Cyclin-dependent kinase inhibitor p16 and p21 expression, and cell cycle change in human lens epithelial cell line SRA 01/04 following contact inhibition in normal culture.

PURPOSE: To describe the pattern of expression of the cyclin-dependent kinase inhibitors (CDKIs) p16, p21 and p27, and the cell cycle in SRA 01/04 cells relative to contact inhibition. METHODS: SRA 01/04 cells were grown to overconfluence under normal conditions. At various phases of the cell growth, cells were assayed by flow cytometry and Western blotting for the expression of CDKIs. RESULTS: Expression of p16 was detected from early logarithmic growth to stationary phases, during which the number of cells in G(0)/G(1) increased from 46 to 69%. Expression of p21 was detected only during the overgrowth phase, when 60% of the cells were in G(0)/G(1). Expression of p27 was not observed in SRA 01/04 cells. CONCLUSIONS: p16 expression was likely mediated by G(0)/G(1) arrest to induce contact inhibition in SRA 01/04. p21 expression may be related to withdrawal, and p27 deficiency may be related to the immortality of this cell line. It is possible for p16 to stop proliferation of lens epithelial cells like progressing posterior capsular opacification, by overexpression to mimic contact inhibition.

Lecithin-bound superoxide dismutase in the treatment of noninfectious corneal ulcers.

PURPOSE: To evaluate the effects of a lipophilic analog of superoxide dismutase in the treatment of persistent epithelial defects of the cornea. DESIGN: Interventional case series. METHODS: Nineteen eyes of 19 patients with noninfectious corneal ulcers were enrolled. Patient profiles consisted of seven cases with Mooren-type peripheral ulcers, three cases with chemical or thermal burns, two cases with vernal keratoconjunctivitis, four cases with cicatricial keratoconjunctivitis, and three cases with sterile ulcers after corneal surgery. Patients consisted of 11 men and 8 women, with a mean age of 51.5 +/- 17.9 years (range, 14-77). Only patients who did not respond to conventional therapy were recruited for the study. Lecithinated superoxide dismutase was applied for 2 weeks, and sketches and/or fluorescein slit micrographs were recorded before and at the end of the study. The main outcome measure was decrease in ulcer size. RESULTS: As a group, the average ulcer size relative to the entire cornea decreased from 18.2 +/- 15.1% to 10.0 +/- 15.0% after 2 weeks (P <.05). A dramatic effect (>90% decrease in ulcer size) was observed in eight cases (100% in six cases), whereas no apparent change was found (<30% decrease in ulcer size) in five cases. The presence of polymorphonucleocytes within the ulcerated tissue was confirmed by brush cytology. CONCLUSION: Lecinthinated superoxide dismutase was effective in decreasing persistent epithelial defect size in a subset of patients with sterile corneal ulcers refractive to conventional therapy. A large-scale clinical investigation is merited.

Safety comparison of additives in antiglaucoma prostaglandin (PG) analog ophthalmic formulations.

PURPOSE: To investigate the safety of five types of antiglaucoma prostaglandin analog ophthalmic formulations, and to clarify their differences in accordance with contained additives (preservatives and surface-active agents). METHODS: THE FOLLOWING FIVE TYPES OF OPHTHALMIC SOLUTIONS AND THREE TYPES OF ADDITIVES WERE INVESTIGATED: latanoprost (Xalatan(®); latanoprost), tafluprost (Tapros(®); tafluprost), bimatoprost (Lumigan(®); bimatoprost), travoprost (Travatan(®); travoprost), travoprost (Travatan Z(®); travoprost-Z), benzalkonium chloride (BAK), polyoxyethylene hardening castor oil 40 (HCO-40), and polysorbate 80 (P-80). These experimental solutions were exposed to the cultured cells of a rabbit-derived corneal cell line for a certain time, and the exposure time causing 50% cell damage (CD50), indicated by the ratio of viable cells to total cells was calculated (in vitro). In addition, corneal resistance (CR) was measured and CR ratio (post-treatment CR/pretreatment CR × 100) was calculated (in vivo). RESULTS: CD50 of each ophthalmic solution was the longest with tafluprost, followed by travoprost-Z, bimatoprost, travoprost, and latanoprost. CD50 of 0.005%, 0.01%, and 0.02% BAK was 14.5 minutes, 8.1 minutes, and 4.0 minutes, respectively. The number of viable cells decreased to 60%, 8 minutes after exposure with HCO-40, and 30 minutes after being exposed to P-80. The CR ratio was 81.0% with travoprost and 82.0% with latanoprost, indicating a significant posttreatment reduction of CR (P < 0.05). The CR ratio did not decrease after treatment with tafluprost, travoprost-Z, or bimatoprost. The CR ratio of 0.005%, 0.01%, and 0.02% BAK was 105.0%, 90.5%, and 68.7%, respectively, and that of HCO-40 and P-80 was 108.7% and 114.2%, respectively. CONCLUSION: BAK, HCO-40, and P-80 were thought to be involved in corneal injuries caused by each ophthalmic solution. Corneal injuries due to surface action were observed when using HCO-40 and P-80. When HCO-40 was combined with BAK, it induced micellar BAK and reduced corneal injuries by BAK.

Identification of the COL2A1 mutation in patients with type I Stickler syndrome using RNA from freshly isolated peripheral white blood cells.

Stickler syndrome type I is caused by mutations in the type II collagen gene (COL2A1), which is specifically expressed in cartilage and vitreous humor. We developed a simple and noninvasive strategy for identifying the COL2A1 mutation using RNA from freshly isolated peripheral white blood cells and identified a new 3' splice site mutation in a Japanese family with Stickler syndrome. RNA was isolated from a patient's peripheral white blood cells that had been incubated with cycloheximide, an inhibitor of nonsense-mediated mRNA decay. COL2A1 cDNA fragments covering the entire coding region were obtained by RT-polymerase chain reaction cloning using a high-fidelity DNA polymerase and sequenced. Whole sequencing of the patient's cDNA resulted in identification of a 49-bp deletion in the region corresponding to exon 18. The deletion introduced a premature termination codon. Targeted genome sequencing identified a base substitution at the A (-2) position of the 3' splice acceptor site of intron 17. This mutation led to utilization of the cryptic splice site, which is located 49 bases downstream of the normal splice site and causes aberrant mRNA splicing, resulting in a 49-base deletion in the patient's mRNA. Our method is much easier than conventional genomic screening and provides a simple and noninvasive diagnostic test for patients with Stickler syndrome.