Biomedical subjects

W J Gauderman

Publications and source records attributed to W J Gauderman.

43 records · Page 3Linked to original sources

PubMed1992

Sample size calculations for ophthalmologic studies.

Sample size calculations are shown for some common ophthalmologic study designs in which two treatments are to be compared. Included are the following three designs: 1, only one eye per subject; 2, both eyes, with each eye assigned to a different treatment; and 3, both eyes undergoing a common treatment. Continuous and binary outcomes are considered. The correlation between eyes is accounted for in the computations using a simple correction factor. For design 3, the formulas allow for a mixture of single-eye and double-eye eligible subjects. A computer program that performs the calculations is available.

Humans↗

PubMed1992

Intravitreal penetration of oral ciprofloxacin in humans.

Nineteen patients about to undergo elective vitreous surgery received 1 oral dose of 750 mg of ciprofloxacin before surgery. Specimens of serum and vitreous were collected 90 minutes to 18 hours after drug administration and were assayed for antibiotic content with a microbiologic disk agar technique. From 4 hours and 50 minutes to 16 hours and 50 minutes after a single oral dose, ciprofloxacin reached intravitreal levels above its minimal inhibitory concentration for 90% of Staphylococcus epidermidis, Bacillus species, and Enterobacteriaceae. However, intravitreal levels never exceeded the MIC90 for Staphylococcus aureus and Pseudomonas.

Administration, Oral↗

PubMed1992

Anti-inflammatory therapy and outcome in a guinea pig model of Pseudomonas keratitis.

Corneal scarring as a consequence of bacterial keratitis is an important cause of visual loss and a major indication for penetrating keratoplasty. Anti-inflammatory agents might be useful in this condition for limiting corneal damage, but benefit from adjunctive anti-inflammatory therapy has never been demonstrated. In this limited pilot study, we compared the effect on clinical outcome of treating Pseudomonas keratitis in guinea pigs with prednisolone (a corticosteroid), flurbiprofen (a cyclo-oxygenase inhibitor), nordihydroguaiaretic acid (a lipoxygenase inhibitor), and a leukotriene antagonist, SKF104353 [R-(R*, S*)]-beta-[(2-carboxyethyl) thio-alpha-hydroxy-2-(8-phenyloctyl) benzenepropanoic acid, zinc salt]. None of the anti-inflammatory agents prevented sterilization of ulcers with antibiotic (ofloxacin) therapy. Therapy with the leukotriene antagonist appeared to reduce infiltrate size more quickly and produce a more rapid reduction in lesion size, but the differences were not statistically significant. Sample size calculations suggest that very large numbers of animals would be required to prove efficacy. The role of anti-inflammatory agents in reducing the stromal destruction caused by bacterial keratitis remains controversial.

Analysis of Variance↗

PubMed1992

Computer-assisted study of diurnal variation in corneal topography after penetrating keratoplasty.

Diurnal changes in corneal topography have been documented to be greater in eyes following radial keratotomy that in normal eyes. To determine whether substantial changes of this nature result from corneal incisions in general or are a specific complication of radial keratotomy, we examined 12 corneas (10 patients) after penetrating keratoplasty for diurnal changes, using a computerized corneal topographic analysis system. Diurnal changes in keratometry readings, central corneal thickness, intraocular pressure, and refraction also were analyzed. From morning to evening, central corneal curvature flattened by an average of 0.74 +/- 0.18 diopters in eight eyes (67%), and steepened by an average of 2.00 +/- 0.53 D in four eyes (33%). Diurnal changes in central corneal thickness were correlated with diurnal changes in central corneal curvature (r = 0.63, P less than .05). These data suggest that changes in corneal thickness over the course of the day may partially account for the changes in corneal curvature demonstrated to occur following penetrating keratoplasty.

Adult↗

PubMed1991

Pituitary tumor volume as a predictor of postoperative visual field recovery. Quantitative analysis using automated static perimetry and computed tomography morphometry.

We attempted to define the relationship between the volume of pituitary adenomas and postoperative visual field recovery. Fourteen consecutive patients (27 eyes) were studied who presented with visual complaints and who were confirmed to have pituitary macroadenomas at the time of resection. For each eye, preoperative visual field loss in each quadrant as well as whole field loss were analyzed. Tumor volume was determined from computed tomography scans by summing serial axial sections. Statistically significant correlations (p less than 0.05) of preoperative superonasal and whole visual field loss with tumor volume were found. Postoperative visual field recovery was determined for each patient by subtracting the postoperative visual field loss from the preoperative field loss. Postoperative inferonasal field recovery was significantly correlated (p less than 0.01) with whole tumor volume, with markedly greater recovery in patients with tumor volumes of 5 cc or less. In general, tumor volume proved to be a poor predictor of postoperative visual field recovery.

Adenoma↗

PubMed1990

Pars plana vitrectomy for acute retinal detachment in penetrating ocular injuries.

We studied 41 eyes with acute retinal detachment after penetrating ocular trauma in a retrospective cohort analysis. Pars plana vitrectomy was performed in 28 eyes, while the remaining 13 eyes had only primary repair and closure of the wound. The two groups differed in the type of trauma (more gunshot wounds in the vitrectomy group and more blunt injuries in the nonvitrectomized group). Visual success (visual acuity of 5/200 or better) was observed in 10 (37%) of the eyes treated by vitrectomy compared with one (8%) of the eyes in the nonvitrectomy group. Anatomic success was achieved in 21 (75%) of the eyes in the vitrectomy group but in only one (8%) of those in the nonvitrectomy group. Enucleation or phthisis was observed in seven (54%) of the eyes in the nonvitrectomy group compared with only five (18%) in the vitrectomy group. Significant prognostic factors for anatomic outcome in the vitrectomy group were the location of the laceration and the presence of the lens.

Acute Disease↗

PubMed1990

Clearance rate of macrophages from the vitreous in rabbits.

Macrophages are usually present in epiretinal membranes from eyes with proliferative vitreoretinopathy (PVR). Information on the kinetics of macrophages in the eye may be of help in identifying their role in this disease. To determine the half-life of macrophages in the vitreous, peritoneal macrophages were labeled by allowing them to phagocytose 141Cerium (gamma-emitter) labeled microspheres, and were then injected into the vitreous of the same rabbit from which they were obtained. The animals were sacrificed at various times post-injection and the radioactivity remaining in the vitreous was measured. Using this procedure, the half-life was found to be 4.8 days.

Animals↗