Biomedical subjects
S Barabino
Publications and source records attributed to S Barabino.
An evaporative stress test for borderline dry eye detection.
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Topical non-preserved diclofenac therapy for keratoconjunctivitis sicca.
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Daily tonometric curves after cataract surgery.
AIM: To evaluate daily tonometric curves after cataract surgery in patients with cataract only and in patients with cataract and glaucoma. METHODS: 108 patients scheduled for cataract surgery were randomly allocated to two groups: 57 patients with cataract only (normal) and 51 with cataract and primary open angle glaucoma (POAG). All patients underwent extracapsular cataract extraction (ECCE) (manual technique with long wound), phacoemulsification (automated technique with short wound), or nucleus capture (manual technique with short wound). Intraocular pressure (IOP) was measured by Goldmann tonometry in all patients every 2 hours for 12 hours before the operation and at 1 and 6 months postoperatively. RESULTS: 79 patients completed the 6 month examination. ECCE resulted in greater reductions in IOP than the other procedures (ECCE: 27% and 36% in normal patients and those with POAG, respectively; nucleus capture: 20% and 31%, respectively; phacoemulsification: 19% and 22%, respectively). The fluctuations in IOP before and after surgery were not statistically significant. CONCLUSION: Cataract surgery in normal patients reduces IOP but does not eliminate fluctuations which are directly proportional to the IOP value and result partly from circadian rhythms. This important finding might influence our approach to treatment of patients with glaucoma.
Studying pre-mRNA splicing using antisense 2-OMe RNA oligonucleotides.
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Antisense probing of the human U4/U6 snRNP with biotinylated 2'-OMe RNA oligonucleotides.
We have used antisense 2'-OMe RNA oligonucleotides carrying four 5'-terminal biotin residues to probe the structure and function of the human U4/U6 snRNP. Nine oligonucleotides, complementary to multiple regions of U4 and U6 snRNAs, bound stably and specifically to U4/U6 snRNP. This allowed for efficient and selective removal of U4/U6 from HeLa cell nuclear extracts. Binding of oligonucleotides to certain snRNA domains inhibited splicing and affected the U4-U6 interaction. Pre-mRNA and splicing products could also be affinity-selected through binding of the oligonucleotides to U4/U6 snRNPs in splicing complexes. The results suggest that U4 snRNP is not released during spliceosome assembly.
Perturbation of DNA tertiary structure by physical and chemical carcinogens: effects on DNA repair processes.
DNA within the cell is organized into higher-order structures characterized by negative supercoiling. Supercoiling is a property of any DNA molecule lacking ends capable of rotation. Parameters defining the properties of supercoiled DNA are significant for the description of the reactive state of DNA molecules. We have investigated whether physical and chemical DNA modifying agents alter the parameters describing the DNA tertiary structure. The variations in DNA tertiary structure of partially relaxed topoisomers obtained from plasmid DNA have been studied by one dimensional agarose gel electrophoresis, a technique allowing the measurement of alterations in the degree of supercoiling equivalent to fractions of superhelical turns. Unwinding angles of 8.5 degrees for pyrimidine dimers and of 8.5 degrees for acetyl-4-hydroxyaminoquinoline-I-oxide (Ac-4-HAQO) adducts have been determined by titrating for each topoisomers the number of damaged sites necessary to reduce the superhelical turns by one. Analogous unwinding was observed for topoisomers obtained from in vivo irradiated plasmid DNA. We have also shown that local alterations in DNA structure caused by UV irradiation inhibit bacterial type I DNA topoisomerases. In addition, we have demonstrated that E. coli mutants lacking DNA topoisomerase I are sensitive to UV light. The pronounced inhibition of DNA synthesis as well as the chromosome instability observed after UV irradiation of this strain, suggest that DNA topoisomerase I might be involved in those cellular responses elicited by the proximity of damaged bases to sites of active replication.(ABSTRACT TRUNCATED AT 250 WORDS)