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Biomedical subjects

R O Schultz

Publications and source records attributed to R O Schultz.

At least 37 records · Page 2Linked to original sources
PubMed1983

Diabetic keratopathy as a manifestation of peripheral neuropathy.

In a study of 102 patients (64 women and 38 men; 63 whites and 39 nonwhites; 77 with adult-onset disease and 25 with juvenile-onset disease), the data, after being adjusted for age, showed that diabetic peripheral neuropathy was associated with diabetic keratopathy. The strongest predictor of both keratopathy and corneal fluorescein staining was vibration perception threshold in the toes (P less than .01); the severity of keratopathy was directly related to the degree of diminution of peripheral sensation. Other predictors of keratopathy were reduced tear break-up time (P less than .03), the type of diabetes (P less than .01), and metabolic status, shown by fasting C-peptide levels (P less than .01). No significant relationships were found between keratopathy and tear glucose levels, endothelial cell densities, corneal thickness, or duration of disease.

Aged↗
PubMed1983

The effects of sodium hyaluronate, chondroitin sulfate, and methylcellulose on the corneal endothelium and intraocular pressure.

Sodium hyaluronate (Healon), chondroitin sulfate, and methylcellulose have been used to protect the corneal endothelium from intraocular lens trauma. A study of the efficacy and toxicity of these compounds showed that 1% sodium hyaluronate, 0.4% methylcellulose, and 20% chondroitin sulfate were nontoxic to the corneal endothelium, but that 20% chondroitin sulfate caused a marked decrease in corneal thickness because of its hypertonicity. Anterior chamber injection of these viscous substances resulted in an increase in intraocular pressure. Within one to four hours the maximum intraocular pressure with 1% sodium hyaluronate was 67 +/- 4.1 mm Hg and that with 20% chondroitin sulfate was 55 +/- 3.5 mm Hg. The intraocular pressure did not increase to these high levels with 10% chondroitin sulfate or 0.4% methylcellulose or when the test substances were washed out of the anterior chamber. The corneal endothelium was protected from injury with 1% sodium hyaluronate and 20% chondroitin sulfate, but 10% chondroitin sulfate and 0.4% methylcellulose provided only minimal protection.

Animals↗
PubMed1983

Ultraviolet light, cataracts, and spectacle wear.

Two groups of patients older than 60 years were examined for degree of development of nuclear sclerotic cataracts. The first group of patients had worn glass spectacles for a majority of their lives, while the patients in the second group had never worn spectacles or had worn only reading glasses. Subjects in the group with spectacles showed significantly less development of sclerotic nuclear lens changes. These findings may be due to the screening effect by spectacle glass of light in the ultraviolet range and suggest that uv light may be one of the risk factors in the development of nuclear sclerotic cataracts.

Adolescent↗
PubMed1983

Diabetic corneal neuropathy.

Corneal epithelial lesions can be found in approximately one-half of asymptomatic patients with diabetes mellitus. These lesions are transient and clinically resemble the keratopathy seen in staphylococcal keratoconjunctivitis. Staphylococcal organisms, however, can be isolated in equal percentages from diabetic patients without keratopathy. Diabetic peripheral neuropathy was found to be related to the presence of diabetic keratopathy after adjusting for age with analysis of covariance. The strongest predictor of both keratopathy and corneal fluorescein staining was vibration perception threshold in the toes (P less than 0.01); and the severity of keratopathy was directly related to the degree of diminution of peripheral sensation. Other predictors of keratopathy were: reduced tear breakup time (P less than 0.03), type of diabetes (P less than 0.01), and metabolic status as indicated by c-peptide fasting (P less than 0.01). No significant relationships were found between the presence of keratopathy and tear glucose levels, endothelial cell densities, corneal thickness measurements, the presence of S epidermidis, or with duration of disease. It is our conclusion that asymptomatic epithelial lesions in the nontraumatized diabetic cornea can occur as a manifestation of generalized polyneuropathy and probably represent a specific form of corneal neuropathy.

Conjunctiva↗
PubMed1982

Corneal edema and the intraocular use of epinephrine.

Commercially prepared dilutions (1:10,000) of epinephrine can cause marked increases in corneal thickness and loss of corneal endothelial cells when injected into the anterior chamber of the eye. Endothelial toxicity is related to the buffer capacity of the epinephrine solution, which is in turn controlled by the concentration of the antioxidant (sodium bisulfite) as well as by the vehicle formulation and a low pH value.

Animals↗
PubMed1981

Effects of timolol on bovine corneal endothelial cultures.

The chronic use of timolol (Timoptic) maleate to control glaucoma may produce cytotoxic complications in the cornea. We have therefore compared the relative toxic effects of the commercial ophthalmic preparation with that of the pure compound. Commercial vehicle, either with or without 16 mM timolol maleate, killed cultures within the first five minutes of exposure. Pure timolol maleate, however, caused rapid but reversible cellular contractions, and cells remained viable in it for over 24 hours. Dilution with culture medium reduced both the cytotoxicity and the speed of the contractions. Incubation in 1:100 dilutions of vehicle or commercial drug preparations or in 0.16 mM pure timolol maleate did not alter cellular morphology. The results indicate that while undiluted vehicle is toxic, timolol maleate is not.

Animals↗
PubMed1979

The effect of phenylephrine on the cornea.

Rabbit corneas were treated with three drops of phenylephrine hydrochloride with the epithelium intact or denuded. Corneal thickness was measured before and after drug treatment, and at various times after treatment the corneas were fixed for scanning and transmission electron microscopic observation. The results of this study show that phenylephrine caused a dramatic increase in corneal thickness (drug-induced edema) and cellular vacuolation within the keratocytes and endothelial cells in the corneas without the epithelium. Corneal thickness did not change and the ultrastructural changes were minimal following drug application in those corneas with the epithelium intact. Results of this study also suggest that phenylephrine has a cytotoxic effect on the corneal endothelium and keratocytes when used in corneas where the epithelium has been removed. In coreas with intact epithelium, the damage was less severe and limited to the epithelium.

Animals↗
PubMed1979

Effect of phenylephrine on normal and regenerated endothelial cells in cat cornea.

Topical commercial phenylephrine HCl (Neo-Synephrine 10%) has been shown to cause an increase in corneal thickness and reversible vacuolization of corneal endothelial cells in rabbits. Using an in vivo model of regenerated corneal endothelial cells in the cat, we compared the cytotoxicity of phenylephrine-HCl 10% to regenerated and to normal, nonregenerated cells. Following removal of the epithelium, topical application of the drug causes the appearance of anterior and posterior bands of stromal edema and reversible vacuolization in both normal and regenerated endothelial cells. Phenylephrine was not more damaging to the regenerated cells. Polymorphonuclear leukocytes infiltrated between the regenerating cells 24 hr after treatment but did not appear to destroy them. Phenylephrine may therefore be implicated as a causative factor of corneal edema and postoperative inflammation.

Animals↗
PubMed1978

Trifluridine in resistant human herpetic keratitis.

Patients with active dendritic herpetic keratitis that was unresponsive to topical idoxuridine or vidarabine therapy were treated topically with a 1% solution of trifluridine. The dendritic ulcers healed in an average time of 6.1 days. All patients tolerated the drug well except for one patient in whom a reversible crystalline epithelial keratitis developed.

Adolescent↗
PubMed1978

Trephination of donor corneal buttons: a scanning electron microscopic study.

Corneal buttons were cut from cat and human donor eyes by anterior trephination (with or without scissor completion) and from excised corneoscleral rims by posterior trephination (with or without a press). Scanning electron microscopy was used to evaluate the slope and quality of the cut edge, the diameter of the section of Descemet's membrane that was actually cut, and the loss of endothelial cells around the cut edge. With anterior trephination, the diameter of the section of Descemet's membrane that is cut was found to be less than that of the trephine because the cut edge slopes inward. Posterior trephination with or without a press consistently produced circular buttons with accurately cut outward-sloping edges. This resulted in a diameter of Descemet's membrane which was greater than in the anteriorly trephinated buttons. There also was less damage to peripheral Descemet's membrane and endothelium with the posterior method, especially when compared to scissor cut buttons. A 360 degree peripheral ring of Descemet's membrnae (0.05 to 0.28 mm in width) was denuded of endothelial cells with all techniques.

Animals↗
PubMed1977

Neurotrophic corneal ulcers in diabetes mellitus.

Three patients with juvenile-onset insulin-dependent diabetes mellitus had neurotrophic keratitis and/or ulceration presumably related to their diabetes. We suggest that significant neurotrophic corneal disease can occur in diabetic patients. The neurotrophic keratitis and corneal ulcers responded to treatment.

Adult↗
PubMed1976

Comparative toxicity of intraocular irrigating solutions on the corneal endothelium.

Isolated rabbit and human corneas were perfused in vitro with Plasma-lyte 148 solution and with a glutathione bicarbonate Ringer's solution. The corneal swelling rate and ultrastructure were compared to corneas perfused with three commonly used intraocular irrigating solutions. Corneas perfused with Plasma-lyte 148 swelled at a rate of 47 mu/gr and the endothelial cells separated from each other and showed extensive damage after three hours of perfusion. By comparison, corneas perfused with 0.9% NaCl increased in thickness by 98 mu/hr, lactated Ringer's by 39 mu/hr, balanced salt solution by 24 mu/hr, and glutathione bicarbonate Ringer's solution by 4 mu/hr. These results indicate that endothelial cell damage and increased corneal thickness observed during perfusion was related to the incomplete composition of 0.9% NaCl, Plasma-lyte 148, and lactated Ringer's and that endothelial cell damage can be prevented if the intraocular irrigating solution contains concentrations of inorganic and organic constituents that are similar to those in aqueous humor.

Animals↗
PubMed1975

Intraocular irrigating solutions. Their effect on the corneal endothelium.

The effects of several intraocular irrigating solutions on the corneal endothelium of rabbit and monkey corneas were evaluated, utilizing a specular microscope perfusion system with both scanning and transmission electron microscopy. Corneas perfused with 0.9% sterile isotonic physiological saline swell at a rate of 60mum to 90mum/hr; endothelial cells separate from each other and show extensive degenerative changes. Corneas perfused with lactated Ringer solution swell at a rate of 37mum to 40mum/hr, and the endothelial cells show slower, but progressive degeneration. Corneas perfused with balanced salt solution swell at 24mum to 31mum/hr, and degenerative changes become severe only after two hours. Corneas perfused with Ringer solution containing bicarbonate, reduced glutathione, and adenosine do not increase in thickness, and there is minimal deterioration of endothelial ultrastructure for periods of up to six hours.

Animals↗
PubMed1975

Endothelial survival in corneal tissue stored in M-K medium.

Cat corneas were stored at refrigerator temperatures in M-K medium (TC-199, 5% dextran), modified M-K medium (TC-199, 1% chondroitin sulfate), or on the intact globe in moist chambers for intervals of one to nine days. Less than 5% of the endothelial cells stained with trypan blue in corneas stored one to four days, regardless of the method of storage. In contrast, after five days, 20% or more of the cells took up the stain in 17 to 21 corneas stored in M-K medium. Although stain uptake indicated nonviability of cells, most of the endothelial cells remained structurally intact when observed by scanning and transmission electron microscopy unless the corneas were incubated in fresh TC-199 for two hours at 35 degrees C before trypan blue staining. In that case, the percentages of disrupted cells observed at each time interval correlated with the percentages of cells that had stained in each cornea. These results indicated that storage in M-K medium did not extend the time donor coreas can be stored before transplantation beyond four days.

Animals↗
PubMed1975

Keratomycosis in Wisconsin.

Candida albicans was the most common fungus responsible for mycotic keratitis in our series from a northern climate, as opposed to southern climates where other fungi were more common. Pimaricin was effective in our patients with Candida infections and in one patient with Aspergillus infection that had been unresponsive to previous amphotericin B.

Acetazolamide↗