Abscisic acid supports colonization of Eucalyptus grandis roots by the mutualistic ectomycorrhizal fungus Pisolithus microcarpus.

The pathways regulated in ectomycorrhizal (EcM) plant hosts during the establishment of symbiosis are not as well understood when compared to the functional stages of this mutualistic interaction. Our study used the EcM host Eucalyptus grandis to elucidate symbiosis-regulated pathways across the three phases of this interaction. Using a combination of RNA sequencing and metabolomics we studied both stage-specific and core responses of E. grandis during colonization by Pisolithus microcarpus. Using exogenous manipulation of the abscisic acid (ABA), we studied the role of this pathway during symbiosis establishment. Despite the mutualistic nature of this symbiosis, a large number of disease signalling TIR-NBS-LRR genes were induced. The transcriptional regulation in E. grandis was found to be dynamic across colonization with a small core of genes consistently regulated at all stages. Genes associated to the carotenoid/ABA pathway were found within this core and ABA concentrations increased during fungal integration into the root. Supplementation of ABA led to improved accommodation of P. microcarpus into E. grandis roots. The carotenoid pathway is a core response of an EcM host to its symbiont and highlights the need to understand the role of the stress hormone ABA in controlling host-EcM fungal interactions.

Use of novel devices for control of intraocular pressure.

This brief review in honor of Douglas Johnson, MD describes the rationales and initial clinical outcomes in studies to date on Trabectome, Glaukos iStent, iScience (canaloplasty), and Solx (suprachoroidal shunt), all newly developed surgical technologies for treatment of open-angle glaucomas. These new approaches to angle surgery have been demonstrated in preliminary case series to safely lower IOP in the mid-teens with far fewer complications than expected with trabeculectomy and without anti-fibrotics. Trabectome and iStent are relatively non-invasive, aim to improve access of aqueous to collector channels and do not preclude subsequent standard surgery. Canaloplasty, modified from viscocanalostomy, is thought to improve trans-trabecular flow. Solx potentially offers an adjustable aqueous outflow into the suprachoroidal space.

Initial clinical experience with the trabecular micro-bypass stent in patients with glaucoma.

This study was undertaken to evaluate the efficiency of a trabecular micro-bypass stent designed to allow direct aqueous drainage from the anterior chamber into Schlemm's canal in patients with glaucoma. In this prospective case series of 6 patients with open-angle glaucoma, the microstent was inserted ab interno under local anesthesia in an ophthalmic operating room. Patients were seen postoperatively at 1 to 2 d, 1 wk, and 1, 2, 6, and 12 mo. All stents were successfully placed within Schlemm's canal. Mean intraocular pressure (IOP) at preoperative baseline was 20.2+/-6.3 mm Hg (range, 14-31 mm Hg). Mean IOP decreased during the immediate postoperative period to approximately 12 to 13 mm Hg and was stabilized at 14 to 15 mm Hg with reduction of medication throughout 1 y of follow-up. No major complications occurred. According to observations reported in this feasibility study, the microstent was effective in reducing IOP and in decreasing the number of glaucoma medications required to control IOP. Implantation procedures were safe, and stents remained in place throughout the follow-up period. None of the complications traditionally associated with filtering surgery were reported. Further research on this stent in a larger group of patients is needed to assess its role in glaucoma therapy.

Clinical experience with the double-plate Ahmed glaucoma valve.

PURPOSE: To evaluate the clinical efficacy and safety of the double-plate Ahmed Glaucoma Valve. DESIGN: Multicenter, retrospective observational case series. METHODS: We reviewed 50 eyes in 50 patients treated with the double-plate Ahmed Glaucoma Valve with mean follow-up of 11.7+/-7.9 months. RESULTS: Average intraocular pressure was reduced from 36.0+/-12.4 mm Hg before surgery to 15.8+/-7.7 mm Hg at the most recent follow-up after surgery (P<.001). The number of glaucoma medications was decreased from 3.3+/-0.8 before surgery to 1.4+/-1.4 after surgery (P<.001). The percent of success was 76% of eyes at the latest follow-up. Choroidal effusion occurred in four eyes (8%) and did not require surgical treatment in any eye. CONCLUSIONS: Despite a poor prognosis group of patients in this study, the double-plate Ahmed Glaucoma Valve was effective in lowering intraocular pressure with a low incidence of complications associated with hypotony.

Tenon's traction sutures: an aid for trabeculectomy and aqueous drainage device implantation.

PURPOSE: To describe a surgical technique to improve visualization and surgical access for trabeculectomy and implantation of aqueous drainage devices. MATERIALS AND METHODS: After the corneal traction suture (6-0 polygalactin; S-29 needle) is placed, a second suture is passed through Tenon's capsule alone, either at the anterior edge of a limbus-based conjunctival flap for trabeculectomy or at the incisional edge of a fornix-based conjunctival flap for drainage implant surgery. RESULTS: The incision for limbus-based peritomies must be posterior enough to take advantage of the posterior thickening of Tenon's capsule when placing the traction suture. The use of traction sutures enhances visualization and limbal surgical access for trabeculectomy. They also enhance posterior ocular surface visualization and aid placement of scleral fixation sutures for securing the explants of aqueous drainage devices. CONCLUSIONS: Tenon's traction sutures are an aid to visualization and to surgical access during glaucoma filtering surgery.