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Biomedical subjects

J S Myers

Publications and source records attributed to J S Myers.

18 recordsLinked to original sources
PubMed2000

Excisional bleb revision to correct overfiltration or leakage.

OBJECTIVES: To evaluate the effectiveness of excisional revision of filtering blebs for hypotony or leakage when more conservative measures have failed. PATIENTS AND METHODS: Retrospective review of all patients who underwent excisional revision of a filtering bleb for hypotony (intraocular pressure [IOP] < 5 mm Hg) or leakage during a 3 year period. The revision consisted of excision of the avascular bleb, mobilization of the surrounding conjunctiva, and suturing of the conjunctiva at the limbus. RESULTS: Sixteen patients were included in the study. The average age was 66.3 +/- 14.8 years (range, 39-83). Revision followed trabeculectomy in 11 cases, combined phacoemulsification-trabeculectomy in three cases, and inadvertent blebs in two cases. Five cases had bleb leaks without hypotony, four cases had hypotony alone, and seven cases had both hypotony and a bleb leak. Average follow-up after bleb revision was 25 +/- 11 months (range, 9-43). Average IOP increased from 3.8 +/- 5.6 mm Hg (range, 0-22) to 11.9 +/- 4.1 mm Hg (range, 3-18), with an average of 1.1 +/- 1.1 medication (range, 0-3). The IOP at the last visit was < 15 mm Hg in all but two patients, with 10 of the 16 patients requiring medications. At the last follow-up examination, visual acuity had improved > or = two lines in nine patients and was reduced two lines in one patient. Five patients had early postoperative limbal wound leaks; resuturing was required in one case. CONCLUSIONS: Excisional bleb revision is an effective technique to correct hypotony or leakage after filtering surgery when other methods have failed. Intraocular pressure control is often maintained with the use of medications.

Adult↗
PubMed1998

Laser energy reaching the posterior pole during transscleral cyclophotocoagulation.

OBJECTIVE: To measure scattered laser energy reaching the posterior pole during transscleral cyclophotocoagulation. METHODS: Transscleral cyclophotocoagulation was performed on 4 cadaver eyes with Nd:YAG noncontact, Nd:YAG contact, and diode contact lasers. Energy was measured with a photodiode through a 7-mm trephined hole in the posterior pole. Average percentage power, average power, and average energy transmission were calculated. American Conference of Governmental Industrial Hygienists (ACGIH) guidelines were used to calculate allowable energy exposures for each laser. RESULTS: All 3 lasers transmitted 3% to 5% of the power to the posterior pole. The average energy transmission was 240 to 260 mJ for all lasers. The contact lasers had an average power transmission of 120 mW. The noncontact Nd:YAG laser, with shorter pulse duration, had an average power transmission of 13,000 mW, significantly greater than that of the other lasers. The ACGIH guidelines for allowable energy exposures were 93 mJ for the noncontact Nd:YAG laser, 1300 mJ for the contact Nd:YAG laser, and 440 mJ for the contact diode laser. CONCLUSIONS: Three percent to 5% of laser power delivered during cyclophotocoagulation reaches the posterior pole. Exposure energies may approach or exceed ACGIH guidelines. The clinical significance of these findings remains to be shown.

Aged↗
PubMed1998

Use of latanoprost in the treatment of glaucoma associated with Sturge-Weber syndrome.

PURPOSE: To determine if latanoprost reduces intraocular pressure in eyes with glaucoma associated with Sturge-Weber syndrome. METHODS: We conducted a prospective study in which eyes with uncontrolled intraocular pressure associated with Sturge-Weber syndrome were treated with latanoprost 0.005% once daily. All eyes were already receiving at least two other antiglaucoma medications. Intraocular pressure was measured at baseline and after treatment for at least 1 month. All intraocular pressure measurements were taken within 24 hours of drug instillation. RESULTS: Six eyes of six patients received latanoprost. Two (28%) of the six eyes demonstrated an intraocular pressure decrease that averaged 8.8 mm Hg. These two responders had juvenile onset glaucoma, whereas the four nonresponders had congenital onset glaucoma. CONCLUSIONS: Latanoprost may significantly reduce intraocular pressure in selected patients with glaucoma associated with Sturge-Weber syndrome.

Adolescent↗
PubMed1997

Effect of topical anti-transforming growth factor-beta on corneal stromal haze after photorefractive keratectomy in rabbits.

PURPOSE: To determine the relationship between anti-transforming growth factor-beta (anti-TGF-beta) antibodies and the amount of corneal stromal haze after excimer laser photorefractive keratectomy (PRK). SETTING: Wills Eye Hospital, Philadelphia, Pennsylvania, USA. METHODS: Nineteen rabbits had bilateral PRK. Dichlorotriazinyl fluorescein was used to stain the exposed stroma; all rabbits were then treated with antibiotic ointment for 4 days. Ten rabbits were randomized to treatment with topical anti-TGF-beta1, -beta2, and -beta3 antibody 50 microg three times a day for 4 days; the others received diluent three times a day for 4 days. Stromal haze was graded weekly for 8 weeks on a 0 to 4+ scale. At the end of the study, all corneas were examined histopathologically. RESULTS: All treated eyes developed appreciable haze. Seven control rabbits and one antibody-treated rabbit had an epithelial erosion (P = .00001). Antibody-treated rabbits had significantly less haze at 3, 4, and 5 weeks (right eyes) and 3, 4, 5, 7 and 8 weeks (left eyes) (P < .05). Histopathology and fluorescence microscopy showed subepithelial collagen deposition consistent with clinical haze. CONCLUSIONS: Topical anti-TGF-beta antibody reduced stromal haze after PRK in the rabbit model and may be clinically beneficial in humans.

Administration, Topical↗
PubMed1993

Intermediate-term intravenous therapy: a pilot study.

Midline catheters provide an effective alternative for intermediate-term intravenous therapy. During a pilot study, 27 midline catheters were inserted in patients who met specific criteria. The insertion success rate was 64%, and the infection rate was 7%. One mechanical phlebitis occurred, but it was resolved by the application of warm, moist heat. One chemical phlebitis occurred during antibiotic therapy. The average dwell time was 8.7 days, and the longest dwell time was 49 days. Patients reported the catheters to be very comfortable and did not experience limitations in mobility.

Adult↗
PubMed1978

Specific conversion of D-galactose into D-galacturonic acid residues in glycoproteins: a facile method for carbohydrate linkage-analysis.

The terminal D-galactopyranosyl residues of asialoglycopeptides isolated from human alpha1-acid glycoprotein were oxidized in nearly quantitative yield to the corresponding uronic acid residues by a two-step sequence employing D-galactose oxidase followed by treatment with Tollens reagent, Ag(NH3)+2. Mild acid hydrolysis of the oxidized glycopeptides led to the isolation of the corresponding aldobiuronic acid(s). Structural and colorimetric analysis revealed that only one aldobiuronic acid 2-amino-2-deoxy-4-O-(beta-D-galactopyranosyluronic acid)-D-glucose, was isolated from the oxidized glycopeptides of alpha1-acid glycoprotein. This method can readily distinguish between the (1 leads to 3), (1 leads to 4), and (1 leads to 6) isomers of the corresponding aldobiuronic acids.

Chemical Phenomena↗
PubMed1975

Glycerol as an agent eliciting small conformational changes in alcohol dehydrogenase.

Yeast alcohol dehydrogenase is an example of a protein in which the K-m for substrate is substantially decreased by the presence of glycerol. The polyol has the effect at pH 8.0 or above of decreasing K-m and K-s for substrate and of altering both the protein's intrinsic fluorescence and ultraviolet absorption difference spectrum. The relationship between each of thse parameters and glycerol concentration displays a transition at a glycerol concentration of 20%. Circular dichroism values for the enzyme are not affected by glycerol over a large range of concentration and temperature. Treatment of the enzyme with glutaraldehyde results in the formation of cross-linked tetramers, the K-m of which are not altered by the presence of the solvent. The data are interpreted as reflecting a change in the conformation of the protein induced by glycerol.

Alcohol Oxidoreductases↗
PubMedDate not supplied

Effect of transforming growth factor beta 1 on stromal haze following excimer laser photorefractive keratectomy in rabbits.

BACKGROUND: Transforming growth factor beta (TGF-beta) has been shown to affect wound repair. Anti-transforming growth factor beta 1 antibodies have been shown to neutralize its activity. METHODS: Seventeen New Zealand White rabbits underwent unilateral photorefractive keratectomy followed by corneal staining with dichlorotriazinyl fluorescein. Three groups received topical transforming growth factor beta 1: 1 microgram/ml, 10 micrograms/ml, and 100 micrograms/ml; one group topical anti-transforming growth factor beta antibody (200 micrograms/ml); and a control group vehicle only. Corneal haze was graded from 0 to 4, weekly. Rabbits were sacrificed at 5 weeks and histopathological analysis and fluorescence microscopy performed. RESULTS: All treated eyes developed haze and had epithelial erosions. No statistically significant differences in haze score were seen among individual treatment groups (Kruskal Wallis p > 0.05). The anti-transforming growth factor beta antibody group had less haze than all other groups at every week after the first. Comparing all transforming growth factor beta 1 treated eyes as one group to the antibody group, significantly less haze was seen at weeks 3 and 4 in the antibody treated group (p = 0.028 and 0.013, respectively). This study is limited by small group size and further studies are needed to confirm these results. CONCLUSION: TGF-beta may be involved in stromal haze formation, and topical anti-TGF-beta 1 antibody may help reduce the development of stromal haze.

Administration, Topical↗
PubMedDate not supplied

Peripherally inserted central catheters. Development of a hospital-based program.

Peripherally inserted central catheter lines (PICCs) are the "new kids on the block" for intravenous therapy. This paper reports on the development of a protocol and training program for nurses at a 350-bed community hospital. The paper describes the development and implementation of this pilot program in 25 patients over a 1-year period.

Catheterization, Central Venous↗