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Biomedical subjects

R F Meyer

Publications and source records attributed to R F Meyer.

At least 55 records · Page 3Linked to original sources
PubMed1990

Endothelial rejection following penetrating keratoplasty using Healon or BSS.

In order to evaluate the effect of a commonly used sodium hyaluronate preparation (Healon, Pharmacia AB, Uppsala, Sweden) on the incidence of endothelial rejection, endothelial cell loss, intraocular pressure, and corneal thickness after penetrating keratoplasty, we conducted a randomized clinical trial. Patients were allocated to receive Healon (n = 41) or BSS (Alcon Laboratories, Inc., Fort Worth, TX, U.S.A.; n = 37) during surgery. At 1 year after surgery, the Kaplan-Meier estimate of the proportion remaining free of endothelial rejection was 78.1% (SE 6.5%) in the Healon group, and 70.6% (SE 7.9%) in the BSS group. Survival analysis showed no overall difference in endothelial rejection between groups. The percent loss in endothelial cell density showed substantial variability within each group, but for those followed 2 years after surgery, the amount of loss was significantly less in Healon-treated patients (17.3% versus 30.2%). Four Healon patients required medication for intraocular pressure rises in the early postoperative period, and the average intraocular pressure 1 day after surgery was greater in the Healon group (18.2 versus 13.7 mm Hg). Corneal thickness was slightly greater in patients receiving Healon, but no clinically important differences were noted.

Acetates↗
PubMed1990

A death resulting from trichlorotrifluoroethane poisoning.

Fatalities due to accidental exposure to chlorinated hydrocarbon in an industrial setting have been infrequently reported. The deaths in these cases have occurred within poorly ventilated, enclosed compartments or areas. A case is presented of a 16-year-old male who died as a result of exposure to trichlorotrifluoroethane while working in an open pit. Chromatographic results and tissue concentrations are presented.

Adolescent↗
PubMed1989

Implantation of posterior chamber intraocular lenses in the absence of lens capsule during penetrating keratoplasty.

We retrospectively studied the clinical records and the corneal endothelial cell counts of 133 consecutive eyes that received sutured posterior chamber intraocular lenses during penetrating keratoplasty in the absence of lens capsular support. Postoperative follow-up time ranged from three to 24 months, with 82 patients having at least one year of follow-up. At one year, 45.1% of these patients had 20/40 or better visual acuity, 30.5% had a visual acuity between 20/50 and 20/100, and 24.4% had a visual acuity of 20/200 or worse. At two years, 63.6% had a visual acuity of 20/40 or better, 18.2% had a visual acuity between 20/50 and 20/100, and 18.2% had a visual acuity of 20/200 or worse. Ninety-seven percent of the grafts remained clear at their latest follow-up examination. Cystoid macular edema (36.4%) and age-related macular degeneration (14.0%) accounted for poor visual acuity in most cases. Less common problems included graft rejection, retinal detachment, glaucoma, and endophthalmitis. At one year, the endothelial cell loss in the grafts averaged 19% with sutured posterior chamber intraocular lenses.

Aged↗
PubMed1989

Risk of endothelial rejection after bilateral penetrating keratoplasty.

Using univariate and multivariate survival analyses, the risk of endothelial rejection (ER) was compared between a group of patients undergoing penetrating keratoplasty (PK) in one eye only (unilateral PK) and a concurrent group who underwent PK in both eyes (bilateral PK). There was no significant difference in the time-related risk of ER between the bilateral and unilateral PK groups, after controlling for the increased risk of ER associated with younger age and preoperative stromal vascularity. Further analysis showed no increased ER risk to the first eye after the second eye's PK in the bilateral PK group. The documentation of simultaneous ER episodes in both eyes of two bilateral PK patients, however, may be evidence of an uncommon sharing of histocompatibility antigen(s) in the donor tissue used in these eyes.

Adolescent↗
PubMed1989

Corneal astigmatism after penetrating keratoplasty. The role of suture technique.

A randomized clinical trial was conducted to contrast two techniques of suturing in penetrating keratoplasty (PK) surgery: double running 10-0 and 11-0 sutures (DR), and a combination of 12 interrupted 10-0 sutures with a single running 11-0 suture (IR), followed by selective suture removal. The primary outcome evaluated in the 60 patients within each group was keratometric astigmatism. A decreasing trend in astigmatism over postoperative year 1 was observed only in the IR group (from 4.00 diopters [D] at 3 months to 2.50 D at 12 months). The difference in median astigmatism at 1 year (IR, 2.50 D; DR, 4.00 D) approached statistical significance (P = 0.06, Mann-Whitney U test). Both groups showed comparable steepening of almost 1 D during postoperative year 1. Assessment of the rate of visual rehabilitation was limited by a greater proportion of IR patients showing cystoid macular edema (CME) after surgery. These results, while favorable toward the IR/selective suture removal technique, must be substantiated by a final assessment after all sutures have been removed.

Aged↗
PubMed1989

Penetrating keratoplasty for corneal scarring due to herpes zoster ophthalmicus.

We retrospectively studied the postoperative results in nine patients with corneal scarring due to herpes zoster ophthalmicus who underwent penetrating keratoplasty. This was a highly selected group that satisfied all of the following criteria: (a) absence of active disease of the ocular surface and eyelids, (b) intraocular pressure under control, and (c) absence of active keratouveitis. Penetrating keratoplasty after herpes zoster ophthalmicus may do well in patients with long preoperative quiescent periods in whom these restrictive preoperative criteria are observed.

Aged↗
PubMed1989

Use of in situ hybridization for the detection of foot-and-mouth disease virus in cell culture.

Biotinylated complementary DNA (cDNA) and RNA probes were prepared from a specific and highly conserved section of the foot-and-mouth disease virus (FMDV) genome coding for the RNA-dependent RNA polymerase. Hybridization was conducted on FMDV-infected, bovine enterovirus (BEV)-infected, and noninfected swine kidney cell cultures. The detection system utilized the enzyme system streptavidin-alkaline phosphatase, the substrate phosphate, and the chromogen nitroblue tetrazolium. Intense cytoplasmic granular staining was present at 2 and 4 hr postinfection (hpi), with less staining observed at 24 hpi. The staining was specific for FMDV, as indicated by a lack of staining of noninfected cells and BEV-infected cells. With the RNA probe, positive cells were detected up to the highest viral dilution assayed, which was approximately 96 TCID50. The cDNA probe was slightly less sensitive, detecting positive cells at 10-fold lower dilutions. This technique could prove useful in the diagnosis of foot-and-mouth disease in animals or in the detection of FMDV in biologics submitted for importation.

Animals↗
PubMed1989

Changes in aqueous immunoglobulin and albumin levels following penetrating keratoplasty.

The feline model of induced rejection of corneal allografts was employed to define the changes in the concentrations of immunoglobulins and albumin in the anterior chamber prior to, and concomitant with the rejection of the transplanted cornea. Fourteen animals received unilateral exchange corneal allografts. Aqueous humor obtained by anterior chamber paracentesis at regular intervals prior to and following the performance of the penetrating keratoplasties was analyzed for IgG, IgM and albumin concentrations using the micro enzyme-linked immunosorbant assay (ELISA). Two patterns of anterior chamber protein modulation were observed. Eight of the animals demonstrated a biphasic pattern in which both immunoglobulin and albumin concentrations were elevated two- to five-fold above presurgical values 14 days postkeratoplasty, returning to preoperative values by day 42. Three to 5 weeks after corneal rejection was induced increases in protein concentrations were observed that correlated with the appearance of clinical signs of rejection. A second, monophasic pattern of anterior chamber protein modulation following keratoplasty was observed in four of the animals. It was distinguishable from the biphasic pattern in that levels did not return to baseline values after the initial rise following keratoplasty until the rejection process was completed. The monophasic response was found to be characteristic of more rapid and vigorous corneal rejection. Examination of albumin to immunoglobulin ratios suggested that all changes in protein levels following keratoplasty were a result of increased influx of serum proteins into the anterior chamber, rather than due to local immunoglobulin synthesis.

Animals↗
PubMed1989

Problems associated with penetrating keratoplasty for corneal edema in congenital glaucoma.

Corneal edema from congenital glaucoma is a rare indication for penetrating keratoplasty. We report the complications and problems associated with eight consecutive penetrating keratoplasties performed in adult eyes with a history of congenital glaucoma. Only 25% of the eyes achieved 20/40 or better vision after surgery. These generally poor results can be attributed to previous glaucomatous optic nerve damage, to complications related to previous surgery, and possibly to amblyopia. The most common surgical complication was postoperative elevation of intraocular pressure, which occurred in all the cases (8/8 eyes), and required permanent augmentation of glaucoma medications in seven eyes (88%), and glaucoma surgery in four eyes (50%). Two eyes (25%) developed corneal graft failure, one from immune rejection and the other from severe postoperative glaucoma necessitating cyclocryotherapy. In view of these complications and the multiple impediments to good postoperative vision, we advise that penetrating keratoplasty be reserved for patients with severe visual disability whose preoperative glaucoma is well controlled.

Adolescent↗
PubMed1988

A study of race matching between donor and recipient in corneal transplantation.

We investigated the influence of a racial match or mismatch between the corneal donor and recipient on the risk of endothelial rejection and subsequent graft failure in 998 corneal transplant recipients. Actuarial survival analysis showed no significant difference in the cumulative risk of endothelial rejection between the 676 race-matched and 322 race-mismatched recipients. Recipients who had preoperative factors that placed them at a higher risk of endothelial rejection (n = 208) also were not subject to a higher incidence of endothelial rejection if they received race-mismatched tissue. Graft failure after endothelial rejection was not found to differ among race-matched or -mismatched groups.

Black People↗
PubMed1988

The effect of removing running sutures on astigmatism after penetrating keratoplasty.

To evaluate astigmatic change after removal of the double running sutures used in penetrating keratoplasty, all patients (N = 131) in the Michigan Corneal Transplantation Patient Registry, Ann Arbor, whose eyes were phakic after penetrating keratoplasty were evaluated. The primary reasons for surgery in this group were keratoconus (n = 44, 34%) and Fuchs' corneal dystrophy (n = 19, 15%). The average effect of 10-0 suture removal in 58 eyes with documented keratometry readings was a 0.30-diopter (D) decrease in astigmatism, with 59% showing 2 D or less of astigmatic change. In 83 eyes with keratometry readings before and after 11-0 suture removal, an average increase of 0.37 D of astigmatism was observed, with 81% showing less than 2 D of astigmatic change. In eyes that were highly astigmatic (greater than 6 D) before suture removal, a reduction in astigmatism exceeding 2 D was observed in 39% and 11% after 10-0 and 11-0 suture removal, respectively.

Astigmatism↗
PubMed1988

Prospective evaluation of a regression-determined formula for use in triple procedure surgery.

A surgeon-specific regression equation was applied prospectively to determine the intraocular lens (IOL) power for use in 52 consecutive patients undergoing triple procedure surgery. At their final refraction, 85% (44/52) of these patients could see 20/40 or better. Upon comparing the preoperatively determined refractive goal with that actually obtained, an "ideal" IOL power which would have resulted in the refractive goal was determined. The IOL power selected by the regression formula was within 2 diopters (D) of the ideal IOL power in 67% (35/52) of the cases. For comparison, the power which would have been selected if the Sanders-Retzlaff-Kraff (SRK) or Binkhorst formula was used would have been within 2 D of the ideal IOL power in 62% (SRK, 32/52) and 58% (Binkhorst, 30/52) of the cases. Deviations from the ideal IOL power were predominantly in the undercorrected category for all three formulas evaluated. The authors conclude that even though a surgeon-specific regression formula relying on preoperative axial length performed fully as well as either the SRK or Binkhorst formulas, the choice of which formula to apply remains in the surgeon's hands.

Cataract Extraction↗
PubMed1988

Fistula excision and peripheral grafts in the treatment of persistent limbal wound leaks.

Most small scleral wound leaks at the limbus are treated successfully with suturing, patching, bandage lenses, or cyanoacrylate adhesive, but occasionally a wound leak may continue and a fistula may develop. Although rare, most such fistulas are usually associated with cataract surgery or trauma. Failure of a scleral fistula to close may be due to epithelialization or chronic necrosis of the lumen. In three cases, persistent fistulas of the limbal sclera were excised with a trephine, and a peripheral graft using corneal donor tissue was used to seal the circular defect. This resulted in permanent wound closure and provided a tissue diagnosis of epithelial downgrowth (2 cases) and chronic scleral necrosis (1 case).

Adult↗
PubMed1988

Comparison of rapid NFT and API 20E with conventional methods for identification of gram-negative nonfermentative bacilli from pharmaceuticals and cosmetics.

The accuracy of the Rapid NFT and the API 20E identification systems was evaluated by comparing them with conventional biochemical methods for the identification of gram-negative, nonfermentative bacilli. The organisms were recovered from preserved, nonsterile pharmaceutical and cosmetic products. A total of 123 test isolates that are commonly encountered in these products were used. By using the criteria of accurate and reliable identification without employing additional tests, Rapid NFT was found to be more accurate after 48 h of incubation than API 20E for characterizing isolates to the species level. Therefore, close agreement between NFT and conventional methods for identification of industrial gram-negative isolates provides evidence that the Rapid NFT system is an improved and rapid method for identifying these organisms to the species level with minimal use of supplementary tests.

Cosmetics↗
PubMed1987

Assessment of success and complications of triple procedure surgery.

In an effort to quantify both the success and complications of triple procedure surgery, we studied a consecutive series of 166 patients who underwent this procedure. The average length of follow-up was 17 months. Of 166 patients, 138 (83%) achieved a visual acuity of 20/40 or better after surgery; in the most recent 52 patients, 26 (50%) achieved this within two months. The most frequent complications during the postoperative period were glaucoma (40 patients, 24%), endothelial graft rejection episodes (two-year cumulative risk, 16%), and astigmatism (mean keratometric cylinder, 4.97 D). Additional surgical interventions were required in 27 patients (16%).

Aged↗