Contribution to oral and maxillary surgery and surgical technique of osteo-odontokeratoprosthesis in Japan.

Osteo-odontokeratoprosthesis (OOKP) is a technique invented by Strampelli in 1963, in which the patient's own tooth root is used to support an optical cylinder. It uses an autologous tooth-bone-periodontal complex to mount an optical cylinder, which is stabilised by overlying autologous buccal mucosa. OOKP involves two, staged procedures done by ophthalmologists and oral surgeons, and the main contribution from the oral surgeon is during the first stage. To date we have done nine first-stage, and completed eight second-stage, OOKP operations in Japan with a mean follow-up of eight years and 11 months by modifying the original method of the oral surgery. All OOKP procedures were unilateral, and canines were selected as the donor teeth. Patients developed ocular blindness as a result of Stevens-Johnson syndrome, ocular cicatricial pemphigoid, and chemical and thermal burns to the cornea and ocular surface. All eight patients who completed the second stage have been stable, and there have been no major perioperative or postoperative oral complications. The patients' visual acuities were stable with no serious complications. Here we report the technical details of the oral contribution to OOKP.

Condensation of silicone oil on the posterior surface of a silicone intraocular lens during vitrectomy.

PURPOSE: We experienced a complication caused by the condensation of silicone oil on the surface of a silicone intraocular lens during pars plana vitrectomy. METHODS: A 74-year-old woman with proliferative vitreoretinopathy underwent a pars plana vitrectomy in her left eye, which contained silicone oil and a silicone intraocular lens. RESULTS: Intraoperatively, condensation of silicone oil on the posterior surface of a silicone intraocular lens caused a loss of visibility during fluid/gas exchange. The silicone oil droplets could not be removed. CONCLUSION: Surgeons should avoid direct contact of silicone oil with silicone intraocular lens.

Visual function after foveal translocation with 360-degree retinotomy and simultaneous torsional muscle surgery in patients with myopic neovascular maculopathy.

PURPOSE: To assess functional and anatomical outcomes after foveal translocation with 360-degree retinotomy and simultaneous torsional muscle surgery in patients with myopic neovascular maculopathy. METHODS: Foveal translocation with 360-degree retinotomy was performed in 11 eyes of 11 patients with myopic neovascular maculopathy. Ten eyes had simultaneous torsional muscle surgery with recession of the superior oblique muscle and tucking of the inferior oblique muscle. Silicone oil removal with or without intraocular lens implantation was performed 2 to 8 weeks after the primary procedure. Visual acuity, binocular function, and degree of cyclotorsion were assessed preoperatively and postoperatively. Angles of retinal and globe rotation, distance of foveal shift, and surgical complications were also investigated. RESULTS: With a mean postoperative follow-up of 6.2 months (range, 3 to 13 months), vision improved (greater than 0.2 logarithm of minimal angle of resolution [logMAR] units) in eight eyes, was unchanged in two eyes, and worsened (greater than 0.2 logMAR units) in 1 eye. Seven of 11 eyes (64%) had a final visual acuity of 20/50 or better. Five patients developed or maintained binocular fusion, four patients continued to have suppression, and two patients developed diplopia that was managed by spectacles with Fresnel prisms. Subjective cyclotorsion was less than 8 degrees in 10 eyes. Mean retinal and globe rotations were 23.4 degrees and 19.8 degrees, respectively. Average size of the choroidal neovascular membrane was 0.8 disk diameter, whereas the average distance of foveal shift was 1.5 disk diameter. After the primary procedure, three eyes developed retinal detachment, one eye macular hole, and one eye proliferative vitreoretinopathy. These complications were successfully managed by additional surgery. CONCLUSION: Foveal translocation with 360-degree retinotomy is effective in restoring vision in some patients with myopic neovascular maculopathy. Although the development of torsional diplopia is generally obviated by simultaneous extraocular muscle surgery, a relatively high incidence of surgical complications should be taken into account with this procedure.

Properties and biodegradability of ultra-high-molecular-weight poly[(R)-hydroxybutyrate] produced by a recombinant Escherichia coli.

Ultra-high-molecular-weight poly[(R)-3-hydroxybutyrate] (P(3HB)) (Mw = 3-11 x 10(6)) was produced from glucose by a recombinant Escherichia coli XL1-Blue (pSYL105) harboring Ralstonia eutropha H16 polyhydroxyalkanoate (PHA) biosynthesis genes. Morphology of ultra-high-molecular-weight P(3HB) granules in the recombinant cells was studied by transmission electron microscopy. The recombinant E. coli contained several P(3HB) granules within a cell. Freeze-fracture morphology of ultra-high-molecular-weight P(3HB) granules showed the needle-type as that of P(3HB) granules in R. eutropha. Both the P(3HB) granules in wet cells and wet native granules isolated from the recombinant cells proved to be amorphous on the X-ray diffraction patterns. Mechanical properties of ultra-high-molecular-weight P(3HB) films were markedly improved by stretching over 400%, resulting from high crystallinity and highly oriented crystal regions. Biodegradability of the films of ultra-high-molecular-weight P(3HB) was tested with an extracellular polyhydroxybutyrate depolymerase from Alcaligenes faecalis T1. The rate of enzymatic erosion of P(3HB) films was not dependent of the molecular weight but was dependent of the crystallinity. In addition, it is demonstrated that all ultra-high-molecular-weight P(3HB) films were completely degraded at 25 degrees C in a natural river freshwater within 3 weeks.

Reopening of macular holes in highly myopic eyes with retinal detachments.

BACKGROUND: Gas tamponade with or without vitrectomy is commonly used to treat retinal detachment resulting from a macular hole in a highly myopic eye. Redetachment of the retina occurs frequently, however, and the pathogenesis of redetachment is unclear. One possible mechanism leading to redetachment is tangential traction caused by an epiretinal membrane of the posterior retina. METHODS: Eleven consecutive highly myopic eyes with retinal detachment resulting from a macular hole were treated by vitrectomy, gas or silicone oil tamponade, and removal of an epiretinal membrane. Surgical outcomes and clinical characteristics of these patients were reviewed. RESULTS: An epiretinal membrane was found to be present in all eyes. Of 11 eyes, removal of an epiretinal membrane was complete in six eyes, and macular holes remained closed in all 6 eyes. In five of the 11 eyes, removal of the epiretinal membrane was incomplete. In four of these five eyes, the macular hole reopened. CONCLUSION: Reopening of the macular holes most likely were caused by tangential traction of the remaining epiretinal membranes. It seems that it is important to remove epiretinal membranes as completely as possible during vitrectomy for retinal detachment resulting from a macular hole in a highly myopic eye.

Molecular mass of poly[(R)-3-hydroxybutyric acid] produced in a recombinant Escherichia coli.

Poly[(R)-3-hydroxybutyric acid] (PHB) was produced at 37 degrees C by a recombinant Escherichia coli harboring the Alcaligenes eutrophus biosynthesis phb-CAB genes in Luria-Bertani media containing glucose at 10-30 g/l at different pH values and the time-dependent changes in the molecular mass of PHB were studied. PHB polymers accumulated within cells while glucose was present in the medium. The number-average molecular mass of PHB decreased with time during the course of PHB accumulation, and the values for PHB were markedly dependent on the cultivation conditions of the E. coli, ranging from 0.5 MDa to 20 MDa. Under specific conditions (pH 6.0), E. coli produced PHB with an extremely high molecular mass (20 MDa). It has been suggested that a chain-transfer agent is generated in E. coli cells during the accumulation of PHB.