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Biomedical subjects

T O Wood

Publications and source records attributed to T O Wood.

At least 19 recordsLinked to original sources
PubMed2001

Quantification of MUC5AC protein in human tears.

PURPOSE: MUC5AC has been identified as a major secretory mucin of conjunctival goblet cells and precorneal tear film. However, no method has been reported to quantify MUC5AC protein in human tears. The objective of this study was to establish a method to measure the amount of MUC5AC in human tears and to correlate the amount of MUC5AC with age, gender, and dry eye diseases. METHODS: A goat antibody was raised to synthetic peptides corresponding to nonglycosylated epitopes of human MUC5AC mucin. This antibody and a horseradish peroxidase-coupled second antibody were used to develop a quantitative immunoassay to measure the MUC5AC concentration of tear samples collected on Schirmer strips. Porcine stomach mucin was used as a standard for the assay. The chemiluminescent MUC5AC signal was digitized and quantified. Tear samples from 19 healthy volunteers and 31 clinically diagnosed dry eye patients were analyzed. RESULTS: MUC5AC concentration in human tears ranged from undetectable to more than 200 microg/mL porcine stomach mucin equivalent. In the healthy population, low, moderate, and high concentrations were found in the tear samples from younger and older persons and from both men and women. The mean MUC5AC content in tears was lower in the dry eye patients than in the age- and gender-matched healthy individuals. CONCLUSIONS: A method was established to quantify MUC5AC in human tear samples obtained on Schirmer strips. There was no correlation between the amount of MUC5AC and age or gender in the healthy population. Dry eye disease patients, however, typically showed reduced concentrations of soluble MUC5AC in the tear film.

Adult↗
PubMed1997

Long-term evaluation of corneal endothelial cell transplantation.

PURPOSE: This report describes the clinical course, refractive changes, confocal microscopic and histological evaluation of corneal endothelial cell transplantation in rabbits with long-term follow-up. METHODS: Transplantation of corneal endothelial cells using a cell/carrier device was performed in 19 rabbits. Clinical evaluation between 1-25 months included slit-lamp examination, keratometry, retinoscopy and surface topography. Two grafts in rabbits with 12 and 24 month survivals were evaluated in vivo by 3D tandem scanning confocal microscopy. The same grafts were then processed for transmission electron microscopy. BrdU labeling of the grafted cells in one transplant was performed in order to distinguish between host and grafted endothelial cells. RESULTS: All grafts cleared and remained clear for an average of one year without signs of rejection or inflammation. Postoperative refraction data and topography of the transplants showed progressive development of myopia and steep corneas compared to the unoperated eyes in each case. Confocal microscopy in vivo demonstrated a regular hexagonal pattern of the transplanted endothelial cells and a thickened Descemet's membrane, which correlated with the light and electron microscopic findings. BrdU labeling of the grafted endothelial cells showed a homogenous labeling of cell nuclei 6 months after the transplantation. CONCLUSIONS: This study demonstrates that corneal endothelial cells grown on a biomaterial can be replaced and remain functional for a long period of time.

Animals↗
PubMed1994

Transplantation of corneal endothelial cells using a cell carrier device.

Penetrating keratoplasty is currently the only treatment for corneal endothelial dysfunction. Although corneal transplantation has a high success rate, a few problems still remain, such as the limited availability of donor grafts, the change in refraction after penetrating keratoplasty, and the higher chance of immune rejection. In this study, a coated hydrogel lens (Chiron Ophthalmics Inc., Irvine CA, U.S.A.) has been used as a carrier to transplant cultured homologous kitten and rabbit corneal endothelial cells into adult cats and rabbits. The transplantation procedure was the same in both species. Corneal endothelial cells from homologous rabbits or cats were seeded on coated hydrogel lenses and cultured until they reached a complete monolayer with an average cell density of 2,500 cells/mm2. Five weeks before transplantation surgery, corneal endothelial cells were scraped to induce corneal edema. The cell carrier device was then transplanted as follows: a trephine cut (7.7 mm) was made into the stroma, producing an outer corneal plug. The inner cornea was then cut by using a 5.5-mm trephine, and this inner plug was discarded. The implant was inserted and the outer corneal plug was sutured back into place. Corneas cleared completely within 3 days in both rabbits and cats, and stayed clear for an average of 40 days in rabbits and 50 days in cats. The histopathological evaluation of the rejected grafts showed vascularized retrocorneal membrane formation in cats, whereas in rabbits severe cellular infiltration of the stroma with neovascularization occurred without retrocorneal membrane formation.

Animals↗
PubMed1993

Corneal endothelial cell transplantation using Descemet's membrane as a carrier.

Rabbit corneal endothelial cells were transplanted into the right eyes of four New Zealand white rabbits using bovine Descemet's membrane as a cell carrier. Descemet's membranes were dissected from cow eyes, flattened on 36 mm culture dishes, and cut into discs with a 6 mm trephine. Rabbit corneal endothelial cells were seeded onto the discs and maintained in tissue culture conditions for seven days until a complete monolayer with a cell density of 3,000 cells/mm2 was formed. Before transplantation, corneal edema was induced in the host animals by an endothelial scrape wound, which removed the corneal endothelium. Five weeks later, the animals were prepared for transplantation. A corneal button was cut and placed on a dissection table so the host Descemet's membrane could be removed. The donor Descemet's membrane with a complete monolayer of rabbit corneal endothelial cells was placed on the stroma of the corneal button. To keep the donor membrane in place, the button was cauterized at three peripheral points and sutured back into the host eye. Prednisolone sodium phosphate eyedrops and dexamethasone eyedrops and ointment were applied twice daily during the post-operative period. All grafts stayed clear for a period of 12 to 17 weeks. This study shows the potential for using Descemet's membrane as a carrier for corneal endothelial cell transplantation.

Animals↗
PubMed1992

Growth of human corneal endothelium on altered Descemet's membrane.

To determine whether Descemet's membrane (DM), which is altered by disease, interferes with endothelial cell growth, healthy human corneal endothelial cells were seeded onto DM from normal corneas and diseased corneal buttons from patients with Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy (PBK). DM was first peeled off the corneal specimens and the endothelial cells removed by trypsinization. A suspension of first-passage corneal endothelial cells (2,000 cells/microliters; obtained from donor eye bank eyes and grown in Dulbecco's minimal essential medium with 10% fetal bovine serum and 1.5% chondroitin sulfate) were seeded on DM. Epidermal growth factor (10 ng/ml) and insulin (1 U/ml) were added to the medium after seeding cells on the DM. The cells attached and flattened within 1 hour and reached confluency in 1 week on normal DM. Cells grown on DM from corneas of patients with Fuchs' endothelial dystrophy also flattened and grew to confluency in 1 week. Cells grown on DM from corneas of patients with PBK did not grow to confluency. Further studies with bovine and rabbit corneal endothelial cells showed similar growth pattern to human cells. These data indicate that DM from corneas of patients with Fuchs' dystrophy does not interfere with the growth of corneal endothelial cells but that DM from corneas of patients with PBK does interfere with cell growth.

Animals↗
PubMed1991

Simultaneous penetrating keratoplasty, extracapsular cataract extraction, and intraocular lens implantation.

The postoperative results of 210 consecutive eyes in 177 patients who had simultaneous penetrating keratoplasty, extracapsular cataract extraction, and posterior chamber intraocular lens (IOL) implantation (triple procedure) were reviewed. All procedures were performed by one surgeon between January 1980 and December 1989. The most common diagnosis requiring a triple procedure was Fuchs' endothelial dystrophy. The remainder of the patients required the procedure for either corneal scarring, keratoconus, or Chandler's syndrome. Of the 210 grafts, 191 (91%) remained clear with a mean follow-up of 53 months (range 6 to 116 months). The mean preoperative keratometry (K) reading (n = 161) was 44.51/44.85 (SD 4.86/4.94), and the mean postoperative K reading (n = 111) was 44.29/43.50 (SD 3.83/3.63). The mean IOL power (n = 196) was + 20.87 diopters (D) (SD 2.86). The mean postoperative best visual acuity (n = 166) was 20/65 with a range from 20/20 to less than 20/400, although 61% had 20/50 acuity or better and 92% had 20/100 acuity or better. The mean spherical correction in 155 eyes was - 1.38 (SD 2.89), and the mean positive refractive cylinder was + 3.21 (SD 2.20). One hundred forty six of the 155 eyes with reported refractions (96%) had 6 D or less of refractive cylinder. Correlation of the recipient-donor disparity % and refractive cylinder was significant such that as disparity increased refractive cylinder increased (r = 0.197, P = .021). Correlation of the recipient-donor disparity % and keratometric cylinder indicated a similar trend but was not significant (r = 0.105, P = .310).

Adult↗
PubMed1991

Electron microscopic findings in corneal epithelial basement membrane degeneration.

In an attempt to correlate basement membrane changes with clinical symptoms we examined 29 specimens from 28 patients who had undergone corneal epithelial basement membranectomy for corneal epithelial basement membrane degeneration (CEBMD). Twenty-two of the 28 patients were women. Recurrent erosion was the most frequent symptom and occurred in 24 of the 29 eyes. The most common electron microscopic finding was reduplication of the basement membrane with loculated connective tissue. The electron microscopic finding that predicted clinical symptoms was absence of the basement membrane and hemidesmosomes, which occurred in 4 eyes with severe recurrent erosion.

Adult↗
PubMed1991

Suture adjustment for postkeratoplasty astigmatism.

Excessive corneal astigmatism following penetrating keratoplasty is a frequent problem. A technique that adjusts a single running 10-0 nylon suture after keratoplasty was used in this series of patients. The procedure requires a keratometer, slitlamp, topical anesthesia, and tying forceps. In 52 eyes, with an average of 10.0 diopters of keratometric astigmatism, we adjusted the suture to flatten the steep corneal axis. We were able to reduce astigmatism an average of 7.2 diopters and this remained stable three months post wound revision.

Adult↗
PubMed1991

Postkeratoplasty astigmatism control. Single continuous suture adjustment versus selective interrupted suture removal.

Two different suturing techniques performed during keratoplasty were retrospectively evaluated to compare postkeratoplasty astigmatism, number of suture manipulations, and time to optical stability. One group of patients (n = 31) received a combination of continuous 11.0 nylon suture and 12 or 16 interrupted 10.0 nylon sutures (CCIS), which were selectively removed post-operatively to reduce astigmatism. The second group of patients (n = 26) received a single continuous 10.0 nylon suture (SCS) that was adjusted postoperatively at the slit lamp to regulate corneal astigmatism. Compared with the CCIS technique, adjusting the single continuous suture resulted in less postoperative astigmatism (SCS, 1.5 +/- 1.1 diopters [D]; CCIS, 3.2 +/- 1.9 D), fewer suture manipulations per patient (SCS, 0.9 +/- 0.7; CCIS, 3.8 +/- 1.8), and earlier optical stability for visual rehabilitation (SCS, 2.6 +/- 1.5 months; CCIS, 9.6 +/- 4.7 months) (P less than 0.01). No continuous sutures were broken during adjustment. The adjustable single continuous suture may offer an improved method for early control of postkeratoplasty astigmatism.

Astigmatism↗
PubMed1990

An index for estimating probabilities of surgical success for cataract patients with retinal disease.

Patients with cataracts and coincident retinal disease are at increased risk for unsuccessful cataract surgery. We developed a method for estimating probabilities of surgical success for older cataract patients with retinal disease. Using data from a prospective study of cataract surgery outcomes, 36 patients with both cataracts and retinal disease were identified, 13 of whom attained surgical success with 20/40 or better vision 4 months after surgery. Age, presurgical Snellen letter acuity, location of retinal lesions, and presurgical visual function in everyday life (newspaper reading or television viewing) were all reliable correlates of surgical outcome. These data were analyzed using multiple logistic regression to develop a clinical index combining presurgical Snellen letter acuity, location of retinal lesions, and age to predict surgical success. The resulting index demonstrated 83% sensitivity and 85% specificity in sample data, correctly predicting 83% of patients (predictive value positive: 73%; predictive value negative: 90%).

Activities of Daily Living↗
PubMed1990

Cataract formation following corneal transplantation in eyes with Fuchs' endothelial dystrophy.

In a retrospective analysis, 78 eyes in 58 patients that underwent corneal transplantation for Fuchs' endothelial dystrophy were examined for the presence of cataracts. Follow-up ranged from 1 to 17 years, with an average of 6.62 years. Thirty-four (44.1%) of the eyes developed cataracts sufficient enough to require surgical removal. The mean time from transplant to cataract formation averaged 4.9 years. The average age at the time of transplant surgery in the eyes that did not develop cataracts was 55.6, and in those that developed cataracts, 60.3 (p = 0.049). Thirteen percent of the transplants lost transparency following cataract extraction. The incidence of postkeratoplasty cataract increased at age 50 and occurred in 75% of eyes grafted in patients 60 years of age or older.

Adult↗
PubMed1990

Salzmann's nodular degeneration.

Fifteen eyes in 12 patients with Salzmann's nodular corneal degeneration developed symptoms of recurrent erosion, decreased vision, or both. A history or evidence of ocular surface disease was present in 14 of 15 eyes. Removal of the nodule and accompanying pannus or corneal epithelial basement membrane degeneration, provided symptomatic improvement in all patients.

Adult↗
PubMed1990

Anterior stromal micropuncture electron microscopic changes in the rabbit cornea.

Anterior stromal micropuncture has become an effective treatment for recurrent erosion. The healing process in rabbit corneas was investigated. Following micropuncture of the corneal surface with a 27-gauge needle knife, electron microscopy was carried out at regular intervals from time 0 through 5 months. The corneal incisions began to fill with epithelium by day 1. Activated keratocytes were adjacent to the basement membrane defect by 7 days. The basement membrane appeared to be healed at 2 and 4 weeks. Epithelial projections into the stromal incisions with underlying mature basement membrane persisted at 5 months postsurgery. Basement membrane reproduction occurred much more rapidly following needle puncture than after microdiathermy. This was thought to occur because the corneal epithelial cell was immediately exposed to type I collagen, whereas following microdiathermy, new type I collagen must be secreted on the necrotic collagen before the corneal epithelium will secrete basement membrane.

Animals↗
PubMed1990

Aqueous humor protein and complement in pseudophakic eyes.

Intraocular lens (IOL) insertion is now the standard method of aphakic correction in this country. Previous studies have shown that an IOL can activate the alternative complement system of normal human serum in vitro, thereby generating peptides capable of stimulating inflammation that can result in visual morbidity in pseudophakic eyes. The objective of the present study was to determine if human aqueous humor (AH) levels of total protein, total C3, and C3a cleavage products (activated C3) are influenced by an IOL in pseudophakic eyes as compared with phakic and aphakic eyes. AH from five diagnostic categories was examined: cataract, posterior capsulotomy-IOL, Fuchs' endothelial dystrophy with corneal edema, aphakic bullous keratopathy, and pseudophakic bullous keratopathy. The results of this study do not support the hypothesis that IOLs affect AH protein and complement levels. Statistically, there was no significant difference in AH protein levels when pseudophakic eyes were compared with phakic and aphakic eyes. No significant difference in C3a levels was demonstrated between pseudophakic and phakic eyes, whereas aphakic eyes had significant higher levels than those with pseudophakia. There were significantly greater levels of protein, C3, and C3a in eyes with edematous corneas versus those with clear corneas. Although these studies are difficult to interpret, AH levels of these substances appear to be more related to dysfunctional corneal endothelium and corneal edema than to the presence of an IOL.

Aphakia↗
PubMed1989

Moderate Fuchs' endothelial dystrophy ATPase pump site density.

The Na+, K+-ATPase pump site density on corneal endothelial cells from Fuchs' endothelial dystrophy corneas has been shown to be drastically decreased in end-stage disease (McCartney et al, Invest Ophthalmol Vis Sci 28:1955, 1987) and significantly increased in the early stages (Geroski et al, Ophthalmology 92:759, 1985) as compared to normal endothelium. In order to provide values for corneas between these two extremes, eye bank corneas from donors with no evidence of corneal edema but with guttata across the extent of the cornea were processed for autoradiography as well as immunohistochemistry. Pump site density was increased compared to end-stage disease but was less than values reported for either functional tissue or early stage disease. Similarly, immunohistochemistry results showed the amount of Na+, K+-ATPase antibody localization to be increased in respect to end-stage disease, but reduced as compared to functional tissue. These results suggest that pump site density on endothelial cells affected with Fuchs' endothelial dystrophy follows a gradual decline towards end-stage disease values as opposed to a sudden sharp deterioration after an initial increase.

Aged↗
PubMed1988

A clinical index for predicting visual acuity after cataract surgery.

We developed a clinical index for predicting postoperative visual acuity of cataract patients and cross-validated it using data from 182 patients aged 70 years and older. The index consisted of four statistically combined indicators: age, preoperative visual acuity, frequency of reading, and comorbidity. Validation of the index included comparisons to two standard technical instruments for measurement of retinal visual acuity. For the clinical index, 72% of predictions were accurate within one Snellen line of postoperative visual acuity compared to 37% using a laser interferometer and 33% using a potential acuity meter. Testing of the clinical index's external validity using data from 111 patients in a different ophthalmology clinic disclosed 61% of predictions accurate within one Snellen line.

Aged↗