Hitoshi Ishigooka

Quantitative Analysis of Lens Changes After Vitrectomy by Fluorophotometry

We measured the amount of autofluorescence in the lens to evaluate quantitatively lens changes after vitrectomy. Thirteen phakic patients, ranging in age from 12 to 75 years, were studied after unilateral vitrectomy, with a follow-up period of more than two years (range, 26 to 55 months). Autofluorescence in the lens was measured at the center along the ocular axis by fluorophotometry. Lens autofluorescence in the eyes that underwent vitrectomy was significantly higher than in the contralateral eyes that were not operated on (P = .0003). The increase of autofluorescence was correlated significantly with the age at time of vitrectomy (P = .0008). There was no correlation between the increase in autofluorescence and the length of postoperative follow-up or the use of air during vitrectomy. Based on these results, we believe that oxidation of lens proteins intraoperatively may be one of the causes of development of nuclear cataract after vitrectomy.

Increasing cell density down-regulates the expression of acidic FGF by human RPE cells in vitro

Previous studies have reported the expression of acidic fibroblast growth factor (aFGF) by rat, bovine, and human retinal pigment epithelium (RPE) in vivo. To critically examine the expression of aFGF by RPE cells, we studied the density dependence of steady-state levels of mRNA and protein expression in vitro. Northern blot analysis demonstrated 5 transcripts ranging from 4.5 kB to 1 kB. Steady-state levels of all the transcripts decreased as a function of culture density. A polyclonal antibody was raised against recombinant human aFGF and affinity purified on aFGF coupled to AffiGel-10. The resulting antibody crossreacted with bFGF but not FGF-5, but this crossreactivity could be eliminated by absorption of the antibody on bFGF coupled to AffiGel-10. The final antibody preparation recognized only a single band at approximately 18.5 kD in lysates of RPE. Immunohistochemical staining with this antibody preparation demonstrated a marked dependence on cell density after 3 days in culture. Low culture density yielded cells staining moderately for aFGF, while confluent cells exhibited little or no staining. The reduction of aFGF from RPE cells in culture in a density-dependent fashion could also be demonstrated by Western blot analysis.

Vitreous seeds in retinoblastoma, clinical significance and ultrastructure.

Vitreous seeds in retinoblastoma were studied clinically and pathologically. Vitreous seeds were found in 36.6% of retinoblastoma eyes. When tumors involved more than three quadrants of the retina and vitreous seeds were present, the prognosis was poor. When the tumor involved less than one-quarter of the retina, vitreous seeds were rare. Vitreous seeds were found most frequently in cases of undifferentiated tumor cells and endophytum type of proliferation. Although most vitreous seeds were necrotic tumor cells, some were almost intact tumor cells which were apt to be situated along blood vessels. The blood vessels in vitreous seeds had no pericytes and were derived from the tumor itself. Thus it is possible that tumor cells in the vitreous body can migrate to the anterior segment of the eye. Some tumor cells in vitreous seeds had much cytoplasm which contained mitochondria, ribosomes, fibrils, centrioles, and cilia with a presumed photoreceptor outer segment and intercellular junctions. These cytoplasmic features are very similar to those of neuroepithelial-type retinoblastoma cells. Undifferentiated cells were necrotic. Calcium deposition was found mainly in the necrotic cytoplasm of the tumor cells and occasionally on the chromatin granules of the nucleus. This may provide evidence that calcium can be bound to DNA to form radiopaque masses. No calcium-producing cells were found. Vitreous seeds contain a small number of almost intact tumor cells which are neuroepithelial in type, but most cells are necrotic. Although tumor cells may migrate to the anterior segment of the eye along or through blood vessels, the presence of vitreous seeds in itself is not always a bad prognostic sign. The prognosis is probably more closely related to the extent of the invasion of a tumor associated with vitreous seeds. Glaskörper-Absiedlungen beim Retinoblastom wurden klinisch und histo-pathologisch untersucht. In 36,6% der Fälle wurden bei der klinischen Untersuchung Glaskörper-Absiedlungen in Retinoblastom-Augen gefunden. Wenn die Tumoren mehr als 3 Quadranten der Retina einnahmen und Glaskörper-Absiedlungen vorhanden waren, so war die Prognose schlecht. Wenn der Tumor mehr als 1 Quadranten der Retina befallen hatte, waren Glaskörper-Absiedlungen selten. Glaskörper-Absiedlungen wurden hauptsächlich in Fällen von undifferenzierten Tumorzellen und beim endophytischen Proliferationstyp gefunden. Obwohl die meisten Glaskörper-Absiedlungen nekrotische Tumorzellen waren, so bestanden doch einige aus fast völlig intakten Tumorzellen, die mit Bevorzugung entlang der Blutgefäße lagen. Die Blutgefäße in den Glaskörper-Absiedlungen hatten keine Pericyten und leiteten sich vom Tumor selbst her. Auf diese Weise ist es möglich, daß Tumorzellen im Glaskörperraum wandern können zum vorderen Augensegment. Einige Tumorzellen in Glaskörper-Absiedlungen hatten viel Cytoplasma, welches Mitochondrien, Ribosomen, Fibrillen, Centriolen und Cilien-ähnliche Fortsätze mit einem vermuteten Fotorezeptoraußensegment und intercellulären Verbindungen. Diese cytoplasmatischen Bilder sind sehr ähnlich den Retinoblastomzellen vom neuroepithelialen Typ. Undifferenzierte Zellen waren nekrotisch. Kalkniederschläge wurden vorwiegend im nekrotischen Cytoplasma gefunden und gelegentlich auf den Chromatinkörnern des Nukleolus. Sie mögen zu der Vermutung beitragen, daß Kalzium sich mit DNA verbinden kann, um Massen zu bilden, die im Röntgenbild einen Schatten geben. Zellen, die Kalzium produzieren, wurden nicht gefunden. Zusammenfassend wird festgestellt, daß Glaskörper-Absiedlungen eine kleine Zahl von fast intakten Tumorzellen enthalten, welche vom neuroepithelialen Typ sind; die meisten Zellen sind jedoch nekrotisch. Obwohl Tumorzellen zum vorderen Segment entlang oder mit den Blutzellen wandern können, so ist doch die Anwesenheit von Glaskörper-Absiedlungen selbst nicht immer ein schlechtes prognostisches Zeichen. Die Prognose ist wahrscheinlich eher abhängig von der Ausdehnung des Tumors, welcher von Glaskörper-Absiedlungen begleitet ist.

Surgical techniques and visual prognosis in retinal detachment due to macular hole.

In 250 eyes with retinal detachment due to macular hole, the visual prognosis of each surgical technique was evaluated. (1) Macular diathermy adversely affected the visual prognosis. (2) Macular buckling+macular diathermy produced a poorer visual prognosis than macular buckling alone. (3) The visual prognosis resulting from gas tamponade alone or vitrectomy+gas tamponade was better than that resulting from macular diathermy. It is not clear whether there is a significant difference in visual prognosis between gas tamponade alone and vitrectomy+gas tamponade. (4) Macular laser photocoagulation does not adversely affect the visual prognosis. Judging from these results, gas tamponade, which has the possibility of better visual prognosis and less operation stress, should be selected as the initial technique.

Cytochemical studies of transitional area between retina and optic nerve

Abstract We have investigated the fine structural features of the transitional area between retina and optic nerve with special emphasis on the identification of Müller cells using the cytochemical method for detecting the localization of G6Pase activity, which is specific to the endoplasmic reticulum (ER) of Müller cells in the guinea pig retina. This cytochemical method enabled us to differentiate Müller cells from astrocytes or other cells easily and also allowed topographical, three dimensional analysis by high voltage electron microscopy because of the high contrast of the reaction products. Our study demonstrates that Müller cells are a major constitutional element of intermediary tissue of Kuhnt, which is considered to be the possible site of barrier between optic nerve and retina. These findings may indicate that Müller cells contribute to the barrier function in this region of the eye.

Combined Cytochemical Detection of Müller-Cell-Specific Enzyme Activity and Permeability Tracers

A combination of cytochemical methods in one tissue section was studied in order to detect the contribution of Müller cells to the blood-ocular barrier. Applications are shown for the detection of Müller cells and peroxidatic enzymes. The following advantages of the present method were demonstrated: superior sensitivity of glucose-6-phosphatase (G6Pase) activity, which allows the detection of these cells even in the coagulated retina. The reaction products showed no deleterious change after a subsequent reaction. These factors, and the contrasting reaction products of G6Pase and the enzymatic tracers (especially those of horseradish peroxidase) allow the distinction of Müller cells and the functional barrier site.

Regeneration of damaged ciliary epithelium in aphakic and pseudophakic eyes.

Mechanically damaged ciliary epithelium in aphakic and pseudophakic rabbit eyes was studied for up to 2 years after extracapsular lens extraction. Histopathological examination of the epithelium revealed more severe damage in pseudophakic eyes. The nonpigmented epithelium (NE) was missing from the middle to basal portion of each ciliary process. Regenerative ability of the NE was extremely poor. The damaged NE continued to disappear for at least 2 years, and only the pigmented epithelium (PE) covered the stroma. In some of the affected areas, the stroma of the ciliary body (CB) was substituted by fibrous materials.