[Retinal pigment epithelial cells: the first case of transplantation in man].
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Fetal Tissue Transplantation↗
Biomedical subjects
B Ehinger
Publications and source records attributed to B Ehinger.
In vivo staining of oligodendroglia in the rabbit retina.
We have discovered that a strongly fluorescent dye, sulforhodamine 101, when injected intravitreally in vivo, very effectively stains a class of star-shaped cells in the innermost layers of the rabbit retina. The cells were strictly confined to the region containing medullated fibers and emitted dichotomously branching processes that ended up running some distance along the myelinated fibers. In favorable cases they could be seen to ensheath the fibers in a tube-like fashion. No other retinal cells were stained. Shortly (hours) after the injection, the stain appeared in the cell cytoplasm, but it later became progressively more localized to intracellular granules. Most of the dye had disappeared after 2 days. Oligodendrocytes and astrocytes are the only cells known to be confined to the region of the medullated fibers in the rabbit retina, and hence the sulforhodamine 101-stained cells should be one of these two types. Sulforhodamine 101-stained cells were indistinguishable from oligodendrocytes identified by 2',3'-cyclic nucleotide phosphodiesterase (CNP) immunohistochemistry, and sequential staining showed them to be the same. Sulforhodamine 101-stained cells were microinjected with lucifer yellow after lightly fixing rabbit retinas with formaldehyde and were found to be indistinguishable from oligodendrocytes. Glial fibrillary acidic protein staining for astrocytes showed fiber bundles that to some extent were similar to the bundles stained by sulforhodamine 101, but at the level of individual fibers, it was impossible to establish any concordance. Sulforhodamine 101 thus appears to stain oligodendrocytes rather than astrocytes in the rabbit retina. A related dye, rhodamine 123, also stained rabbit oligodendrocytes, but with poor contrast because many other cells and structures were also stained.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Development of cell markers in subretinal rabbit retinal transplants.
Retinas from embryonic rabbits at day E15 were transplanted to the subretinal space in adult rabbits. After survival times between 7 and 193 days, the rabbits were killed, and the transplants were processed for immunohistochemistry. The results show that subretinal transplants from embryonic rabbit retinas develop many, if not all, retinal neuronal types. The cells show approximately normal morphology and express a variety of cell-type-specific markers: photoreceptor cells express visual pigment proteins as identified by antibodies against rhodopsin (R2-15), color-specific cone pigments (COS-1, OS-2) and the cone specific antigen 50-1B11, rod bipolar cells express PKC, horizontal cells HPC-1 antigen and neurofilament 160 kDa, amacrine cells HPC-1 antigen, GABA and neurofilament 160 kDa, and glial cells express vimentin and glial fibrillary acidic protein. The high degree of rosette formation seen in many young grafts, diminishes with time; many transplant cells disappear, and the remaining cells present a less prominent formation of rosettes.
Animals↗
Interphotoreceptor matrix components in retinal cell transplants.
To further investigate the functional potential of retinal transplants we have used immunocytochemistry to study the distribution of four different interphotoreceptor matrix (IPM)-specific components in rabbit retinal transplants. The different components were: interphotoreceptor retinoid-binding protein (IRBP), chondroitin-6-sulfate, F22 antigen and peanut agglutinin (PNA) binding structures. IRBP acts as a retinoid-transport protein between the neural retina and the retinal pigment epithelium. Chondroitin-6-sulfate is a glycosaminoglycan and a part of the insoluble IPM skeleton. The identity and role of the F22 antigen is not known. However, it is a 250 kDa protein localized to specific extracellular compartments such as teh IPM. PNA is a lectin with a high binding affinity for D-galactose-beta (1-3) N-acetyl-D-galactosamine disaccharide linkages and binds to IPM domains surrounding cones, but not rods. The transplants (15-day-old embryonic rabbit retina) were placed between the neural retina and retinal pigment epithelium in adult hosts. The transplants developed the typical rosette formations with photoreceptors toward the center. IRBP labeling was distinct in the IPM in the host retina. However, no IRBP labeling could be detected in the transplants. The chondroitin-6-sulfate and F22 antibodies strongly labeled the IPM in the host retina and corresponding structures in the center of rosettes. A cone-specific labeling with PNA could be seen in the host retina. In the transplants, however, PNA labeling appeared in association with many more photoreceptors than in the host retina. There is no previous study available on the IPM in retinal cell transplants.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Cataract patients in a defined Swedish population 1986-1990. II. Preoperative observations.
With the Cataract Analysis System (CAS) we have analyzed 5.878 consecutive patients undergoing cataract operations from 1986 through 1990. The material is complete enough to be regarded as representative of the cataract surgery performed in the Lund Health Care District cataract surgery referral region during this period. There has been a striking increase in the number of operations, in 1990 reaching 3.6 per 1000 inhabitants in the referral region. A number of demographic factors have been analyzed previously, and the preoperative status of the patients is reported in this paper. In 1986, the cataract patients showed more visual impairment than in 1990, but the average age at surgery did not change between the years. We therefore suggest that the increase in the number of patients which were operated on represents a new category that was added. During the period, the planned refraction has changed towards emmetropia, presumably reflecting several kinds of improvements in the procedure. About 78 per cent of the population had a preoperative astigmatism < 1.5 D. As expected males had slightly longer eyes than women, and their corneal curvature was also slightly less.
Adolescent↗
Neuropeptide Y inhibits adenylyl cyclase activity in rabbit retina.
Neuropeptide Y is known to be present in significant amounts in the retina of most vertebrates, but its physiological actions are largely unknown. We have therefore studied its effects on the intracellular cyclic AMP accumulation in rabbit retina. Neuropeptide Y had no effect on the basal cyclic AMP level but was found to inhibit the forskolin induced cyclic AMP accumulation. There were no differences between the effects of neuropeptide Y 1-36 and neuropeptide Y 13-36 (2.4 x 10(-6) M) suggesting the presence of the Y2 subtype of neuropeptide Y receptor. D-myo-inositol-1,2,6-trisphosphate, a novel neuropeptide Y-antagonist, reduced per se the forskolin induced cyclic AMP production. The pronounced inhibitory effect of neuropeptide Y on the forskolin induced cyclic AMP production was, on the other hand, totally abolished by D-myo-inositol-1,2,6-trisphosphate. The results indicate that neuropeptide Y acts on Y2 receptors in the retina to cause an inhibition of the adenylyl cyclase activity which could be antagonized by D-myo-inositol-1,2,6-trisphosphate. Such an inhibitory action of neuropeptide Y is similar to what has been found in brain tissue, but it has not previously been reported in the retina for neuropeptide Y or any of the other retinal neuropeptides.
1-Methyl-3-isobutylxanthine↗
Full-field electroretinograms in patients with central areolar choroidal dystrophy.
Patients with central areolar choroidal dystrophy are often difficult to diagnose because they are similar in fundus appearance to other retinal disorders. Nineteen patients with the diagnosis were studied in order to estimate the diagnostic and prognostic value of full-field electroretinography in this disorder. Our results showed that the cone b-wave amplitude in the ERG is decreased, that there is a progression in this decrease during a follow-up period of 5 years, and that the cone b-wave implicit time is prolonged. Central areolar choroidal dystrophy is considered to be primarily a choroidal disease. Our results indicate that it also affects most or all of the retinal cones. Further, our observations suggest that the disease is slowly progressive and that full-field electroretinography is of value in its early diagnosis.
Adult↗
Cataract patients in a defined Swedish population 1986-1990. I. Resources and epidemiology.
With the Cataract Analysis System (CAS) we have analyzed 5878 consecutive cataract patients operated from 1986 through 1990. The material is complete enough to be regarded as representative of the cataract surgery performed in the entire referral region of the Lund Health Care District during this period. There has been a striking increase in the number of operations, in 1990 reaching 3.6 per 1000 inhabitants in the referral region. Simultaneously, surgery has changed from being mainly an in-patient to an out-patient procedure. Females predominate in the material, also after adjustment for the female preponderance in the population. Most likely, this is due to a higher incidence of cataract in women than in men.
Adolescent↗
Complementary cone fields of the rabbit retina.
PURPOSE: Complementary cone fields have been considered a unique feature of the mouse retina. In an attempt to map the arrangement of the color-specific cones in other mammals, the authors investigated the rabbit, a commonly used experimental animal for vision research. METHODS: For the identification of the different cone types immunocytochemistry was used with two monoclonal antibodies, each specific to the middle- to long-wave (red-green) and short-wave (blue) sensitive visual pigments, respectively. RESULTS: The major part of the retinal surface, including the visual streak, exhibited a dominance of M (middle-wave sensitive) cones (6 to 13,000/mm2) versus S (short-wave sensitive) cones (1 to 2,500/mm2). In contrast, the lower 5% to 6% of the total retinal area showed a complete lack of green cones and a high density of blue cones (11,000/mm2). The authors designate this crescent-like area the blue streak of the rabbit retina. CONCLUSION: In addition to the visual streak primarily abundant in green cones, there is a specialized area of the rabbit retina that is densely and exclusively populated with blue cones. Although the relative extension of this peculiar cone field is considerably smaller than the S-field of the mouse retina, its position is similar in that it occupies the lowermost part of the retina. The functional implication of this area is unknown.
Animals↗
[Vitamin A in retinitis pigmentosa. An effective treatment, for the first time].
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Blindness↗
[What causes macular degeneration? 2 recently identified components can be the answer].
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Aged↗
Full-field electroretinogram in a patient with cutaneous melanoma-associated retinopathy.
A patient operated for malignant melanoma developed night blindness and a sensation of shimmering light, strong enough to make him unable to work. Shortly afterwards, melanoma metastases became apparent. A full-field ERG examination showed absence of rod responses but normal cone amplitudes, suggesting a malfunctioning rod system in the retina. The patient was not on chemotherapy. A few similar cases have previously been reported. The disease appears to differ from the cancer-associated retinopathy (CAR) syndrome, which affects mainly the photoreceptor cells.
Electroretinography↗
Full-field electroretinograms during general anesthesia in normal children compared to examination with topical anesthesia.
Full-field electroretinograms were obtained from 20 normal children during general anesthesia and compared with electroretinograms obtained with topical anesthesia. Disoprofol and fentanyl induced a reduction in the b-wave amplitudes and an increase in the cone b-wave implicit time, but the changes were small and fall within the range limits seen with topical anesthesia (i.e., average +/- 2 SD).
Anesthesia, General↗
NPY-induced neurotransmitter release from the rabbit and chicken retina.
Neuropeptide Y (NPY) or closely related peptides are present in the retina of certain vertebrates, but their actions are not known. We have therefore studied the NPY-induced release of [3H]-GABA, [3H]-glycine, [3H]-dopamine, [3H]-5-hydroxytryptamine, and [3H]-choline chloride-derived radioactivity in the rabbit and chicken retina. NPY affected the release of [3H]-glycine, [3H]-dopamine, [3H]-5-hydroxytryptamine, and [3H]-choline chloride-derived radioactivity in rabbit retina and of [3H]-GABA, [3H]-5-hydroxytryptamine and [3H]-choline chloride-derived radioactivity in chicken retina in an energy requiring, NA+K(+)-ATPase dependent and calcium dependent manner. Certain related peptides, APP (= avian pancreatic polypeptide), BPP (= bovine pancreatic polypeptide), and PYY (= peptide YY), had variable and less pronounced effects. The results suggest a neurophysiological role in both chicken and rabbit retina for NPY or some related peptide.
Animals↗
Histochemical identification of hyaluronan in the rabbit anterior segment during the healing period after extracapsular lens extraction.
Extracapsular lens extractions were performed in rabbits. The eyes were examined at different time intervals after surgery with a histochemical method visualizing hyaluronan. There was positive staining for hyaluronan in the wound region from 2 to 90 days postoperatively. The staining was most intense and widespread between 7 and 14 days after surgery. A hyaluronan staining in the corneal stroma extended from the wound towards the central cornea 4 to 14 days postoperatively. The iris showed increased staining on the second postoperative day, but much less so at the other times studied. Cells on the posterior lens capsule were surrounded by hyaluronan from the seventh postoperative day throughout the observation time up to 90 days postoperatively. It is concluded that hyaluronan reacts during corneal wound healing.
Animals↗
Heterogeneity of receptor immunoreactivity at synapses of glycine-utilizing neurons.
Neurons often contain, and probably release, more than one neuroactive substance that may have diverse or opposite actions on the postsynaptic cell. It remains unexplained how these neurons utilize their multiple neuroactive substances while maintaining appropriate resolution of neurotransmitter functions. Here, we have examined the ultrastructural localization of glycine receptors by using a monoclonal antibody directed to the intracellular domain of the strychnine-sensitive glycine receptor. We have found that glycine receptors are only localized to 56% of the synapses made by presumed 'glycinergic' (more accurately, glycine-utilizing) amacrine cells in the turtle retina. The remaining synapses made by these same boutons show no evidence of glycine receptors. As there is no evidence to suggest the presence of a second type of glycine receptor, these data indicate that only a portion of the postsynaptic sites contacted by the glycine-utilizing neurons can respond to glycine. They also suggest that a neuron containing multiple neuroactive substances can selectively affect postsynaptic elements by means of heterogeneous receptor localization.
Animals↗
[The excimer laser--start of a new era?].
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Humans↗
Dose response and duration of action of dorzolamide, a topical carbonic anhydrase inhibitor.
The multiple-dose, dose-response relationship and duration of action of the novel topical carbonic anhydrase inhibitor dorzolamide (previously known as MK-507) were investigated in a double-masked, randomized, placebo-controlled, parallel study in 73 patients with bilateral primary open angle glaucoma or ocular hypertension. Dorzolamide (0.7%, 1.4%, or 2%) or placebo was administered every 12 hours for 5 days and then every 8 hours for 7 days. Intraocular pressure was investigated with multiple 12-hour diurnal curves. All concentrations of dorzolamide demonstrated substantial lowering of intraocular pressure throughout the day when given twice daily (9% to 21%) or three times daily (14% to 24%). Although a dose-dependent response was observed immediately following the first dose, there were no significant differences between concentrations or dose response at either the twice or three times daily dosing regimen. Three times daily administration of 2% dorzolamide demonstrated a mean percent decrease in intraocular pressure of 18% to 22% throughout the day (mean decrease, 4.5 to 6.1 mm Hg). Dorzolamide appears to have substantial potential in the treatment of glaucoma and ocular hypertension.
Administration, Topical↗