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Biomedical subjects

K Egan

Publications and source records attributed to K Egan.

14 recordsLinked to original sources
PubMed1995

Ocular blood flow velocity in age-related macular degeneration.

BACKGROUND: Changes in the structure of the ocular blood vessels associated with age-related macular degeneration (AMD) have been described in some detail, but comparatively little is known of the concomitant circulatory changes. The goal of this study is to evaluate changes in the ocular circulation that may be associated with AMD. METHODS: Ocular blood flow velocities and vessel pulsatilities were measured in volunteers with and without AMD using a color Doppler imaging unit. Spectral analyses were recorded from the ophthalmic artery, central retinal artery and vein, the temporal and nasal short posterior ciliary arteries, and the four vortex veins. RESULTS: Adjusting for age, pulsatility indices of all arteries were higher in subjects with AMD (central retinal artery [P = 0.02]; temporal and nasal short posterior ciliary arteries [P = 0.06 and 0.002, respectively]; and ophthalmic artery [P = 0.24]). End-diastolic blood flow velocity of the short posterior ciliary arteries tended to decrease in the presence of AMD. CONCLUSIONS: The combination of increased pulsatility and decreased velocity of the short posterior ciliary arteries, observed in the presence of AMD, are interpreted as evidence of increased vascular resistance. The clinical signs of AMD may be related to degradation of the metabolic transport function of the retinal pigment epithelium, resulting from impaired choroidal perfusion.

Aged↗
PubMed1995

Vitamin D inhibits angiogenesis in transgenic murine retinoblastoma.

PURPOSE: Vitamin D compounds have been shown to inhibit tumor growth in a transgenic retinoblastoma murine model. The mechanism of action has not been defined clearly, although an antiangiogenic action has been proposed. METHODS: Transgenic retinoblastoma mice received high (0.05 microgram) and low (0.025 microgram) doses of vitamin D3 by intraperitoneal injection 5 times per week for 5 weeks. Control animals were injected with mineral oil vehicle alone. At 5 months of age, the animals were killed and eyes were enucleated and processed for light microscopy. Paraffin-embedded sections were stained with an immunoperoxidase stain (GS-1) specific for mammalian vascular endothelium. Sections were graded by a single masked reviewer, and intraobserver reliability was assessed. Mean vessel counts were made for each group. RESULTS: The high-dose group had the lowest mean vessel count (8.5), followed by the low-dose group (10.1). The control group had the highest mean vessel count (14.1). Vitamin D-treated animals (high- and low-dose groups combined) had significantly fewer vessels P = 0.001) than untreated controls. CONCLUSIONS: These results support the hypothesis that inhibition of angiogenesis is a mechanism of action for vitamin D in the transgenic retinoblastoma mouse model.

Animals↗
PubMed1991

Standardized data collection and coding in eye disease epidemiology: the Uveal Melanoma Data System.

The Uveal Melanoma Data System of the Massachusetts Eye and Ear Infirmary is a computerized data-base designed for data management and analysis with a broad range of clinical research applications. The system was created in 1980 and has evolved to include standardized data collection forms for all aspects of uveal melanoma patient care such as initial examination, treatment, and follow-up, as well as precoded forms for computer entry, which facilitate quality control measures and data analysis. Excerpts from current versions of these forms are presented. The Uveal Melanoma Data System has been used for a variety of clinical epidemiologic investigations. Examples of its application, including descriptive studies, prognostic factor studies, and treatment evaluations, are discussed. The model has potential broad application for clinical ophthalmic research in other specialty areas.

Data Collection↗
PubMed1987

Long-term results of proton beam irradiated uveal melanomas.

The first 128 consecutive patients with uveal melanomas treated with proton beam irradiation were studied in order to evaluate survival and visual acuity status of patients with relatively long-term follow-up. The median follow-up was 5.4 years, and no patient was lost to follow-up. All tumors showed regression. The most recent visual acuity was 20/40 or better in 35% and 20/100 or better in 58%. Eight eyes were enucleated because of complications. Metastasis developed in 26 patients (20.5%) from 3 months to 7 years after treatment. Results indicate that proton irradiation is quite successful for achieving local control of uveal melanomas. A large proportion of the treated eyes maintained useful vision. Five-year follow-up data indicate that proton irradiation has no deleterious effect on the likelihood of the development of metastasis.

Eye Diseases↗
PubMed1985

Chronic pain: lifetime psychiatric diagnoses and family history.

Thirty-seven patients with chronic pain admitted to a 3-week inpatient pain program were interviewed using the NIMH Diagnostic Interview Schedule and the family history method. The most frequent psychiatric diagnoses were major depressive disorder (current episode = 32.4%, past episode = 43.2%) and alcohol abuse (40.5%). More than half of the patients had a history of one or more episodes of major depression and/or alcohol abuse before the onset of their chronic pain. Family history revealed that 59.5% of the patients had at least one first-degree family member with chronic pain, 29.7% had a family member with affective illness, and 37.8% had a family member with alcohol abuse.

Adult↗