Search

Objectives: Prolonged cardiopulmonary bypass (CPB) is associated with hemolysis, resulting in increased plasma oxyhemoglobin and vascular nitric oxide depletion. The authors hypothesized that hemolysis associated with CPB would reduce nitric oxide bioavailability, resulting in high pulmonary and systemic vascular resistances that after CPB would normalize gradually over time, due to clearance of plasma oxyhemoglobin. The authors also investigated whether prolonged CPB (≥140 min) produced increased levels of hemolysis and greater pulmonary and systemic vasoconstriction., Design: Prospective cohort study., Setting: Single-center university hospital., Patients: The study comprised 50 patients undergoing elective cardiac surgery requiring CPB., Interventions: Plasma hemoglobin and plasma nitric oxide consumption were measured before surgery and after CPB. Pulmonary and systemic hemodynamics were measured after CPB. The effects of short (<140 min) and prolonged (≥140 min) CPB on these parameters were considered., Measurements and Main Results: Pulmonary and systemic vascular resistances and plasma hemoglobin and nitric oxide consumption were highest at 15 minutes after CPB and then decreased over time. Pulmonary and systemic vascular resistances and plasma hemoglobin and plasma nitric oxide consumption were higher in patients requiring prolonged CPB. The reduction in plasma nitric oxide consumption from 15 minutes to 4 hours after CPB was correlated independently with the reductions in pulmonary and systemic vascular resistances., Conclusions: Prolonged CPB was associated with increased plasma hemoglobin and plasma nitric oxide consumption and pulmonary and systemic vascular resistances. The reduction in plasma nitric oxide consumption at 4 hours after CPB was an independent predictor of the concomitant reductions in pulmonary and systemic vascular resistances., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Healing of corneal alkali injuries remains a severe clinical challenge. The authors evaluated the effect of a new synthetic inhibitor of matrix metalloproteinases (GM6001 or N-[2(R)-2-(hydroxamido carbonylmethyl)-4-methylpentanoyl]-L-tryptophane methylamide) on preventing ulceration of rabbit corneas after alkali injury. Topical treatment of corneas with severe alkali injuries with 400 micrograms/ml or 40 micrograms/ml GM6001 alone prevented ulceration for 28 days, although 8 of 10 corneas treated with vehicle perforated. Corneas treated with 4 micrograms/ml GM6001 had midstromal depth ulcers. Corneas treated with 400 micrograms/ml of GM6001 contained very few inflammatory cells and had significantly reduced vessel ingrowth compared with vehicle-treated corneas. Epithelial regeneration after moderate alkali injuries also was investigated. Persistent epithelial defects developed 4 days after moderate alkali injury in rabbit corneas treated with vehicle and progressively increased to an average of 20% of the original 6 mm diameter wound by 27 days after moderate alkali injury. By contrast, epithelial regeneration was complete and persisted for 21 days for corneas treated with a formulation containing GM6001 (400 micrograms/ml), epidermal growth factor (10 micrograms/ml), fibronectin (500 micrograms/ml), and aprotinin (400 micrograms/ml). Sporadic punctate staining developed in 20% of the corneas treated with the combination of agents between days 21-28 after moderate alkali injury. These results demonstrate that topical application of GM6001 prevented corneal ulceration after severe alkali injury and that a combination containing GM6001, epidermal growth factor, fibronectin, and aprotinin promoted stable regeneration of corneal epithelium after moderate alkali injury.

Ninety-two nonglaucomatous patients undergoing extracapsular cataract extraction with implantation of a posterior chamber intraocular lens by residents at a Veterans hospital were randomized in double-masked fashion to receive either a topical nonsteroidal antiinflammatory agent, diclofenac sodium 0.1%, or a placebo consisting of vehicle only. One drop of placebo or diclofenac sodium 0.1% was administered on an inpatient basis by trained staff every 6 hours for three doses, starting the afternoon prior to surgery. A further drop was given at 90, 60, 30, and 15 minutes before the operation. Starting 24 hours after surgery, all patients received diclofenac sodium 0.1%. All patients remained hospitalized for 72 hours postoperatively. Mean baseline intraocular pressure (IOP) was 14.0 and 14.1 mm Hg in the diclofenac and placebo groups, respectively. IOP rose 8.6 mm Hg in both groups at 6 hours after surgery. At 24 hours, the mean IOP elevation from baseline was 11.3 mm Hg in the diclofenac group and 9.6 mm Hg in the placebo group (P = .47). Within the first 24 hours, IOP spiked more than 10 mm Hg in 57% (26/46) of the diclofenac patients and in 54% (25/46) of the placebo patients. These results suggest that diclofenac sodium 0.1% drops affect neither the incidence nor the height of IOP elevation following cataract surgery.

Twenty-nine suture removals from 20 eyes (21 patients) on which penetrating keratoplasty had been performed were analyzed in a nonrandomized consecutive study to evaluate the role of computer-assisted corneal topography in selective suture removal to reduce astigmatism. Topographic guidance for suture removal resulted in a net decrease in refractive and keratometric astigmatism in 21 of the 29 cases. The net reduction in astigmatism averaged 1.4, 0.9, and 1.0 diopters when measured by refraction, keratometry, and topography, respectively. The preliminary choice of sutures to be removed on the basis of refraction, keratometry, and inspection was changed in 20 of the 29 cases when information added by the topographic map was considered. Although many variables of suture removal remain unpredictable, computer-assisted corneal topography is a powerful means of describing corneal power after penetrating keratoplasty and is useful as a guide in selective suture removal for reduction of astigmatism.

A simple method for electrophoretic elution of nucleic acids from gel slices is described. The procedure utilizes a standard tube gel system and can be completed in as little as one hour. Nucleic acids are recovered in a small volume with almost 100% efficiency. The procedure is applicable equally to acrylamide and agarose gels, and small as well as large RNA and DNA molecules. The eluted nucleic acids are essentially undegraded and are suitable for a variety of structural and biological analyses.