Search PubMed⌕ Search

Biomedical subjects

B H Doft

Publications and source records attributed to B H Doft.

At least 37 records · Page 2Linked to original sources
PubMed1989

Intraocular distribution of intravitreally administered amphotericin B in normal and vitrectomized eyes.

A study was performed to determine how amphotericin B is distributed in the eye after direct intravitreal injection. Radiolabeled amphotericin B was administered by direct injection into the vitreous space of unmodified phakic control or vitrectomized aphakic eyes in the rabbit model. The eyes were removed at different post-injection times, frozen and dissected into anatomical subparts of cornea, aqueous, iris, lens, vitreous and sclera-choroid-retina. The parts were assayed for total radioactivity (expressed as remaining amphotericin B). No accumulation of drug was observed in the cornea, lens, iris or aqueous region. The majority of drug was found in the vitreous cavity. The rate of disappearance of radiolabeled drug or radiolabeled drug degradation products from the vitreous space was similar to the rate of disappearance from the eye. However, progressive accumulation of radioactivity was observed in the sclera-choroid-retina tissue in the unmodified phakic eyes. This was not observed in vitrectomized aphakic eyes. The accumulated radioactivity could have represented drug degradation products or active drug. These results shed light on the distribution of amphotericin B in the eye after direct intravitreal injection, a procedure often employed clinically for fungal endophthalmitis.

Amphotericin B↗
PubMed1988

An epidemiologic approach to the study of retinopathy: the Pittsburgh diabetic morbidity and retinopathy studies.

Diabetic retinopathy was studied in two cohorts of insulin-dependent diabetics (IDDs) from the Children's Hospital of Pittsburgh. The first cohort (n = 696) consisted of IDDs of long duration. Severe retinopathy was self-reported in 70% of this cohort by 30 years duration of diabetes. Associations between severe retinopathy, hypertension and smoking were observed. In order to examine the relationship between metabolic control and early diabetic retinopathy, a second cohort of adolescent IDDs (n = 58) were referred for standardized fluorescein angiography. Sixty-four percent had early retinopathy. None had proliferative changes. Significant differences in individual mean whole blood glycosylated hemoglobin (GHb), averaged over 3 years before angiography, were consistently seen between those with and without early retinopathy. Also, the number of microaneurysms was positively correlated with individual mean GHb. Before the advent of GHb testing, those IDDs who later had retinopathy were more likely to have experienced at least one hospitalization for diabetic ketoacidosis. These observations provide strong support that poor metabolic control preceded the development of diabetic retinopathy. Results are consistent with the hypothesis that improvement of metabolic control early in the course of IDDM may prevent or delay the development of the early changes of diabetic retinopathy.

Adolescent↗
PubMed1987

Pars plana vitrectomy for vitreous amyloidosis.

Thirty-six pars plana vitrectomies were performed on 30 eyes of 17 patients with biopsy-proven vitreous amyloidosis. Reopacification of the retrolental vitreous was the most common reason for vitrectomy revision, required in 24% of patients. Complications of amyloid or vitrectomy included retinal detachment requiring scleral buckling in 17% of eyes and glaucoma requiring filtering surgery in 17% of eyes. After a mean 35-month post-vitrectomy follow-up, 48% of eyes had visual acuities of 20/40 or better, and 32% of eyes had visual acuities between 20/50 and 20/100. Twenty percent of eyes had visual acuities of 20/200 or worse due either to persistent retinal detachment, open angle glaucoma, or residual opacification of the vitreous.

Amyloidosis↗
PubMed1987

A psychophysical technique for measuring cone photopigment bleaching.

A new, clinically applicable test has been developed to measure the bleaching of the foveal cone photopigments. This noninvasive test is called steady-state color matching. Steady-state color matching is based on the dependence of a color match on the optical density of the cone photopigments. By measuring the color match as a function of retinal illuminance, it is possible to compute the optical density of the cone photopigments at each illuminance. Thus, abnormalities of photopigment bleaching can be detected. This study demonstrates that the technique is readily performed by a clinical population. Patients with central serous retinopathy and retinitis pigmentosa are shown to have low effective optical densities.

Adolescent↗
PubMed1987

Cone photopigment bleaching abnormalities in diabetes.

We have used a color-matching technique to obtain estimates of the optical density of cone photopigments as a function of retinal illuminance in patients with insulin-dependent diabetes mellitus (IDDM). We found that the half-bleach illuminance of some patients is abnormally high. That is, it takes more light to bleach an equivalent amount of photopigment in these patients. Since low illuminance color matches for these patients are normal, this implies that these patients have normal amounts of photopigment, but the photopigment is not bleaching normally. This result clearly points to abnormalities in the outer retina of these diabetic patients. The most likely causes of this abnormality are either decreases in the ability of the cones to absorb light, or an increased rate of regeneration of the cone photopigments.

Adolescent↗
PubMed1986

Outer retinal layer toxoplasmosis.

It is widely held that ocular toxoplasmosis (1) involves inner retinal layers and (2) shows marked vitreous cellular reaction. This article reports on punctate outer retinal layer toxoplasmosis, a subset of ocular toxoplasmosis characterized by grey-white lesions of deep retina and retinal pigment epithelium, and associated with little or no overlying vitreous reaction. Acute lesions may resolve and become fine punctate white dots. Recognition of this uncommon presentation of toxoplasmosis is important, since this may allow for potentially efficacious therapy.

Child↗
PubMed1986

Retinal toxicity of amphotericin B in vitrectomised versus non-vitrectomised eyes.

The retinal toxicity of intravitreally administered amphotericin B was compared in non-vitrectomised versus vitrectomised rabbit eyes. Doses of 5 and 10 micrograms in both groups resulted in transient vitritis but had no effect on electroretinograms. Histopathological examination four weeks after injection showed vitreous cells and minimal areas of retinal necrosis in both groups at 5 or 10 micrograms doses. At these doses vitrectomy did not modify the retinotoxic effects of intravitreally administered amphotericin B. At higher doses marked toxicity was found in both vitrectomised and non-vitrectomised groups.

Amphotericin B↗
PubMed1985

Punctate outer retinal toxoplasmosis.

Classic ocular toxoplasmosis initially involves inner retinal layers and is associated with marked vitreous reaction. We encountered three cases of punctate outer retinal toxoplasmosis, a subset of ocular toxoplasmosis that is characterized by multifocal gray-white lesions at the level of deep retina and retinal pigment epithelium and that is associated with little or no overlying vitreous reaction. Acute lesions may resolve to form fine granular white dots. Recognition of this uncommon presentation of toxoplasmosis is important, since there is some evidence that treatment of toxoplasmosis may be effective.

Adolescent↗
PubMed1985

Amphotericin clearance in vitrectomized versus nonvitrectomized eyes.

Ocular clearance of amphotericin B after direct intravitreal injection was studied in a rabbit model. Unmodified phakic eyes, Candida-infected eyes, aphakic eyes, and aphakic vitrectomized eyes were employed. Using high pressure liquid chromatography to assess drug level, the half-lives of drug disappearance after single 10-microgram (microgram) intravitreal injections were 9.1, 8.6, 4.7, and 1.4 days, respectively. The disappearance slope for vitrectomized eyes was significantly different from all nonvitrectomized eyes with P less than 0.001. The rapid disappearance of amphotericin from vitrectomized eyes must be considered in clinical management of patients with fungal endophthalmitis.

Amphotericin B↗
PubMed1984

Immunocytochemical demonstration of prealbumin in the vitreous in heredofamilial amyloidosis.

Vitreous material obtained at pars plana vitrectomy from a patient with heredofamilial amyloidosis with vitreous involvement and control vitreous from a patient without amyloidosis were subjected to immunocytochemical studies. P component (AP), a minor constituent of all amyloid deposits, was found in trace amounts in the familial amyloid vitreous, but other amyloid proteins, which occur in secondary amyloidosis or in primary amyloidosis, were not found. The major amyloid protein in the vitreous in heredofamilial amyloidosis (but not control vitreous) was found to be prealbumin.

Adult↗
PubMed1984

Retinopathy risk factor regression after laser panretinal photocoagulation for proliferative diabetic retinopathy.

Fifty eyes of patients with proliferative diabetic retinopathy were followed at frequent intervals to determine the rapidity and stability of retinopathy risk factor regression after argon laser panretinal photocoagulation. Retinopathy risk factors regress rapidly after laser photocoagulation. The incidence of eyes at high risk for severe visual loss (eyes with 3 or more retinopathy risk factors) decreased from 100% prior to treatment to 28% three weeks after treatment. The early response to treatment was a good prognostic indicator of longer term results. Seventy-two percent of eyes which improved from a high- to a low-risk category by three weeks continued to remain at low risk at six months. Sixty-four percent of eyes which failed to improve to a low-risk category by three weeks continued to remain at high risk at six months. The early response to laser panretinal ablation may be used to predict longer-term results.

Diabetic Retinopathy↗
PubMed1984

The association between long-term diabetic control and early retinopathy.

A study was performed to determine the relationship between level of long-term antecedent diabetic control and early diabetic retinopathy changes. Fifty-eight insulin dependent diabetics aged 14 to 17 1/2 years, with duration of diabetes of at least 8 years, were studied. Glycosylated hemoglobins were assessed a mean of 8.5 times per patient, over a mean period of 3.1 years, representing 28% of the mean duration of diabetes in this patient population. Fluorescein angiography, obtained according to a standardized technique, was assessed in masked fashion for number of microaneurysms, presence of abnormal areas of capillary nonperfusion, and presence of intraretinal dye leakage. Sixty-four percent of the study population showed some evidence of retinopathy. There was a high correlation found between degree of metabolic control as measured by glycosylated hemoglobin level, and presence of early retinopathy changes as defined by angiography.

Adolescent↗
PubMed1983

Choroidoretinal vascular anastomosis.

Vascular anastomoses between the retina and choroid may occur in different congenital and acquired conditions. It has been postulated that the direction of blood flow in these anastomoses follows a pressure gradient characterized as follows: choroidal artery greater than retinal artery greater than retinal vein greater than choroidal vein. Of the four possible directions of blood flow between the two circulations that this theory allows, only three have previously been reported. The fourth, described in this report, is a choroidoretinal vascular anastomosis with blood flow from a choroidal vessel into a retinal vein.

Child↗
PubMed1983

An experimental model to assess factors associated with scleral buckle infection.

A reproducible rabbit model to assess factors associated with scleral buckle infection was developed. Buckle exoplant material incubated with staphylococcus was sutured to rabbit sclera, covered with conjunctiva, then removed after 24 hours. Colony counts from removed exoplant material were used to define experimentally the degree of infection. Experimental modifications of the model were used to determine how differences in perioperative treatment may affect infection. Soaking sponge exoplant in antibiotic or subconjunctival injection of antibiotic had a marked beneficial effect, while prophylactic topical antibiotic drops, or systemically administered antibiotics had a less marked effect. Silicone sponge exoplant material showed a greater tendency towards bacterial contamination than did solid silicone.

Administration, Topical↗
PubMed1982

Combined ocular infection with cytomegalovirus and cryptococcosis.

To our knowledge, this is the first published description of the clinical and pathologic features of combined ocular infection with both cytomegalovirus and Cryptococcus. Infection occurred in a patient treated by immunosuppression and corticosteroid therapy. This article emphasizes that ocular findings may be the first sign of disseminated opportunistic infection and that clinical manifestations may be sufficient to allow accurate diagnosis of opportunistic retinitis.

Cryptococcosis↗
PubMed1982

Single versus multiple treatment sessions of argon laser panretinal photocoagulation for proliferative diabetic retinopathy.

A prospective, randomized study was performed to demonstrate whether there was a difference in the beneficial or adverse effects of argon laser photocoagulation for proliferative diabetic retinopathy depending on whether treatment was administered in a single session as compared with multiple sessions spaced over time. Results show no major differences between groups in the effect of treatment on visual acuity, visual field scores, or retinopathy risk factors. Exudative retinal detachment, choroidal detachment, and angle closure occurred more commonly in single session treatment group eyes, but these effects were transient, and no long-term difference between treatment groups was found.

Adolescent↗