endophthalmitis due to Listeria monocytogenes developed suddenly in a 52-year-old man receiving immunosuppressive therapy for a renal transplantation carried out 2 months previously. The treatment combined low doses of ciclosporin and prednisone. The initial clinical picture was of acute hypertensive uveitis with hypopyon. Despite prompt paracentesis and appropriate antibiotic therapy, the long-term course was unfavorable, and enucleation became necessary. The occurrence of listeriosis is classic in renal-transplant recipients, but no ocular form has been reported hitherto.
A case of unilateral serous hemorrhagic maculopathy with a very acute course is reported in an eight year old girl fluorescein angiography revealed the presence of a subretinal neovascular membrane extending from the inferotemporal part of the disc to the macula; CT scan identified calcified drusen of the optic disc. Ophthalmoscopy and angiography one year later showed a glial macular scar, absence of hemorrhage and serous detachment. Visual acuity was reduced to counting fingers. This unusual type of maculopathy combining optic disc drusen and a neovascular membrane contradicts the classically benign prognosis of optic disc drusen.
Although the single binocular visual field provides an indication of the area free of horizontal or vertical diplopia, it does not assess cyclorotary diplopia. A cylindric glass is adapted on the Goldmann perimeter and gives a linear spot, allowing the determination of the cyclorotary component of diplopia.
28 patients with high myopia (over-10 dioptries) were implanted in anterior chamber with a myopic IOL. 3 months postoperatively the visual acuity without correction was equal to the preoperative acuity. With a light correction, especially of residual astigmatism, we noticed a gain of acuity of 0.2.
Authors report a Pasteurella Multocida corneal abscess after a scratch from a cat. The evolution was torpid and needed a transfixiant keratoplasty. They recall bacterial tanks, infestation ways, clinical manifestations and bacteriological identification. They note the low occurrence of ophthalmological manifestations and the sensibility of Pasteurella to various antibiotics, especially Beta lactams, phenicol and cyclins.
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We comparatively studied histopathologic impairments following subconjonctival injections of long and short acting corticosteroids and saline. 44 conjunctival biopsies were performed in the site of injection. The tissues were evaluated by light and electron microscopy. The histopathologic findings, following saline subconjonctival injection were very slight. On the other hand, histopathologic findings following corticoids injection, and particularly long action products, were remarkable. We noted crystalline deposits inclusions of drug particles in fibroblast and macrophages, loss of collagen definition and degenerative changes of these phagocytosing cells, with release of their cytoplasmic contents. Our findings are according with previous studies about long acting corticosteroids, supporting their relative histologic toxicity, by local way of administration.
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Authors report clinical and computed tomographic evolutive course of 15 cases of orbital idiopathic inflammatory pseudotumors. 3 patients had complete disappearance of the symptoms but did not have a computed tomography scanning control, 3 patients had clinical and CT recovery. 4 had clinical resolving with a CT-residual hyperdensity. 5 patients had a partial response to treatment with a CT residual hyperdensity in 4 cases. Sequelae were not very important except one case with a loss vision and ophthalmoplegia. Authors tried to analyse the evolutive course, clinical and/or CT scan sequelae, and to specify the prognostic factors. CT scanning permits a precise anatomic assessment of orbital lesions, and the localisation of the pseudotumor is often in correlation with the therapeutic response. Asymptomatic residual hyperdensity on CT were not very known until now.
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