Kinome siRNA-phosphoproteomic screen identifies networks regulating AKT signaling

To identify regulators of intracellular signaling we targeted 541 kinases and kinase-related molecules with siRNAs and determined their effects on signaling with a functional proteomics reverse phase protein array (RPPA) platform assessing 42 phospho and total proteins. The kinome wide screen demonstrated a strong inverse correlation between phosphorylation of AKT and MAPK with 115 genes that when targeted by siRNAs demonstrated opposite effects on MAPK and AKT phosphorylation. Network based analysis identified the MAPK subnetwork of genes along with p70S6K and FRAP1 as the most prominent targets that increased phosphorylation of AKT, a key regulator of cell survival. The regulatory loops induced by the MAPK pathway are dependent on TSC2 but demonstrate a lesser dependence on p70S6K than the previously identified FRAP1 feedback loop. The siRNA screen also revealed novel bi-directionality in the AKT and GSK3 interaction, whereby genetic ablation of GSK3 significantly blocks AKT phosphorylation, an unexpected observation as GSK3 has only been predicted to be downstream of AKT. This method uncovered novel modulators of AKT phosphorylation and facilitated the mapping of regulatory loops.

Laser in situ keratomileusis with a scanning excimer laser for the correction of low to moderate myopia with and without astigmatism

PURPOSE

To evaluate the safety and effectiveness of and patient satisfaction with laser in situ keratomileusis (LASIK) performed with a scanning excimer laser by experienced surgeons to correct low and moderate levels of myopia and astigmatism.

SETTING

Clinique Laservue, Montreal, Quebec, Canada.

METHODS

A consecutive series of 125 patients (236 eyes) with myopia of -0.5 to -7.0 diopters (D) and cylinder less than 2.5 D were enrolled in this single-center prospective clinical trial. The patients were treated with LASIK and followed for 6 months. The System-ALK Automated Corneal Shaper microkeratome (Bausch & Lomb Surgical) with a 180 microm thickness plate and the Technolas 217 excimer laser (Bausch & Lomb Surgical) with PlanoScan software for the stromal ablation were used in all procedures. Since this version of PlanoScan tended to undercorrect, a mean of 14.7% was added to the standard nomogram. Patient satisfaction was assessed by questionnaires administered preoperatively and 1 and 6 months postoperatively. Retreatments for enhancement were not performed during the 6-month follow-up.

RESULTS

Six months after LASIK (86.4% follow-up), the mean postoperative manifest spherical equivalent was +0.02 D +/- 0.64 (SD) compared with a preoperative mean of -4.01 +/- 1.59 D. The uncorrected visual acuity was 20/40 or better in 94.6% of eyes and 20/20 or better in 81.9%. A total of 91.2% were within +/-1.0 D of emmetropia and 73.0% were within +/-0.5 D. Only 2 eyes were overcorrected by >1.0 D. Of the eyes with astigmatic myopia, 86.8% were within +/-1.0 D of the intended cylinder correction (by vector analysis) and 73.0% were within +/-0.5 D. The refractions were generally stable after 1 month, and the change in refraction between postoperative examinations was within +/-0.5 D in 88.0% of eyes. A 1-line decrease in best spectacle-corrected visual acuity was seen in 11.3% of eyes, and no eye lost more than 1 line. An increase of 1 or 2 lines was seen in 45.1%. No intraoperative problems occurred, and the interface was clear in all eyes. At 6 months, most symptoms present significantly more frequently than preoperatively were "mild"; none were "marked" or "severe." A total of 90.5% of eyes were reported with marked to extreme improvement in the overall quality of vision, and 99.0% of patients said they would choose LASIK surgery again.

CONCLUSIONS

Mild to moderate myopia, with and without astigmatism, was corrected safely, effectively, and predictably with a high degree of patient satisfaction using LASIK with a scanning excimer laser and the System-ALK Automated Corneal Shaper.

Treatment of encapsulated blebs with 30-gauge needling and injection of low-dose 5-fluorouracil

We describe a simplified needling procedure, performed at the slit-lamp, with injection of low-dose 5-fluorouracil to treat encapsulated filtering blebs. Between August 1989 and December 1990 we treated 17 eyes of 14 patients with this procedure. At 2 months 13 of the eyes had needed only one needling procedure. Risk factors for reencapsulation of the bleb were a history of three or more previous surgical procedures (p less than 0.05) and prolonged preoperative use of topical adrenergic drugs (p less than 0.05). At 1 year all but one eye had an intraocular pressure below 21 mm Hg (median 15 mm Hg). Twelve of the eyes had needed more than one needling procedure. There were no serious complications of the 32 procedures performed. The incidence rate of minor complications (wound leaks, corneal erosion and small hyphemas) was 38%.

Noncontact thermal mode Nd:YAG laser transscleral cyclocoagulation in the treatment of glaucoma. Intermediate follow-up

Noncontact transscleral Nd:YAG laser thermal mode cyclocoagulation is known to reduce intraocular pressure (IOP). Thirty-five eyes were treated at a mean of 2.5 Joules and followed for a mean of 28 months. The mean preoperative IOP of 39.8 mmHg (standard deviation, 11.7) was consistently decreased by 45% to 55% over the follow-up period (standard deviation, 19.9 to 30.8), along with a significant reduction of medical therapy. This effect is comparable with that obtained by investigators using much higher energy levels. Successful control was defined as IOP between 5 and 21 mmHg for eyes with visual acuity of counting fingers or better, between 5 and 25 mmHg for eyes with hand motions to light perception, and as control of ocular pain for eyes with no light perception; 71% to 75% of the eyes were successfully controlled for up to 3 years. The use of lower energy levels appears to be associated with a lower incidence of vision loss and, therefore, merits further controlled investigation.

[The neuro-retinal rim region in early glaucoma]

The true neuro-retinal rim area of the optic disc was obtained by calculating the magnification using axial length, refraction and corneal curvature. Patients with very early chronic open angle glaucoma and normals were compared. The neuro-retinal rim area separated these two populations better than the standard cup/disc ratios. The size of the optic nerve did not appear to change with age. The implications for clinical practice are outlined.

Relationship between baring of circumlinear vessels of the optic disc and glaucomatous visual field loss

Stereo disc photographs of the eyes of 232 patients with normal or elevated intraocular pressure were reviewed to assess the value of baring of circumlinear vessels of the optic nerve head as a sign of glaucomatous damage. Baring and the presence of glaucomatous visual field defects were significantly correlated, as were this sign and consistent elevation of the intraocular pressure in patients without a visual field defect. Baring was absent in 35% of the eyes with circumlinear vessels and known glaucomatous visual field defects. However, it was present in only 6% of the eyes with normal pressure, a normal visual field and circumlinear vessels. Therefore, this sign should lead to further evaluation.