Elith Bjarne Olsen

Regional glycosaminoglycans composition of the human sclera

Abstract Human sclera from different parts of the normal adult eye was analyzed for content of uronic acid and the distribution of specific glycosaminoglycan types. Uronic acid is widely determined as representative of glycosaminoglycans in biological substances and variations of about 2‐fold were found. Differences of up to 50% were detected in the relative abundance of hyaluronic acid and of dermatan sulphate, depending on the site on the globe from which the sample was taken. Sclera from around the papilla was found to be rich in content of dermatan sulphate. Sclera from the posterior eyeball showed a higher percentage of chondroitin sulphate as compared with sclera from equator and limbus. Equatorial sclera was richer in hyaluronic acid than posterior sclera. Sclera from the posterior eyeball showed a higher content of uronic acid as compared with sclera from equator and limbus. This work is an addition to the understanding of the scleral biochemistry and this finding may have some relevance in connection with ocular disease, as the proteoglycans and their content of glycosaminoglycans play a key role in the regulation of collagen fibril assembly and in the biomechanical strength of collagen fibrils.

Biochemical and ultrastructural changes in rabbit sclera after treatment with 7-methylxanthine, theobromine, acetazolamide, or L-ornithine

AIMS To examine a possible effect of 7-methylxanthine, theobromine, acetazolamide, orl-ornithine on the ultrastructure and biochemical composition of rabbit sclera. METHODS Groups of pigmented rabbits, six in each group, were dosed during 10 weeks with one of the substances under investigation, and one untreated group was the control. Samples of anterior and posterior sclera were taken for determination of hydroxyproline, hydroxylysine, proline, proteoglycans, uronic acids and dermatan sulphate, chondroitin sulphate, and hyaluronic acid. Sections were examined with electron microscopy, and the diameter of the individual collagen fibrils was measured. RESULTS Treatment with theobromine produced a significant increase in the contents of hydroxylysine, hydroxyproline, and proline in both anterior and posterior sclera, while 7-methylxanthine increased the contents of hydroxyproline and proline selectively in posterior sclera. Acetazolamide, on the other hand, significantly decreased the contents of hydroxyproline and proline in samples from anterior sclera. Uronic acids in both anterior and posterior sclera were significantly reduced by treatment with 7-methylxanthine, and l-ornithine significantly reduced uronic acids in posterior sclera. An inverse correlation between contents of hydroxyproline and uronic acids was found. The mean diameter of collagen fibrils was significantly higher in the posterior sclera from rabbits treated with 7-methylxanthine or theobromine, and significantly lower in rabbits treated with acetazolamide or l-ornithine compared with controls. In the anterior sclera, fibril diameter was significantly reduced in all treatment groups compared with controls. A positive, significant correlation between fibril diameter and content of hydroxyproline and proline was found in posterior sclera. CONCLUSION 7-Methylxanthine, a metabolite of caffeine, increases collagen concentration and the diameter of collagen fibrils in the posterior sclera, and may be useful for treatment or prevention of conditions associated with low level and/or inferior quality of scleral collagen, such as axial myopia, chronic open angle glaucoma, and possibly neovascular age related macular degeneration. The apparent loss of collagen induced by chronic treatment with acetazolamide should be taken into consideration as a potentially harmful side effect. These results may indicate that scleral biochemistry and ultrastructure are influenced by the retinal pigment epithelium. One possible explanation is that the scleral fibroblasts which produce the collagen are sensitive to changes in the physiological electric field created by the retinal pigment epithelium.

Glycosaminoglycans in human breast cancer

Abnormal concentrations of glycosaminoglycans (GAG) have been reported for various types of tumors, suggesting that they may play a role in neoplasia. The correlation between the content of individual GAGs was studied in breast tumor tissues. The total content of GAG was estimated by uronic acid analysis. The relative distributions of dermatan sulphate, heparan sulphate, hyaluronic acid and chondroitin sulphate were measured after cellulose acetate electrophoresis. Mammary tissue samples were obtained at the time of surgery from 11 women, 6 with fibroadenomata and 5 with carcinoma. From each patient, biopsies were obtained centrally in the tumor and perilesional areas adjacent to the tumor, and also from clinically uninvolved tissue in the same region. In the central areas, it was found that carcinoma had a significant increase in chondroitin sulphate and uronic acid content, and a significant decrease in dermatan sulphate content, as compared with fibroadenoma. The chondroitin sulphate content in perilesional carcinomatous tissue was significantly greater than in clinically uninvolved tissue.

Collagen and uronic acid distribution in the human sclera

Abstract In the normal adult eye the content of uronic acid, hydroxyproline, hydroxylyxine and proline from different parts of sclera was examined. Scleral samples from the posterior eyeball showed a higher content of uronic acid than the scleral samples from papilla, equator and limbus. Apart from a lower concentration of hydroxyproline in sclera from equator, no major differences in concentration of hydroxyproline, hydroxylysine or proline was found in sclera samples.

The effect of hyaluronic acid on cartilage in the immobilized rabbit knee

Out of 30 adult rabbits, 20 had one knee immobilized with a plaster of Paris cast for 6 or 12 weeks, and 10 rabbits were used as untreated controls. Prior to immobilization, 10 knees were injected with high-molecular weight hyaluronic acid. The articular cartilage of the femoral condyles was studied by light microscopy, whereas that of the patella and tibia was analyzed biochemically. Degenerative changes of the articular cartilage similar to those seen in arthrosis were observed after 6 weeks. The intraarticular injection of hyaluronic acid did not prevent these changes; instead, the reparative processes seemed inhibited.

Decidual prolactin content and secretion at term: Correlations with the clinical data

This study was conducted to describe the distributions of the initial decidual PRL content (D‐PRL) and the decidual PRL secretion (D‐PRL‐s) in vitro at term and to ascertain whether the clinical data might influence these decidual PRL measures and their correlation with the amniotic fluid PRL concentration (A‐PRL). Decidual tissue was obtained after 134 normal pregnancies at term. D‐PRL and D‐PRL‐s into the medium after an 8 h incubation were determined. The distributions of D‐PRL and D‐PRL‐s were skewed to the right. A logarithmic transformation generated symmetric distibutions. Eight women who were delivered by vacuum extraction due to intra‐uterine asphyxia had D‐PRL values similar those in normal vaginal parturition, whereas D‐PRL‐s values were significantly reduced (p < 0.02). No significant difference (p>0.05) was found in the decidual PRL measures in the vaginal deliveries between those receiving labor stimulating medication and those without, or between women who gave birth vaginally and women undergoing elective cesarean section. Stepwise multiple regression analyses of data obtained from 30 women who gave birth after uncomplicated or various pathological pregnancies showed logarithmically transformed A‐PRL to be closely correlated with D‐PRL, and these correlations were improved by including the week of gestation as a second step (p < 0.00001). After normal pregnancy, D‐PRL‐s was significantly correlated with D‐PRL (p < 0.01), and D‐PRL was correlated with the week of gestation (p < 0.05). None of the remaining clinical data improved the correlations. The results indicate that a logarithmic transformation is appropriate when evaluating D‐PRL and D‐PRL‐s at term and that special attention should be paid to the differences in week of gestation and deliveries complicated with intra‐uterine as Dhvxia.

Effect of ouabain and bumetanide on the basal and the osmolality-affected prolactin secretion from human decidual cells in vitro

Human decidual explants were incubated in vitro in media containing 10(-5) mol/l ouabain or 10(-4) mol/l ouabain or 0.5 X 10(-4) mol/l bumetanide to change the intracellular ionic concentrations. In isosmotic incubations (osmolality 315 mmol/kg), no significant effect of either 10(-5) mol/l ouabain or 0.5 X 10(-4) mol/l bumetanide was found on the decidual prolactin secretion (D-PRL-s). 10(-4) mol/l ouabain significantly decreased both decidual prolactin production and D-PRL-s (P less than 0.05) and was therefore not used for the following cross-over experiments. Hyperosmotic media (387 mmol/kg) were produced by changing the concentration of either sodium chloride, potassium chloride, or mannitol. All increased D-PRL-s compared with the isosmotic media (315 mmol/kg). 10(-5) mol/l ouabain significantly diminished the increase otherwise elicited by the sodium chloride and the mannitol hyperosmotic media. However, in the hyperosmotic potassium chloride medium with 10(-5) mol/l ouabain, the D-PRL-s remained increased. The hyperosmotic medium (252 mmol/kg) reduced D-PRL-s compared with the isosmotic media (315 mmol/kg) and no significant effect of ouabain was found. Bumetanide did not change the D-PRL-s into any of the hypo- or hyperosmotic media compared with the secretion at 315 mmol/kg. Based on experience from other cell types, the results further indicate that the intracellular ionic concentrations could be of importance to the secretion of decidual prolactin in vitro.

Biochemical changes in rabbit sclera following destruction of pigment epithelium

Abstract The long‐term effect of destruction of the pigment epithelium by sodium iodate on the biochemistry of rabbit sclera was studied in one group with intravenous injection of sodium iodate, and in a second group with injection of sodium iodate into the right eye. Intravenous treatment produced a non‐significant increase in the uronic acid concentration. In the second group the untreated fellow eye was microscopically intact, but was shown (as the treated eye) to alter the concentration of uronic acid in different parts of the sclera. All eyes from treated animals exhibited changes in the relative content of the various glycosaminoglycans and in the content of hydroxyproline, hydroxylysine and proline. This work indicates that the pigment epithelium may play a key role in the control mechanism of the scleral connective tissue, and this again has major implications in terms of a possible medical treatment of axial myopia.