Biomedical subjects

S Sawaguchi

Publications and source records attributed to S Sawaguchi.

At least 55 records · Page 3Linked to original sources

PubMed1994

Lysosomal enzyme and inhibitor levels in the human trabecular meshwork.

PURPOSE: To examine in the human trabecular meshwork lysosomal enzymes and one inhibitor of serine proteases that actively participate in the degradation of macromolecules into low molecular weight constituents. METHODS: Using an avidin-biotin-peroxidase technique, lysosomal proteases and alpha 1-proteinase inhibitor were examined in the trabecular meshwork of 23 human eyes with donor ages ranging from 2 to 90 years. These eyes were categorized into three age groups (< or = 20, 21 to 49, and > or = 50 years). Histochemical staining for lysosomal hydrolases was also performed on frozen sections of 20 human eyes. The staining was analyzed by an image analyzer and the levels of lysosomal proteases were further measured by biochemical assays. RESULTS: The trabecular meshwork from all the eyes stained intensely against antibodies to cathepsins B and G and alpha 1-proteinase inhibitor. The staining for elastase was weaker but evident. Image analyses revealed that the staining intensity for each protease or inhibitor was similar in all age groups. The staining in the uveal meshwork appeared to be the strongest among all the trabecular meshwork regions. Biochemical assays of tissue extracts confirmed that the enzyme and inhibitor levels were comparable among the three donor age groups. Activities of two lysosomal hydrolases, acid phosphatase and acid esterase, were also found in trabecular meshwork cells of 20 eyes. No apparent difference in enzyme activities was found with increasing age, and variation related to region was not observed. CONCLUSIONS: This study demonstrated the age-independent distribution of a variety of lysosomal enzymes and a protease inhibitor in the human trabecular meshwork. The presence of these proteins suggests a possible role in the metabolic operation of the trabecular meshwork.

Adolescent↗

PubMed1993

Diffuse corneal clouding in siblings with fetal alcohol syndrome.

Three of four siblings born to parents with a history of heavy alcohol abuse had bilateral diffusely cloudy corneas at birth. These three siblings, who had mild systemic features of fetal alcohol syndrome, underwent corneal transplantations, and their specimens were examined by light and electron microscopy. Histologically, the alterations in Bowman's layer ranged from thickening to total loss. There were varying degrees of corneal stromal edema. The unique pathologic feature in the corneas was the anomaly of the anterior banded zone of Descemet's membrane, which was either absent, poorly formed, or thinned in the central and peripheral cornea. The corneal endothelium was attenuated or multilayered. The diffuse clouding and the range of histologic abnormalities in the corneas might be related to the maternal alcohol abuse.

Child, Preschool↗

PubMed1993

An immunohistochemical study of opsin in photoreceptor cells following light-induced retinal degeneration in the rat.

Light-induced retinal degeneration has been hypothesized to be rhodopsin-mediated. However, the alterations induced in the opsin moiety of the rhodopsin molecule and its distribution in the rod cell after a photic insult have not been definitively established. We used light and electron immunohistochemistry to study the alterations in retinal opsin immunoreactivity in a rat model of retinal photic injury. In normal unexposed rat retinas, opsin immunoreactivity was restricted to the rod outer segments. At 6 h after a 24-h light exposure, opsin immunoreactivity was present in the rod outer segments in both the superior and inferior retina, but in addition marked immunoreactivity was present in the inner segments in the superior quadrant of the light-damaged retina. At 6 days after exposure, intense immunoreactivity was noted around the severely degenerating rod nuclei and inner segments. However, at 21 days following light exposure, opsin immunoreactivity in areas of recovery was again restricted to the short regenerated rod outer segments. It appears that, despite severe light-mediated retinal degeneration, anti-opsin immunoreactivity persisted in the photoreceptor cells but with an altered pattern in damaged rod outer segments and photoreceptor perikarya. However, opsin immunoreactivity relocated to the regenerated rod outer segments in the recovery phase.

Animals↗

PubMed1993

Nd:YAG laser trabeculopuncture (YLT) for glaucoma with traumatic angle recession.

Traumatic angle recession caused by blunt trauma often induces uncontrollable glaucoma despite the maximum medical therapy tolerated, such as argon laser trabeculoplasty (ALT), with no or little benefit. Therefore, instead of ALT, we tried Nd:YAG laser trabeculopuncture (YLT) on 11 patients with this type of glaucoma. The intraocular pressure of these patients was followed up for 15 +/- 7 months (average +/- SD). In 6 of 7 eyes treated initially with YLT, the IOP was significantly reduced, so medication was discontinued. Four other cases with uncontrollable IOP after failed ALT were treated with YLT. The IOP of 3 cases was successfully controlled by medication after YLT. These YLT results were then compared with those of ALT in 11 glaucoma patients with traumatic angle recession. Seven of 11 cases treated initially with ALT failed in less than 3 months, and surgical intervention or additional laser treatments were required. The probability of success from the time-series analysis at 12 months after each laser application was 0.909 in YLT, 0.273 in ALT. YLT offers significant advantages over ALT for the treatment of glaucoma with traumatic angle recession after blunt trauma and thus merits further study.

Adolescent↗

PubMed1993

Conjunctival biopsy in adult form galactosialidosis.

Conjunctival biopsy was performed in two siblings with adult-form galactosialidosis. Electron microscopically, several types of intracytoplasmic inclusion were observed in the fibroblasts in conjunctival stroma, lymphatic capillary endothelial cells, Schwann cells, and epithelial cells. Membrane-bound vesicles with fibrillogranular content were frequently observed, and occasional lamellar structures were noted in these inclusions. Dense granular inclusions and oil droplets were also seen. Dense granular inclusions have not been reported in this disease previously.

Adult↗

PubMed1993

Intraocular pressure-dependent progression of visual field loss in advanced primary open-angle glaucoma: a 15-year follow-up.

We studied the relationship between intraocular pressure (IOP) and progression of visual filed loss in 83 eyes of 83 patients with advanced primary open-angle glaucoma (loss of at least one quarter of the visual field on Goldmann perimetry). During the 15-year follow-up study, 71 eyes (86%) showed progression of visual field loss. The mean IOP was significantly lower in eyes that remained stable (13.4 +/- 1.3 mm Hg) than in those that showed progression of visual field loss (19.4 +/- 2.6 mm Hg). These results suggest that it is necessary to reduce IOP to below 15 mm Hg to prevent further progression of visual filed loss in advanced glaucoma.

Adult↗

PubMed1993

Age-related changes of sulfated proteoglycans in the human lamina cribrosa.

Sulfated proteoglycans in the lamina cribrosa of the optic nerve head from individuals aged 2 months, 18 months, and 23, 35, 44, 55, 67, 74, and 88 years were studied by electron microscopy after cuprolinic blue dye binding. Within the cores of the laminar plates, cuprolinic blue-positive chondroitin/dermatan sulfate proteoglycan filaments of different sizes were found associated with collagen fibers. In addition, small punctate and filamentous structures that represented heparan sulfate proteoglycan molecules were associated with the basal laminae of astrocytes and blood vessels. In the eyes of older individuals, the chondroitin/dermatan sulfate and heparan sulfate proteoglycan filaments were found to be shorter than those in younger persons. A mild decline with aging in the diameter of the filaments was also noted. Our findings illustrate the age-related changes in the proteoglycans in the human lamina cribrosa, which may help explain why the optic nerve head is more susceptible to damage with aging.

Adult↗

PubMed1993

[Expression of proliferating cell nuclear antigen following filtration surgery in rabbits].

We evaluated cell replication in wound healing following experimental filtration surgery. Cell replication was measured via immunohistochemistry for proliferating cell nuclear antigen, which is a marker of cell proliferation. Trabeculectomy was performed on albino rabbit eyes, with the filtering site harvested on postoperative days 1, 4, 7, and 14. Samples were fixed with 10% buffered formalin and prepared for paraffin section, and proliferating cell nuclear antigen was detected in filtering site tissue using the labeled streptavidin-biotin method. The number of immunoreactive cells increased at days 4 to 7 and was markedly decreased at day 14; the filtering site was obstructed at days 7 to 14. These findings may have clinical implications for the administration of antiproliferative agents after filtration surgery. Evaluation of cell replication following filtration surgery by detecting proliferating cell nuclear antigen is a simpler technique than autoradiography.

Animals↗

PubMed1993

[Histopathology of corneal plaque in vernal keratoconjunctivitis].

The author reported 2 cases of vernal keratoconjunctivitis with corneal plaque showing a white board-like appearance. Conventional medications were not effective in both cases and during the course of the disease corneal ulcer developed followed by formation of corneal plaque. After the plaque spontaneously peeled off, or were surgically removed, the ulcers of both cases healed. The histological specimens from the 2 cases were examined by light and electron microscopy. The plaques showed lamellae-like structures, and formed alternate accumulation of hyaline-like material and another amorphous material. No cell components, such as corneal epithelial cells, keratocytes, or fibroblasts, were found either on the surface of and within the plaques. The corneal epithelial cells and/or eosinophils, however, were found at the edge of the plaque. These findings may suggest that these corneal plaques were formed by repeated episodes of deposition and that corneal epithelial cells and eosinophils may have been involved.

Adolescent↗

PubMed1993

[Proteoglycan abnormality in a nanophthalmos sclera].

We examined a scleral specimen obtained from a nanophthalmos eye with uveal effusion at the surgery, using cuprolinic blue (CB) dye binding and electron microscopy. The nanophthalmic sclera was separated into two areas electron microscopically. One was an area composed of tightly packed collagen fibers, the other with irregularly arranged collagen fibers. In irregular areas, several abnormal findings, such as twisting or fraying, were detected in collagen fibers, which were surrounded by fine fibrous materials. Furthermore, CB-positive materials were fewer in number and less in size and electron density around the collagen fibers and in fine fibrous materials than in the normal eye. Since the nanophthalmic sclera in this study showed some abnormalities both in collagen fibers and in proteoglycans, we suggest that the function and/or interaction of both of these were abnormal, which might be related to the onset of uveal effusion.

Adult↗

PubMed1992

Effects of intracameral injection of chondroitinase ABC in vivo.

A glycosaminoglycan-degrading enzyme, chondroitinase ABC, was introduced into the anterior chamber of three cynomolgus monkeys. Following the injection, the intraocular pressure decreased in the experimental eyes. Depending on the monkey, the intraocular pressure was lowered for 5, 7, or 14 days before it returned to the normal level. Repeated injections produced a similar response. Structurally, the intertrabecular spaces appeared widened, and marked ballooning of the juxtacanalicular tissue was observed. The outer trabecular beams and the inner wall of Schlemm's canal were greatly disorganized. Considerable loss of the juxtacanalicular tissue was noted even 2 months after the enzyme was injected into the anterior chamber. These observations suggest that chondroitinase ABC digested the trabecular glycosaminoglycans, triggering intraocular pressure reduction and causing disorganization of the extracellular matrices of the disorganized trabecular beams, especially in areas near Schlemm's canal.

Animals↗

PubMed1992

Extracellular matrix changes of the optic nerve lamina cribrosa in monkey eyes with experimentally chronic glaucoma.

Using light microscopic immunohistochemistry, we studied the immunolocalization and immunoreactivity of the extracellular matrix, including collagen types III, IV, VI, laminin, and alpha elastin in the lamina cribrosa of monkey eyes with normal and experimentally chronic glaucoma. Our results showed: (1) abnormal linearlike immunodeposits of both collagen type IV and laminin in the margin of the lamina cribrosa with significant density in the glaucomatous eyes; (2) the immunoreactivity of collagen type III resembled that of the normal eye, but was slightly stronger at the laminar surface; (3) findings with collagen type VI resembled those of type III with an enhanced linearlike staining surrounding the nerve-fiber bundles. Furthermore, staining of alpha elastin demonstrated dramatic changes in both reactivity and localization. The lamina cribrosa of glaucomatous eyes showed a markedly reduced immunoreactivity as well as an irregular, interrupted pattern. These observations suggest that the changes might be a secondary to the long-standing elevation of intraocular pressure. The alteration of these macromolecules may modify the course of glaucomatous optic damage.

Animals↗

PubMed1992

Long-term results of anterior chamber tube shunt to an encircling band in the treatment of refractory glaucomas.

We performed the anterior chamber tube shunt to an encircling band procedure in 34 patients (36 eyes) with refractory glaucoma, and evaluated the long-term outcome. The preoperative mean intraocular pressure (IOP) was 36.8 +/- 9.6 mmHg, the postoperative mean IOP was 21.6 +/- 13.6 mmHg, a statistically significant (p < 0.01) reduction of IOP following this procedure. The final postoperative IOP was under 21 mmHg in 23 (63.9%) of the 36 eyes. The success rate of IOP control 36 months after the operation without any elevation of post-operative IOP was 30.3% (life-table method). Complications of this procedure included flattening of the anterior chamber (61.1%), damage to the corneal endothelium (25%), hyphema (25%), and a transient IOP elevation (25%). As filtering surgery with 5-fluorouracil is more effective and simple to perform, we conclude that the anterior chamber tube shunt to an encircling band procedure should be reserved for those with refractory glaucoma who have had multiple surgical interventions.

Adolescent↗

PubMed1992

Ischemic optic neuropathy in a female carrier with Fabry's disease.

We report ocular findings of a patient with anterior ischemic optic neuropathy (AION) and cilioretinal artery occlusion in a female carrier of Fabry's disease. Fluorescein angiography revealed delayed filling of the upper and temporal part of peripapillary choroidal vessels and capillaries of the right optic disk and late filling of the cilioretinal artery. CT scanning was performed several times in early stages and demonstrated thickening of the intraorbital optic nerve due to ischemic edema. About 5 months later, the fellow eye showed optic disk edema, an early sign of AION, and was treated by systemic corticosteroid and urokinase whereby AION did not progress.

Adult↗

PubMed1992

Ascorbic acid modulates collagen type I gene expression by cells from an eye tissue--trabecular meshwork.

The trabecular meshwork, a specialized tissue in the anterior chamber of the eye, plays a major role in the regulation of aqueous humor outflow. We studied the effects of ascorbic acid, a significant component in the aqueous humor, on gene expression of type I collagen in cultures of bovine trabecular meshwork cells. These cells were plated for 6 days, exposed to ascorbic acid in concentrations of 100, 250 and 500 micrograms/ml for 3 days and labeled with (3H)proline for the last 24 hrs. Cultures that did not receive ascorbic acid served as controls. Bacterial collagenase assays showed enhanced incorporation of (3H)proline into collagenous proteins in cultures treated with 100 and 250 micrograms/ml of ascorbic acid. Gel electrophoresis and fluorography revealed that ascorbic acid caused a 2.6- to 4.9-fold increase in production of alpha 1 (I) and alpha 2(I) collagen chains by trabecular meshwork cells. Such an increase was found, using a cDNA probe specific for pro alpha 1(I) chains, to be accompanied by an increase in steady-state mRNA levels. Similar findings were also yielded from in situ hybridization experiments. These results, coupled with previously demonstrated ascorbate-induced effects on glycosaminoglycan, fibronectin and laminin synthesis, suggest that ascorbic acid is a key mediator of the extracellular matrix production by trabecular meshwork cells. Fluctuations in its concentration may lead to alterations in the makeup and assembly of matrices underlying the cells.

Animals↗

PubMed1992

[Changes in sulfated proteoglycans in alkali injured rabbit cornea].

Morphological changes of sulfated proteoglycans (S-PGs) in the stroma of alkali injured rabbit corneas were examined electron-histochemically following cuprolinic blue (CB) dye binding. The injured eyes were followed for 2 months by slitlamp microscope and photographs. At 1 hour, 3 days, 1 week, 2 weeks, 1 month, and 2 months after the injury, the eyes were enucleated and studied. After 1 hour, while both collagen fibrils and the filaments of S-PGs had already become disarranged; the number of S-PGs appeared to decrease. From 3 days to 1 week after, the number as well as the electron-density of S-PGs were markedly decreased in all areas. After 2 weeks, CB-positive large filaments appeared in anterior stroma. These became larger, more abnormal in shape, and displayed a higher electron density 1 month later. Normally arranged S-PGs can be seen at 2 months later. It was concluded that S-PGs were diminished in alkali-injured corneas. Once they were replaced by abnormal filaments, they gradually recovered normal morphology. Further more the time course of S-PG change correlated with that of corneal transparency after alkali injury.

Animals↗

PubMed1992

Sulfated proteoglycans in the human lamina cribrosa.

The sulfated proteoglycans in the normal human lamina cribrosa were studied by electron microscopy after cuprolinic blue dye binding. Within the cores of the laminar plates, three types of cuprolinic blue-positive proteoglycan filaments with different sizes were associated with collagen fibers. These filaments, which were partially sensitive to chondroitinase AC and chondroitinase B, were completely removed by chondroitinase ABC and were identified as chondroitin/dermatan sulfate proteoglycans. In addition, small punctate and filamentous structures that stained with cuprolinic blue were associated with the basal laminae of astrocytes and blood vessels. Enzyme chondroitinase ABC had no effect, but heparinase digested all of these basement membrane-associated structures, indicating that they represented heparan sulfate proteoglycan molecules. Keratanase did not affect any of the cuprolinic blue-positive materials. This investigation illustrates the ultrastructural distribution and morphology of proteoglycans in the human lamina cribrosa and provides baseline information for future studies regarding the roles of proteoglycan molecules in diseases such as glaucoma.

Aged↗

PubMed1991

Late-infantile type galactosialidosis. Histopathology of the retina and optic nerve.

We studied histopathologic findings from the retina and optic nerve of a patient with the late-infantile type of galactosialidosis and related them to clinical features of the condition. Markedly fewer ganglion cells were evident histopathologically using light microscopy. Results of histochemical studies demonstrated abnormal accumulation of lipid and proteinaceous material in the residual swollen ganglion cells. Marked loss of myelinated nerve fibers and thickening of the pial septum were also observed in the optic nerve. Both retinal ganglion cells and amacrine cells had intracytoplasmic inclusion bodies, but none were found in the optic nerve. These findings suggested that optic atrophy was induced by axonal wallerian degeneration secondary to retinal ganglion cell death. Although the fundus showed advanced optic nerve atrophy, a cherry red spot was not evident, possibly because of the marked decrease in ganglion cells in this case.

Adolescent↗