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Biomedical subjects

D H Char

Publications and source records attributed to D H Char.

At least 145 records · Page 8Linked to original sources
PubMed1985

Monoclonal antibodies: current status in eye research.

Hybridoma technology has made a major impact on basic immunology and has many research and clinical applications in ophthalmology. Monoclonal antibodies can be used to characterize ocular receptors, proteins, and cell surface antigens. Clinically, these antibodies can be used in vitro and in vivo diagnosis and therapy. T-cell hybridoma products may have important research and clinical ramifications. They can be used along with monoclonal antibodies to increase our understanding of immunological circuit abnormalities in ocular autoimmune, immunodeficiency, and malignant diseases. As the specific abnormalities in these diseases are delineated, the hybridoma-produced lymphokines may be used therapeutically to correct them.

Animals↗
PubMed1985

Pre-enucleation irradiation of uveal melanoma.

The relative efficacy of various types of treatment in preventing metastatic uveal melanoma is unclear. We have performed a phase I-II non-randomised trial to determine if patients with large (greater than 15 mm in diameter or greater than 5 mm in thickness) uveal melanomas would benefit from pre-enucleation irradiation. Twenty-eight patients were treated between 1978 and 1983 by means of 5 X 5 cm anterior wedge pair ports on a 4 me V linear accelerator. Each patient received five 4 gray (400 rad) fractions over a five-day period for a total of 20 Gy. Enucleation was performed by a single surgeon within five days after treatment. The mean follow-up of the patients was 24 months (range 7-54 months). All melanomas were histologically confirmed. Four patients (14%) have developed metastatic tumour with a mean interval between diagnosis and death of 25 months. No significant perioperative or long-term morbidity was observed.

Clinical Trials as Topic↗
PubMed1985

Adenoid cystic carcinoma presenting as an orbital apex syndrome.

Adenoid cystic carcinomas (cylindromas) are distinctive neoplasms characterized by slow growth, perineural spread, extensive local invasion, frequent recurrence, and high mortality. A case of paranasal sinus adenoid cystic carcinoma presenting as an orbital apex syndrome is described.

Adult↗
PubMed1984

Microtechniques for flow cytometric analysis of aqueous humor lymphocytes.

Flow cytometric analysis of monoclonal antibody labelled lymphocytes is an important tool in understanding the immune response. Microtechniques were developed to analyze lymphocytes in small amounts of ocular fluids. Optimal labelling volumes and concentrations for Leu 2a, Leu 3a, Leu 4 and Leu M3 antibodies were determined. The ability to label and reproducibly analyze cell samples with as few as 1000 cells is demonstrated.

Antibodies, Monoclonal↗
PubMed1984

Helium ion charged-particle therapy for choroidal melanoma. Histopathologic findings in a successfully treated case.

A 47-year-old man with a large (20 X 20 X 12-mm) choroidal melanoma in his only eye was treated with helium ion radiation. The patient retained 6/7.5 visual acuity for 2 1/2 years before he was killed in an automobile accident. The eye was ruptured at the time of death; however, histopathologic examination of the eye revealed no residual tumor. The residual ocular mass was composed of eosinophilic amorphous material and macrophages. Necropsy failed to reveal any evidence of metastasis at the time of death. Helium ion charged-particle irradiation in this case was able to completely eradicate the tumor while preserving useful vision.

Choroid↗
PubMed1984

Fine needle biopsy in retinoblastoma.

We studied three cases of retinoblastoma in which fine needle biopsy established the correct diagnosis inside the eye or at extraocular sites.

Adolescent↗
PubMed1984

Retinoblastoma. CT diagnosis.

Computed tomography (CT) scan is a valuable adjunct in the differential diagnosis and management of retinoblastoma. Thirty-one of 33 retinoblastoma patients studied with high resolution computed tomography had intraocular calcification demonstrable in at least one eye. Over 80% of tumors showed evidence of calcification on CT scan. The degree of calcification appeared to depend upon tumor size; only small tumors were devoid of calcification. The amount and distribution of calcification was similar on both histological and CT review. In patients under three years of age in whom a retinoblastoma is suspected, the presence of calcification on CT scan is virtually diagnostic of retinoblastoma; patients with leukocoria without calcification on CT probably have a simulating lesion.

Calcinosis↗
PubMed1984

Orbital tumors in children. Characterization by computed tomography.

CT characteristics of orbital masses in 39 children were reviewed. Histological types and their relative frequencies differed considerably from reported adult cases. Analysis of seven separate CT characteristics for each type of mass indicated certain trends which may aid in the differential diagnosis.

Adolescent↗
PubMed1984

Retinoblastoma: tissue culture lines and monoclonal antibody studies.

Retinoblastoma patients have cellular and humoral reactivity towards antigens expressed on retinoblastoma cells. We report the ultrastructural, cytogenetic, and immunologic features of four new retinoblastoma derived tissue culture cell lines. Studies with hybridoma produced monoclonal antibodies demonstrate that these lines share antigens with a previously described long-term allogeneic retinoblastoma derived tissue culture cell line, as well as with antigens on fresh retinoblastoma.

Antibodies, Monoclonal↗
PubMed1984

Histiocytic disorders of the orbit.

Four cases of different types of orbital, benign and malignant histiocytosis syndromes are presented to demonstrate the diagnostic presentation, medical evaluation, and therapy of these diseases with orbital involvement. Newer concepts have altered our understanding of the pathophysiology of histiocytic syndromes. An abnormality of Langerhans' cells and the T-cell suppressor population appears to be important in the development of histiocytosis. It is important for the ophthalmologist to be aware that histiocytic lesions of the orbit may be an indication of widespread and at times life-threatening disease.

Adolescent↗
PubMed1984

Uveitis. A review.

Uveitis is the term used to describe most intraocular inflammations. The classification of uveitis into anterior, posterior and diffuse is based on the physical appearance of an inflamed eye. Diagnosis is usually on the basis of a thorough history, a review of systems to uncover any systemic diseases known to be associated with uveitis and a complete eye examination. We review the most common types of uveitis, the pertinent laboratory investigations and different therapeutic aspects.

Arthritis, Juvenile↗
PubMed1984

Toxicity of a monoclonal F(ab')2:ricin A conjugate for retinoblastoma in vitro.

The toxic A chain of the poison ricin has been conjugated to the F(ab')2 fragment of a retinoblastoma-specific murine monoclonal antibody. The conjugate was toxic in vitro to Y-79 retinoblastoma cells at a concentration of approximately 5 X 10(-10) M; Y-79 retinoblastoma cells were the immunizing cells in the production of the monoclonal antibody. Against a second retinoblastoma cell line, the conjugate was toxic at a concentration of approximately 10(-9) M. Ricin A chain alone was not toxic to either of these cell lines at concentrations less than 4 X 10(-8) M. The conjugate was no more toxic than was ricin A chain against five control cell lines in vitro. The effect of the conjugate on retinoblastoma-derived cells was concentration dependent. Concentrations less than a "minimum" concentration were not cytotoxic, despite an excess of conjugate molecules over target cells. Concentrations greater than the minimum toxic concentration rapidly reached maximal toxicity, suggesting that antigenic sites were saturated. No clinical, hematologic, or renal toxicity was noted when mice were given injections of the conjugate at 1 mg/kg, or free ricin A chain at 0.375 mg/kg.

Antibodies, Monoclonal↗
PubMed1983

Failure of choroidal melanoma to respond to helium ion therapy.

Helium ion irradiation is a promising alternative therapy for choroidal melanoma. In short-term follow-up (less than 5 years), more than 90% (18/19) of treated patients demonstrated tumor regression. We had to enucleate five eyes after helium ion therapy either because of continued tumor growth (four patients) or other complications (one patient). Two melanomas continued to grow and seemed to be radioresistant. In two other tumors it retrospectively seemed that the entire lesion was not inside the radiation field. In one patient total retinal detachment and glaucoma developed; enucleation was performed because of a painful eye. Metastatic disease developed in no patients. The treatment failures emphasize that there are a number of unresolved issues regarding the use of charged-particle irradiation in the treatment of melanoma. Further studies must be performed to answer these questions and better delineate the use of these newer forms of therapy.

Aged↗
PubMed1983

Helium ion therapy for choroidal melanoma.

Eighty-two patients with choroidal melanomas were treated with helium ion charged particle irradiation. Seventy-eight of 82 patients have either remained stable or demonstrated tumor shrinkage. Forty-five of 46 patients followed for at least 1 year after therapy have demonstrated tumor regression with a mean tumor shrinkage of approximately 31%. No tumor-related mortality has been observed. 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↗
PubMed1983

Antiretinoblastoma monoclonal antibodies.

Mouse-mouse somatic hybridization techniques were used to produce monoclonal antibodies directed towards antigen expressed on retinoblastoma-derived tissue culture cell lines. Four monoclonal antibodies were produced with varying avidity which were reactive against allogeneic retinoblastoma-associated antigens. Sensitivity and specificity was demonstrated using ELISA and chromium release assays. Immunofluorescent antibody studies suggest that these monoclonal antibodies may be useful diagnostically.

Animals↗