Search PubMed⌕ Search

Biomedical subjects

T R Smith

Publications and source records attributed to T R Smith.

At least 73 records · Page 4Linked to original sources
PubMed1980

Intransitivity, the spatial interaction model, and U.S. migration streams.

"The flows predicted by a large class of spatial interaction models are transitive, yet US migration tables have been shown to contain large numbers of intransitivities. This paper investigates a number of possible conditions under which flows regulated by the spatial interaction model might be observed to be intransitive. A singly constrained gravity model is calibrated for a number of flow tables, and distorted by sampling error, by aggregation over strata, and by an independently distributed error term.... The results of the calibration of the spatial interaction using US interstate migration flows, 1935-1970, are given and compared with others previously published."

Americas↗
PubMed1979

Intraocular reticulum cell sarcoma: a case report and literature review.

A 66-year-old white woman with a confusing spectrum of central nervous system signs and symptoms had a diagnostic enucleation of her blind left eye showing retinal infiltration. Histopathologic examination showed reticulum cell sarcoma involving the retina. The patient died one month later and autopsy revealed diffuse central nervous system reticulum cell sarcoma along with right eye and systemic involvement. A review of the literature indicates intraocular reticulum cell sarcoma to be an apparently uncommon occurrence, although ocular examination may be frequently overlooked.

Aged↗
PubMed1979

Late diagnosis of choroidal malignant melanomas in eyes with clear media and low visual acuity.

Five patients seen in a one-year period with advanced malignant melanoma of the choroid in eyes with low visual acuity and clear media are reported. The low visual acuity appeared clinically to be antecedent to the malignant tumor; although in certain cases it may have been related to the occult melanoma, this was not appreciated clinically. Because of the low visual acuity, these patients did not have vision symptoms referable to the melanoma, and the malignancy was diagnosed late in its course. All five cases had extrascleral extension of the tumor at the time of surgical treatment; three are dead of metastatic disease, and two have undergone orbital exenteration with only brief follow-up periods. This experience suggests that eyes with clear media and low vision owing to presumably unrelated causes should undergo periodic examination to rule out the presence of a growing malignant melanoma and to prevent its late diagnosis.

Abdominal Neoplasms↗
PubMed1979

Vascular basophilia in ocular and orbital tumors.

The occurrence of vascular basophilia in ocular tumors has been a selective histologic feature of retinoblastomas. We recently observed a metastatic oat-cell carcinoma to the choroid which also demonstrated such a vascular hematoxyphilia. Histologic review of a variety of ocular and orbital metastatic carcinomas failed to yield a similar basophilic pattern. Examination of 100 consecutive retinoblastomas for vascular basophilia revealed an incidence of 6.0%. Similar material was not seen in any of 125 melanomas, including 10 with areas of necrosis. Histochemical studies showed the basophilic material to be DNA, and electron microscopy revealed the nuclear debris of pyknotic tumor cells to be continuous with identical material surrounding the adjacent blood vessels. The pathogenesis of vascular deposition of DNA in these two ocular tumors remains unclear. This finding most likely represents a form of tumor activity requiring comparatively healthy blood vessels to adequately precipitate liberated nucleic acids being filtered from the necrotic and degenerating tumor tissue.

Basophils↗
PubMed1979

Ocular and orbital metastatic carcinoma.

One hundred cases of metastatic carcinoma to the eye and orbit were reviewed. Fifty-nine patients were female and 35 were male. The average age of the females was 60 years and the males 52 years. Breast carcinoma was the most common primary in the females and lung carcinoma in the males. The left eye and orbit were involved more frequently than the right (30 to 27). The choroid and the orbit were the most common site of metastasis.

Adenocarcinoma↗
PubMed1979

Angioma-like lesion in hemoglobin sickle cell disease.

A lesion resembling a retinal angioma is reported in a 52-year-old man with hemoglobin S-C disease. Following surgery to destroy the tumor, the patient died. Postmortem examination confirmed sickle cell disease and the ocular findings revealed an angioma on the anterior side of the retina. It is believed this is the first report of sickle cell disease showing a large retinal angioma.

Anemia, Sickle Cell↗
PubMed1978

Glaucoma-inducing mechanisms in eyes with retinoblastoma.

A total of 149 eyes with retinoblastomas were examined histopathologically to determine the types and frequencies of mechanisms inducing glaucoma. The most common mechanism was iris neovascularization with secondary peripheral anterior synechiae formation. In such cases, the tumor was almost always located at the posterior pole with involvement of central retinal vessels and with growth of a highly vascularized tumor mass into the vitreous. The second most common mechanism was massive exudative retinal detachment causing pupillary block and angle closure. In such cases, tumor growth was present within and under the retina. The third most common mechanism was a combination of the aforementioned mechanisms. Uveitis and/or necrotic tumor tissue in the anterior chamber as the sole mechanism inducing glaucoma was infrequently seen.

Cornea↗
PubMed1978

Choroidal melanocytic tumor observed for 41 years before enucleation.

A pigmented choroidal lesion was observed 41 years prior to enucleation. The patient, with a clinical diagnosis of malignant melanoma in an eye with good visual function, was followed up for the last 25 years by one of the authors. Sudden growth of the lesion and loss of vision led to enucleation and allowed histologic confirmation of the diagnosis of malignant melanoma. A pigmented iris lesion in the same eye was also present for 25 years and showed no notable growth under observation. The patient died of metastatic disease approximately one year after enucleation.

Aged↗
PubMed1978

False-positive 32P uptake tests.

Three patients had suspected choroidal melanoma and positive results for radioactive phosphorus (32P) uptake tests, leading to enuclearion in two of the patients. No malignancy was present on histopathologic examination. This experience reemphasizes the need for the ophthalmologist to evaluate the total clinical picture and not to give inappropriate consideration to a "positive" 32P uptake test in deciding for or against enucleation in a suspected choroidal melanoma. The positive 32P uptake test, even with high values, cannot be equated with malignancy, and a variety of nonmalignant lesions may give false-positive results.

Adult↗
PubMed1978

Melanocytic tumor of the anterior uvea.

A patient with spindle melanoma involving the iris and ciliary body refused enucleation at the time of diagnosis in 1933. The eye developed painful glaucoma 13 years later and was enucleated. Histopathologic examination indicated spread of the tumor intrasclerally and subconjunctivally. The patient is still alive without evidence of metastases, 32 years after enucleation and 45 years after initial diagnosis.

Adult↗
PubMed1978

The corneal endothelium and the spectrum of essential iris atrophy.

We found that the spectrum of essential iris atrophy (progressive essential iris atrophy, Chandler's syndrome, and the Cogan-Reese syndrome) began as a corneal endothelial degeneration, which, with ectopic endothelial membrane overgrowth over an open angle, followed by contraction of this membrane and further growth onto the iris, accounted for all aspects of the syndrome. The contractile membrane caused the synechiae, the glaucoma, the corectopia, the ectropion uveae, the occasional iris nodules, and the iris atrophy. Thus we found this disease to be primarily of the cornea, and only secondarily of the iris. The results of this study led us to propose a new designation for this spectrum: primary proliferative endothelial degeneration.

Adult↗
PubMed1978

Clinical manifestations of brawny scleritis.

We studied four patients with posterior brawny scleritis. Two underwent enucleation for suspected melanoma, and in the other two, the correct diagnosis was made and effective therapy begun. Of seven other eyes with brawny scleritis from other sources, five were enucleated after diagnosis of choroidal melanoma and one for suspected intraocular tumor. This experience and other previous reports indicate the high incidence of diagnostic confusion regarding brawny scleritis. We therefore emphasized clinical symptoms and signs of brawny scleritis: inflammation, tenderness or pain of the globe, history of collagen vascular disease, proptosis, bilaterality, and retinal and choroidal detachment. A preserved normal choroidal vascular pattern over an elevated subretinal mass may be indicative of posterior brawny scleritis. Scleral biopsy is useful for tissue diagnosis. Radioactive phosphorus uptake tests and ultrasonography may erroneously indicate choroidal melanoma and lead to enucleation of a potentially salvageable globe.

Adult↗
PubMed1978

Renal pseudotumor on urography secondary to gallbladder empyema.

A case of gallbladder empyema is presented, which opacified initially on excretory urography and then on nephrotomography, mimicking a renal mass. Correct diagnosis was accomplished by angiography and ultrasound examination. With normal renal function gallbladder visualization on urography is indicative of a gallbladder abnormality.

Aged↗