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Biomedical subjects

M L Rubin

Publications and source records attributed to M L Rubin.

At least 19 recordsLinked to original sources
PubMed1992

Diabetic retinopathy: newer therapies to prevent blindness.

Diabetic retinopathy is a common cause of blindness in the adult population in the United States. Ophthalmologists now have laser and surgical treatment modalities available that can significantly decrease the risk of blindness in the diabetic population. The American Academy of Ophthalmology, through its Diabetes 2000 program, is making a national effort to educate all physicians who care for diabetic patients to recognize the problem and to be aware of the therapies available to prevent blindness.

Aged↗
PubMed1991

Cystoid macular edema secondary to juxtafoveolar telangiectasis in Coats' disease.

A 28-year-old man with unilateral Coats' disease and cystoid macular edema secondary to juxtafoveolar telangiectasis underwent successful juxtafoveolar argon green laser photocoagulation therapy with resolution of the edema and improvement in metamorphopsia and visual acuity. Despite this success, the effect of laser therapy in these patients remains uncertain. It should be considered only after detailed discussion with the patient about the possibility of posttreatment paracentral scotomata and the alternative of a reasonable period of observation for possible spontaneous resolution of the edema.

Adult↗
PubMed1990

Posterior vitreous cyst.

We observed two patients who had unilateral posterior vitreous cysts; one patient had been observed for 17 years. Both patients were young females who reported transient, infrequent obscurations of vision that were not disabling. One involved eye was emmetropic, and the other was highly myopic. No other ocular abnormalities were present. In the patient observed for 17 years, the physical characteristics of the posterior vitreous cyst remained unchanged. With this stable clinical course, posterior vitreous cyst that does not visually disable the patient may be managed by periodic observation.

Adolescent↗
PubMed1990

Distributions of elements in the human retinal pigment epithelium.

Distributions of elements above the atomic number of sodium were mapped in the retinal pigment epithelia of eight human eyes. X-ray energy spectra and maps were collected from cryofixed, freeze-dried, and epoxy-embedded tissues using energy-dispersive x-ray microanalysis. All eyes had high concentrations of phosphorus in the nuclei of retinal pigment epithelial cells. Melanosomes were rich in sulfur, zinc, calcium, and iron. Lipofuscin and cytoplasm contained only phosphorus and sulfur in detectable amounts. Drusen, when present, contained phosphorus and calcium. Six eyes had a prominent aluminum peak recorded from melanosomes, nuclei, and Bruch's membrane. In one pair of 90-year-old eyes, small, electron-dense deposits surrounded many melanosomes and contained mercury and selenium. Retinal pigment epithelial melanosomes may bind and accumulate metals and other potentially toxic ions over time, preventing them from reaching the neural retina.

Aged↗
PubMed1989

Methylprednisolone pulse therapy in severe dysthyroid optic neuropathy.

Five patients with severe dysthyroid optic neuropathy were treated with intravenous methylprednisolone (1 g daily for 3 consecutive days). Before administration, visual acuity of the more severely affected eyes of each patient was counting fingers at 5 feet, 8/200, 20/400, 20/200, and 20/80. Immediately after completion of pulse therapy, visual acuity improved to 20/25 in four patients and 20/30 in one. Remissions were maintained with oral prednisone and external beam irradiation of the orbit. Pulse methylprednisolone therapy appears to be beneficial in the initial management of severe dysthyroid optic neuropathy.

Adult↗
PubMed1989

Behavior of human RPE cultured on Bruch's membrane and on necrotic debris.

Degeneration and necrosis of the retinal pigment epithelium (RPE) is found in several conditions associated with reactive alteration of the cell layer, and is probably involved in the formation of drusen and age-related macular degeneration. In the current study we describe a novel system for culturing human RPE. This system permits evaluation of the effect of necrotic material between the epithelium and Bruch's membrane, of drusen, and of other alterations in Bruch's membrane on the behavior of the RPE. In this system, dissociated RPE cells were seeded onto isolated Bruch's membrane. Cell behavior was assessed in areas with and without drusen, and also in areas covered with necrotic cells and fragmented debris. On both exposed Bruch's membrane and on the membrane covered with debris, the cells developed a polygonal shape, with a varying density of apical microvilli. The cultures were monolayered with some overlapping. In areas containing fragmented debris and dead cells, seeded RPE cells were found to adhere to the apical surface of necrotic cells, but were also seen to intrude between the necrotic debris and underlying Bruch's membrane, appearing to clear the membrane of such debris. Our study demonstrates the stability of epithelial histology of human RPE under not previously tested conditions. Further, it shows that the present system permits exposure of these cells to several in vivo physiological and pathological changes in a controlled in vitro environment.

Cells, Cultured↗
PubMed1988

Electroretinograms in early fungal endophthalmitis.

To facilitate the early diagnosis of exogenous fungal endophthalmitis, we developed a rabbit model for Aspergillus fumigatus endophthalmitis. Six eyes of six New Zealand white rabbits were inoculated with forty spores of A. fumigatus. A control group of their six contralateral eyes received a similar but sterile inoculum. The rabbit eyes were evaluated with respect to clinical appearance and the electroretinogram. Clinically evident endophthalmitis developed in all six infected eyes at an average of five days after injection (range 3-7 days). Data samples each 48 hours showed transient b-wave amplitude elevations in three infected eyes. These were greater than two standard deviations above the mean pre-injection values (p less than 0.05). These amplitude increases preceded the onset of ophthalmoscopically recognizable infection and were observed at 2 to 5 days after injection (mean = 4 days). B-wave amplitudes in the infected eyes fell below two standard deviations of pre-injection values (p less than 0.05) at an average of 5 days (range 3-7 days) after injection, a corresponding to the onset of clinically obvious infection. At an average of 7 days after injection, all the infected eyes exhibited unmeasurable electroretinogram waveforms and severe infection. Histopathologic study of infected eyes showed extensive fungal infiltration of retina and vitreous tissues. The electroretinogram may be helpful in the early diagnosis of fungal endophthalmitis.

Animals↗
PubMed1987

Scanning electron microscopy of human drusen.

Drusen are small, yellowish deposits that form under the retinal pigment epithelium (RPE) with senescence or under certain pathological conditions. The present study examined these structures under the scanning electron microscope. Tissue came from four eyes of 66- and 75-year-old donors who demonstrated widespread drusen of the posterior fundus noted on postmortem examination. Specimens were prepared by either detaching the RPE from Bruch's membrane, or by cryofracturing the tissue for cross-sectional views. Drusen appeared to be composed of irregularly-shaped globular masses and of distinct spherical entities. These particles varied greatly in size, and were situated between the RPE's basement membrane and the outer collagenous zone of Bruch's membrane. Surface views showed drusen components to be embedded in the collagenous zone of Bruch's membrane. Pits corresponding to the sizes of the globular and spherical masses imply that some particles were lost during tissue processing. Fractured cross sections of the irregularly-shaped globular masses revealed a homogeneous, granular matrix with no distinct ultrastructural features, while some of the fractured spherical components demonstrated an internal core. Transmission electron microscopic analysis on the same specimens that were subjected to SEM corroborated these observations. Analytical x-ray microanalysis (Kevex, Foster City, CA) in the SEM revealed major peaks for calcium and phosphorous in the crystalline spherical components, and primarily potassium and chloride in the globular structures.

Aged↗
PubMed1978

The transscleral VER: prediction of postoperative acuity.

In 33 patients with corneal or lens opacities, the VER was recorded in response to a series of retinal stimuli delivered by the transscleral route (TVER). Based on the preoperative TVER characteristics, predictions of the postoperative acuities were made on a 1 to 5 scale. The predicted acuities were compared with those measured 6 months after surgery and showed that the TVER is a good predictor of postoperative acuity (r = 0.8). The criteria used for acuity estimates are presented.

Cataract Extraction↗
PubMed1978

The transscleral VER: normal responses.

Normative data taken on a sample of 10 eyes indicate that transscleral visual evoked response (TVER) stimulation of the cortical evoked response with a range of lights and at lower adaptation levels produces replicable, low-variance responses which may be of sufficient quality for the clinical evaluation of retinal and visual pathway condition. Response amplitudes were related to the radiant peak-power of white stimuli but were greater for red stimuli. Attenuation of the subjective brightness of the stimulus delivered through the inferior lid and sclera was about 0.4 log units compared to corneal delivery. Typical signal:noise ratios were 5:1.

Adolescent↗
PubMed1977

Effect of some substituted pyrimidines on development of desoxycorticosterone-induced hypertension in rats.

Chronic (15-week) dietary administration of 2-thio-6-aminouracil (TAU, 1.0 and 2.0 g/kg food) provided significant protection against elevation of blood pressure and cardiac hypertrophy in male rats treated with desoxycorticosterone trimethylacetate (DTMA) (5.0 mg twice weekly for 10 weeks). Assessment of thyroid activity was made by measurement of 24 h 131I uptake by the thyroid gland, PBI concentration of serum, rate of oxygen consumption, hematocrit ratio, hemoglobin concentration, and thyroid weight. By all these criteria, the rats given either dose of TAU were hypothyroid. In contrast chronic (17-week) dietary administration of 5-carboxy-2-thiouracil (0.50 and 1.00 g/kg food) and 5-carboxy-4-hydroxy-2-thiouracil (2.00 g/kg food) provided minimal protection against elevation of blood pressure and cardiac hypertrophy in male DTMA-treated rats. These compounds appeared to possess little or no antithyroid activity at the doses used. The results suggest a rough correlation between the degree of hypothyroidism produced by the compounds and their effectiveness in preventing rise of blood pressure in DTMA-treated rats.

Animals↗