Biomedical subjects

Dean P Hainsworth

Publications and source records attributed to Dean P Hainsworth.

8 recordsLinked to original sources

PubMed2006

Intravitreal triamcinolone acetonide concentration after subtenon injection.

PURPOSE: To determine concentration of intravitreal triamcinolone after subtenon injection. DESIGN: Prospective series of vitrectomy candidates and laboratory investigation. METHODS: Twenty eyes of 20 patients received subtenon injections of triamcinolone acetonide, 40 mg, before vitrectomy surgery. Exclusion criteria included previous history of vitrectomy, triamcinolone injection, and retinal detachment. Posterior subtenon injections were performed using the standard technique. Undiluted vitreous specimens were obtained at the time of vitrectomy, which was performed from one to 29 days after subtenon injection. Intravitreal triamcinolone concentration was determined by high-performance liquid chromatography. RESULTS: No complications were associated with subtenon injections. Intravitreal triamcinolone concentrations varied considerably, from zero in five eyes to a high of 4.94 microg/ml. CONCLUSIONS: Intravitreal triamcinolone concentrations vary considerably after subtenon injection. The findings indicate that subtenon injection can be a method for administering intravitreal triamcinolone acetonide that is comparable, in some cases, to the levels achieved after intravitreal injection.

Chromatography, High Pressure Liquid↗

PubMed2006

Bruch's membrane abnormalities in dome-shaped and mushroom-shaped choroidal melanomas.

INTRODUCTION: Mushroom-shaped choroidal melanoma is known to be associated with breaks in Bruch's membrane and is more likely to develop when Bruch's membrane is diseased. The study's goal is to determine if diseases causing breaks in Bruch's membrane predispose a choroidal melanoma to develop into a mushroom-shaped melanoma. MATERIALS AND METHODS: A retrospective review of cases of choroidal melanoma seen at our institution was carried out to determine if mushroom-shaped melanomas are more common than dome-shaped tumours in patients with macular abnormalities involving a loss of Bruch's membrane integrity. Forty-nine eyes of 48 patients were included in this retrospective study. A dome-shaped or mushroom-shaped configuration was assigned to each tumour. Macular degeneration, macular drusen, retinal pigment epithelial (RPE) stippling, macular oedema, choroidal neovascularisation (CNV), angioid streaks, disciform scars, lacquer cracks, and myopia greater than -3.00 D, were considered to constitute evidence of potential Bruch's membrane breaks and were determined in both eyes. A chi-square evaluation was used to compare the proportion of eyes with macular abnormalities in the 2 tumour configuration groups. RESULTS: The tumour was dome-shaped in 40 eyes (82%) and mushroom-shaped in 9 eyes (18%). Macular abnormalities, indicative of loss of Bruch's membrane integrity, were seen in 21 (53%) of 40 eyes with dome-shaped melanomas and 5 (56%) of 9 eyes with mushroom-shaped melanomas. The proportion of eyes with macular abnormalities was not statistically different between the dome-shaped and mushroom-shaped tumours, as assessed by chi-square analysis (P = 0.87). CONCLUSIONS: Bruch's membrane disease does not influence the differentiation of choroidal melanoma into mushroom-shaped or dome-shaped tumour growth patterns.

Adult↗

PubMed2005

Electroretinographic effects of an intravitreal injection of triamcinolone in rabbit retina.

OBJECTIVE: To investigate the clinical, histologic, and electroretinographic effects of intravitreal injection of triamcinolone acetonide suspension in the rabbit retina. METHODS: Three groups of 6 rabbits each received intravitreal injections. Group 1 received 4 mg of triamcinolone acetonide, group 2 received an equal volume (0.1 mL) of the corticosteroid supernatant, and group 3 received 4 mg of triamcinolone acetonide with the supernatant replaced with balanced salt solution. Uninjected left eyes served as controls. Electroretinograms were obtained at baseline and at 3 to 4 and 6 to 7 days after injection of triamcinolone. Enucleated eyes were examined histologically. RESULTS: Ocular examination revealed no differences among the 3 groups. When subjected to stimulation with moderate to high flash intensities, eyes that had received intravitreal injections of triamcinolone (groups 1 and 3) had a 10% to 25% increase in dark-adapted a- and b-wave electroretinographic amplitudes. No histologic differences were observed between injected and control eyes. CONCLUSIONS: Intravitreal injection of 4 mg of triamcinolone acetonide does not cause a toxic reaction in the rabbit retina after 7 days. Triamcinolone therapy may augment the rod-driven electroretinographic responses, suggesting a mechanism by which visual function may improve. Clinical Relevance Evaluation of the toxic effects of triamcinolone is useful because of increased applications of intravitreal injection.

Animals↗

PubMed2003

Visual function in patients with optic nerve pallor (optic atrophy).

This cross-sectional study assessed the relationship between the degree of optic nerve pallor (optic atrophy) and visual function. Using a set of "gold standard" stereoscopic slides, the severity of optic atrophy for 270 eyes, each having sustained a bout of optic neuropathy, was graded. Good visual acuity was found in 55/86 (64.0%) mild, 54/119 (45.4%) moderate, and 21/65 (32.3%) marked optic atrophy eyes. Good visual field was found in 6/28 (21.4%) mild, 4/43 (9.3%) moderate, and 2/28 (7.1%) marked optic atrophy eyes. Good color vision was found in 31/46 (67.4%) mild, 12/62 (19.4%) moderate, and 7/31 (22.6%) marked optic atrophy eyes. A significant rank correlation was observed between optic atrophy and visual acuity (P < 0.001; rs = 0.356), visual field (P < 0.001; rs = -0.398), and color vision (P < 0.001; rs = -0.492). As the graded severity of optic atrophy increases, the proportion of eyes with good visual function decreases. Visual field, rather than visual acuity or color vision, appears to be a better indicator of the severity of visual loss, when optic atrophy is present.

Cross-Sectional Studies↗

PubMed2002

Longitudinal analysis of central serous chorioretinopathy and sex.

BACKGROUND: Stress has been proposed as one of the contributing factors of central serous chorioretinopathy (CSC). Because the number of women in the workforce has increased dramatically in past decades, their presumed additional stress may increase their risk for CSC. We performed a study to determine whether the ratio of men to women in whom CSC was diagnosed remained constant between 1970 and 2000 in our patient population. METHODS: We reviewed the medical records of 88 patients (69 males and 19 females) in whom CSC was diagnosed between 1970 and 2000. Only patients who were noted to have subretinal fluid on stereoscopic colour fundus photographs and focal retinal pigment epithelial hyperfluorescence on fluorescein angiography were included. Logistic regression analysis was performed to determine the probability of a patient's being male over the study period. RESULTS: No significant change was found in the proportion of male patients in whom CSC was diagnosed over the study period (p = 0.69). INTERPRETATION: The ratio of males to females with a diagnosis of CSC did not change significantly over 30 years in our study population. If stress is a contributing factor of CSC and if women are experiencing increased stress from changing societal roles, women may have different adaptations to stress than men, or other mechanisms of CSC formation may be present.

Adolescent↗

PubMed2002

Interpretation of flow cytometric measurement of lymphocytes after fluorescein angiography.

PURPOSE: By use of flow cytometry (FCM), lymphocyte subsets were evaluated with fluorochrome-labeled monoclonal antibodies (MoAbs). Recent fluorescein angiography (FA) produces temporary elevation of serum background fluorescence at certain wavelengths of light, producing falsely decreased lymphocyte subset quantitations. The authors evaluated the duration of this effect on one subset of lymphocytes after FA. METHODS: CD4 counts were determined by FCM before and 10 minutes, 1, 6, and 24 hours after injection of fluorescein dye in 12 patients. The MoAbs used were directly conjugated to fluorescein isothiocyanate (FITC) or phycoerythrin (PE). RESULTS: Using FITC-labeled MoAbs, falsely decreased CD4 counts occurred in all patients at 10 minutes and in all but one patient 1 hour after injection. Return to baseline levels occurred in 50% (95% confidence interval [CI], 0.21, 0.79) by 6 hours and in 75% (95% CI, 0.43, 0.95] by 24 hours. No such effect was observed using PE-labeled MoAbs. CONCLUSIONS: Falsely decreased CD4 values as determined by FCM were present immediately after FA in all 12 patients and persisted 24 hours in some patients when FITC-labeled MoAbs were used. CD4 evaluation should be delayed in patients who have undergone recent FA or the analysis should be performed with PE-labeled MoAbs.

Adult↗

PubMed2002

Retinal capillary basement membrane thickening in a porcine model of diabetes mellitus.

PURPOSE: Current animal models of diabetic microangiopathy, including diabetic retinopathy (DR), have substantial limitations. To determine whether the diabetic pig would provide an improved large animal model of DR, a 20-week porcine model of diabetic dyslipidemia that manifests appreciable macrovasculopathy was evaluated for development of retinal microvascular changes associated with diabetes mellitus (hereafter referred to as diabetes) in humans. METHODS: The effect of diabetes alone or in combination with high dietary fat intake on retinal capillary morphology was assessed. Cell density in the retinal capillaries was evaluated by use of elastase digestion isolation of the retinal vascular bed, and retinal capillary basement membrane thickness was determined by use of electron microscopic analyses. RESULTS: Diabetic pigs fed a normal diet had significantly (P < 0.001) thicker retinal capillary basement membranes than did nondiabetic animals. High fat intake did not contribute to basement membrane thickening. Significant effects of diabetes or diet on retinal capillary cell densities were not observed, nor did diabetes induce formation of microaneurysms typical of advanced diabetic retinopathy. CONCLUSIONS: The rapid development of retinal capillary basement membrane thickening in diabetic pigs makes this animal model useful for early intervention and mechanistic studies for this diabetes-associated microvascular change.

Animals↗

PubMedDate not supplied

The challenge of preventing vision loss from diabetic retinopathy.

Diabetes is present in 7% of Missourians. Another 52% are at risk. Periodic eye examinations are key to averting vision loss from diabetic retinopathy. Signs of diabetic retinopathy are evident long before vision loss and include microaneurysms, retinal hemorrhage, microvascular and venous caliber abnormalities and neovascularization. Loss of vascular integrity can lead to retinal edema and neovascular growth. Laser ablation of the peripheral retina can curb neovascular growth. It can also help stabilize macular edema.

Blindness↗