Macular configuration determined by optical coherence tomography after idiopathic macular hole surgery with or without internal limiting membrane peeling.

AIMS: To evaluate the effect of pars plana vitrectomy (PPV) with or without internal limiting membrane (ILM) peeling on the closure and configuration of idiopathic macular holes (IMH). METHODS: PPV was performed for IMH on 44 eyes with ILM peeling (ILM peeled group) and on 42 eyes without ILM removal (ILM preserved group). Optical coherence tomography (OCT) was performed on 34 ILM peeled eyes and 14 ILM preserved eyes after successful surgery. The repaired macular holes were classified by the OCT images as being of "good shape" (nearly normal foveal contour) or "poor shape" (abnormal foveal contour with flat fovea and steep edge, or with a thick retina without a foveal pit). RESULTS: The anatomical closure rate was significantly higher in the ILM peeled group (93.2%) than in the ILM preserved group (76.2%) (p = 0.028). In the ILM peeled group, 31 eyes had a fovea of good shape and three eyes had a fovea with a poor shape, while in the ILM preserved group, six eyes had a fovea of good shape and eight eyes had a fovea of poor shape. The percentage of eyes with good macular configuration in the ILM peeled group was significantly higher than in the ILM preserved group (p = 0.0003). No significant difference was found in the postoperative visual acuity and the increase of visual acuity between the ILM peeled group and the ILM preserved group (p = 0.26, and p = 0.91 respectively). There was also no significant difference in the postoperative visual acuity and improvement in visual acuity between eyes with a fovea of good shape and those with fovea of poor shape fovea (p = 0.99 and p = 0.66, respectively). CONCLUSIONS: ILM peeling may provide better anatomical success and recovery of the macular shape, but the postoperative visual acuity and improvement of visual acuity were not related to the morphological results.

Early attachment of uncultured retinal pigment epithelium from aged donors onto Bruch's membrane explants.

Retinal pigment epithelium (RPE) transplantation might replace cells lost as a consequence of choroidal neovascular membrane excision in patients with age-related macular degeneration (AMD). Autologous transplantation of RPE cells harvested from a peripheral biopsy may overcome problems of immune rejection. To study the feasibility of autologous RPE cell transplantation, the authors examined the attachment of freshly harvested RPE cells from aged donors onto Bruch's membrane explants, debrided to (1) remove or (2) preserve the RPE basement membrane. Human retinal pigment epithelial sheets were harvested from adult donor eyes (N = 12, mean age 79.00 +/- 9.40 years) and, following incubation in collagenase, were mechanically fragmented into microaggregates. Microaggregates (approximately 120 000 cells) were seeded onto the paired explants (7 mm diameter) and incubated for 20 min, 1, 4, or 24 hr at 37 degrees C. The percent coverage of the debrided surface by microaggregates was determined by sampling the center of the explants with scanning electron microscopy. RPE microaggregate attachment to Bruch's membrane was significantly greater at all time points analysed in samples with intact basement membrane versus those with an exposed inner collagenous layer. Coverage of debridements retaining intact RPE basement membrane was 1.83 +/- 1.10% at 20 min, 3.54 +/- 2.14% at 1 hr, and 8.68 +/- 2.63% at 4 hr. Coverage of debridements lacking basement membrane was 0.10 +/- 0.04% at 20 min, 0.39 +/- 0.25% at 1 hr, and 0.63 +/- 0.42% at 4 hr. Based on their morphologic appearance, many cells were dying as early as 1 hr following seeding. To increase surface coverage, the authors seeded four times the above number of cells and incubated the specimens for 1 hr. Coverage on explants lacking RPE basement membrane showed no increase in the number of cells attached to the inner collagenous layer. There was a significant approximately three-fold increase in the number of cells attached in the presence of basement membrane. These results indicate that if RPE cells from aged human donors are used for transplantation, some modification of the Bruch's membrane surface or the cells must be considered for cell attachment and eventual cell survival.

Short-term study of allogeneic retinal pigment epithelium transplants onto debrided Bruch's membrane.

PURPOSE: To investigate the survival and behavior of retinal pigment epithelium (RPE) microaggregates transplanted onto hydraulically debrided Bruch's membrane and to compare results of using three different vehicles for cell delivery. METHODS: RPE microaggregates obtained from male cats were transplanted onto the tapetal area of female cats after native RPE was debrided. For the control, one of three vehicles was introduced into the debridements. Each transplant or control specimen was analyzed histologically and immunohistochemically. Transplanted male RPE cells were identified by in situ labeling of the cat Y chromosome. RESULTS: Histologically, significant numbers of condensed, darkly stained RPE nuclei were observed in all transplants compared with few TUNEL-positive RPE cells. Cellular retinaldehyde-binding protein was present up to day 7 in all RPE cells in transplants. In both transplant and control specimens, the antibody against the Ki-67 nuclear antigen labeled some RPE cells at day 3. TUNEL-positive outer nuclear layer nuclei were most frequently observed at day 1, but were much less frequent at 7 days in both transplant and control specimens. CONCLUSIONS: Transplanted RPE appeared to retain at least some markers of differentiation up to 7 days after surgery. Some proliferation of transplanted RPE cells was also seen. Apoptotic cell death of transplanted RPE, as judged by TUNEL staining was observed rarely. RPE transplants imposed no adverse effect on the overlying retina. RPE survival appeared to be similar with each of the three vehicles for cell delivery.

Surgical outcomes in juvenile retinal detachment.

PURPOSE: To evaluate retrospectively clinical features and surgical outcomes of rhegmatogenous retinal detachment in juvenile patients. METHODS: Between 1991 and 1996, 28 patients younger than 15 years of age with rhegmatogenous retinal detachment (32 eyes) underwent the first surgical procedure, scleral buckling and/or pars plana vitrectomy, at our hospital. RESULTS: The major types of juvenile detachment, in order of frequency, were idiopathic, familial exudative vitreoretinopathy, trauma, and high myopia. Proliferative vitreoretinopathy (PVR) of grade C or D was involved in 12 cases (37.5%). Among the 12 eyes with PVR, 7 attained retinal reattachment after the first surgery with scleral buckling. The overall reattachment rate was 28/32 (87.5%) after the first operation and 30/32 (93.8%) after the second operation. CONCLUSION: These findings indicate that the reattachment rate and visual prognosis can be as good in juvenile retinal detachment as in adult cases, when appropriate surgical procedures are used.

[Surgical outcomes of vitrectomy for retinal detachment due to macular hole with proliferative vitreoretinopathy].

We retrospectively studied surgical outcomes in 13 patients (13 eyes) who underwent vitrectomy for proliferative vitreoretinopathy (PVR) due to macular hole. While the success rate of the initial surgery was only 46% (6 eyes), retinal reattachment was ultimately obtained in 92% (12 eyes) with additional surgery. Reattachment rate in the initial was poor in eyes with posterior staphyloma. It was better in eyes treated with macular buckling and/or scleral encircling, and in eyes without iatrogenic retinal tears. These results indicate that appropriate treatment for the macular hole as well as extensive removal of vitreous gel and vitreoretinal traction are necessary in order to obtain the successful results in vitrectomy for PVR due to macular hole.

Localization of nonspecific lipid transfer protein (nsLTP = sterol carrier protein 2) and acyl-CoA oxidase in peroxisomes of pigment epithelial cells of rat retina.

We investigated the localization of nonspecific lipid transfer protein (nsLTP) in rat retina, especially in the pigment epithelial (RPE) cells, by the avidin-biotin-peroxidase complex method on cryosections for light microscopy and by the cryoimmunogold method for electron microscopy. Light microscopic observation revealed that the RPE, inner segment layer, nerve fiber layer, and Müller cells contain nsLTP. In the RPE cells gold particles were exclusively concentrated in the small peroxisomes (microperoxisomes; 0.1-0.3 micron in diameter), which were identified by double staining using anti-nsLTP and anti-catalase antibodies. In the peroxisomes gold particles were distributed homogeneously in the matrices and no preferential binding to the limiting membrane was observed. Acyl-CoA oxidase was also localized in the matrices of the peroxisomes. We suggest that the peroxisomes in RPE cells play important roles in the metabolism of lipids of the outer segment disk membranes, especially in the beta-oxidation of polyunsaturated long-chain and very long-chain fatty acids, such as docosahexaenoic acid which is composed of approximately one third of fatty acids in the disk membranes.

The effect of RO15-1788 on cardiovascular depression caused by fentanyl and diazepam.

Cardiovascular depression occurring when diazepam is combined with fentanyl has been investigated using the benzodiazepine antagonist RO15-1788 in the dog. After the initial administration of fentanyl (40 mcg/kg), the mean arterial pressure (MAP) decreased to 89% of its control value. Following the administration of diazepam (1.2 mg/kg), the MAP and the total peripheral resistance (TPR) decreased significantly, to 75% and 83% of their control values respectively. After the administration of RO15-1788 (0.4 mg/kg), the MAP increased significantly to 90% and the TPR to 102% of their control values and, lastly, the administration of naloxone (40 mcg/kg) increased the MAP to 108% of its control value. No relationship was found between the changes in the catecholamines and the changes in the MAP after the administration of fentanyl, diazepam, and RO15-1788. The mechanism of circulatory depression when diazepam was used with fentanyl is interpreted as being a peripheral vasodilatory effect of diazepam acting by way of the benzodiazepine receptors since RO15-1788 was found to antagonize this effect.

The degradation of alpha-crystallin at its carboxyl-terminal portion by calpain in bovine lens.

Bovine lens calpain (Ca2+-dependent cysteine proteinase; EC 3.4.22.17) was shown to catalyze limited proteolysis of A and B chains of alpha-crystallin in vitro. The sites of cleavages were determined by isolating and analyzing the peptide fragments formed using several different methods, including high-performance liquid chromatography, cyanogen bromide cleavage, and carboxypeptidase digestion. The results indicated that calpain cleaved both A and B chains at their respective carboxyl-terminal regions. A chain was cleaved at A(Arg163-Glu164) bond and A(Ser162-Arg163) bond, the former being split with 2.4 times preference over the latter. B chain was cleaved at B(Thr170-Ala171) bond and B (Arg163-Glu164) bond, the former being preferred 6.5 times. Peptide cleavage at any other sites were not detected by the present method of analysis.

Effects of mannitol on cerebral circulation after transient complete cerebral ischemia in dogs.

The effects of hypertonic mannitol on postischemic cerebral circulation were studied in 20 dogs. Mannitol, 2 g/kg iv, was infused into ten dogs during a 2-h period starting 1.5 h after 6 min of complete cerebral ischemia. One hour postischemia, regional cerebral blood flow (rCBF) was 36% in the control group (ten dogs) and 39% in the mannitol group. In the control group, rCBF increased gradually thereafter to 70% of the preischemic value 10 h postischemia, whereas the restoration of rCBF was suppressed in the mannitol group. During the postischemic period, intracranial pressure (ICP) increased significantly in the control group, but it did not change significantly in the mannitol group. The effects of mannitol on rCBF and ICP in the present study can be explained primarily by decreased body water due to urinary loss. The administration of mannitol does not necessarily improve postischemic cerebral circulation.

A new model for total cerebral ischemia in dogs.

We have developed a new method producing total cerebral ischemia (TCI) in dogs; clamping ascending aorta with aorto-atrial bypass formation. Clamping ascending aorta provides TCI, the duration of which can be controlled up to the periods of 10 min. Beyond this interval, it is difficult to maintain TCI because of heart failure from high afterload. Blood outflow from left ventricle is completely obstructed except for coronary circulation which is small relative to the blood volume expelled from left ventricle, even if venous return to the heart is reduced. Aorto-atrial bypass formation during aortic clamping provides two distinctive advantages. First, adjusting aortic pressure in an appropriate level low enough not to overload myocardium but still high enough to maintain sufficient coronary blood flow is possible by regulating the blood flow through the bypass tubing, and secondly drug administration and blood volume control is possible through the tubing. These result in better preservation of myocardium, enabling longer TCI and longer survivals after TCI. We were successful in having up to 18 min of TCI with this method. Seventy-five percent of dogs of 12 min TCI and 40% of 15 min TCI survived 7 days, limit of experiment, after TCI, but no dogs of 18 min TCI survived for more than 3 days.

Metabolism of glycoproteins in cultured retinal pigment epithelium.

The turnover and migration of synthesized glycoproteins in the cultured retinal pigment epithelium have been studied. Quantitative study indicated that half-time of 3H-fucosylglycoproteins was 11.6 days. Autoradiography was performed several times after incubation of 3H-fucose. Retinal pigment epithelium constantly synthesized glycoproteins and released them into the basal extracellular material. Possible functions of the glycoproteins are discussed.

Experimental chloroquine retinopathy.

Chloroquine retinopathy was produced experimentally in the eye of the albino corydoras (one of the tropical fish) by daily administration of chloroquine (0.1 mg per os). The enucleated eyes were examined from the 14th day to 3 months after the beginning of drug administration under light and electron microscopy. The first change of retina was the appearance of membraneous cytoplasmic body (MCB) in the cytoplasm of ganglion, amacrine, bipolar and horizontal cells. MCB might be degenerated lysosome. They showed lamellar figures or crystalline lattice-like structures. Secondarily, these MCB appeared in the inner segments of photoreceptor cells. The outer segments of rod cells disappeared, and then those of cone cells. Although photoreceptor cells were diminished in number in advanced degeneration, the cells of inner nuclear layer and ganglion cells were maintained in number. The presence of MCB dose not mean death of cells. The retinal pigment epithelial cells contained MCB in its cytoplasm only in severe degenerative cases, and did not show other remarkable changes. MCB also appeared in the cytoplasm of pericytes of retinal vessels. Chloroquine is considered to damage directly photoreceptor cells most severely.