Outcomes of fibrin glue-assisted conjunctival versus conjunctivolimbal autograft in primary pterygia with a new technique of conjunctival resection and Tenon extended removal.

PURPOSE: The aim of this study was to compare the recurrence rates for primary pterygia after fibrin glue-assisted conjunctival autograft (CAG) versus conjunctivolimbal autograft (CLAG) transplantation, using a technique of limited conjunctival resection and Tenon extended removal. METHOD: In this comparative case series, 49 eyes of 47 patients with primary nasal pterygium were included. Patients were randomized into 2 groups to undergo fibrin glue-assisted CAG (group 1, 24 eyes) or fibrin glue-assisted CLAG (group 2, 25 eyes) following excision of pterygium. The surgical technique used in all patients involved limited conjunctival resection combined with extensive removal of the Tenon capsule up to the caruncle medially and also 5 mm beyond the inferior and superior free edges of the conjunctiva. The main outcome measure studied was the absence or presence of recurrence. RESULTS: There was 0% recurrence rate in both groups after a mean follow-up of 63 weeks (range, 54-81 weeks) with all eyes completing at least 1-year of follow-up. CONCLUSIONS: Fibrin glue-assisted CAG and CLAG using the technique of conjunctival resection and Tenon extended removal were equally efficacious in terms of preventing recurrences in patients with primary pterygia in our series.

Long-term results after primary intraocular lens implantation in children operated less than 2 years of age for congenital cataract.

PURPOSE: To study the long-term outcome of cataract surgery with primary intraocular lens (IOL) in children <2 years. MATERIALS AND METHODS: Retrospective analysis of bilateral cases that were operated before 2 years age for congenital cataract. All underwent primary posterior capsulotomy with anterior vitrectomy and primary IOL implantation. Only those with a follow-up of at least 8 years were evaluated. RESULTS: Twenty-six eyes of 13 children with bilateral cataract met the inclusion criteria. Average age at surgery was 14.15 months with a mean follow-up of 102 months. Average preoperative axial length (AL) was 19.93 mm. There was a refractive shift from a mean spherical equivalent of 1.64 D at 2 weeks after surgery to -1.42 D measured at last follow-up. Twenty-four eyes out of 26 (92%) achieved final visual acuity (VA) of 6/18 or more at last follow-up with 19/26 (73%) having acuity of 6/12 or greater. Raised intraocular pressure was documented in one eye only. Average AL recorded at last follow-up was 22.21 mm. CONCLUSION: Primary IOL implantation in children <2 years is a safe surgical procedure with excellent long-term results. The myopic shift is well-controlled and final VA achieved is reasonably good.

Determination of the gas-phase acidities of oligopeptides.

Amino acid residues located at different positions in folded proteins often exhibit different degrees of acidities. For example, a cysteine residue located at or near the N-terminus of a helix is often more acidic than that at or near the C-terminus (1-6). Although extensive experimental studies on the acid-base properties of peptides have been carried out in the condensed phase, in particular in aqueous solutions (6-8), the results are often complicated by solvent effects (7). In fact, most of the active sites in proteins are located near the interior region where solvent effects have been minimized (9,10). In order to understand intrinsic acid-base properties of peptides and proteins, it is important to perform the studies in a solvent-free environment. We present a method to measure the acidities of oligopeptides in the gas-phase. We use a cysteine-containing oligopeptide, Ala3CysNH2 (A3CH), as the model compound. The measurements are based on the well-established extended Cooks kinetic method (Figure 1) (11-16). The experiments are carried out using a triple-quadrupole mass spectrometer interfaced with an electrospray ionization (ESI) ion source (Figure 2). For each peptide sample, several reference acids are selected. The reference acids are structurally similar organic compounds with known gas-phase acidities. A solution of the mixture of the peptide and a reference acid is introduced into the mass spectrometer, and a gas-phase proton-bound anionic cluster of peptide-reference acid is formed. The proton-bound cluster is mass isolated and subsequently fragmented via collision-induced dissociation (CID) experiments. The resulting fragment ion abundances are analyzed using a relationship between the acidities and the cluster ion dissociation kinetics. The gas-phase acidity of the peptide is then obtained by linear regression of the thermo-kinetic plots (17,18). The method can be applied to a variety of molecular systems, including organic compounds, amino acids and their derivatives, oligonucleotides, and oligopeptides. By comparing the gas-phase acidities measured experimentally with those values calculated for different conformers, conformational effects on the acidities can be evaluated.