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Biomedical subjects

F S Ashburn

Publications and source records attributed to F S Ashburn.

8 recordsLinked to original sources

Vitreous fluorophotometry in three models of experimental diabetes mellitus.

Fluorophotometry was performed on rats eight to ten days after they were made diabetic with streptozotocin (85 mg/kg), alloxan (50 mg/kg), or pancreatectomy. When compared with normal control animals, no significant differences in aqueous or vitreous fluorescein levels were noted in any of the diabetic models studied. We did note significant depressions of plasma fluorescein levels in pancreatectomized and streptozotocin-treated rats. We normalized our data for these plasma differences by calculating the ratios of aqueous and vitreous fluorescein to plasma fluorescein levels (RA and RV). Both RA and RV were significantly elevated in streptozotocin-induced diabetes; RV alone was elevated following pancreatectomy, while no change in either ratio was apparent in diabetes induced with alloxan. Treatment of streptozotocin-diabetic rats with cortisol for one week caused plasma fluorescein levels and RV to return toward normal, although RA remained elevated. We are cautious in assigning any meaning to changes in RA and RV, especially in view of the paucity of information on the behavior of fluorescein in the blood.

Alloxan↗

Timolol and epinephrine: a clinical study of ocular interactions.

In a crossover design study, we assessed effects on intraocular pressure, pupillary diamter, pulse rate, and blood pressure over six hours of one drop of 0.5% timolol maleate and 2% epinephrine hydrochloride in one eye. Both eyes of each patient had been pretreated for one week with twice-daily applications pf epinephrine or timolol, respectively. In random sequence, 20 patients (40 eyes) participated in both phases of the study. Pretreatment with timolol significantly reduced the ocular hypotensive effect of epinephrine (from 15.3% to 4.6%); epinephrine pretreatment did not affect the pressure reduction of timolol. Pretreatment with timolol enhanced the mydriatic effect of epinephrine (from 35.8% to 71.9% pupillary dilation); pretreatment with epinephrine resulted in an apparent mydriatic effect for timolol.

Aged↗

The effects of iodate and iodoacetate on the retinal adhesion.

Sodium iodate and sodium iodoacetate were employed as biological probes to evaluate component forces contributing to the strength of retinal adhesion to the retinal pigment epithelium (RPE). Iodate treatment produced a rapid reduction in the strength of adhesion, which was complete within 1 hr without evidence of concurrent structural change. The adhesive strength reduction produced by iodoacetate required 8 to 12 hr, corresponding to the appearance of early structural changes in the photoreceptor outer segments, although delayed metabolic disturbances in the RPE might also have been involved. The study suggests that metabolic activity in the RPE may account for a portion of the strength of adhesion and that structural changes in the photoreceptor outer segments may also contribute to the forces of adhesion.

Adhesiveness↗

Efficacy and patient acceptance of pilocarpine gel.

Fifteen patients with symmetrically increased intraocular pressure (IOP) participated in a single-masked random 30-day clinical trial comparing 4% pilocarpine hydrochloride gel applied at bedtime to one eye with 4% pilocarpine hydrochloride drops instilled four times daily in the fellow eye. Both forms of pilocarpine reduced IOP significantly at 8 A.M., 12 noon, and 4 P.M. (P less than .01). At these times there was no significant difference in effect between the two forms of pilocarpine (P greater than .05). The mean IOP of eyes treated with gel showed no significant difference from the pretreatment value at 10 P.M. (P = .37), whereas at this time eyes treated with drops did maintain a significant IOP reduction (P = .02). At 10 P.M. pilocarpine drops reduced IOP significantly more than did pilocarpine gel (P = .002). Pupil diameter was affected by the gel and drops in a similar pattern to that of IOP. Patients tolerated the gel with few side effects and were pleased by the convenience of administration once daily.

Administration, Topical↗

Timolol plus maximum tolerated antiglaucoma therapy: a one-year followup study.

Thirty-three eyes of 22 patients with primary open-angle glaucoma or severe ocular hypertension had topical timolol maleate added to their maximally tolerated medical regimens. With minimal side effects, 25 eyes (76%) could be treated medically for one year, and only eight eyes (24%) required filtering surgery. Thirteen (39%) of the medically treated eyes achieved intraocular pressures of 21 mm Hg or less. After the addition of timolol, 17 of the 33 eyes (52%) completed the one-year protocol with final mean intraocular pressure decreases of 5 mm Hg or more on medical therapy.

Aged↗

Compliance with ocular therapy.

Patient noncompliance with the physician's prescribed therapeutic regimen can present serious obstacles both to individual patient care and to the obtaining of information necessary for controlled drug trials. Unfortunately, the physician often is unable to determine whether and to what extent a patient is not complying with therapy. This article reviews the problem of patient noncompliance with particular emphasis on how and why noncompliance occurs, and methods of predicting, detecting and coping with the defaulting patient.

Eye Diseases↗