Boston type I keratoprosthesis for treatment of gelatinous drop-like corneal dystrophy after repeated graft failure.

PURPOSE: To describe the use of a Boston type I keratoprosthesis as a secondary penetrating procedure to treat gelatinous drop-like corneal dystrophy (GDLD), with presentation of pathologic findings, genetic analysis, and discussion of other surgical options. METHODS: A 43-year-old woman with GDLD in both eyes, best corrected visual acuity (BCVA) of counting fingers in both eyes, and recurrent corneal opacification following two penetrating keratoplasties presented for visual rehabilitation. A Boston type I keratoprosthesis was implanted in her left eye after extracapsular clear lens extraction. RESULTS: The surgery was uneventful and one month after surgery, best corrected vision improved to 20/30, which has been maintained for a period of more than nine months. At the 12-month visit, her vision was noted to be diminished to 20/200 due to a retroprosthetic membrane and improved to 20/25 two weeks after a Yag capsulotomy. Histopathologic examination of the corneal specimen disclosed predominantly subepithelial amyloid deposition. Genetic analysis is presented. CONCLUSIONS: GDLD is a rare disorder of primary corneal amyloidosis. Recurrence of this condition following surgery is very common. Boston type I keratoprosthesis as a secondary procedure can be successful in restoring vision in affected patients.

Evaluation of umbilical cord serum therapy for persistent corneal epithelial defects.

AIMS: To evaluate umbilical cord serum therapy as a means of promoting the healing of persistent corneal epithelial defects. METHODS: Umbilical cord serum or autologous serum drops were used to promote the healing of persistent epithelial defects. The study design was a prospective randomised controlled clinical trial. 60 eyes of 59 patients were divided into two groups, 31 in the cord serum group and 29 in the autologous serum control group. Epithelial defects measuring at least 2 mm in linear dimension resistant to conventional medical management were included. Serial measurements of the size of the epithelial defects-namely, two maximum linear dimensions perpendicular to each other, and the area and perimeter was done at start of therapy and follow up days 3, 7, 14, 21. Rate of healing of the epithelial defects were measured as percentage decrease from the baseline parameter at each subsequent follow up. The data were analysed by the non-parametric Wilcoxon rank sum test using STATA 7.0. RESULTS: The median percentage decrease in the size of the epithelial defect was significantly greater in the cord serum group at days 7, 14 and 21 (p<0.05) when measured in terms of the area and perimeter. A greater number of patients showed complete re-epithelialisation with umbilical cord serum (n = 18) than with autologous serum (n = 11) (Pearson chi = 0.19). None of the patients reported any side effects or discomfort with either treatment. CONCLUSIONS: Umbilical cord serum leads to faster healing of the persistent corneal epithelial defects refractory to all medical management compared to autologous serum.

LASIK complications: etiology, management, and prevention.

Laser in situ keratomileusis (LASIK) is a rapidly evolving ophthalmic surgical procedure. Several anatomic and refractive complications have been identified. Anatomic complications include corneal flap abnormalities, epithelial ingrowth, and corneal ectasia. Refractive complications include unexpected refractive outcomes, irregular astigmatism, decentration, visual aberrations, and loss of vision. Infectious keratitis, dry eyes, and diffuse lamellar keratitis may also occur following LASIK. By examining the etiology, management, and prevention of these complications, the refractive surgeon may be able to improve visual outcomes and prevent vision-threatening problems. Reporting outcomes and mishaps of LASIK surgery will help refine our approach to the management of emerging complications.

Late traumatic dislocation of laser in situ keratomileusis corneal flaps.

PURPOSE: To report the management and outcome of late-onset traumatic dislocation of laser in situ keratomileusis (LASIK) flaps. DESIGN: Retrospective, observational case series. PARTICIPANTS: Four patients with late-onset LASIK flap dislocation occurring after mechanical trauma at various intervals (10 days-2 months) after the procedure. INTERVENTION: In all cases of postoperative traumatic LASIK flap dislocation, the flap was refloated with scraping and irrigation of the underlying stromal bed within 12 hours of the injury. A bandage contact lens was placed, and a regimen including topical antibiotics and corticosteroids was instituted in all cases. MAIN OUTCOME MEASURES: Best spectacle-corrected visual acuity and complications associated with the surgery were monitored. RESULTS: Postoperative follow-up ranged from 4 to 21 months. Nonprogressive epithelial ingrowth was noted in one patient and diffuse lamellar keratitis developed in another patient. All patients recovered pretrauma spectacle-corrected visual acuity. CONCLUSIONS: Corneal LASIK flaps are prone to mechanical dislocation as late as 2 months after the procedure. Appropriate management results in recovery of optimal visual outcomes.

Photochemical keratodesmos for repair of lamellar corneal incisions.

PURPOSE: To determine the efficacy of photochemical keratodesmos (PKD) for closing surgical incisions in the cornea of enucleated rabbit eyes compared with that achieved using sutures and self-sealing incisions. METHODS: A 3.5-mm incision, at an angle parallel to the iris, was made in the cornea of enucleated New Zealand White rabbit eyes. The intraocular pressure required to cause leakage (IOP(L)) from the untreated incision was then recorded. Photochemical keratodesmos treatment was then performed by application of a dye, Rose Bengal (RB), in saline solution to the surfaces of the incision wound, followed by laser irradiation at 514 nm from an argon ion laser. Immediately after treatment, the IOP(L) was measured. Both dose and laser irradiance dependencies were studied in five or more eyes for each condition and appropriate control eyes. The IOP(L)s were compared with those obtained using conventional interrupted 10-0 nylon sutures. Other dyes were tested in a similar fashion. RESULTS: The IOP(L) of 300 mm Hg was obtained using a fluence of 1270 J/cm(2) with an irradiance of 1.27 W/cm(2) (laser exposure time, 16 minutes 40 seconds). No sealing was observed using dye or light alone where control pressures of approximately 30 mm Hg were found. At higher dose (1524 J/cm(2)) and irradiance (3.82 W/cm(2); 6 minutes 35 seconds), PKD was less effective, which may be attributable to thermal effects. PKD produced IOP(L)s similar to those in closure by sutures. Other dyes such as riboflavin-5-phosphate and N:-hydroxy-pyridine thione also produced efficient bonding after PKD. Nonphotochemically active dyes did not produce significant increases in the IOP(L) at which leakage occurred. CONCLUSIONS: The increase in IOP(L) after PKD treatment, comparable with that with sutures, in enucleated rabbit eyes demonstrates the feasibility of this technique ex vivo.

Effect of topical povidone-iodine versus topical ofloxacin on experimental Staphylococcus keratitis.

PURPOSE: To compare the antibacterial effect of povidone-iodine (PI) with that of ofloxacin in an experimental model of bacterial keratitis. METHODS: Staphyloccocal keratitis was induced in 21 eyes of Dutch Belted rabbits by intrastromal inoculation of approximately 280 organisms of Staphylococcus aureus. Six hours later, the animals were divided in four groups treated topically with saline 0.9%, Betadine 10%, Betadine 0.5% or Ofloxacin 0.3% (2 gtt every 30 min for 8 h). The central 8-mm cornea was excised, washed and homogenized. Colony counts were performed on serial 10-fold dilutions plated on blood and brain infusion agar and incubated overnight. RESULTS: Colony-forming units per cornea were 7.4x10(7) for the saline group compared to 8.2x10(7) for PI 10% (P>0.5), 4.3x10(7) for PI 0.5% (P<0.01) and no organisms for ofloxacin 0.3%. CONCLUSIONS: Betadine 0.5% demonstrates a statistically significant bactericidal effect compared with untreated staphyloccocal keratitis in our experimental model. Ofloxacin has superior antibacterial effect under the conditions studied. Further improvements in the povidone-iodine formulation are warranted prior to consideration for human keratitis.

Potential acuity pinhole: a simple method to measure potential visual acuity in patients with cataracts, comparison to potential acuity meter.

OBJECTIVE: To describe the potential acuity pinhole (PAP) test and compare its accuracy to the potential acuity meter (PAM) in predicting visual outcome after cataract surgery. STUDY DESIGN: Prospective case series. PARTICIPANTS: A total of 56 preoperative patients with cataracts participated. MAIN OUTCOME MEASURES: Accuracy of predicting postoperative distance visual acuity was measured. METHODS: Lines of inaccuracy were calculated by subtracting actual postoperative best-corrected distance visual acuity (BCVA) from predicted values. Variables analyzed were method of prediction, preoperative BCVA, and preoperative spherical equivalent. RESULTS: The PAP test predicted visual outcomes within 2 lines in 100%, 100%, and 56% of eyes with preoperative BCVA of 20/50 and better (group 1), 20/60 to 20/100 (group II), and 20/200 and worse (group III), respectively. The PAM predictions within 2 lines for the same groups were 42%, 47%, and 0%, respectively. Mean lines of inaccuracy of PAP predictions were 0.83, 1.11, and 3.50 lines for groups I, II, and III, respectively. Mean lines of inaccuracy for PAM predictions were 2.50, 2.68, and 6.22 lines for the same groups. Differences in lines of prediction between PAM and PAP were 1.67 (P = 0.004), 1.58 (P = 0.0002), and 2.72 lines (P = 0.0001) for groups I, II, and III, respectively. There was no statistically significant correlation between PAP predictions and preoperative myopic spherical equivalent. CONCLUSIONS: The PAP test is a simple, inexpensive, and relatively reliable method to estimate visual outcome after uncomplicated cataract surgery in eyes with no coexisting disease. It is less accurate in patients with preoperative BCVA worse than 20/200. It appears to be more predictive than PAM.

Expression of the adipocyte fatty acid-binding protein in streptozotocin-diabetes: effects of insulin deficiency and supplementation.

The adipocyte fatty acid-binding protein, aP2 or ALBP, is an abundant cytosolic protein postulated to function in binding and intracellular transport of long-chain fatty acids. In this report, we investigated levels of aP2 mRNA and protein and transcriptional activity of the aP2 gene in tissues from streptozotocin-diabetic rats at different time periods following the induction of diabetes. An average 75% decrease in mRNA for aP2 (relative to mRNA for beta-actin) was observed in all diabetic rats at 7 days post-STZ injection. Insulin supplementation rapidly (2 h) restored aP2 mRNA and the insulin effect was cycloheximide-sensitive. Nuclear transcription assays measured a 60% decrease in transcription of the aP2 gene in diabetic rats that was reversed by insulin administration. Levels of aP2 protein were still high, in some cases, 1 day after the decrease in mRNA levels consistent with a long half-life of the protein. Decreases in aP2 protein were rapidly reversed by insulin administration. There were no changes in aP2 protein in the absence of changes in aP2 mRNA supporting a pretranslational mechanism of regulation. The decrease in aP2 mRNA was delayed in onset when compared with the rapid decline (at day 2 of diabetes) of mRNA for the lipogenic enzyme, fatty acid synthase, and with the accelerated depletion of adipose tissue lipid. Adipose tissue weight and lipid content had decreased by more than 80% 3 days before any significant changes in aP2 expression were observed. Changes in aP2 could not be related to changes in the levels of circulating fatty acids that regulate aP2 expression in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Glycerolipid synthesis in isolated adipocytes: substrate dependence and influence of norepinephrine.

Studies of fatty acid (FA) esterification by adipocytes have led to conflicting views with respect to how the process is regulated by norepinephrine (NE). It remains unclear whether NE directly modulates the pathway or whether its effects are indirect and reflect its well-known action to activate lipolysis. Changes in lipolysis can complicate estimation of esterification rates by altering both medium FA and the hydrolysis of newly formed FA esters. In this report, we describe an experimental approach that determined the effect of NE on FA esterification, amidst the complications introduced by activation of lipolysis. Esterification rates were estimated from the simultaneous incorporations (0.1-60 min) of [14C]glucose and [3H]oleate into diglyceride (DG), phospholipid (PL), and triglyceride (TG). Saturation kinetics of incorporation rates, with respect to FA, and more specifically to unbound or albumin-free FA (ubFA), were determined in both basal and NE-treated cells. To obtain true estimates of ester synthesis, incorporation rates were adjusted for label loss from breakdown of labeled esters. Our findings were: 1) In basal versus NE-treated cells, [3H]oleate, on its pathway to esterification, was diluted, respectively, by 2 and 50% of measured cell FA, and the diluting FA appeared derived from lipolysis. 2) Syntheses of PL, DG, and TG, estimated from incorporation of [14C]glucose, saturated at low ubFA. The Km for TG synthesis (0.06 microM) was within the physiological range of ubFA which meant that changes in plasma FA will modulate TG synthesis. PL synthesis, on the other hand (Km less than 0.01 microM), would be largely saturated under physiological conditions. 3) NE treatment increased the molar ratio of FA to albumin in the medium an average 8-fold and ubFA about 87-fold. In addition, NE accelerated hydrolysis of labeled PL and DG. Adjusting incorporation rates for these changes indicated that NE does not directly regulate glyceride synthesis. The assays described should allow estimation of glycerolipid synthesis under various metabolic or disease states and will distinguish direct effects from those reflecting changes in FA concentration or in hydrolysis of labeled FA esters.

Metabolism of oleic acid in differentiating BFC-1 preadipose cells.

Incorporation of [3H]oleate and [14C]glucose into cellular lipids was studied in the preadipose cell line BFC-1 to determine flux changes that accompany the adipose conversion process. Dilution of oleate by intracellular fatty acids (FA) was estimated from the 3H/14C incorporation ratios and from relating steady-state radioactivity in diglycerides to their measured cellular levels. The data indicated that exogenous FA mixed with less than 1% of endogenous FA on its pathway to esterification. Conversion of preadipocytes to adipocytes increased uptake of FA and glucose by approximately 3-fold and synthesis of diglycerides and triglycerides by 5- and 16-fold, respectively, with little if any increase of phospholipid synthesis. A 50% drop in 3H/14C incorporation ratio indicated a doubling of the rate at which endogenous FA mixed with the exogenous FA that had entered the cell. Adipocytes compared with preadipocytes exhibited a 50% greater cell diameter and a doubling of intracellular water volume and of protein and phospholipid levels, reflecting cellular enlargement consequent to the arrest of cell division that precedes adipose conversion. Diglyceride levels were also increased in adipocytes, however, since their turnover was fast, as indicated by rapid equilibration of diglyceride labeling; the increase reflected changes in their relative rates of synthesis and disposal. Diglyceride levels related to cell phospholipid, and other indexes of cell size remained constant. This indicated that the supply of diglycerides was tightly coupled to the synthesis of triglycerides and phospholipids, which suggested feedback regulation of diglyceride formation. The studies provide a methodological approach to measurement and interpretation of rates of lipid deposition in cultured cells.