ABSTRACT
PURPOSE: To compare the efficacy and safety of subconjunctival and intrascleral applications of mitomycin C (MMC) in trabeculectomy for high-risk glaucomas. METHODOLOGY: A randomized prospective clinical study was conducted on 41 consecutive eyes with a high risk of glaucoma surgery failure. Patients were randomized to trabeculectomy and application of subconjunctival MMC or to trabeculectomy and application of intrascleral MMC. MMC solution 0.2 mg/ml was applied for 3 minutes under the conjunctival flap overlying the proposed site of trabeculectomy in Group I (n=21), or intrasclerally under the superficial scleral flap in Group II (n=20) RESULTS: After a follow-up of one year, the intraocular pressure (IOP) decreased from a mean basal IOP of 33.0 +/- 8.4 mm Hg to 12.56 +/- 2.54 mm Hg in Group I and from 30.9 +/- 6.6 mm Hg to 11.6 +/- 2.21 mm Hg in Group II. The IOP was 6-21 mmHg, without medication, in 90.5 % of the eyes in Group I and 75 % of the eyes Group II. Ocular hypotony, hypotony maculopathy, choroidal detachment and a shallow anterior chamber were more frequent with the intrascleral application of MMC during trabeculectomy, but the difference was not statistically significant. The overall success of the surgery at one year, i.e., achieving an IOP of 6-21 mmHg and a stable vision, (reduction in visual acuity of < or = 2 lines), was 90.5% in Group I and 75 % in Group II. CONCLUSION: No significant difference was seen in overall success or complication between subconjunctival and intrascleral application of MMC-augmented trabeculectomies in glaucomatous eyes at high risk of surgical failure.
Subject(s)
Alkylating Agents/administration & dosage , Glaucoma/surgery , Mitomycin/administration & dosage , Sclera/surgery , Trabeculectomy/methods , Adolescent , Adult , Aged , Child , Child, Preschool , Female , Glaucoma/diagnosis , Humans , Infant , Intraocular Pressure , Male , Middle Aged , Postoperative Complications , Prospective Studies , Treatment Outcome , Visual AcuityABSTRACT
About 50% of the Oriental population have less liver mitochondrial aldehyde dehydrogenase (ALDH2) activity than do other people. It was found that they possessed an enzyme with a lysine at position 487 (E487K) instead of glutamate (Glu487). We previously found that the Km for NAD of recombinant human and rat E487K enzymes increased more than 150-fold (Farrés, J., Wang X., Takahashi, K., Cunningham, S. J. , Wang, T.T., and Weiner, H (1994) J. Biol. Chem. 269, 13854-13860). Many aldehyde dehydrogenase-deficient people were found to be heterozygous when genotyped for ALDH2. In this study liver tissue from heterozygous people was analyzed and found to possess mRNAs for both the glutamate and the lysine subunits. Western blot analysis showed that the glutamate subunit was present. The cDNAs for Glu487 and E487K were coexpressed on one plasmid in Escherichia coli, and the enzyme forms were separated from each other by isoelectric focusing to show that heterotetramers were formed. Only one Km value for NAD could be measured with the purified heterotetrameric enzyme that possessed just 16-18% activity of the glutamate homotetrameric enzyme. The E487K homotetramers had 8% specific activity of the Glu487 enzyme. There was no pre-steady state burst of NADH formation with the heterotetramer, a property found with the glutamate enzyme. Similar results were found for the coexpressed rat liver enzyme, except that a higher specific activity, 48%, was obtained. Thus, we conclude that presence of the lysine subunit altered the activity of the glutamate subunit in the heterotetramer to make it function more like an E487K enzyme.
Subject(s)
Aldehyde Dehydrogenase/chemistry , Asian People , Mitochondria, Liver/enzymology , Multienzyme Complexes/chemistry , Aldehyde Dehydrogenase/genetics , Animals , Escherichia coli , Glutamic Acid , Humans , Isoelectric Focusing , Kinetics , Multienzyme Complexes/genetics , Polymerase Chain Reaction , Protein Conformation , RNA, Messenger/metabolism , RatsABSTRACT
Mutants of Saccharomyces cerevisiae deficient in mitochondrial aldehyde dehydrogenase (ALDH) activity were isolated by chemical mutagenesis with ethyl methanesulfonate. The mutants were selected by their inability to grow on ethanol as the sole carbon source. The ALDH mutants were distinguished from alcohol dehydrogenase mutants by an aldehyde indicator plate test and by immunoscreening. The ALDH gene was isolated from a yeast genomic DNA library on a 5.7-kb insert of a recombinant DNA plasmid by functional complementation of the aldh mutation in S. cerevisiae. An open reading frame which specifies 533 codons was found within the 2.0-kb BamHI-BstEII fragment in the 5.7-kb genomic insert which can encode a protein with a molecular weight of 58,630. The N-terminal portion of the protein contains many positively charged residues which may serve as a signal sequence that targets the protein to the mitochondria. The amino acid sequence of the proposed mature yeast enzyme shows 30% identity to each of the known ALDH sequences from eukaryotes or prokaryotes. The amino acid residues corresponding to mammalian cysteine 302 and glutamates 268 and 487, implicated to be involved at the active site, were conserved. S. cerevisiae ALDH was found to be localized in the mitochondria as a tetrameric enzyme. Thus, that organelle is responsible for acetaldehyde oxidation, as was found in mammalian liver.
