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Biomedical subjects

K Kon

Publications and source records attributed to K Kon.

At least 55 records · Page 3Linked to original sources
PubMed1993

Differential fatty acid release from CA1 and CA3 regions of rat hippocampal slices under hypoxia and hypoglycemia.

Rat hippocampal slices were subjected to hypoxia and/or hypoglycemia for 10 min, and free fatty acids released in CA1 and CA3 regions were separately analyzed. Fatty acid accumulation in CA1 was not so significant under hypoglycemia, but very prominent under hypoxia. Free fatty acid levels in CA3 were much less than those in CA1 even under hypoxia plus hypoglycemia. This observation seems to be consistent with the selective vulnerability of CA1 neurons seen in in vivo ischemia. The decreasing order of accumulation of free fatty acid species in CA1 was C16:0 > C18:0 > C18:1 > C20:4 > C22:6. The increment fold as compared to control level was decreasing as follows: C22:6, 28 times; C20:4, 13 times, C18:1, 10 times; C18:0 = C16:0, 3 times. The present experimental conditions using hippocampal slices provided a good in vitro model to prove the selective hypoxic damages of the CA1 subfield in terms of free fatty acid release in association with the membrane degradation.

Animals↗
PubMed1993

Isolation and characterization of a trisialyllactosylceramide, GT3, containing an O-acetylated sialic acid in cod fish brain.

An O-acetylated ganglioside that generated a trisialyllactosylceramide or GT3 by base treatment was found for the first time in cod fish brain. This ganglioside was isolated by high-performance liquid chromatography, and characterized by fast atom bombardment mass spectrometry, and proton nuclear magnetic resonance spectroscopy in addition to chemical analysis. The structure was identified as a modified GT3 in which the external sialic acid is O-acetylated at the C-9 position. The chemical structure is as follows: II3(9-O-Ac-NeuAc2-8NeuAc2-8NeuAc2-3)Lac Cer.

Acetylation↗
PubMed1993

A new O-acetylated trisialoganglioside, 9-O-acetyl GT2, in cod brain.

An O-acetylated trisialoganglioside that is converted to GT2 on mild base treatment was found in cod brain. This alkali-labile ganglioside was isolated using high-performance liquid chromatography, and its chemical structure was characterized. This novel ganglioside was identified as a GT2 derivative having an acetyl group at the C-9 position of the external sialic acid. Its chemical structure is as follows.

Acetylation↗
PubMed1993

Glomerulonephritis with various crystalline deposits.

A 60-year-old Japanese male was admitted with nephrotic syndrome complaining of facial and pedal edema. Renal biopsy revealed mesangial and endocapillary proliferation with massive mesangial and subendothelial deposits. Deposits of IgA, IgG, IgM, C3 and fibrinogen were identified by immunofluorescence technique in both mesangial and subendothelial areas. Deposits of kappa and lambda light chains were also recognized in similar patterns. Electron microscopy revealed crystalline structures of various appearance in these deposits. A large deposit consisted of various small triangular, quadrilateral and polygonal shapes of deposits with crystalline structures. These crystalline structures exhibited lattice or parallel lamellar lines with different periodic distances. Although a disease producing paraproteinemia was suspected, no immunoglobulin disorder or light chain abnormality could be detected on clinical and laboratory examinations. On the second biopsy, a faint reaction for cryoglobulin was recognized. However, the crystalline deposits observed in this case were absolutely different from the tubular structures seen in cryoglobulinemic nephropathy. This was a very rare and unclassified case.

Crystallization↗
PubMed1992

Structural characterization of a novel cholinergic neuron-specific ganglioside in bovine brain.

A new ganglioside antigen, termed Chol-1 alpha-b, recognized by cholinergic neuron-specific antibody, Chol-1 alpha, was isolated from bovine brain ganglioside mixture using Q-Sepharose. The yield was approximately 1.3 mg from 5 g of the total ganglioside. The chemical structure was characterized as a novel ganglioside by means of gas-liquid chromatography, a permethylation study, mild acid hydrolysis, thin layer chromatography-enzyme immunostaining, fast atom bombardment mass spectrometry, and proton nuclear magnetic resonance spectroscopy. The ganglioside has the following unique structure. [formula: see text] When examined by thin layer chromatography immunostaining and enzyme-linked immunosorbant assays, this ganglioside has the most intense immunoreactivity with Chol-1 alpha antibody among bovine brain gangliosides. As combined with our previous results (Hirabayashi, Y., Hyogo, A., Nakao, T., Tsuchiya, K., Suzuki, Y., Matsumoto, M., Kon, K., and Ando, S. (1990) J. Biol. Chem. 265, 8144-8151; Ando, S., Hirabayashi, Y., Kon, K., Inagaki, F., Tate, S., and Whittaker, X. (1992) J. Biochem. (Tokyo), 111, 287-290), the present study indicates the occurrence of a new series of gangliosides containing N-acetylneuraminic acid residue attaching to N-acetylgalactosamine as cholinergic specific antigens.

Animals↗
PubMed1992

Human meconium gangliosides. Characterization of a novel I-type ganglioside with the NeuAc alpha 2-6Gal structure.

Three monosialogangliosides containing the NeuAc alpha 2-6Gal structure have been detected in human meconium by immunological analysis using a monoclonal antibody, MSG-15, and purified by repeated silica beads column chromatography. One was previously shown to be NeuAc alpha 2-6Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer. The remaining two were characterized by proton NMR, fast atom bombardment mass spectrometry, methylation analysis by gas chromatography-mass spectrometry, and immunological studies, and their structures were concluded to be as follows. [formula: see text] The second ganglioside has the same structure that was isolated from bovine buttermilk (Takamizawa, K., Iwamori, M., Mutai, M., and Nagai, Y. (1986) J. Biol. Chem. 261, 5625-5630), and this is the first description of the occurrence of the ganglioside with the branched structure with two N-acetyllactosamines linked to lactosylceramide via beta 1-6 and beta 1-3 in human linked to lactosylceramide via beta 1-6 and beta 1-3 in human tissues. The third ganglioside is a novel ganglioside with blood group I-type and a NeuAc alpha 2-6Gal structure.

Amino Sugars↗
PubMed1992

A trisialoganglioside containing a sialyl alpha 2-6 N-acetylgalactosamine residue is a cholinergic-specific antigen, Chol-1 alpha.

Cholinergic-specific antigens termed the Chol-1 family have been suggested to be of a ganglioside nature by Richardson et al. (J. Neurochem. 38, 1605-1614, 1982). Two molecular species of polysialogangliosides among bovine brain gangliosides were found to react with anti-Chol-1 alpha antiserum. One of them, Chol-1 alpha-a, was isolated and characterized as a trisialoganglioside containing the gangliotetraose backbone in which 1 mol of sialic acid was attached to each of the reducing end galactose, N-acetylgalactosamine and internal galactose residues, respectively. The chemical structure of Chol-1 alpha-a was determined for the first time, being as follows: IV3NeuAc III6NeuAc II3NeuAc-GgOse4 Cer.

Antigens, Surface↗
PubMed1992

Characterization of two novel pyruvylated glycosphingolipids containing 2'-aminoethylphosphoryl(-->6)-galactose from the nervous system of Aplysia kurodai.

Two novel acidic glycosphingolipids containing pyruvylated galactose were purified from the nervous tissue of Aplysia kurodai by successive Iatrobeads column chromatographies. By component analysis, sugar analysis, permethylation studies, fast atom bombardment-mass spectrometry, and proton magnetic resonance spectrometry, the structures of these acidic glycosphingolipids, named F-9 and FGL-I, were determined to be: [3,4-O-(S-1-carboxyethylidene)]Gal beta 1-->3 GalNAc alpha 1-->3[6'-O-(2-aminoethylphosphonyl)Gal alpha 1-->2] (2-aminoethylphosphoryl 1-->6)Gal beta 1-->4Glc beta 1-->1ceramide and [3,4-O-(S-1-carboxyethylidene)] Gal beta 1-->3GalNAc alpha 1-->3(Fuc alpha 1-->2)(2-aminoethylphosphonyl-->6 Gal beta 1-->4Glc beta 1-->1ceramide, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. Thus, pyruvylated glycosphingolipids containing phosphoethanolamine in addition to or in place of 2-aminoethylphosphonate are present in the nervous system of Aplysia.

Acidic Glycosphingolipids↗
PubMed1992

Cytotoxicity of activated platelets to autologous red blood cells.

Gel-filtered human platelets exerted lytic activity on autologous red blood cells (RBC) when they were coincubated at 37 degrees C with platelet-activating agents, such as thrombin, collagen, ADP, LPS or PMA in the absence of plasma. Lysis of activated platelets themselves did not occur during the incubation period examined. Morphological observations showed that RBC exposed to thrombin-activated platelets were fragmented and/or transformed into spherocytes. This haemolytic reaction by thrombin-activated platelets did not occur at 4 degrees C, or in the presence of agents which inhibited glycolysis or elevated intracellular levels of cAMP, indicating that energy-dependent and cAMP-regulated platelet metabolism was required for this reaction. When platelets and RBC were incubated in the same vessel, but were prevented from coming into direct cell to cell contact by means of a membrane barrier, their cytotoxicity was reduced but not eliminated completely. No cytotoxic activity against RBC was detected in platelet-free supernatants obtained by centrifugation after activation of platelets with thrombin. On the contrary, activated and washed platelets retained the activity. These observations suggested that the cytotoxic activity was carried by some diffusible and easily inactivated factors, which were continuously produced and liberated from activated platelets. Cyclo-oxygenase inhibitors inhibited the haemolytic activity of thrombin-activated platelets, suggesting a role for some products of platelet-cyclo-oxygenase pathway in platelet-mediated haemolysis. These results provide the first evidence for a direct role of activated platelets in mediation of RBC-damage in the absence of any plasma factors.

Blood Platelets↗
PubMed1992

A review of patients with a 'normal' coronary angiogram over a 3-year period.

Over a period of 36 months, we detected 54 patients with normal coronary arteries or non-critical coronary artery stenosis within our study series of coronary angiography. We studied these patients to determine their clinical, electrocardiographic, stress testing and angiocardiographic characteristics. We detected among them a preponderance of female sex and a higher incidence of ethnic Indians. The majority of the patients studied had one or more coronary risk factors. 52% had a normal resting ECG. In those with a positive stress test and reports available for review, there is a near equal distribution of horizontal and J-type ST depression. Those patients with a positive treadmill tend to have a higher left ventricular end diastolic pressure (LVEDP) at cardiac catheterization. We also noted in this group of patients a higher proportion with a small distal left anterior descending artery. These patients also tend to have higher LVEDP even in the presence of normal left ventriculogram. Our current series suggests the possibility of raised left ventricular end-diastolic pressure and the presence of a "small distal left anterior descending artery" syndrome in association with patients with a 'false positive' treadmill test.

Adult↗
PubMed1991

A NeuGc-containing trisialoganglioside of bovine brain.

A N-glycolyneuraminic acid containing trisialoganglioside was isolated from bovine brains ganglioside mixture using Q-Sepharose. Its chemical structure was characterized as IV3NeuAc, II3NeuAc-NeuGc, Gg4Cer by gas-liquid chromatography, a permethylation study, sialidase degradation, TLC/enzyme-immunostaining, fast atom bombardment-mass spectrometry, fluorometric HPLC and proton nuclear magnetic resonance spectroscopy. This was unique in the mixed sialic acid constituents. (formula; see text) This accounted for 0.78% of the gangliosides. The ceramide structure was almost identical with those of major bovine brain ganglioside, as mainly composed of 18:0 fatty acid (90.9%) and d20:0 sphingosine base.

Animals↗
PubMed1991

Novel phosphonoglycosphingolipids containing pyruvylated galactose from the nervous system of Aplysia kurodai.

We have reported the existence of a phosphonoglycosphingolipid containing a pyruvylated galactose, FGL-IIb, in nerve fibers of Aplysia kurodai (Araki, S., Abe, S., Ando, S., Kon, K., Fujiwara, N. & Satake, M. (1989) J. Biol. Chem. 264, 19922-19927). We have now isolated two other pyruvylated galactose-containing phosphonoglycosphingolipids, named FGL-V and FGL-IIa, from the nervous tissue of Aplysia, and characterized them as [3,4-O-(S-1-carboxyethylidene)]Gal beta 1----3GalNAc alpha 1----3[6'-O-(2- aminoethylphosphonyl)Gal alpha 1----2] (2-aminoethylphosphonyl----6) Gal beta 1----4Glc beta 1----1 ceramide and [3,4,O-(S-1-carboxyethylidene)] Gal beta 1----3GalNAc alpha 1----3[6'-O-(2-aminoethylphosphonyl)Gal alpha 1----2]Gal beta 1----4Glc beta 11----ceramide, respectively. Their major aliphatic components are palmitic acid, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. Thus, the nervous system of Aplysia contains several pyruvylated phosphonoglycolipids.

Animals↗
PubMed1991

Characterization of a novel Le(x)-active ganglioside from chick intestinal tissues recognized by murine monoclonal antibody 188C1.

A monoclonal antibody, 188C1, raised against skin tissue from the back of bullfrogs (Rana catesbeiana) was found to recognize a common antigen in neural and intestinal tissues of chicken (Fujita, S. (1989) in Biological Transduction Mechanisms (Kasai, M., Yoshioka, T., and Suzuki, H., eds) pp. 159-177, Japan Scientific Societies Press, Tokyo Japan). The 188C1 antigen was isolated from chick intestinal tissues and characterized as a novel ganglioside by means of Q-Sepharose and Iatrobeads column chromatography, and chemical, immunochemical, and immunohistochemical analyses. The chemical structure was as follows: Gal beta 1-4 GlcNAc beta 1-3Gal beta 1-3GalNAc beta 1-4Gal beta 1-4Glc beta 1-1'Cer Fuc alpha 1-3 NeuAc alpha 2-3 This represents a novel hybrid structure of type 2 Le(x) epitope and GM1 ganglioside core structure, designated as Le(x)-GM1. Monoclonal antibody 188C1 reacted strongly with Le(x)-GM1 on thin layer chromatography, but its reactivity was greatly reduced when sialic acid was removed from the antigen. This indicated that the internal sialic acid residue might participate in antigenicity of the Le(x) determinant. In addition to 188C1, a more specific antibody reacting with Le(x)-GM1 but not with asialo-Le(x)-GM1 was raised by immunizing a rabbit with Le(x)-GM1. TLC/enzyme immunostaining using this specific antibody showed the presence of Le(x)-GM1 in chick intestinal tissue, but not in chick brain.

Animals↗
PubMed1991

Structure of triphosphonoglycosphingolipid containing N-acetylgalactosamine 6-O-2-aminoethylphosphonate in the nervous system of Aplysia kurodai.

A phosphonoglycosphingolipid, named F-21, was found in the nervous system of Aplysia kurodai by two-dimensional thin-layer chromatography (Abe, S., Araki, S., and Satake, M. (1986) Biomed. Res. (Tokyo) 7, 47-51). F-21 was isolated from the nervous tissue of Aplysia in this study, and its chemical structure was characterized as follows, where 2-AEP is 2-aminoethylphosphonate. (Formula; see text) The major aliphatic components of the ceramide portion were palmitic acid (75%), stearic acid (22%), octadeca-4-sphingenine (43%), and anteisononadeca-4-sphingenine (54%). Some information on the steric interactions in the sugar moiety was obtained by NMR spectroscopy. The ring protons of the internal galactose, H1, H3, and H4 and the H3 of the side chain galactose were shifted, as compared to the corresponding protons of dephosphonylated F-21. This may indicate the interactions between the 2-AEP residue of N-acetylgalactosamine and the internal galactose and between the N-acetyl group of N-acetylgalactosamine and the side chain galactose, implying a sterically restricted and unique structure that may relate to some biological functions of F-21.

Acetylgalactosamine↗
PubMed1991

Isolation and characterization of major urinary oligosaccharides excreted by a patient with type 3 GM1 gangliosidosis.

Two major oligosaccharides were isolated from the urine of a patient with type 3 GM1 gangliosidosis. From structural studies including compositional sugar analysis, fast-atom bombardment mass spectrometry, direct-inlet chemical ionization mass spectrometry, methylation analysis, chromium trioxide oxidation, and proton magnetic resonance spectroscopy, their structures were deduced to be as follows: [formula: see text] Both oligosaccharides have beta-linked galactose at the non-reducing ends. Oligosaccharide 1 is one of the most common urinary oligosaccharides found in type 1 and type 2 GM1 gangliosidosis. Oligosaccharide 2, lacto-N-difucohexaose II, has not been described in the urine of GM1 gangliosidosis patients. Excretion of oligosaccharide 1 in the type 3 patient was much less than that of a type 2 patient. Thin-layer chromatographic analysis revealed that the excretion of oligosaccharides with higher molecular weight than that of oligosaccharide 1 (octasaccharide) in the type 3 patient was much less than that of a type 2 patient, raising the possibility that the mutant beta-galactosidase of type 3 GM1 gangliosidosis can still act to some extent on higher molecular weight oligosaccharides containing beta-linked galactose at the non-reducing end.

Carbohydrate Conformation↗