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Biomedical subjects

D H Char

Publications and source records attributed to D H Char.

At least 163 records · Page 9Linked to original sources
PubMed1983

Choroidal melanoma growth patterns.

Thirty patients with choroidal melanoma in whom tumour thickness was found to increase on serial examination were retrospectively studied. Often when tumours started to increase in thickness, after a period of relative quiescence, the growth rate was relatively rapid. Increased tumour thickness was associated with increased tumour growth. During the phase of active tumour growth the height of the lesion tended to increase more than exponentially. Possible inadvertent biases in the selection of the patients studied prohibit wide-ranging conclusions from these data.

Choroid Neoplasms↗
PubMed1983

Computed tomography in the diagnosis of retinoblastoma.

The role of orbital computed tomography (CT) in the management of retinoblastoma is reviewed. All 21 patients with retinoblastoma studied with high-resolution computed tomography had intraocular calcification demonstrable in at least one eye. 83% of tumours showed evidence of calcification on CT scan. The degree of calcification appeared to depend on tumour size; only small tumours were devoid of calcification. The amount and distribution of calcification was similar on both histological study and CT scan. In patients under 3 years old in whom a retinoblastoma is suspected the presence of calcification on CT is virtually diagnostic of it. Patients with leucocoria without calcification on CT probably have a simulating lesion.

Calcinosis↗
PubMed1982

The potential for adjuvant radiotherapy in choroidal melanoma.

Controversy exists regarding the efficacy of enucleation in the management of choroidal melanoma. The effect of any form of ocular therapy on the prevalence of choroidal melanoma metastases is unknown. In a number of other systemic tumors, preoperative irradiation may lessen the occurrence of widespread disease. This type of therapeutic approach might be useful in the management of high-risk choroidal melanoma. In preliminary studies using 2,000 rad of preenucleation irradiation in patients with choroidal melanoma who have a poor prognosis, we have not observed notable morbidity. There are a number of limitations to the use of this adjunct therapy in choroidal melanoma management; however, a prospective national randomized trial of preenucleation irradiation in patients with high-risk choroidal melanoma might allow us to indirectly determine the effect of enucleation on the prevalence of choroidal melanoma metastases as well as delineate the potential role of this type of adjunct therapy in ocular melanoma.

Choroid Neoplasms↗
PubMed1982

Helium ion therapy for choroidal melanoma.

Forty patients with choroidal melanomas received radiation therapy with helium ion-charged particles. Thirty-six of 30 patients either remained stable or demonstrated tumor shrinkage. Seventeen of 18 patients followed up for at least one year after therapy demonstrated tumor regression, with a mean tumor shrinkage of approximately 40%. The most effective method of choroidal melanoma management is unclear. Charged-particle external-beam irradiation may be more applicable and have less ocular morbidity than either radioactive plaques or photocoagulation.

Adult↗
PubMed1982

Binding of retinoblastoma and normal sera to retinoblastoma-derived cultured cells.

We have observed increased binding of retinoblastoma patients' sera to a retinoblastoma-derived cultured cell line (Y-79). This reactivity was mediated by the serum IgG fraction and was directed toward different tumor or target cell (Y-79, Molt, Raji, and fibroblasts) cultured in media containing fetal calf serum. Normal pooled serum IgG fractions did not demonstrate any similar binding. When target cells were cultured in media containing human serum instead of fetal calf serum, a considerable reduction in retinoblastoma sera binding activity was observed. Reactivity against target retinoblastoma cells could be reduced but not entirely eliminated by quantitative absorption with nonretinoblastoma (Molt) cells grown in media with fetal calf serum. Retinoblastoma and normal sera binding to autologous fibroblasts, nonautologous fibroblasts, and cultured melanoma cells was also minimal. These findings suggest that residual binding activity in the sera tested may be directed against retinoblastoma tumor antigens. The fetal calf serum component responsible for reactivity with certain retinoblastoma sera was shown by immunoprecipitation, competitive inhibition, and gel electrophoresis to be bovine serum albumin.

Adolescent↗
PubMed1982

Intraocular granuloma: a Schistosoma mansoni model of ocular inflammation.

An experimental uveitis model was developed in New Zealand rabbits by an intraocular injection of Schistosoma mansoni eggs. An inflammatory response was clinically apparent after 5 days and histologically was characterized by an eosinophilic infiltrate into the vitreous and choroid. The chorioretinitis that developed resulted in the disruption of the photoreceptor layer. After 30 days, eggs were enveloped by a granulomatous host response similar to that observed in animals infected systemically with Schistosoma mansoni. Reduction (immunomodulation) of granuloma size and cellularity compared with controls was observed in paraffin sections of eyes challenged (100 eggs) 4 weeks after a priming injection (500 eggs) in the contralateral eye. The granulomatous response was not evident when heat-killed eggs were injected intraocularly. Extracts made from viable eggs also induced an intense vitreous infiltrate 12 hr after injection. Serum collected from rabbits injected with 500 or more eggs showed antibody (7s) reactivity for 125I-labeled bovine S antigen, as demonstrated by immunoprecipitation with Staphylococcus aureus (Pansorbin). This model is useful for analyzing immunologic parameters involved in ocular granulomatous and parasitic diseases, humoral and cellular responses mediating autosensitization to retinal or other ocular antigens, and possible for screening chemotherapeutic agents for immunomodulation of potentially injurious host inflammatory responses.

Animals↗
PubMed1982

Aqueous immune complexes in immunogenic uveitis.

A primary immunogenic uveitis was produced in rabbits by the intravitreal injection of bovine plasma albumin or ovalbumin. A secondary or recurrent uveitis was induced by intravenous injection of the specific soluble antigen several months after the cessation of primary inflammation. Aqueous antigen-antibody complexes were studied at times of maximal clinical response in both primary and recurrent forms during resolution of primary immunogenic uveitis, and in a nonspecific protein extravasation induced by aqueous paracentesis. Immune complexes could be demonstrated only during times of clinically evident inflammation in immunogenic uveitis. The results indicate the importance of antigen-antibody complex formation in the pathogenesis of this form of experimental ocular inflammatory disease.

Animals↗
PubMed1981

Ocular reticulum cell sarcoma.

Three patients with ocular reticulum cell sarcoma underwent treatment with a combination of chemotherapy and irradiation. All three patients have survived an average of 36 months after treatment, significantly longer than would have been expected with radiation therapy alone. The chemotherapy appears to arrest the progression of central nervous system disease that eventually kills most patients with ocular reticulum cell sarcoma.

Adult↗
PubMed1981

Orbital melanocytic hamartoma.

A male Chinese neonate had a melanocytic hamartoma that involved the entire orbit and the eye, but did not involve the orbital bones or eyelid skin. Although usually benign, these hamartomas may be locally invasive, and rare cases of malignant transformation have occurred.

Cornea↗
PubMed1981

Fc and C3b receptors on cultured retinoblastoma cells.

Fc and C3b receptors were identified on cultured retinoblastoma cells. Labeled receptor protein bound to affinity gels prepared with IgG, Aggregated IgG, and Fc but not to control gels prepared from Fab'2 or Sepharose-4B alone. Eluted Fc receptors was partially characterized by polyacrylamide gel electrophoresis. Molecular weight of the isolated receptor or its subunit was approximately 4.3 X 10(4) daltons. Cultured retinoblastoma cells were found to rosette with human indicator erythrocytes specific for C3b and Fc receptors. This study indicates that considerable reactivity between retinoblastoma patients' sera and cultured tumor cells may be mediated by these receptors as well as by reactivity toward retinoblastoma antigens.

Cells, Cultured↗
PubMed1981

Orbital melanoma.

A case of choroidal melanoma metastatic to the contralateral orbit is presented. Ultrasound and orbital computerized tomographic scan data are shown. In patients with a history of choroidal melanoma and a contralateral orbital mass, metastatic orbital melanoma should be suspected.

Aged↗
PubMed1980

The role of radiation therapy in the management of ocular reticulum cell sarcoma.

Nine patients with ocular lymphomas were seen in the Department of Ophthalmology and the Division of Radiation Oncology at UCSF and Ralph K. Davies Medical Center, San Francisco, from 1978 through 1974. Six of the 9 patients had visual symptoms as the first manifestation of their disease. Eight of the 9 patients developed intracranial lymphoma at some time during the course of the disease. Despite lymphoma work-up including bone marrow biopsies and lymphangiogram, only 1 patient was found to have documented systemic involvement. The diagnosis of ocular lymphoma was based on pathologic material from the eye in 5 cases or from central nervous system biopsy in 4 patients in association with tumor cell infiltrates in the retina and vitreous clouding. Radiation therapy to the eyes improved vision in 10 of 13 eyes treated in 8 patients. The usual dose was in the range of 3500 to 4500 rads given over 4-5 weeks. In addition, 7 patients received central nervous system irradiation. Review of the literature reinforced the findings of this series showing the frequent association of ocular lymphoma with intracranial lymphoma and the rare systemic dissemination. This disease process has previously been referred to as ocular reticulum cell sarcoma.

Adult↗
PubMed1980

Diagnostic modalities in choroidal melanoma.

We prospectively studied 51 patients with choroidal melanomas in a masked manner to determine the accuracy of clinical, ultrasound, and fluorescein diagnosis as well as the accuracy of tumor size measurements. In patients with clear media, clinical diagnosis was the most accurate means of detecting a choroidal melanoma. There was excellent correlation between clinical, ultrasound, and pathology measurements of tumor size. In small melanomas, clinical examination was the most accurate means of measuring tumor diameter and ultrasound the most accurate method of measuring tumor height. Even with a trained ocular oncologist, there was a significant variability in tumor measurements on serial ophthalmoscopic examinations.

Choroid Neoplasms↗
PubMed1980

Immune complexes and carcinoembryonic antigen levels in metastatic choroidal tumors.

We studied 11 patients with metastatic choroidal tumors and one patient with a metastatic choroidal melanoma by using the Raji cell radioimmunoassay to detect immune complexes, and the carcinoembryonic assay. Ten (91%) patients with choroidal metastases had an increase of either immune complex levels or carcinoembryonic antigen results.

Antigen-Antibody Complex↗
PubMed1980

Ocular metastases from systemic melanoma.

We studied two patients, a 72-year-old man and a 27-year-old woman, with metastatic melanoma documented by cytologic examination of the ocular fluids. Neither patient had a clinically detectable ocular mass. Fine-needle aspiration with cytologic examination may be useful in the diagnosis of metastatic ocular melanoma.

Adult↗
PubMed1980

Helium ion charged particle therapy for choroidal melanoma.

Nine patients with choroidal melanomas were treated with helium ion charged particle irradiation. No patient demonstrated tumor enlargement, and most lesions followed for more than five months have demonstrated tumor shrinkage. The most effective method of choroidal melanoma management is unclear. Heavy charged particle irradiation may be more applicable and have less ocular morbidity associated with it in either radioactive plaques or photocoagulation.

Adult↗
PubMed1980

Diffuse melanoma of the choroid.

An 81-year-old woman with good vision was followed up with the diagnosis of a minimally active melanoma. This tumour was eventually found to be a diffuse melanoma with extraocular extension. Diffuse melanomas of the uvea are difficult to diagnose, have frequent and early extrascleral extension, and have a poorer prognosis than most melanomas of the uveal tract.

Aged↗