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T Kaiya

Publications and source records attributed to T Kaiya.

At least 37 records · Page 2Linked to original sources
PubMed1996

A novel enzyme enantio-selectively synthesizes (R)salsolinol, a precursor of a dopaminergic neurotoxin, N-methyl(R)salsolinol.

In the human brain, only (R)enantiomer of 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline ((R)salsolinol) and N-methyl-salsolinol, a dopaminergic neurotoxin, were detected, suggesting their enzymatic biosynthesis. This paper reports the isolation and characterization of a novel enzyme, which enantio-selectively synthesizes (R)salsolinol from dopamine and acetaldehyde. Dopamine, acetaldehyde, formaldehyde and pyruvic acid were the substrates of this synthase, whereas N-methyldopamine, adrenaline, noradrenaline and L-DOPA were not. The possible function of this enzyme under physiological and pathological conditions in the brain is discussed.

Brain↗
PubMed1995

[Ultrastructural changes in the lamina cribrosa in experimental monkey glaucoma].

We examined the ultrastructural changes in the lamina cribrosa in monkeys with experimental chronic glaucoma. In normal monkey eyes, the extracellular matrix consists of tightly packed collagen fibers, elastic fibers and less ground substance in the beams, and basement membranes associated with vascular cells and astrocytes in the lamina cribrosa. In the experimental glaucomatous eyes there was a marked destruction of collagenous bundles. The empty spaces were expanded and filled with fine fibrillar materials. There were normal by appearing parts and clearly destroyed parts mixed in the same region. Elastic fibers looked isolated from the collagenous bundles around them. Basement membranes were generally thick, multi-laminated, and bent. In addition, basement membrane-like materials, separated from the cells, were often seen in the laminar beams. The lamina cribrosa in experimental chronic glaucoma showed evidence of both destruction and healing or remodeling. These changes might have a influence to the worse for the tissue characterization of the lamina cribrosa, such as resistence to intraocular pressure changes. In conclusion, this may be a factor related with the progression of glaucomatous optic nerve damage.

Animals↗
PubMed1994

Sulfated proteoglycans in the lamina cribrosa of normal monkey eyes and monkey eyes with laser-induced glaucoma.

The distribution of the sulfated proteoglycans in the lamina cribrosa of normal monkey eyes and monkey eyes with laser-induced glaucoma were analysed by electron microscopy after cuprolinic blue dye binding. Three types of cuprolinic blue-positive filaments, CB-1, CB-2 and CB-3, were identified in the laminar beams of normal monkey eyes. CB-1 and CB-2 were both small filaments representing chondroitin and dermatan sulfate proteoglycan copolymers. The former lined up perpendicularly to the long axis of collagen fibrils, whereas the latter ran axially parallel to collagen fibrils. The large CB-3 filaments, representing chondrotin sulfate proteoglycans, were located around collagen bundles or in loose spaces within the beams. In addition, small CB-4 filaments or punctate structures representing heparan sulfate proteoglycans were found aligned on the basal laminae of blood vessels and glial cells. In the glaucomatous eyes, accumulation and enlargement of collagen-associated proteoglycan filaments were seen, accompanied by the destruction of collagenous beams. Accumulation of chondroitin sulfate proteoglycans was most evident. Prominent filamentous heparan sulfate/heparin proteoglycans were also noted in thickened astrocytic and vascular basal laminae. These may be alterations secondary to the destruction of collagen bundles. They may also represent cellular responses related to intraocular pressure elevation.

Animals↗
PubMed1994

The collagen fibrillar network in the human pial septa.

The three-dimensional organization of the collagen fibrils in the human pial septa was studied by transmission electron microscopy and by scanning electron microscopy after cell maceration with sodium hydroxide. The collagen fibrils along the nerve fibers were loosely distributed thin filaments with a diameter ranging from 25 to 40 nm (mean, 32 +/- 6 nm). Most fibrils were oriented perpendicularly to the long axis of the nerve fiber. In the deeper stroma of the pial septa, collagen fibrils were well packed and the diameter was 40 +/- 6 nm (range, 35 to 50 nm). The scanning electron microscopic study demonstrated a smooth, fabric-like structure formed by wavy and loosely interwoven thin collagen fibrils. Under high magnification, multiple collagenous sheets were observed in the pial septa by scanning electron microscopy. In addition to the structure of loosely arranged thin fibrils on the surface layer adjacent to the nerve fibers, two distinct patterns of collagen fibril network were demonstrated in the deeper stroma. One exhibited fibrils with random distribution, and the other showed well-packed, undirectionally oriented collagen. Small openings corresponding to elastic tissues were also observed. This collagen architecture may contribute to the flexibility and tensile strength of the pial septa required in the intraorbital portion of the optic nerve.

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

MMPs and proteinase inhibitors in the human aqueous humor.

PURPOSE: This study was performed to examine the gelatinolytic and caseinolytic activities and the levels of two proteinase inhibitors, alpha 1-proteinase inhibitor (alpha 1-antitrypsin) and alpha 2-macroglobulin, in the human aqueous humor. METHODS: Aqueous humor samples were collected during elective surgery in patients with cataracts. Zymography with gelatin- and casein-containing gels was performed. The inhibitors were examined by Western blot analyses, enzyme-linked immunosorbent assay, and dot blot assays. RESULTS: The aqueous humor contained a major band of gelatinolytic activity at a molecular weight of 66 kD and minor bands at 125, 95, and 62 kD. These gelatinases were inhibited by 10 mM ethylenediaminetetraacetic acid (EDTA) or 1,10-phenanthroline. After extended incubation (48 hours), zymography on casein-containing gels showed proteinase bands with molecular weights in the 80- to 84-kD range. Additional bands at 68 and 48 kD also were observed. All the caseinase activities were inhibited by 10 mM phenylmethylsulfonyl fluoride and 1 microgram/ml aprotinin. No inhibition was observed with 5 mM EDTA, 5 microM E-64, or 1 microM pepstatin. These results indicated that the caseinases are serine proteinases. Western blot analysis showed a 53-kD alpha 1-proteinase inhibitor band in the aqueous humor. The concentration was 32.2 +/- 9.9 micrograms/ml, constituting approximately 15% of the total protein. A 360-kD protein band immunoreactive to anti-alpha 2-macroglobulin also was detected. Its level in the aqueous humor was 3.2 +/- 1.3 micrograms/ml. CONCLUSIONS: The gelatinases, serine-like proteinases, and proteinase inhibitors found in the aqueous humor may participate in the remodeling of extracellular matrices in the trabecular meshwork and other tissues bordering the anterior chamber.

Aged↗
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

A spirostanol glycoside from Yucca aloifolia.

From an ethanolic extract of the influorescence of Yucca aloifolia a new spirostanol glycoside has been isolated and characterized as 3-O[(alpha-L-rhamnopyranosyl(1----3)-beta-D-xylopyranosyl(1----2))(beta- D-glucopyranosyl(1----3)-beta-D-glucopyranosyl(1----3)-beta-D-glucopy ranosyl]-25R,5 alpha-spirostan-2 alpha, 3 beta-diol.

Carbohydrate Sequence↗
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

[The distribution and characterization of sulfated-proteoglycans in the normal human lamina cribrosa].

The distribution and morphological characterization of the sulfated-proteoglycans in the normal human lamina cribrosa under the electron microscope after staining with cationic-dye (Cuprolinic-Blue) in critical electrolyte condition were studied. Three types of Cuprolinic-Blue positive filaments were identified associated with collagen in the lamina cribrosa according to their size, electro-density and their relation to the collagen fibrils. The thin and short Cuprolinic-Blue positive filaments (referred to as CB-1 filament in this communication) distributed over the collagen fibers in relatively regular fashion. The intermediate-sized Cuprolinic-Blue positive filaments (CB-2) were seen randomly associated with collagen fibers. The clusters of large CB-3 filaments were seen unevenly associated with loosely packed collagen fibers. The higher electron density of CB-2 and CB-3 filaments than those of CB-1 filaments were also demonstrated. Cuprolinic-Blue positive dots and blots as well as various sizes of filaments could be identified in the basal lamina surrounding the collagen beams and in the basement membrane of the blood vessels.

Aged↗
PubMed1990

Observation of blood-aqueous barrier function after posterior chamber intraocular lens implantation.

Fluorophotometry was performed on 306 eyes of 306 patients who had posterior chamber intraocular lens implantation after phacoemulsification or planned extracapsular cataract extraction procedures to compare the ratio of fluorescein concentration in the anterior chamber of operated eyes and of unoperated fellow eyes for age, postoperative period, and operative procedure. In this study, the breakdown and reestablishment of the blood-aqueous barrier after posterior chamber intraocular lens implantation was observed for a long period.

Aged↗
PubMed1987

Structure-mutagenicity relationship among aminoquinolines, aza-analogues of naphthylamine, and their N-acetyl derivatives.

The mutagenicity of 7 positional isomers of aminoquinolines (AQ) and their N-acetyl derivatives (AcAQ) was tested in Salmonella typhimurium TA100 and TA98 in the presence and absence of S9 mix. In a series of aminoquinolines, the order of mutagenic potency in the presence of S9 mix is: 5-AQ greater than 8-AQ greater than 7-AQ greater than 3-AQ greater than 2-AQ much greater than 4-AQ, 6-AQ. The alpha-positional isomers, 5-AQ and 8-AQ, are more mutagenic than the beta-isomer, 2-, 3-, 6-, 7-AQ's. These results are in contrast to the finding that beta-naphthylamine is more mutagenic than alpha-naphthylamine. In a series of N-acetylaminoquinolines, the order of mutagenic potency in the presence of S9 mix is: 7-AcAQ greater than 6-AcAQ greater than 8-AcAQ much greater than all the others. It is suggested that the AQ and AcAQ series might exert their mutagenicity through different molecular mechanisms (i.e., metabolic activation) from each other. The rate of metabolic activation does not seem to be correlated with the mutagenic potency of the compounds. It is noteworthy that 7-AQ and 8-AQ are mutagenic in both the strains tested in the absence of S9 mix.

2-Naphthylamine↗
PubMed1983

Quantitative structure-inotropy relationship applied to substituted grayanotoxins.

Nine 14 beta-O-acylated grayanotoxins were synthesized by ozonolysis of 14,16-alkylidenegrayanotoxin III. The correlation between positive inotropic potency (PIE) in guinea pigs and physicochemical parameters (Vw, Mw, and Rm50) in 14 14-substituted grayanotoxins were quantitatively analyzed. It became clear that a parabolic relation existed between the bulkiness of the 14-substituents and PIE and that some electronic factor and the hydrophilic-hydrophobic balance would be related to the development of PIE.

Animals↗