The use of live-animal micro-computed tomography to determine the effect of a novel phospholipase A2 inhibitor on alveolar bone loss in an in vivo mouse model of periodontitis.

BACKGROUND AND OBJECTIVE: Live-animal micro-computed tomography is a new and promising technique that can be used to quantify changes in bone volume for periodontal disease models. The major aim of this study was to develop the methodology of live-animal micro-computed tomography and to determine the effect of a novel secretory phospholipase A2 inhibitor on alveolar bone loss. MATERIAL AND METHODS: Periodontitis was induced in mice by oral infection with Porphyromonas gingivalis over a period of 13 wk, and live-animal micro-computed tomography scans were taken at different time-points to determine bone volume changes with disease progression. This enabled conclusions to be made as to when treatment was most likely to be effective. In addition, the model was used to investigate a novel drug, the secretory phospholipase A2 inhibitor, KHO64, and its potential ability to inhibit osteoclast bone resorption and treat periodontitis. RESULTS: The results from live-animal micro-computed tomography scans revealed greater, statistically significant, bone volume loss in diseased mice compared with normal mice (p < 0.05). This corresponded to a larger area from the cemento-enamel junction to the alveolar bone crest, as assessed by stereo imaging (p < 0.001). These techniques can therefore detect and quantify alveolar bone loss. Both methods revealed that KHO64 had no significant effect on the volume of bone resorption. CONCLUSION: Live-animal micro-computed tomography is a robust, reproducible technique that clearly demonstrates significant time-dependent changes in alveolar bone volume in a small-animal model of periodontitis.

Microcephaly-lymphedema-chorioretinal dysplasia: a unique genetic syndrome with variable expression and possible characteristic facial appearance.

We report on a follow-up examination of a family with microcephaly and lymphedema. The finding of chorioretinal dysplasia with variable visual deficit in multiple relatives, which was not previously discovered, supports the concept of microcephaly, lymphedema, and chorioretinopathy as being a single autosomal dominant genetic entity with variable expression. We recommend that fundoscopic examination be performed in all patients with microcephaly with or without lymphedema.

Effect of scleral buckling on unsutured cataract wound strength.

BACKGROUND AND OBJECTIVE: Modern cataract surgery has evolved to include small, unsutured wounds with rapid visual rehabilitation and fewer complications. Properly constructed, these unsutured wounds can withstand increased intraocular pressures without leakage, rupture, or incarceration of intraocular contents. However, scleral buckling surgery may alter the architecture of these wounds and thus their strength. The authors wanted to study the effect of scleral buckling on the integrity of these unsutured cataract wounds. MATERIALS AND METHODS: Eighteen fresh human globes underwent creation of scleral and limbal corneal incisions so as to create self-sealing wounds. Scleral buckles were then placed. Intraocular pressures were elevated to 400 mm Hg before and after placement of the scleral buckles and evidence for wound leakage was sought. RESULTS: Two globes with clear corneal incisions and no scleral buckles leaked slightly at 300 mm Hg, but no globe with a scleral buckle, regardless of incision type or silicone element style, leaked at pressures to 400 mm Hg. CONCLUSION: Sutureless cataract incisions, if properly constructed, provide a strong, pressure-resistant wound. Scleral buckling does not appear to affect the strength of these wounds.

Age-related changes of glycosidases in human retinal pigment epithelium.

This study was undertaken to determine whether there are age-related changes in the specific activities of several glycosidases in fresh retinal pigment epithelial cells (RPE) isolated from the posterior pole of human donor eyes. One hundred and twenty-one pairs of eyes from human donors, between the ages of 43 and 95 years, were obtained from the National Disease Research Interchange (NDRI, Philadelphia, PA) and the Cleveland Ohio Eye Bank within 18 to 24 h of death. None had histories of diabetes, hepatitis, HIV infection, intraocular surgery, or documented age-related macular degeneration, although several older donors with evidence of drusen were included in the study. RPE cells were isolated from the posterior third of the retina using the conventional rush method and homogenized with a glass, Broeck tissue grinder. All post-nuclear supernatants were analyzed for glycosidase activity; a smaller number of nuclear pellets were assayed to verify that the majority of the enzyme activity was associated with the post-nuclear sypernatants. Glycosidase activity was quantitated fluorometrically by measuring the enzymatic release of umbelliferone from synthetic substrate preparations, specific for each enzyme. Total protein was determined by a micro BCA protein assay. Regression analysis revealed statistically significant age-related decreases for the specific activities of alpha-mannosidase (p = 0.0001), beta-galactosidase (p = 0.0001), N-acetyl-beta-glucosaminidase (p = 0.0001), and N-acetyl beta galactosaminidase (p = 0.0001) in fresh human donor RPE cells taken from the region of the posterior third of the retina that included the macula. Mannose and N-acetyl-glucosamine are major carbohydrate monomers of the oligosaccaride chains of human rhodopsin, and a relatively high percentage of the oligosaccharide chains are galactosylated. Defects in their degradation may lead to the accumulation of undigested residual material in the RPE.

Chorioretinal folds. A comparison of unilateral and bilateral cases.

We retrospectively reviewed the records, photographs, and fluorescein angiograms of patients with chorioretinal folds to compare features of unilateral and bilateral involvement. We studied 78 eyes of 54 patients and found that 30 (56%) of these patients had unilateral folds and 24 (44%) had bilateral folds. No significant difference was found in comparing visual acuity, refractive error, age, or race in the unilateral vs the bilateral cases. There were significantly more women in the bilateral group (P = .043). The frequency of causes of unilateral cases differed from bilateral cases, but this could not be statistically proven owing to our small sample size. This analysis contains the largest number of chorioretinal folds reported in the literature, and is the first attempt to compare unilateral and bilateral cases.

A simple method for practicing unimanual pars plana vitrectomy with the binocular indirect ophthalmoscope.

Bimanual vitrectomy has become the method of choice for performing closed vitrectomy. In certain situations, visualization is improved by using indirect ophthalmoscopy to see the vitrectomy instrument. A simple method using a +20.00-diopter condensing lens is described as a means of practicing the initially difficult unimanual technique, which requires working in an inverted operative field.

Ocular thrombosis associated with antiphospholipid antibodies.

Four patients with isolated acute ocular ischemic syndromes also had circulating antiphospholipid antibodies. Two patients had vaso-occlusive retinopathy and two, anterior ischemic optic neuropathy (which was successive in one). Extensive clinical laboratory evaluation identified vascular risk factors in two patients. One patient had essential thrombocytosis, confirmed by bone marrow biopsy; the other had stable hypertension and a history of coronary artery disease. These cases suggest that small vessel thrombosis in situ may be a mechanism for antiphospholipid-associated ocular and cerebral ischemia.

Scleral fixation suture for dislocated posterior chamber intraocular lens.

The posterior dislocation of an intraocular lens is a serious complication of extracapsular cataract extraction with implantation of a posterior chamber intraocular lens. We describe a method of repositioning and suturing such a lens, using pars plana techniques. The method we recommend has several advantages over previously described methods, including the use of radially oriented scleral fixation sutures.

A donor-age-dependent change in the activity of alpha-mannosidase in human cultured RPE cells.

Six acidic glycosidase activities in cultured human retinal pigment epithelium (RPE) cells from donors of different ages (19 to 80 years) were studied with regard to pH optimum, Km, Vmax and specific activity. For alpha-mannosidase we found significant age-dependent decreases in specific activity and Vmax but not in Km. The other glycosidases and acid phosphatase, lactate dehydrogenase (LDH) and citrate synthase showed no change in these parameters with donor age. The alpha mannosidase activity of older donor cells could be activated almost 2-fold by the addition of zinc. This is the first report of age-dependent change in a human RPE lysosomal enzyme. Since alpha-mannosidase is probably required for the degradation of rhodopsin in the phagolysosomal system of the RPE, decrease in this enzyme activity may lead to accumulation of undigested rod outer segments (ROS) and drusen, both of which are associated with age-related macular degeneration (AMD).

Sustained release of 5-fluorouracil from ethylene acetate copolymer.

Pharmacologic inhibition of fibroblast proliferation and scar formation remains an important consideration in many ophthalmologic surgical procedures. Such inhibition is particularly important in glaucoma filtration surgery. A sustained release system for 5-fluorouracil (5-FU) using ethylene vinyl acetate copolymer (Elvax) was characterized in vitro. 5-FU was incorporated into Elvax discs of 4 mm diameter. Discs were coated to allow sustained and predictable release over a 14 day period. Alteration of coatings, which act as rate-controlling membranes, allowed variation in the pattern of 5-FU release from the core which acts as the drug reservoir. This system for the sustained release of 5-FU may prove valuable in glaucoma surgery where the suppression of cellular proliferation is desired. The non-inflammatory nature of Elvax suggests this compound may provide an alternative means of 5-FU delivery.

Lysosomal enzyme levels in corneal storage media. K-Sol versus McCarey-Kaufman.

Evidence indicates that lysosomal enzymes can carry out corneal autolysis during corneal storage and that they are damaging to the corneal endothelium. The authors investigated the release of lysosomal enzymes into two corneal storage media (K-Sol and McCarey-Kaufman [M-K]) by paired human donor corneas during 4 degrees C storage. The authors also studied the interaction of these media with lysosomal enzymes from human cornea. K-Sol and M-K stimulated (P less than 0.01) both beta-glucuronidase and alpha-galactosidase about equally. beta-N-Acetyl-glucosaminidase, a major catabolic enzyme of the cornea, was inhibited by the chondroitin sulfate in K-Sol by over 90% (P less than 0.01). Corneas stored in M-K released more lysosomal enzymes than corneas stored in K-Sol. At 4 days, the values approached significance (P less than 0.06) and by day 10 significantly higher values were found in the M-K media (P less than 0.01). Both storage methods showed a linear release. Individual corneas were found to vary in their release rates. Whether corneas that release more enzyme will show higher endothelial cell loss or produce less successful penetrating keratoplasty grafts deserves further study.

Bilateral retinal detachments in thrombotic thrombocytopenic purpura.

Bilateral serous retinal detachments are rare complications of thrombotic thrombocytopenic purpura (TTP). We report the case of a 28-year-old woman with chronic relapsing TTP with bilateral serous retinal detachments, which resolved after prompt aggressive medical therapy. Unlike several previous reports, the retinal detachments in our patient were unrelated to systemic hypertension.

Indirect choroidal rupture secondary to blunt ocular trauma. A review of eight eyes.

We retrospectively studied eight eyes of seven patients sustaining indirect choroidal rupture secondary to blunt trauma. Clinical and fluorescein angiographic findings were reviewed. The ruptures were single in five eyes and multiple in three eyes. Four eyes contained macular ruptures, and three eyes contained extramacular ruptures. Peripapillary ruptures were noted in three eyes. Three eyes developed subretinal neovascularization as a complication. Location of the rupture but not visual acuity at presentation was predictive of visual outcome. All ruptures were concentric with the optic nerve and vertically oriented, consistent with a break in Bruch's membrane and an associated tethering effect by the optic nerve.

Evidence of subclinical extrapyramidal hemosiderosis in cystic fibrosis.

We are presenting evidence of subclinical extrapyramidal hemosiderosis in chronic cystic fibrosis (CF) by histological staining and quantitative analysis. Comparison was made between age-matched control (eight cases) and CF brains (14 cases). None of the CF patients had extrapyramidal or other focal CNS symptoms but showed an increased iron pigment, and four cases had a few dystrophic axons (DA) in pallidonigral areas. Histological stain revealed significantly increased iron pigment in pallidonigral and subthalamic nuclei (P less than 0.05, 0.01, 0.01, respectively). The pigment was located in astrocytes, macrophages, neuronal perikarya, and neuropils. The increase was directly proportional to age and numbers of DA in nucleus gracilis/cuneatus. As in previous reports [5, 22], the numbers of DA in nucleus gracilis/cuneatus were higher in CF (P less than 0.01) and varied directly with age (correlation coefficient 0.72). Quantitative analysis disclosed an upward trend of mean iron content in pallidonigral areas. Aluminum was detected in four cases of CF but not in the controls.