Biomedical subjects

R N Ross

Publications and source records attributed to R N Ross.

At least 37 records · Page 2Linked to original sources

PubMed1988

Ocular allergy.

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Conjunctivitis, Allergic↗

PubMed1988

Retinal illuminance using a wide-angle model of the eye.

A computer model of relative retinal illuminance, based on our optical wide-angle model of the eye, is proposed for the cases of Ganzfeld illumination and the Maxwellian view through a range of visual field angles from 0 degrees to 80 degrees. The proposed model is designed to be functionally correct and to represent closely the anatomical parameters of the eye. Unlike earlier proposed models, this model is based on our previously reported measurements of spherical aberration in 100 eyes in vivo and is designed to be correct in the peripheral field and with large pupils. Data are reported for pupil diameters of 2, 4, and 8 mm. The effect of crystalline lens extinction on retinal illumination is also estimated for average eyes of young (age 19 years) and old (age 63 years) individuals at two wavelengths (410 and 532 nm). In the Ganzfeld case, illumination of the retina decreases with increasing visual angle. In the Maxwellian view, retinal illuminance increases with increasing visual angle.

Adult↗

PubMed1988

Dark-staining bodies in the conjunctival epithelium of rats after multiple topical challenges with compound 48/80.

Over a 17-day period, 96 Sprague-Dawley rats received approximately daily topical applications of compound 48/80 to the ocular surface of one eye and phosphate-buffered saline (PBS) to the other eye. On histologic examination, dark-staining bodies appeared in the conjunctival epithelium in all 48/80-challenged eyes after day 3. These epithelial dark bodies (EDBs) rarely appeared in PBS-challenged or in single-dose 48/80-challenged tissues. The EDBs, between two and 15 per 30 fields at x 1000 under light microscopy, were limited to the conjunctiva near the fornix rather than near or over the tarsal plate. We hypothesize that these EDBs are associated with repeated application of secretagogue to the conjunctiva.

Administration, Topical↗

PubMed1988

Cost-effectiveness of including cromolyn sodium in the treatment program for asthma: a retrospective, record-based study.

The treatment of chronic mild to moderately severe asthma is expensive for families and for society. Controlling the costs of asthma-related medications, physician visits, emergency room visits, and hospital admissions is therefore an important consideration. A retrospective, record-based study was undertaken to determine the costs of treating asthma in patients for whom cromolyn sodium was included in the routine treatment plan (n = 27) and those for whom treatment did not include cromolyn sodium (n = 26). Significant reductions in the number of emergency room visits and hospital admissions were obtained in patients who were treated with cromolyn sodium. The estimated average cost of emergency room visits was $33 a year for the patients given cromolyn sodium compared with $624 a year for patients in the comparison group. The estimated average cost of hospital admissions was reduced by $1,298 for the cromolyn sodium group compared with a $357 reduction for the comparison group. Computed for the entire course of treatment, the average (+/- SD) daily cost of medications for the comparison group was $0.84 +/- $0.37 versus $0.93 +/- $0.25 for the cromolyn sodium treatment group. Thus dramatic savings in costs of emergency room visits and hospitalizations when cromolyn sodium was included in therapy were effected at a small increase in the overall cost of medications. Analyzed visit by visit, the average daily cost of treatment that included cromolyn sodium decreased while that of the comparison group increased. We conclude that including cromolyn sodium in a regular anti-asthma regimen is a cost-effective and therapeutically effective treatment strategy.

Adrenal Cortex Hormones↗

PubMed1987

Effect of multiple applications of compound 48/80 on mast cells of rat conjunctiva.

We sought to determine the effect on rat conjunctival mast cells of chronic exposure to a degranulating agent. Compound 48/80 (250 micrograms in 10 microliter) was applied daily to the ocular surface of rats for a total of 13 treatments administered in 17 days. A single application of compound 48/80 was given to rats for comparison. Four groups of animals (6 in each group) were evaluated 1 or 48 h after the last application of compound 48/80 in both chronic exposure and single exposure studies. Although a single exposure to compound 48/80 induced significant degranulation of mast cells in animals observed 1 h after treatment, no significant degranulation of mast cells was observed 1 h after the last dose of compound 48/80 was given to rats whose conjunctiva had been chronically exposed to this degranulating agent. Thus, multiple applications of compound 48/80 attenuated the mast cell response to compound 48/80. This acquired tolerance to compound 48/80 was reflected in the lessened clinical signs in rats receiving repeated applications compared with those given a single application.

Animals↗

PubMed1986

Treating coexisting cardiovascular and pulmonary disease with calcium antagonists.

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Adrenergic beta-Antagonists↗

PubMed1984

Survey of ultrasound therapy devices in Manitoba.

In 1982 a survey was performed of 89 ultrasound therapy devices in use in medical and paramedical organizations in Manitoba. Field measurements of ultrasonic output power, intensity, and timer accuracy in the clinical operating range were made together with maximum output power and transducer operating frequency. Results of the measurements are presented and the performance characteristics of the units compared with manufacturers' performance criteria for ultrasound therapy devices as given in the Canadian Radiation Emitting Devices (RED) Act.

Equipment Safety↗

PubMed1984