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Biomedical subjects

D H Char

Publications and source records attributed to D H Char.

At least 127 records · Page 7Linked to original sources
PubMed1987

Sympathetic ophthalmia complicating helium ion irradiation of a choroidal melanoma.

Sympathetic ophthalmia was diagnosed 49 months after helium ion irradiation of a left choroidal melanoma. The patient maintained good vision until 18 months after therapy, when she developed neovascular glaucoma. This complication required multiple therapeutic procedures, including topical anti-inflammatory and antiglaucomatous drops, 360 degrees peripheral panretinal cryoblation, and a single 180 degrees application of inferior cyclocryotherapy over a 2 1/2-year period. Four weeks after the cyclocryotherapy, inflammation was noted in both eyes, and, one month later, enucleation of the left sympathogenic eye was performed. Serial histopathologic sections showed a full-thickness, fibrovascular, scleral scar and tantalum marker ring suture without uveal incarceration. Penetrating surgical trauma, a uveal melanoma, and multiple nonpenetrating treatments resulted in the development of sympathetic ophthalmia.

Aged↗
PubMed1987

Histopathology of uveal melanomas treated with charged particle radiation.

The authors have treated 255 uveal melanomas with helium ion radiation. Twenty-three eyes have been enucleated because of complications and five eyes have been obtained at autopsy. We have evaluated 27 of these eyes. Neovascular glaucoma (10 eyes), painful keratitis (6 eyes), continued tumor growth (4 eyes), and vitreous hemorrhage (2 eyes) were the major complications of treatment that led to enucleation. The degree of tumor necrosis correlated with the size, pigmentation, and anterior extent of the tumor. It did not correlate with the interval from irradiation or with the amount of tumor shrinkage. Mitotic figures were extremely rare in treated tumors, suggesting that the tumor cells have lost their ability to cycle.

Adult↗
PubMed1987

DNA and cell cycle analysis of retinoblastoma.

We retrospectively analyzed archival retinoblastomas from 44 eyes. The percentage of cycling cells were increased in younger patients, those with advanced disease, and cases with poor prognosis. These data suggest that all cell cycle studies may yield important insights in retinoblastoma.

Aging↗
PubMed1986

Uveal melanoma necrosis after helium ion therapy.

A 71-year-old man underwent enucleation because of intractable pain ten months after receiving helium ion therapy for a uveal melanoma. There was no clinical or ultrasonographic evidence of tumor regression but histologically the tumor appeared almost entirely necrotic.

Aged↗
PubMed1986

Lymphocyte subpopulations in uveitis.

We have used a fluorescence-activated cell sorter to study the lymphocyte subpopulations in the intraocular fluids and peripheral blood of 27 patients with uveitis. T lymphocytes predominated in intraocular fluids. A wide variation in the ratio of Leu 3a-positive (helper) cells to Leu 2a-positive (suppressor) cells was found. No correlation was seen between the specific lymphocyte subpopulations and the clinical uveitis activity or steroid treatment. A statistically significant correlation was found between T-cell subsets present in aqueous humor and peripheral blood. Many lymphocytes seem to be present in intraocular fluids secondary to a breakdown of the blood-ocular barrier.

Adrenal Cortex Hormones↗
PubMed1986

Spontaneous regression of a choroidal melanoma.

Although spontaneous regression of uveal malignant melanoma is rare, its occurrence is not uncommon in cutaneous melanomas. We report a 15-year follow-up of an enlarging posterior pigmented tumor. It initially appeared to spontaneously regress into a flat chorioretinal scar, but, ten years later, it grew markedly and the eye was enucleated. Histopathologic changes similar to those found in regressed cutaneous melanomas were located in the region of the chorioretinal scar.

Adult↗
PubMed1986

DNA content abnormalities and prognosis in uveal melanoma.

Recent advances in flow cytometry allow for study of DNA content in paraffin-embedded pathology material. Using refinements of published techniques, we retrospectively correlated tumor cell DNA content (ploidy) with histologic findings and clinical outcome in 79 patients with uveal melanoma. Patients were included using these selection criteria: enucleation without adjunctive therapy performed at the University of California at San Francisco between 1956 and 1979, tumor located in ciliary body or choroid, and pathology material and complete follow-up data available. The DNA histograms were classifiable as diploid or hyperploid in 64 cases. The mean coefficient of variation for diploid histograms was 6.6%. Twenty-three patients (36%) had hyperploid tumors. Hyperploidy was correlated with worse outcome. The effect was most marked for DNA indexes of over 1.4. A Cox proportional hazards model showed that the effects of tumor diameter and cell type were insignificant in comparison with the effect of the DNA index.

DNA, Neoplasm↗
PubMed1986

Neovascular glaucoma after helium ion irradiation for uveal melanoma.

Neovascular glaucoma developed in 22 of 169 uveal melanoma patients treated with helium ion irradiation. Most patients had large melanomas; no eyes containing small melanomas developed anterior segment neovascularization. The mean onset of glaucoma was 14.1 months (range, 7-31 months). The incidence of anterior segment neovascularization increased with radiation dosage; there was an approximately three-fold increase at 80 GyE versus 60 GyE of helium ion radiation (23% vs. 8.5%) (P less than 0.05). Neovascular glaucoma occurred more commonly in larger tumors; the incidence was not affected by tumor location, presence of subretinal fluid, nor rate of tumor regression. Fifty-three percent of patients had some response with intraocular pressures of 21 mmHg or less to a combination of antiglaucoma treatments.

Anterior Eye Segment↗
PubMed1986

Inferences from beading of a retinal vein draining a choroidal melanoma.

Beading of a retinal vein draining a choroidal melanoma is reported, showing that the endothelial proliferation producing the beading is a response to some blood borne factor(s) traversing the vein and that retinal capillary non-perfusion adjacent to the beaded vein is not a necessary part of the process.

Capillaries↗
PubMed1986

Corneal allograft rejection in rabbits.

We performed a phase I study to assess the therapeutic efficacy of an anti-T cell monoclonal antibody conjugated with ricin A-chain in a corneal graft rejection model. Corneal allografts were exchanged between Dutch and New Zealand rabbits. Rejections occurred within 16-22 days in untreated animals. Graft rejection was delayed by topical or retrobulbar cyclosporine, but not by subconjunctival injections of a murine anti-rabbit T cell monoclonal antibody, nor by either subconjunctival or intravenous F(ab')2-ricin conjugate.

Animals↗
PubMed1986

Radiation therapy for uveal melanomas involving the ciliary body.

Thirty-four patients with medium (2) or large (32) uveal melanomas which involved the ciliary body (ciliary-choroidal, ciliary, and iris-ciliary) were treated with helium ion (29) or I-125 brachytherapy (5). Thirty-one of 34 eyes were retained after treatment. Most melanomas were too large for surgical removal with retention of the eye. Eyes containing very large tumours often had poor visual acuity after treatment.

Brachytherapy↗
PubMed1986

Uveitis: lymphocyte subpopulation studies.

Recent advances in cellular immunology have enabled us to delineate numerous lymphocyte subsets and activation stages using monoclonal antibody techniques. lymphocyte subsets and activation stages using monoclonal antibody techniques. We have used a fluorescence activated cell sorter (FACS) and newer monoclonal antibodies to study lymphocyte subpopulations and activation stages of T lymphocytes in intraocular fluids and peripheral blood of uveitis patients. T lymphocytes predominated in aqueous and vitreous. A statistically significant correlation was observed between the T lymphocyte subsets in aqueous and peripheral blood. No correlation was seen between the intravitreal lymphocyte subsets and peripheral blood. Many intraocular lymphocytes are present in the aqueous secondary to a blood ocular barrier breakdown. Using an anti-interleukin-2 (IL-2) receptor monoclonal antibody as a marker for T-cell activation, activated lymphocytes were found in intraocular and peripheral blood of both idiopathic and non-idiopathic uveitis. A statistically significant correlation was found between in vivo lymphocyte activation and clinical uveitis activity. In uveitis, lymphocyte activation in the eye paralleled levels found in the blood. Systemic and intraocular lymphocyte activation occurs in both idiopathic uveitis as well as in systemic syndromes associated with intraocular inflammation. It is possible that idiopathic uveitis is a systemic disease.

Aqueous Humor↗
PubMed1985

Correlation of visual field, treatment fields, and dose in helium ion irradiation of uveal melanoma.

We correlated predicted radiation distributions in 29 patients with uveal melanoma (treated with 5,000 to 8,000 rads of helium ion therapy) with fundus photography and visual field deficits. The tumor was entirely within the treatment region in all patients. The fraction of the predicted high-dose and low-dose regions corresponding with an absolute scotoma was fitted by a linear regression model (r2 = .721) with three independent variables: dose region, initial condition, and time since therapy. The defect in the maximum-dose region increased at an average rate of 0.270/year. This differed (P = .002) from the rate in the penumbra region: (0.104/year). The rate in the penumbra differed (P = .01) from that in the predicted low-dose region, where scotoma did not increase with time. The pattern and time course of visual field loss in the different radiation dose regions tended to support the conclusion that isodose calculations are accurate. The data were consistent with the hypothesis that visual loss secondary to irradiation results primarily from radiation vasculopathy and not from direct damage to photoreceptors or ganglion cells. Development of an absolute scotoma may require a dose in excess of 5,000 rads.

Helium↗
PubMed1985

Return of vision following orbital decompression after 36 hours of postoperative blindness.

A 43-year-old woman undergoing repair of an orbital floor fracture had no light perception postoperatively. Computed tomography showed a normal optic nerve and there was no optic canal fracture, intraorbital hematoma, or intraconal expansion. After a two-wall orbital decompression, visual acuity recovered to 20/70 although only an inferior nasal island of vision remained. Ductions were full and there was no blepharoptosis but a 2+ afferent pupillary defect persisted.

Adult↗
PubMed1985

Radiation therapy for thyroid eye diseases.

Sixty-two patients (28 men and 34 women, 26 to 84 years old) with thyroid ophthalmopathy were treated with approximately 20 Gy of fractionated photon irradiation. Eight of 14 patients with motility problems improved after treatment. Ten of 14 with thyroid optic neuropathy improved or stabilized, but four had recurrences within five months after completion of irradiation. Generally, patients who had disease durations of less than six months responded better than those with more long-term ocular changes.

Adult↗
PubMed1985

Precision, high dose radiotherapy: helium ion treatment of uveal melanoma.

We report on 75 patients with uveal melanoma who were treated by placing the Bragg peak of a helium ion beam over the tumor volume. The technique localizes the high dose region very tightly around the tumor volume. This allows critical structures, such as the optic disc and the macula, to be excluded from the high dose region as long as they are 3 to 4 mm away from the edge of the tumor. Careful attention to tumor localization, treatment planning, patient immobilization and treatment verification is required. With a mean follow-up of 22 months (3 to 60 months) we have had only five patients with a local recurrence, all of whom were salvaged with another treatment. Pretreatment visual acuity has generally been preserved as long as the tumor edge is at least 4 mm away from the macula and optic disc. The only serious complication to date has been an 18% incidence of neovascular glaucoma in the patients treated at our highest dose level. Clinical results and details of the technique are presented to illustrate potential clinical precision in administering high dose radiotherapy with charged particles such as helium ions or protons.

Adult↗
PubMed1985

Magnetic resonance scanning in orbital tumor diagnosis.

We have compared the accuracy of magnetic resonance scanning (MRI) versus computed tomography (CT) in the differentiation of lateral orbital masses. The MRI results did not improve our ability to accurately diagnose malignant epithelial and lymphoid tumors.

Adolescent↗