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Biomedical subjects

F H Davidorf

Publications and source records attributed to F H Davidorf.

At least 19 recordsLinked to original sources
PubMed1992

Systemic immunostimulation after retinal laser treatment in retinitis pigmentosa.

Systemic immunostimulation followed an experimental treatment trial of scatter argon laser photocoagulation directed to the retina of one eye of 10 patients with heredo-degenerative retinitis pigmentosa (RP). Significantly increased RP lymphocyte CD25, CD26, and CD4/CD26 activation epitope expressions over prelaser values and controls were found with a normalization of soluble interleukin-2 receptor secretion after laser treatment. Serum interferon-gamma was low both pre- and postlaser. Interestingly, when a panel of viral antibodies was tested, only those to rubella virus were elevated in the early postlaser period. The character of RP immunostimulation after laser-induced inflammation could be consistent with an antigenic stimulus from laser-released retinal proteins which might be of autoimmune or latent infectious origin. Enhanced immune responses may be a common but unrecognized sequellae of retinal laser.

Adolescent↗
PubMed1992

Retinoblastoma, microphthalmia, coloboma, and neuroepithelioma of the pineal body.

A one-month-old infant boy was examined early in life because his mother had bilateral retinoblastoma and his father had bilateral microphthalmia. The ophthalmologist found his right eye was normal size with a coloboma of the iris, choroid, and retina. The left eye was microphthalmic with a coloboma of the uveal tract and retina. A vascularized fluffy white mass in the posterior pole was diagnosed clinically as a retinoblastoma. The tumor regressed with radiation. When the patient was four years of age, a large tumor was found in the region of the pineal recess, causing hydrocephalus and seizures. A biopsy showed an undifferentiated malignant neuroepithelial neoplasm. The patient died within three months of diffuse central nervous system tumor. The unusual findings of a retinoblastoma in a microphthalmic eye with bilateral colobomas and a neuroepithelial neoplasm of the pineal gland are discussed.

Abnormalities, Multiple↗
PubMed1992

False-positive magnetic resonance imaging of a metastatic carcinoma simulating a malignant melanoma.

Previous studies have shown the value of magnetic resonance imaging (MRI) in the diagnosis of malignant melanoma of the choroid. We describe the case of a patient with a choroidal mass whose MRI study was characteristic of malignant melanoma. Subsequently the eye was enucleated. However, on histopathologic examination, the mass was a metastatic carcinoma to the choroid. This false-positive study makes us question the value of MRI in the diagnosis of malignant melanoma of the choroid.

Aged↗
PubMed1992

Activated retinitis pigmentosa peripheral lymphocytes adhere to and alter cultured human retinal pigment epithelial cells.

Interleukin-2 receptor (IL-2R) is an activation molecule that, when expressed on peripheral blood lymphocyte (PBL) membranes, indicates the secretion of IL-2 and initiation of an immune system activation cascade. Comparing the average of IL-2R expression in 34 patients with retinitis pigmentosa (RP) syndrome (561 +/- 282 cells/mm3; mean +/- standard deviation) with 35 age-matched normal subjects (194 +/- 39 cells/mm3), it was found that those with RP had greater numbers of IL-2R-positive cells (P less than 0.001). The increased amounts of IL-2R on PBL of 29 RP and the homotypic self-aggregation of RP PBL by phase and scanning electron microscopy led to the study of the interaction of RP PBL with cultured human postmortem retinal pigment epithelial cells (RPE). A direct correlation was found between the amount of IL-2R expression and the numbers of RP lymphocytes adhering to RPE monolayers. However, the adherence effect was not unique to RP syndrome but appeared to be a nonspecific result of lymphocyte activation. Greater adherence to RPE than normal also was observed in PBL from disease control subjects with elevated IL-2R values and in PBL stimulated by the mitogen, concanavalin A (Con-A). In addition, RPE monolayers were destroyed by Con-A-stimulated PBL that showed 95-98% IL-2R expression. Similar, but less serious effects, occurring in RPE cells after 1 wk's cocultivation with RP PBL, suggested that activated RP lymphocytes can be cytotoxic to RPE during prolonged contact. Because macrophage-like cells and class II major histocompatibility complex expression have been found in RP-affected retinas, immune-mediated cytopathologic effects may contribute to retinal degeneration in RP.

Adolescent↗
PubMed1991

Modified vitrectomy for impending macular holes.

We report a consecutive series of 13 eyes (11 patients) treated with pars plana vitrectomy, in which surgical manipulation of the prefoveal layer of cortical vitreous was avoided, for stage I (eight eyes) and stage II (five eyes) macular hole formation. Average follow up was 8.1 months (range, 2 to 13 months). There was no significant improvement in vision in the patients with stage II macular holes; however, vision in these patients stabilized and did not fall below 20/400. Visual acuity improved in seven of the eight patients with stage I holes. The results for both these groups achieved by our modified vitrectomy, which is relatively easy to perform and involves minimal intraoperative manipulation of the fovea, are consistent with those obtained by methods involving more aggressive cortical vitreous stripping of the fovea.

Aged↗
PubMed1991

Pathogenesis of retinal dystrophy in the Royal College of Surgeons rat.

The Royal College of Surgeons (RCS) rat is an animal with genetically transmitted progressive retinal dystrophy. We compared histopathologically the RCS rat retina with normal age-matched control retinas (Long-Evans rats) using light and scanning electron microscopy. Retinal degeneration begins with alteration of the rod outer segments. There is a progressive involvement of the entire retina, with all layers affected by 45 days. The three-dimensional view obtained with scanning electron microscopy provides another perspective on the pathogenetic changes of the RCS retina.

Animals↗
PubMed1991

Scanning electron microscopic study of microaneurysms in the diabetic retina.

We describe the clinical and pathologic appearance of the retinal microcirculation in a patient with a 22-year history of diabetes mellitus. A vascular cast of one eye was prepared and studied with scanning electron microscopy. The three-dimensional views obtained give insight into the pathogenesis of microaneurysms.

Aged↗
PubMed1990

A randomized study of methanol-extraction residue of bacille Calmette-Guerin as postsurgical adjuvant therapy of uveal melanoma.

A randomized controlled clinical trial of methanol-extracted residue of bacille Calmette-Guerin adjuvant treatment of posterior uveal melanoma was undertaken. Of 113 patients, 34 patients received adjuvant immunotherapy and 79 patients received no treatment. No difference in survival was observed between the adjuvant-treated group and the control group of patients. This study found that the size of the tumor was a highly significant risk factor for death caused by metastasis of uveal melanomas. The standard deviation of the nucleolar area of the neoplastic cells was a significant risk factor, even though patients with tumors composed of Callender's spindle-type cells were not included in the study.

Adjuvants, Immunologic↗
PubMed1990

Ocular toxicity of vitreal pluronic polyol F-127.

To evaluate pluronic polyol F-127 (PF-127) as a vitreous substitute and an intraocular drug delivery system, a total vitrectomy was performed on 18 New Zealand rabbits (18 eyes). The vitreous was replaced with either PF-127 (9 eyes) or balanced salt solution (9 eyes). There was little difference clinically between the eyes containing PF-127 and the control eyes. Both groups showed mild postoperative inflammation, with no differences in intraocular pressures. Histopathologic findings for the control group showed no significant retinal alteration, and serial ERG findings were within normal limits. In contrast, the eyes containing PF-127 showed marked destruction of the retina by 2 weeks after surgery. The ERG amplitudes decreased dramatically to a flat tracing by 24 hours after surgery. Although it is attractive as a potential vitreous substitute, PF-127 is not safe for human use, at least at the concentration used.

Animals↗
PubMed1977

The prognostic significance of lymphocytic infiltration in malignant melanoma of the choroid.

Lymphocytic and plasmocytic infiltration surrounding a malignant tumor probably represents an immunologic response of the host directed against the neoplasm. It has been documented that lymphocytic infiltration has a favorable effect on prognosis in a number of human tumor systems, including cutaneous melanoma. In the present study, 309 consecutive cases of choroidal melanoma were examined for cellular infiltration, and these data were correlated with other histologic parameters and with prognosis. A intense cellular infiltration was found in 15 tumors (4.9%) and a moderate infiltration in 37 (12.0%). Tumors with cellular infiltration were significantly larger and more vascularized than the remaining tumors, which may be related to the accessibility of the immune system to the tumor. There was a higher percentage of poorly differentiated tumors among the tumors with cellular infiltration. However, it does not appear the cellular infiltration favorably influences the prognosis of choroidal melanoma. The 5-year survival rates of patients with like cell types did not depend upon the degree of cellular infiltration demonstrated by the primary tumor. Although choroidal melanomas are capable of inciting an immune response, this response is apparently ineffective in preventing metastatic spread.

Choroid Neoplasms↗