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Y Kameda

Publications and source records attributed to Y Kameda.

At least 127 records · Page 7Linked to original sources
PubMed1991

Occurrence of colloid-containing follicles in the pars distalis of pituitary glands from aging guinea pigs.

Colloid-containing follicles in the pars distalis of pituitary glands from guinea pigs at various ages ranging from 5 days to 36 months were examined by the periodic acid-Schiff (PAS) reaction, immunohistochemistry, and electron microscopy. The follicles storing PAS-positive colloid were first detected in 6-month-old animals, in which only a few follicles were present and mean diameters of colloid deposits were small: 4.3 +/- 1.0 microns in males and 4.1 +/- 0.4 microns in females. Thereafter, the follicles gradually increased in number and size with age. The largest number of follicles was observed in the senile groups: 410.5 +/- 92.3 in males, 454.7 +/- 84.7 in females. Mean diameters of colloid masses in the senile groups were more than 2 times larger than those in 6-month-old animals: 10.0 +/- 0.1 microns in males, 9.7 +/- 0.1 microns in females. These findings suggest that the formation of colloid-containing follicles in the guinea-pig pars distalis is an aging phenomenon. The follicular lumina were mainly surrounded by thin cytoplasmic processes or cell bodies of folliculo-stellate cells immunoreactive for S-100 protein. The lining folliculo-stellate cells showed aggregations of intermediate-sized filaments, numerous lysosomes and colloid-like inclusions. Granulated cells in contact with colloid were occasionally encountered. Intracellular cavities storing colloid-like and fibrous materials were detected in the syncytial formation of GH cells.

Aging↗
PubMed1991

Hemodynamics and coronary blood flow during exercise after coronary artery bypass grafting with internal mammary arteries in children with Kawasaki disease.

BACKGROUND: Saphenous vein grafts (SVG) and internal mammary artery (IMA) grafts have been used for coronary artery bypass grafting. In adult patients with bypass grafting for atherosclerotic coronary artery disease, IMA grafts have been reported to have long-term patency; however, results are conflicting on whether the graft is sufficient to meet increased myocardial oxygen demand during exercise. There have been no studies on hemodynamics and blood flow during exercise after bypass grafting with IMA in pediatric patients with Kawasaki disease. METHODS AND RESULTS: We studied 17 pediatric patients with Kawasaki disease (average age, 7.5 +/- 3.1 years), who underwent coronary artery bypass grafting with the IMA. The average number of coronary artery bypass grafts was 2.1 +/- 0.7/patient. For all patients, the left IMA was anastomosed to the left anterior descending coronary artery; for eight patients, the right IMA was also anastomosed to the right coronary artery. In addition, 11 SVGs were used. The postoperative patency rates after 1 month were 100% with the IMA graft and 91% with SVG. One year after the operation, the patency rates were 100% with IMA and 50% with SVG. Hemodynamics during exercise were measured with a bicycle ergometer, and coronary sinus blood flow was measured by the continuous thermodilution method in six patients. The relation between delta LVEDP (the difference between left ventricular end-diastolic pressure at rest and during exercise) and delta SVI (the difference between the stroke volume index at rest and during exercise) was analyzed. Four of six patients had reduced cardiac function before operation (delta LVEDP, positive; delta SVI, negative). However, after the operation, all patients demonstrated improvements in cardiac function during exercise (delta LVEDP, positive; delta SVI, positive). Coronary sinus flow per left ventricular mass increased after operation from 70 +/- 46 to 87 +/- 56 ml/min at rest (p less than 0.05) and from 139 +/- 118 to 183 +/- 150 ml/min during exercise (p less than 0.05). CONCLUSIONS: In conclusion, this study reveals improvements in both hemodynamics and coronary blood flow during exercise after coronary artery bypass grafting with IMA grafts in pediatric patients with Kawasaki disease.

Adolescent↗
PubMed1991

All eight possible mono-beta-D-glucosides of validoxylamine A. I. Preparation and structure determination.

Validamycin A is the major and most active compound among the validamycin complex. Since the site of beta-glucosidic attachment to validoxylamine A (1) was expected to affect the activity against the pathogenic fungus, Rhizoctonia solani, all eight possible mono-beta-D-glucosides of 1 were prepared. 2-O-, 4-O-, 4'-O-, and 7'-O-beta-D-glucopyranosylvalidoxylamine A (2, 4, 6 and 9, respectively) were prepared by microbial beta-glycosylation of 1 with strains of Rhodotorula sp. 7-O- and 6'-O-beta-D-glucopyranosylvalidoxylamine A (5a and 8a, respectively) were prepared semisynthetically through microbial formation of 7-O-beta-D-glucopyranosylvalidamine (10), oxidation of the primary amine of 10 to a ketone, and coupling of the ketone derivative with valienamine, and through microbial formation of 6-O-beta-D-glucopyranosylvalienamine (11), and coupling of 11 with (2R)-(2,4/3,5)-2,3,4-trihydroxy-5-hydroxymethylcyclohexanone (12), respectively. 3-O- and 5'-O-beta-D-glucopyranosylvalidoxylamine A (3a and 7a, respectively) were chemically synthesized.

Antifungal Agents↗
PubMed1991

All eight possible mono-beta-D-glucosides of validoxylamine A. II. Biological activities.

The biological activities of all eight possible mono-beta-D-glucosides of validoxylamine A against Rhizoctonia solani were studied. The attachment of the D-glucosyl residue to validoxylamine A generally diminished the inhibitory activity against trehalase. The introduction of the D-glucosyl residue at the C-3 position did not cause serious loss in activity, while substitution at the C-6' position caused complete loss in trehalase inhibitory activity. Of the eight beta-D-glucosides, 4-O-beta-D-glucopyranosylvalidoxylamine A (4-O-beta-Glc-VA), 3-O-beta-Glc-VA and 5'-O-beta-Glc-VA exhibited very strong activity against R. solani in the "dendroid-test method". The antagonistic activity of sugars (1 mM) against validoxylamine A and 4-O-beta-Glc-VA was examined using the "dendroid-test method". The inhibitory effect of validoxylamine A on hyphal extension was not antagonized by any sugars tested, whereas that of 4-O-beta-Glc-VA was antagonized by beta-1,3- and beta-1,4-glucooligosaccharides. Of 2-O-, 3-O-, 4-O- and 7-O-beta-Glc-VAs, 7-O-beta-Glc-VA exhibiting the lowest activity was not antagonized by any beta-glucooligosaccharides tested. The inhibitory effect of 3-O- and 4-O-beta-Glc-VAs was antagonized by most beta-glucooligosaccharides. The uptake of 4-O-beta-Glc-VA into the mycelia was inhibited by laminaribiose and cellobiose but not by maltose.

Antifungal Agents↗
PubMed1991

[Neurilemmomatosis--a sporadic and familial cases].

Three cases of neurilemmomatosis are reported. A 22-year-old man without any relatives with similar symptoms visited our clinic, complaining of multiple skin tumors since the age of 15 and bilateral acoustic nerve symptoms since 19. Physical examination revealed no pigmented or depigmented spots. Histopathological examination of the eight tumors excised from the skin, acoustic nerve and spinal cord showed that these were all neurilemmomas. A 36-year-old man with a 15 year history of multiple skin tumors and one year history of acoustic nerve symptoms was seen at our clinic, revealing no pigmentary disorders. The tumors excised from the skin and bilateral acoustic nerves were all neurilemmomas histopathologically. A 5-year-old boy, who was the only child of the second case and had had several skin tumors since his birth, visited us after postoperative death of his father. He revealed no pigmentary abnormalities. The histology of the skin tumor was neurilemmoma. The absence of neurofibromas and pigmented spots in these patients with neurilemmomatosis suggests that this disorder might be close to, but distinct from neurofibromatosis. Although familial cases of neurilemmomatosis like our case 2 and 3 reported so far are very few, they support a possibility that neurilemmomatosis might be a genetically determined neurocutaneous syndrome, a kind of phacomatosis.

Adult↗
PubMed1990

Innervation of the serotonin-immunoreactive cells distributed in the wall of the common carotid artery and its branches in the chicken.

In the chicken, serotonin-immunoreactive cells were widely distributed not only in the carotid body but also in the wall of the common carotid artery and around each artery arising from the common carotid artery. Almost all of the serotonin cells in the wall of the common carotid artery were intensely immunoreactive to the neuropeptide Y, met- and leu-enkephalin antisera, whereas in the carotid body only a few cells were immunoreactive to these antisera. Innervation of the serotonin cells in and around arteries of chickens was investigated by immunohistochemistry and electron microscopy, in comparison with that of the carotid body. The serotonin cell groups in and around arteries, as well as the carotid body, received numerous peptidergic nerve fibers. Calcitonin gene-related peptide (CGRP)- and substance P-immunoreactive varicose nerve fibers were densely distributed, and somatostatin-immunoreactive fibers were moderately distributed in the serotonin cell groups. Galanin- and vasoactive intestinal peptide (VIP)-immunoreactive fibers were sparsely distributed in the cell groups. By electron microscopy, the serotonin cells in and around arteries were characterized by the presence of numerous dense-cored vesicles, 70-220 nm in diameter. The granule-containing cells were in close association with numerous axons. Naked axons regarded axon terminals were frequently apposed on the granular cells. The axon terminals were usually long and often partly invested the granular cells. Numerous synaptic junctions were detected along the contact between the granular cells and axon terminals. Most of the synaptic junctions showed afferent morphology; the secretory granules were accumulated near and attached to the asymmetrical membrane thickenings. Thus, the serotonin cells in and around arteries, like the carotid body, constitute chemoreceptive tissue.

Animals↗
PubMed1990

Occurrence of colloid-containing follicles and ciliated cysts in the hypophysial pars tuberalis from guinea pigs of various ages.

Colloid-containing follicles and ciliated cysts in the hypophysial pars tuberalis of guinea pigs at various ages ranging from 5 days to 36 months were examined by periodic acid-Schiff (PAS) reaction, immunohistochemistry, and electron microscopy. The follicles storing PAS-positive colloid were encountered in the pars tuberalis of all guinea pigs examined, although only a few were present in young animals. The follicles gradually increased in number with age. The largest number of follicles was found in the senile male group: 141.3 +/- 11.9, about 10 times the number in the 5-day-old male group. The follicles were scattered throughout the entire length of the pars tuberalis. Follicles with enlarged luminal cavities were concentrated in the ventral caudal region surrounding the infundibular stem and merges with the pars distalis. Three different types of follicles were found by electron microscopy: 1) those surrounded by nongranulated follicular cells that may correspond to the stellate-follicular cells in the pars distalis, 2) those surrounded by specific cells that were packed with vesicular inclusions, and 3) those surrounded by granulated cells that may be gonadotropes. In the follicles lined by non-granulated follicular cells, long, prominent microvilli and cytoplasmic processes protruding into the lumen and invaginations of colloid were often observed at the apical cell region. The follicles lined by the specific cells having numerous vesicles were localized only in the ventral caudal portion. The vesicles ranged from 200 to 700 nm in diameter, and the outer surface of their limiting membrane was partly studded with ribosomes. Gonadotropes immunoreactive to the luteinizing hormone (LH) and follicle-stimulating hormone (FSH) antisera were distributed in the guinea pig pars tuberalis. As well as the typical follicles described above, the follicles composed solely of granulated cells showed microvilli protruding into the cavities and junctional complexes at the apical lateral surface. They stored heterogeneous materials in the lumina. Some secretory granules gave the appearance of being discharged into the lumen. Ciliated cysts were frequently observed in the pars tuberalis; their incidence was 71.7%. The ciliated cysts were much larger than colloid-containing follicles. Cystic cavities were only partly filled with heterogeneous materials showing colloid-like, flocculent, and granular features.

Aging↗
PubMed1990

Distribution of serotonin-immunoreactive cells around arteries arising from the common carotid artery in the chicken.

By using an immunoperoxidase method with antiserotonin antiserum, the distribution of serotonin-immunoreactive cells in the carotid body region was investigated in chickens. The thyroid gland, cranial and caudal parathyroid glands, carotid body, and ultimobranchial gland of chickens were located along the common carotid artery as a continuous series and were supplied with branches arising from the artery. Almost all chief cells of the chick carotid bodies were immunoreactive for serotonin. Furthermore, numerous serotonin-immunoreactive cells were widely distributed in the adventitial connective tissue around those arteries that issued from the common carotid artery to supply each endocrine organ, i.e., the carotid body artery, the esophagotracheobronchial artery, the ascending esophageal artery, and the inferior thyroid artery. These arteries usually arose by one trunk from the lateral aspect of the middle portion of the common carotid artery. The serotonin cells were most numerous around the carotid body artery and were dispersed along the whole length of the artery. In addition, they were detected around the common trunk of each artery and the roots of the ascending esophageal artery, the inferior thyroid artery, and the esophagotracheobronchial artery. The serotonin cells were also distributed in the tunica media of the common carotid artery. In that place, they were concentrated around the origin of the common trunk of each artery and were scattered below the origin along the longitudinal axis and on the opposite side of the origin. The serotonin-immunoreactive cells distributed around and in the arteries may be involved in the control of blood flow and may have chemoreceptive properties.

Animals↗
PubMed1990

Distribution and ontogeny of chromogranin A and tyrosine hydroxylase in the carotid body and glomus cells located in the wall of the common carotid artery and its branches in the chicken.

Development and distribution of chromogranin A and tyrosine hydroxylase in the carotid body and glomus cells located in and around arteries were examined in chickens at various developmental stages by an immunohistochemical staining. In 9-day-old embryos, numerous cells immunoreactive for tyrosine hydroxylase were already detected in the connective tissue surrounding the carotid body. Some of these cells also showed immunoreactivity for chromogranin A. At 10 days of incubation, a few cells immunoreactive for tyrosine hydroxylase and chromogranin A were detected within the carotid body parenchyma. At 12 days of incubation, almost all glomus cells of the carotid body were intensely immunoreactive for these substances. Furthermore, numerous tyrosine hydroxylase- and chromogranin A-immunoreactive cells were observed in the wall of the common carotid artery, along the whole length of the carotid body artery, and around the roots of the inferior thyroid artery, the ascending esophageal artery and the esophagotracheobronchial artery; the cells already exhibited adult pattern of distribution at this stage of development. Thereafter, glomus cells immunoreactive for both substances gradually increased in number and in intensity of immunoreactivity with age, although the cells located in the wall of the common carotid artery lost immunoreactivity for tyrosine hydroxylase after hatching.

Animals↗
PubMed1990

Ontogeny of the carotid body and glomus cells distributed in the wall of the common carotid artery and its branches in the chicken.

Developmental patterns of immunoreactivity for serotonin and neuropeptide Y were investigated immunohistochemically in the carotid body and glomus cells in the wall of the common carotid artery and around its branches of chickens at various developmental ages. The development of peptidergic nerve fibers was also studied. Serotonin immunoreactivity began to appear in the glomus cells of the carotid body and around arteries at 10 days of incubation and became very intense from 12 days onwards. Neuropeptide Y immunoreactivity also appeared in these cells at 10 days, became intense at 14 days, and was sustained until 20 days. After hatching, neuropeptide Y immunoreactivity in the carotid body rapidly decreased with age and almost disappeared at postnatal day 10. However, it persisted for life in the glomus cells distributed in the wall of the common carotid artery. Substance P- and calcitonin gene-related peptide (CGRP)-immunoreactive fibers first penetrated into the carotid body parenchyma at 12 days of incubation. These peptidergic nerve fibers in the carotid body and glomus cell groups in and around arteries gradually increased with age, and approached the adult state at 18 days of incubation. Only a few galanin- and vasoactive intestinal peptide (VIP)-immunoreactive fibers were observed in the late embryonic carotid bodies. They rapidly developed after hatching and reached adult numbers at postnatal day 10. During late embryonic and neonatal development, considerable numbers of met-enkephalin-immunoreactive fibers were detected in the connective tissue encircling the carotid body.

Animals↗
PubMed1990

Inhibitory effect of pseudo-aminosugars on oligosaccharide glucosidases I and II and on lysosomal alpha-glucosidase from rat liver.

We examined the inhibitory effect of three pseudo-aminosugars (validamine, valienamine, and valiolamine), which were isolated from the broth of Streptomyces hygroscopicus, on the oligosaccharide-processing glucosidases I and II involved in glycoprotein biosynthesis in rat liver. Both glucosidases I and II were inhibited to the same extent by the pseudoaminosugars, and valiolamine had a more potent inhibitory activity than validamine or valienamine. A 50% inhibition of valiolamine was observed at 12 microM for glucosidase I and glucosidase II activities acting respectively on the substrates Glc3Man9GlcNAc2 and p-nitrophenyl alpha-D-glucopyranoside. Further, in order to investigate further the ability of valiolamine to inhibit glucosidase I, reaction products were analyzed by gel filtration on a Bio-Gel P-4 column. We also compared the inhibitory action of these pseudo-aminosugars on the acid alpha-glucosidase of rat liver lysosomes. They competitively inhibited the hydrolysis of both substrates, maltose and glycogen. Valiolamine again had a more potent lysosomal alpha-glucosidase inhibitory activity than the other two. The Ki values of valiolamine for the hydrolysis of maltose and glycogen were 8.1 and 11 microM, respectively. Valiolamine is a particularly effective inhibitor of oligosaccharide glucosidases I and II and of lysosomal alpha-glucosidase. Hence valiolamine might be useful as a research tool in investigations of carbohydrate metabolism.

Amino Sugars↗
PubMed1990

Inhibitory effect of validamine, valienamine and valiolamine on activities of carbohydrases in rat small intestinal brush border membranes.

Three pseudo-aminosugars, validamine, valienamine and valiolamine, produced by Streptomyces hygroscopicus subsp. limoneus showed potent inhibitory action on rat small intestinal carbohydrase activities such as sucrase, maltase, glucoamylase, isomaltase and trehalase activities, but negligible action on lactase activity and pancreatic alpha-amylase activity. Where inhibition was seen, kinetic analysis showed fully competitive inhibition of the carbohydrase activities by all three inhibitors. Valiolamine has more potent carbohydrase inhibitory activity than validamine or valienamine, and the apparent Ki values of valiolamine for sucrase, maltase, glucoamylase, isomaltase and trehalase activities were 3.2 x 10(-7), 2.9 x 10(-6), 1.2 x 10(-6), 9.1 x 10(-7) and 4.9 x 10(-5) M, respectively, which are 10(-5) to 10(-3) times smaller than the apparent Km values.

Animals↗
PubMed1990

Trehalase inhibitors, validoxylamine A and related compounds as insecticides.

Validoxylamine A showed a potent inhibitory activity against insect trehalase in a competitive manner with a Ki value of 4.3 x 10(-10) M. The other validoxylamines and validamycins also exhibited the activity in vitro. Injection of these compounds to young last instar larvae of the tobacco cutworm, Spodoptera litura, elicited the morphological abnormality followed by death after the cessation of feeding. Validoxylamine A showed 100% mortality at a dose of 10 micrograms/ last instar larva.

Animals↗
PubMed1990

[Percutaneous balloon valvuloplasty of a stenosed bioprosthesis (Carpentier-Edwards xenograft) in the tricuspid valve position].

Two patients with increasing stenosis of a bioprosthesis in the tricuspid valve position were treated by percutaneous balloon valvuloplasty (PBV). Tricuspid valve replacement with a Carpentier-Edwards xenograft and mitral valve replacement with a Duromedics mechanical valve had been performed in both of them 2 to 3 years prior to PBV. Echocardiographic studies revealed tricuspid bioprosthetic stenosis with a prolonged pressure half time. After PBV, the calculated valve area and cardiac index increased and the pressure half time was shortened, although improvement of clinical symptoms was not apparent. Complications related to the procedure did not occur. Further studies are required to determine the indications and to see the long term results of PBV on stenosed bioprosthesis in the tricuspid valve position, but for the moment, we consider PBV be tried with caution for a stenosed bioprosthesis in the tricuspid valve position before the decision for re-replacement of the prosthesis.

Bioprosthesis↗
PubMed1989

Occurrence of calcitonin-positive C cells within the distal vagal ganglion and the recurrent laryngeal nerve of the chicken.

The chicken ultimobranchial glands are richly supplied with nerve fibers originating from both the main trunk of the vagus nerve and its branch--the recurrent laryngeal nerve. C cells immunoreactive for calcitonin were invariably found in the large nerve bundles distributed throughout the ultimobranchial glands. In addition, these cells were often present within the distal vagal ganglia and the recurrent laryngeal nerves. The frequency of occurrence and the pattern of distribution of the C cells in the distal vagal ganglia and the recurrent laryngeal nerves were determined in chickens of various ages by means of an immunoperoxidase method with anticalcitonin and antineurofilament antisera. The left and right sides of the ultimobranchial region were asymmetrical. The left ultimobranchial gland was in close contact with the vagus nerve trunk, especially with the distal vagal ganglion, but it was separated from the recurrent laryngeal nerve. The right gland contacted the recurrent laryngeal nerves, its medial edge being frequently penetrated by the nerve, but the gland was separated from the distal vagal ganglion. On the left side, C cells were found in 25 out of 39 distal vagal ganglia but they were not distributed in the recurrent laryngeal nerve. On the right side, the cells were present in 28 out of 43 recurrent laryngeal nerves but absent in the distal vagal ganglia. The results indicate that the C cells secreting a hormone calcitonin can enter into nerves, but their occurrence is restricted to the nerves in close proximity to the ultimobranchial glands. Electron microscopic studies revealed that C cells in the nerves received numerous axon clusters enveloped with Schwann cell cytoplasm. Naked axons regarded as axon terminals were found in direct contact with the surface of C cells. They were mainly composed of efferent-type nerve endings showing the accumulation of numerous small clear vesicles and a few large dense-cored vesicles. In addition, C cells were partly covered with the long cytoplasmic processes of Schwann cells and were also in contact with the Schwann cell perikarya. The C cells in nerves appear to be controlled by neural stimulation.

Animals↗