Biomedical subjects

F Uehara

Publications and source records attributed to F Uehara.

At least 19 recordsLinked to original sources

PubMed2002

Photoreceptor cell differentiation in retinoblastoma demonstrated by a new immunohistochemical marker mucin-like glycoprotein associated with photoreceptor cells (MLGAPC).

AIMS: For further understanding of specific differentiation in retinoblastoma, we studied the expression of newly detected mucin-like glycoprotein associated with photoreceptor cells (MLGAPC), which is specific for photoreceptor cells of retina and analogous to interphotoreceptor matrix proteoglycan-1 (IMPG1). METHODS AND RESULTS: Surgically enucleated retinoblastomas (n=21; undifferentiated type, n=15, differentiated type, n=6) were immunohistochemically studied with a polyclonal antibody against MLGAPC, and 17/21 cases (81%) showed positive staining of tumour cells. We classified various staining patterns and structures into four groups: type 1 showing a granular intracellular scattered staining pattern with round small cells; type 2 showing a reticular staining pattern between spindle-shaped tumour cells; type 3 showing radiating staining from the centre of Homer-Wright rosettes; type 4 showing ring-shaped, radiating and granular staining associated with Flexner-Wintersteiner rosettes. Eleven of 15 undifferentiated retinoblastomas (73%) showed type 1 or 2, and all the six differentiated cases showed type 3 or 4. Image analysis of immunostaining revealed an increase in MLGAPC-positive area from 0.48% in undifferentiated cases to 1.60% in differentiated cases, and a negative correlation was shown between mitotic frequency and MLGAPC-positive area. CONCLUSIONS: This study proved MLGAPC as a valuable marker of retinoblastoma, and that photoreceptor differentiation takes place even in 'undifferentiated' retinoblastoma.

Biomarkers, Tumor↗

PubMed2001

Isolation and characterization of galectins in the mammalian retina.

PURPOSE: Previous studies have suggested that galectins may be involved in retinal adhesion and photoreceptor cell survival. To elucidate the underlying mechanisms, the authors isolated retinal galectins, determined their types and distributions, and investigated the validity of the hypothesis, using rat models. METHODS: An antibody was prepared against a bovine retinal lectin that was isolated by use of a lactose-agarose column. cDNA of the lectin was isolated by screening of a bovine retinal cDNA library, using the antibody, and then was sequenced. The cDNAs of rat retinal galectins were also isolated by means of polymerase chain reaction and used to produce an antibody against recombinant galectin-3. Using the described antibodies, the authors examined the distributions of galectins in bovine and rat retinas, morphologic changes of rat retinas induced by the antibodies, and distributional changes of galectins in constant-light-exposed rat retinas. RESULTS: The cDNAs of bovine galectin-1, rat galectin-1, and rat galectin-3 were isolated. Galectin-1 was found in various regions, including the retinal pigment epithelium, outer limiting membrane, and outer plexiform layer in bovine and rat retinas. Galectin-3 was increasingly detected in the cytoplasm of Müller cells after constant light exposure after an increase in its transcript. Retinal detachment and vacuolation of the outer plexiform layer were induced in rat eyes by intravitreous injection of the anti-galectin-1 antibody. CONCLUSIONS: Galectin-1 may be involved in adhesion of the photoreceptor and outer plexiform layers by interacting with glycoconjugates with beta-galactoside residues in the interphotoreceptor matrix and synaptic cleft matrix. Galectin-3 may increase in Müller cells of a degenerative rat retina, probably through endogenous anti-apoptosis.

Animals↗

PubMed2000

Isolation and characterization of mucinlike glycoprotein associated with photoreceptor cells.

PURPOSE: Although previous lectin-histochemical studies have shown that O-linked glycoproteins are distributed in cone pedicles and rod spherules, as well as in photoreceptors, including associated interphotoreceptor matrices (IPM), attention has been directed only to those in the IPM. In this study, cloning of the O-linked glycoproteins not only in the IPM but also in the region including the cone pedicles and rod spherules was attempted. METHODS: The cDNA for the core protein of the O-linked glycoprotein in the bovine retina was isolated by screening a bovine retinal cDNA library using a polyclonal antibody against the jacalin (a lectin specific for O-linked sugar residues)-binding glycoproteins (JBGPs) in the whole bovine retina. The expression of the JPGP core protein in the retina was examined by means of in situ hybridization histochemistry and immunohistochemistry. RESULTS: The cDNA was isolated and found to encode an entire core protein [predicted molecular mass (Mr): 101 kDa; rich in Ser and Thr; mucin-like] for the JBGPs with Mr of 120 and 135 kDa. The mRNA was expressed in both cone and rod photoreceptor cells. This protein was distributed in the cone pedicles and rod spherules as well as the photoreceptor layer. CONCLUSIONS: Mucinlike glycoproteins with Mr of 120 and 135 kDa may be synthesized in the cone and rod photoreceptor cells, respectively, and distributed not only in the photoreceptor layer (probably including the IPM) but also in the cone pedicles and rod spherules.

Amino Acid Sequence↗

PubMed2000

Ultrastructural changes associated with accumulation of inclusion bodies in rat retinal pigment epithelium.

PURPOSE: To determine the structural changes in the retinal pigment epithelium (RPE) and neighboring structures induced by intravitreal injection of a lysosomal protease inhibitor. METHODS: Eleven-week-old Sprague-Dawley rats were injected with 5 microliter of a lysosomal protease inhibitor, E-64 (2.22 microM), intravitreally once and killed at 24 hours, 48 hours, or 7 days later. Others received two or three injections at 48-hour intervals or three daily injections, and killed at 1, 4, and 7 days after the last injection. Eyes were enucleated and retinal tissues were processed for light and electron microscopy. RESULTS: A single injection of E-64 caused only a transient accumulation of phagosome-like and phagolysosome-like inclusion bodies in the RPE. By contrast, repeated injection caused progressive accumulation of these inclusions followed by altered RPE cell conformation, and changes in organelles such as loss of smooth endoplasmic reticulum (SER). This was accompanied by shortening and loss of photoreceptor outer segments without prior dysmorphic changes, alteration of choroidal capillaries, and invasion of Bruch's membrane by fibroblasts and pericytes. Intravitreal injection of vehicle as control induced no structural changes. CONCLUSIONS: E-64 treatment induced structural changes in the outer retina. The causal relationship between accumulation of inclusions in RPE and changes in other subcellular organelles and neighboring cells systems is not clear. However, there are possible explanations: physical disturbance of organelles, particularly SER by inclusions; cellular damage by consequent upon accumulation of A2-E; or, shortage of recycled material due to reduced degradation of phagosomes.

Animals↗

PubMed1998

Ultracytochemical demonstration of glycogen in cone, but not in rod, photoreceptor cells in the rat retina.

The presence of native glycogen in photoreceptor cells of the rat retina has not been identified in the literature. We have studied this ultracytochemically. After perfusion with glutaraldehyde fixative, the eyes were enucleated, and the retinal tissues, postfixed with OsO4, were embedded in epoxy resin. Some tissues were treated with saliva before postfixation. Ultrathin sections, stained by the periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) method or with uranyl acetate and lead citrate, were examined by electron microscopy. On routinely stained sections, glycogen particles seemed to be absent in the cytoplasmic matrix of the photoreceptor cells because they were indistinguishable from the numerous ribosomes. This was due to a similarity in size and electron density. After PA-TCH-SP staining, fine electron-dense reaction products appeared on small cytoplasmic particles (but not on ribosomes) in the inner segments, perikarya and synaptic terminals of a subpopulation of photoreceptor cells. These particles, 15-25 nm in diameter, were identified as beta-particles of glycogen because of their susceptibility to enzyme digestion. The glycogen-rich photoreceptor cells were thought to be cone cells by reasons of their morphological features, such as synaptic terminals, nuclei and outer segments. These results suggest that the cone, but not the rod, photoreceptor cells in the rat contain abundant glycogen.

Animals↗

PubMed1997

Reduced sialylation of glycoproteins in nasal glands of patients with chronic sinusitis.

This study was conducted to investigate the sialylations of glycoproteins in the nasal glands of patients with chronic sinusitis. Sialic acids were detected using lectin histochemistry, and the mRNA of sialyltransferase was evaluated by in situ hybridization histochemistry. Sambucus nigra agglutinin (SNA), which recognizes terminal sialic acids, strongly stained the glandular mucous cells of normal subjects, but not those of patients with chronic sinusitis. In situ hybridization histochemistry showed that the expression of alpha2,6 sialyltransferase mRNA was decreased in the secretory cells of patients with chronic sinusitis. Our present results suggest that a reduction in sialyltransferase activity at the mRNA level in the nasal glands may lead to the persistence of chronic sinusitis.

Adolescent↗

PubMed1997

[Lectin histochemistry of the glycoconjugates in conjunctival goblet cells].

The distribution of O- and N-linked glycoconjugates in human conjunctival goblet cells was examined histochemically using biotinylated and fluorescence-labeled lectins simultaneously. Both peanut agglutinin and Erythrina cristagalli agglutinin, specific for O- and N-linked sugar chains, respectively, bound to the same goblet cell, which demonstrated that a conjunctival goblet cell produces and contains both types of glycoconjugates. Maackia amurensis lectin II, specific for sialic acid alpha 2, 3 galactose, bound to the goblet cells, while Sambueus nigra agglutinin, specific for sialic acid alpha 2, 6 galactose, did not. This observation suggested that the terminal galactosyl residue of the glycoconjugates is alpha 2, 3-sialylated in the human conjunctival goblet cells.

Conjunctiva↗

PubMed1997

[Lectin-histochemical analysis of pleomorphic adenoma of the lacrimal gland].

The sugar structures of the glycoconjugates in pleomorphic adenoma of the lacrimal gland were analyzed by examining the binding sites of 5 biotinylated lectins on tissue sections with or without sialidase digestion. Both galactose (Gal) beta 1,3 N-acetylgalactosamine and Gal beta 1,4 N-acetylglucosamine were present on the surfaces of ductal basal cells and stromal cells. The galactsyl residues in the glycoconjugates of ductal basal cells were either sialylated or exposed, whereas those of stromal cells were all sialylated. Since the synthesis of sugar chains of glycoconjugates is terminated by sialylation, their structure may mature as they progress from ductal basal cells to stromal cells.

Acetylgalactosamine↗

PubMed1997

[Glycohistochemical analysis of rat eyelid epithelium].

The glycoconjugates in eyelids of adult rats were examined by lectin histochemistry and in situ hybridization histochemistry. Since Maackia amurensis lectin II and jacalin bound to the cell membranes of basal and apical epithelial cells, sialic acid alpha 2,3 galactose (Gal) beta 1,3 N-acetylgalactosamine (GalNAc) sequence is present in the glycoconjugates of their cell membranes. Peanut agglutinin bound to the cell membranes of spinous cells in the middle of the epithelium, suggesting that Gal beta 1, 3 GalNAc sequence is present in their glycoconjugates. The mRNA of Gal beta 1,3 GalNAc alpha 2,3-sialyltransferase was detected in the cytoplasm of the epithelial cells other than the basal cells. This observation suggests that sialoglycoconjugates may be newly synthesized in the spinous and apical cells, while the glycoconjugates in the cell membranes of basal cells may be produced at an early stage of development and are stable without turnover.

Animals↗

PubMed1997

[Glycohistochemical analysis of seborrheic keratosis in eyelids].

The glycoconjugates of seborrheic keratosis in the eyelids were examined by in situ hybridization histochemistry using cRNA probes for sialyltransferase (ST) and lectin histochemistry. We considered that the cells, which expressed both cytoplasmic distribution of ST-mRNA and binding of lectins specific for sialic acids to the cell surfaces, were actively producing sialoglycans. We also considered that the cells whose surfaces were stained with the lectins without cytoplasmic distribution of ST-mRNA have completed the synthesis of sialoglycans. These viewpoints suggest that the O-linked sialoglycan, whose turnover-rate is slow, may be distributed over the cells of the thickened spinocellular layer in the tumor of seborrheic keratosis and involved in its pathomechanism. It also appears that the turnover rate of the terminal sialic acids in the N-linked glycan in the spinocellular layer may be fast.

Aged↗

PubMed1997

[Lectin-histochemical study of early postnatal eyelid epithelium of the rat].

The glycoconjugates in neonate rat eyelids at postnatal day 0 or 1 were examined by lectin histochemistry. Maackia amurensis lectin II, which recognizes sialic acid alpha 2, 3 galactose beta 1, 3 N-acetylgalactosamine (Gal beta 1, 3 GalNAc) or sialic acid alpha 2, 3 galactose beta 1, 4 N-acetylglucosamine, bound to the cell membranes of the epithelial basal cells, suggesting that the glycoconjugates containing these sugar chains are present on their cell membranes. With respect to the binding of the Gal beta 1, 3 GalNAc-specific lectin, jacalin, whose binding is not inhibited by the terminal sialic acid, bound to the cell membranes of the epithelial basal cells, whereas peanut agglutinin, whose binding is inhibited by the terminal sialyl residue, did not bind to their cell membranes. These findings suggest that all the residues of Gal beta 1, 3 GalNAc in the glycoconjugates of their cell membranes are sialylated as the mature form.

Animals↗

PubMed1997

[Glycohistochemical analysis of apoptotic bodies in eyelid tumor].

To clarify the relation between the mechanism of apoptosis in tumor tissues and sialic acids on the termini of sugar chains of glycoconjugates, a case of squamous cell carcinoma was examined using immunohistochemistry and glycohistochemistry. Immunohistochemistry and in situ hybridization histochemistry suggested that sialylation by the sialyltransferase in dominant in tumor cells, whereas hydrolysis of sialic acids by the sialidase is dominant in apoptotic bodies. Lectin histochemistry revealed that sialic acid alpha 2, 3 galactose beta 1, 3 N-acetylgalactosamine (Gal beta 1, 3 GalNAc) is present on the surfaces of tumor cells, and Gal beta 1, 3 GalNAc is present on those of apoptotic bodies. The exposed Gal beta 1, 3 GalNAc owing to the decrease in sialic acids on the surfaces of apoptotic bodies may be recognized by the C-type lectin on the macrophage for phagocytosis.

Aged↗

PubMed1997

[Immunohistochemical distribution of keratin in malignant tumors of eyelids].

The type and distribution of keratins (K) in malignant tumors of eyelids were examined immunohistochemically to understand the pathomechanism of intercellular interactions. All of the tumor cells in the basal cell carcinoma were positive for K14, which is specific for basal cells, whereas all of them were negative for K10, which is specific for suprabasal layers in stratified squamous epithelia. These findings suggest that basal cell carcinoma may consist of uniform, basal cell-like tumor cells. On the other hand, the squamous cell carcinoma and sebaceous carcinoma, which were positive for either K14 or K10 to varying extent, may consist of various tumor cells with different types and degrees of differentiation. In these tumors, K14 was frequently detected throughout the border cells of the tumor mass. Apoptotic bodies were detected at the region where this continuous distribution of K14 was interrupted. These findings may help to clarify the pathomechanism of the interactions between the tumor cells and stromal cells.

Adenocarcinoma, Sebaceous↗

PubMed1997

[Immunohistochemical localization of cytosolic sialidase in the epithelium of rat cornea and conjunctiva].

The binding sites of the anti-cytosolic sialidase antibody and Maackia amurensis lectin II (MAL II: specific for sialic acid alpha 2, 3 galactose) in the epithelium of the rat cornea and conjunctiva were immunohistochemically and lectin-histochemically examined, respectively. Cytosolic sialidase was detected in the cytoplasm of the middle and basal epithelium of the cornea and conjunctiva, whereas MAL II bound to the apical region of their epithelium and the mucous of the goblet cells. The predominant action of the cytosolic sialidase, which is stronger than that of the sialyltransferase, may inhibit the terminal sialylation of the glycoconjugates at the middle and basal regions of the epithelium of the cornea and conjunctiva.

Animals↗

PubMed1997

[Effects of the age on the apoptotic and proliferative reactions in the constant light-exposed rat retina].

The effects of age (5-3 weeks old) on apoptotic changes in the rat photoreceptor cells induced by 3 days of constant light exposure were examined using TUNEL (TdT-mediated dUTP nick end labeling). The effects on the expression of the Ki67-antigen, which is a proliferative marker, in these photoreceptor cells were also examined by immunohistochemistry. The results suggested that the number of positive cells in the outer nuclear layer of the superior hemisphere is higher than in the inferior nuclear layer in both the TUNEL reaction and the distribution of the Ki67 antigen, and that the number of positive cells increases with age in general. The cells of monocytes/macrophages may locally proliferate in the retina to phagocytose the apoptotic bodies owing to the degeneration of photoreceptor cells. The present findings revealed that the rates of these reactions may generally increase with age.

Aging↗

PubMed1997

[Selective binding of fucose-recognizing lectin on the cone photoreceptor outer segments].

The distribution of fucose-containing glycoconjugates in the photoreceptor cell layer of rat and human retinas was examined by lectin histochemistry using Aleuria aurantia lectin (AAL), which recognizes L-fucose alpha 1, 6 residue. In the rate retina, AAL diffusely bound to the apical outer segments and to the basal inner segments, whereas it bound to the entire outer segments of other photoreceptors, which were considered to be cones due to their proportion. In the human retina, AAL bound diffusely to the basal inner segments and to the retinal pigment epithelia, but it bound selectively to the outer segments of the cones. The present findings revealed that the glycoconjugates, whose sugar chains contain L-fucose alpha 1, 6 residue on their termini, are present in the cone outer segments.

Animals↗

PubMed1997

[Immunohistochemical localization of MUC 1 and keratin 14 in the invasive regions of malignant eyelid tumors].

The distributional patterns of MUC 1 (the mucin whose cDNA was first cloned) and Keratin 14 (K14) in the invasive regions of malignant eyelid tumors were immunohistochemically examined by comparing with other histochemical markers. The MUC 1-positive tumor cells were detected in several serial, small, invasive tumor masses in the deep subepithelial region of the low differentiated carcinoma. They were also continuously detected in the border region between accumulated lymphocytes including T cells and tumor masses of the sebaceous carcinoma. On the other hand, K14-positive tumor cells were detected in the marginal regions of large tumor masses or those with smooth edges, some of which overlapped the distribution of MUC 1-positive cells in the tissues of undifferentiated carcinoma, squamous cell carcinoma, and sebaceous carcinoma. In general, MUC 1 may be expressed in the invasive tumor cells, whereas K14 may be expressed in the marginal cells of the stable, proliferating tumor masses.

Adenocarcinoma, Sebaceous↗

PubMed1996

Immunohistochemical localization of cytosolic sialidase in photoreceptor cells.

The binding sites of the antibody to cytosolic sialidase on the rat and monkey photoreceptor cells were examined immunohistochemically using the avidin-biotinylated peroxidase method. In the rat photoreceptor cells, the antibody bound diffusely to the inner segment and the outer nuclear layers which are composed chiefly of rod cells. In the monkey photoreceptor cells, the antibody bound to the rod inner segments which were clearly distinct, morphologically, from the cone inner segments. The antibody also bound to the rod cell bodies in the outer nuclear layer. These binding patterns show that the antibody bound preferentially to rod photoreceptor cells. This observation is consistent with previous lectin histochemical findings that sialoglycans are preferentially present on the surfaces of rod photoreceptors, and in the rod-associated interphotoreceptor matrix. Sialidase in rod inner segments may function by balancing with sialyltransferase, also preferentially expressed in rod inner segments, to form sialyl residues on the termini of sugar chains in the rod-associated sialoglycoconjugates.

Animals↗