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Biomedical subjects

G Sanborn

Publications and source records attributed to G Sanborn.

13 recordsLinked to original sources
PubMed1992

Prevention of metastasis of intraocular melanoma in mice treated with difluoromethylornithine.

The antimetastatic potential of a novel chemotherapeutic agent, alpha-difluoromethylornithine (DFMO), was evaluated in a murine model of intraocular melanoma. In vivo studies demonstrated that DFMO retarded the growth and spontaneous metastasis of murine intraocular melanomas. Further studies indicated that oral DFMO also exercised antimetastatic effects against the blood-borne stage of melanoma metastases. In vitro studies revealed that DFMO exerted impressive antiproliferative effects on three murine melanoma cell lines, four human cutaneous melanoma cell lines, one human uveal melanoma cell line, and one conjunctival melanoma cell line. DFMO inhibited in vitro DNA synthesis in human cutaneous melanoma cell lines by 84%-98% and that in two human ocular melanoma cell cultures by 62% and 86%, respectively. DFMO possesses several characteristics that render it an attractive chemotherapeutic agent for potential use in the management of uveal melanoma. These include its antiproliferative effect against a wide range of murine and human melanomas, its extremely low toxicity, and its ease of administration.

Administration, Oral↗
PubMed1989

Isolated symptomatic peripheral neuropathy in type 1 insulin-dependent diabetes mellitus.

Diabetic neuropathy is probably the most frequent of the chronic complications of diabetes, and is usually found in association with diabetic retinopathy and/or nephropathy. We report seven patients with long-standing insulin-dependent diabetes mellitus in whom symptomatic peripheral neuropathy was the first and only documented complication. The diagnosis of peripheral symmetrical neuropathy was based on the presence of symptoms and abnormal physical findings, confirmed with abnormal electrophysiological and/or vibratory and thermal threshold measurements. Diabetic retinopathy and nephropathy were absent. We conclude that in some type 1 insulin-dependent diabetic patients, similar to what has been reported in type 2 non-insulin-dependent diabetes, peripheral neuropathy may be the first chronic complication to become manifest. This observation provides additional evidence to suggest that each of the diabetic complications may have a different pathogenic mechanism.

Adult↗
PubMed1987

Intraocular and episcleral venous pressure increase during inverted posture.

We measured intraocular and episcleral venous pressure in 11 subjects in both the supine and the head-down vertical position. Gonioscopy was performed in eight subjects. The intraocular pressure changes were correlated with the alterations in episcleral venous pressure using linear regression analysis. We found that for each 0.83 +/- 0.21 mm Hg increase in episcleral venous pressure there was a rise of 1 mm Hg in intraocular pressure (r = .80, P = .003). Upon inversion, blood appeared in Schlemm's canal in half of the eyes studied with gonioscopy, suggesting that it refluxed into the canal from increased episcleral venous pressure. The mechanism of a sustained intraocular pressure rise during gravity inversion appears to be closely related to increased venous pressure in the orbit.

Adult↗
PubMed1985

Optic nerve dysfunction during gravity inversion. Pattern reversal visual evoked potentials.

The intraocular pressure (IOP) in humans approximately doubles when a head-down, or inverted, position is assumed. Simultaneously, the ophthalmic artery pressure increases by an even greater absolute magnitude. We recorded pattern reversal visual evoked potentials (PRVEPs) in 16 subjects in both the inverted and upright positions. In ten of the 16 subjects, we performed an additional experiment. On a different day, we obtained control PRVEPs, and then, using a scleral suction cup, we artificially increased the IOPs to the same values reached when the subjects were previously inverted. We found that the PRVEP amplitudes were significantly reduced in both experiments compared with corresponding control recordings, without changes in latency or wave form. Furthermore, the degree of amplitude reduction was even greater during gravity inversion than with suction cup elevation of IOP. The effects of IOP on optic nerve function as measured by the PRVEP appear to be dependent more on the IOP than on vascular perfusion. We also concluded that gravity inversion activities pose potential risks to the eyes.

Adult↗
PubMed1985

The effect of long-term near normal glycemic control on mild diabetic retinopathy.

Thirty-three type l diabetics who used continuous subcutaneous infusion of insulin (CSll) and 24 diabetics on conventional treatment (maximum of two injections per day) were studied prospectively with ophthalmologic examinations, fundus photography, fluorescein angiography, and glycosylated hemoglobin (HbA1) determinations. Both groups were similar with respect to age, duration of diabetes, and length of follow-up. At entry almost all patients had only mild forms of diabetic retinopathy although three CSll patients had early proliferative retinopathy. The CSll groups achieved superior glycemic control throughout the study (mean HbA1 = 7.4% vs. 10.2%). After an average follow-up of more than 30 months, the CSll group showed significantly less progression of diabetic retinopathy as measured by macular aneurysm counts and by modified ETDRS grading. Careful control of glycemia may delay the progression of diabetic retinopathy.

Adolescent↗
PubMed1982

Amodiaquine ocular changes.

A 34-year-old man ingested more then 250 g of amodiaquine hydrochloride (for pain) during one year and was noted to have diffuse conjunctival, corneal, and skin changes and also abnormal results from retinal function tests. Ultrastructural examination of corneal and conjunctival biopsy specimens revealed intralysosomal membranous and amorphous inclusions in corneal epithelial cells, conjunctival epithelial cells, keratocytes, and vascular endothelial cells. Follow-up of more than two years and repeated conjunctival biopsy specimens revealed diminution in both the clinical and electron microscopic abnormalities, but persistence in abnormal results of retinal function tests. These changes are consistent with a drug-induced phospholipidosis.

Adult↗
PubMed1982

Radiation retinopathy.

The wide spectrum of radiation retinopathic manifestations from local or external beam irradiation is described in 36 eyes. The most commonly encountered ophthalmoscopic signs of retinopathy include retinal hard exudates, hemorrhages, microaneurysms, cotton-wool spots, and telangiectases. The fluorescein angiographic hallmark of radiation-induced retinopathy is retinal capillary nonperfusion, supporting the concept that vascular decompensation is the primary mechanism in the production of radiation damage to the posterior segment.

Adolescent↗
PubMed1982

Radiation optic neuropathy.

The ophthalmoscopic findings in a series of 14 eyes with radiation-induced optic neuropathy are described. Typically, the entity manifests acutely as disc swelling with surrounding exudate, hemorrhages, and subretinal fluid. Optic atrophy may ensue in the later stages. Similar to radiation retinopathy, radiation optic neuropathy also seems to occur secondary to vascular damage. In contrast to visual loss secondary to radiation retinopathy, the visual acuity in certain eyes with decreased vision attributable to radiation optic neuropathy may improve over a period of several months.

Adolescent↗
PubMed1982

Microcomputer applications in retinal research.

A low cost microcomputer was used to: (1) word process and edit this manuscript, (2) create a patient file storage and retrieval system, (3) transcribe and store information from video display such as wide-angle fundus photographs and fluorescein angiograms, (4) plot data points in graphic display mode, (5) solve complex equations used to calculate intraocular tumor volumes, (6) search medical literature data bases, and (7) directly interface with sophisticated laboratory equipment performing complicated tasks such as multicomponent analysis and enzyme kinetics.

Computers↗