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Biomedical subjects

T Taketomi

Publications and source records attributed to T Taketomi.

At least 37 records · Page 2Linked to original sources
PubMed1995

Inhibition of neurite outgrowth in murine neuroblastoma NS-20Y cells by calmodulin inhibitors.

The roles of protein kinases and calmodulin in regulating neurite outgrowth in murine neuroblastoma NS-20Y cells were investigated by testing the effect of various inhibitors on the neuritogenesis induced by serum deprivation. The percentage of cells with neurites was low (1-3%) in medium containing 10% serum, but reached about 50-60% when the cells were cultured for 24 h in serum-free medium. W-7 (10 microM), calmidazolium (0.3 microM), and trifluoperazine (0.1 microM), drugs reported to inhibit calmodulin-dependent events, reduced neurite outgrowth. On the other hand, H-7 (inhibitor of protein kinase C and cyclic AMP-dependent protein kinase) and H-89 (inhibitor of cyclic AMP-dependent protein kinase) were ineffective. Genistein (inhibitor of protein tyrosine kinase) and wortmannin (inhibitor of phosphatidylinositol 3-kinase) did not affect the number of cells with neurites. Activation of protein kinases, which is blocked by these inhibitors, does not appear to be essential to the extension and maintenance of neurites. KN-62 and KN-93 (inhibitors of Ca2+/calmodulin-dependent protein kinase II) were also tested but did not inhibit neurite outgrowth. These results suggest that a calmodulin-dependent process, other than the activation of Ca2+/calmodulin-dependent protein kinase II, is involved in the neuritogenesis in murine neuroblastoma NS-20Y cells in serum-free medium.

Animals↗
PubMed1995

Headache associated with aseptic meningeal reaction as clinical onset of Fabry's disease.

This report concerns an 18-year-old boy who is hemizygote for Fabry's disease. Varying degrees of nonpulsating headache crises, lasting from a few hours to several days, began when he was 16 years of age. Painful crises in the extremities, characteristic of Fabry's disease, were not present. Although only occasional, he had several episodes of throbbing headache with vomiting without aura. The meningeal signs were equivocal, although the patient had noninfectious pleocytosis, intracranial hypertension, delayed radioisotope clearance on cisternography, and multiple old cerebral infarcts. Nonsteroidal anti-inflammatory drugs, antidepressants, carbamazepine, and glycerol were of no benefit for his headache. Although its mode of action remains obscure, prednisolone was effective for treating the headache and the aseptic meningeal reaction.

Adolescent↗
PubMed1993

Abnormal excretion of urinary phospholipids and sulfatide in patients with mitochondrial encephalomyopathies.

We found that patients with mitochondrial encephalomyopathies excreted urinary phosphatidylethanolamine, cardiolipin, and phosphatidylserine most likely derived from mitochondria and sulfatide which is specific to myelin or the kidney. It is of interest that four patients with myoclonus epilepsy with ragged-red fibers and one patient with chronic progressive external ophthalmoplegia all showed qualitatively similar abnormal excretion of such urinary lipids. It is conceivable that the urinary acidic phospholipids reflect abnormalities in the mitochondrial phospholipids, which are very important for mitochondrial enzymatic activities.

Adolescent↗
PubMed1993

Metabolism and neurite promoting effect of exogenous sphingosylphosphocholine in cultured murine neuroblastoma cells.

Exogenous sphingosylphosphocholine analogues and naturally occurring sphingomyelin stimulated the neurite outgrowth in cultured murine neuroblastoma cell lines, NS-20Y, Neuro2a, and N1E-115, whereas exogenous sphinganine at a non-cytotoxic concentration inhibited the neurite outgrowth in NS-20Y and Neuro2a cells. The effect of sphingosylphosphocholine on the neurite outgrowth was reversible, indicating that the extended neurites needed to be maintained by continuous stimulation. The uptake and metabolism of the exogenous [3-3H]sphingosylphosphocholine in pulse and chase experiments suggested that the radioactive ceramide and sphingomyelin, which were detected as major metabolic products, were in a precursor/product relationship. It is thus assumed that the exogenous sphingosylphosphocholine taken up by the cells is first degraded into phosphocholine and sphingosine, of which the latter is rapidly acylated to ceramide then converted to sphingomyelin by phosphocholine transfer. Metabolism of sphingosylphosphocholine through sphingomyelin synthesis in the cells may be associated with neurite outgrowth.

Animals↗
PubMed1993

Anticoagulant activity of sulfatide and its anti-thrombotic effect in rabbit.

The mechanism of anticoagulant activity of sulfatide (galactosylceramide I3-sulfate), which exists in serum lipoproteins of various mammals except rodents, was investigated, together with the pharmacological effects of the glycolipid on the blood coagulation system in rabbits. The sulfatide was shown to be an effective anticoagulant when it was added in vitro in the form of pure micelle without auxiliary lipids such as phosphatidylcholine and/or cholesterol. The anticoagulant activity of synthetic galactosylceramide I6-sulfate, a positional isomer with respect to the sulfate group, was stronger than that of the sulfatide. The anticoagulant activity was specifically inhibited by anti-sulfatide antibody. The study on the pharmacological effects of sulfatide showed that the fibrin-precipitation time after single injection of the lipid (10 mg/kg body weight) into rabbits increased 2.5-fold compared with the normal level, and the maximum effect was observed 1 h after the injection. The half-life of anticoagulant activity was 5 h. These results suggest that sulfatide may be effective for the prevention of thrombosis. Sulfatide may be safer than other anticoagulant drugs, because it is a natural component of serum lipoproteins. Further, it may well play an essential role as an endogenous anticoagulant in mammals. Unlike heparin, sulfatide failed to inhibit thrombin and coagulation factor Xa activities in the presence of antithrombin III, indicating that the anticoagulant mechanism of sulfatide is independent of antithrombin III. These results indicate that the anticoagulant activity of sulfatide is potent and specific, and the lipid may be available as a useful and safe antithrombotic drug.

Animals↗
PubMed1993

Inhibition of neurite outgrowth in neuroblastoma cells by sphingosine.

Mouse neuroblastoma NS-20Y cells were induced to grow neurites by removal of serum from the medium. The percentage of cells with neurites reached about 50-60% after 24 h, whereas in medium containing 10% serum only a few cells (1-3%) were bearing neurites. Sphingosine inhibited the neuritogenesis in serum-free medium in a dose-dependent manner; a maximal effect was observed at 1-2 microM. Sphingosine also caused retraction of neurites which had been induced to extend in serum-free medium. N,N-Dimethylsphingosine was 10 times more potent in preventing neurite outgrowth, and N-acetylsphingosine was 10 times less effective compared to sphingosine. However, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) did not inhibit the extension of neurites. Neurite outgrowth in serum-free medium and its inhibition by sphingosine were still observed in the cells made protein kinase C-deficient by prolonged treatment with phorbol ester. These results suggest that the effect of sphingosine is not mediated by inhibition of protein kinase C.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1993

Sulphatide as a major glycosphingolipid in WHHL rabbit serum lipoproteins and its anticoagulant activity.

Sulphatide is found to be a major glycosphingolipid in serum lipoproteins of rabbit and its content is markedly elevated in serum of WHHL rabbit, an animal model for human familial hypercholesterolemia. On analysis of tissue sulphatide contents, serum appears to derive its sulphatide from liver (90%) and small intestine (10%) and passes on to aorta of WHHL rabbit which is found to have a large amount of sulphatide while none is found in normal aorta. Thus it seems that sulphatide finally accumulates in arterial walls along with the progression of atherosclerosis in WHHL rabbit. Since sulphatide at median concentration (8 nmole/ml serum) in various mammals is found to increase activated partial thromboplastin time by 25%, it is suggested that anticoagulant activity may be one of the physiological functions of sulphatide in serum. The observation of an increase in activated partial thromboplastin time by 2.5-fold on injection of sulphatide (10 mg/kg body wt) into rabbit suggests that sulphatide may be an effective and safe antithrombotic agent.

Animals↗
PubMed1991

Characterization and changes of glycosphingolipids in the aorta of the Watanabe hereditable hyperlipidemic rabbit.

Characterization and elucidation of the changes of glycosphingolipids in the aorta along with the progression of atherosclerosis were performed in the Watanabe hereditable hyperlipidemic (WHHL) rabbit, an animal model for human familial hypercholesterolemia, as compared with in the normal rabbit. Neutral glycosphingolipids in aortae of both normal and WHHL rabbits were composed of glucosylceramide, galactosylceramide, lactosylceramide, globotriaosylceramide, globotetraosylceramide, and galactosylneolactotetraosylceramide. The total amount of neutral glycosphingolipids in the aorta of the WHHL rabbit (557 nmol/g tissue) was increased about 5-fold compared to the normal level (107 nmol/g tissue). Prominent increases were observed in glucosylceramide (13-fold the normal level) and lactosylceramide (12-fold the normal level). The amount of total gangliosides in the aorta of the WHHL rabbit (207 micrograms NeuAc/g tissue) was markedly increased, being about 12-fold the normal level (17 micrograms NeuAc/g tissue). GM3 ganglioside was increased about 11-fold compared to normal. GD3 ganglioside, which was almost undetectable in normal aorta, also showed a marked increase in that of the WHHL rabbit (51.7 micrograms NeuAc/g tissue). Sulfatide, which was absent in the aorta of the normal rabbit, was markedly accumulated in that of the WHHL rabbit (280 nmol/g tissue). The fatty acid composition of neutral glycosphingolipids of WHHL rabbit was found to include a higher amount of C23:0, which is the major fatty acid of glycolipids in serum lipoproteins. Gangliosides in the aorta of the WHHL rabbit contained more C16:0 than in the normal rabbit. Sphingosine of sulfatide in the aorta of the WHHL rabbit was composed of sphingenine (86%), sphinganine (9%), 4-D-hydroxysphinganine (4%), and 4-D-hydroxyeicosasphinganine (less than 1%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Effects of an inhibitor of glucosylceramide synthase on glycosphingolipid synthesis and neurite outgrowth in murine neuroblastoma cell lines.

1-Phenyl-2-decanolyamino-3-morpholino-1-propanol (PDMP), an effective inhibitor of UDP-glucose:ceramide glucosyltransferase, caused inhibition of cell growth in murine neuroblastoma cell lines. Metabolic labeling of glycosphingolipids with [14C]galactose in NS-20Y, Neuro2a, and N1E-115 cells showed reduced incorporation of radioactivity into gangliosides and neutral glycosphingolipids when threo-PDMP was present in the medium. Treatment of NS-20Y cells with threo-PDMP resulted in a time-dependent decrease in mass levels of gangliosides and neutral glycosphingolipids. After 24 h in the presence of 50 microM threo-PDMP, neutral glycosphingolipid mass was reduced to 32%, where glucosylceramide was the most affected (90% decrease). The ganglioside mass was reduced to 57% of the original content. Neurite outgrowth from neuroblastoma cells in serum-free medium was significantly inhibited by threo-PDMP in a dose-dependent manner. Threo-PDMP also caused retraction of neurites which had been induced to extend in serum-free medium. Pretreatment of cells with GM1 partially restored the ability of NS-20Y cells for neurite outgrowth in the medium containing threo-PDMP. These results suggest a possible role for glycosphingolipids in neurite outgrowth of murine neuroblastoma cells.

Animals↗
PubMed1991

The existence of galactosylceramide I3-sulfate in serums of various mammals and its anticoagulant activity.

Human, porcine, goat, sheep, bovine, horse, canine, rat, mouse, guinea pig, and chicken serums were investigated for the existence of sulfatide. Among the ten mammal serums, seven were found to be sulfatide positive, and the amounts of sulfatide were determined to be: 16.29 nmol/ml serum (porcine), 9.39 (bovine), 12.71 (goat), 7.75 (horse), 1.21 (sheep), 0.64 (human), and 0.16 (dog). The existence of sulfatide in the serums of human, goat, sheep, cow, horse, and dog is here reported for the first time. It is suggested that sulfatide is widely distributed in the serums of various mammals except for rodents and that it takes part in the anticoagulant systems. The fatty acids of those sulfatides comprised mainly non-hydroxy fatty acids and a significant amount (18-53% of the total fatty acid) of hydroxy fatty acids with chain lengths of C16, C22, C23, and C24. The long chain bases comprised sphingenine, sphinganine, and 4-D-hydroxysphinganine. Experiments to elucidate the mechanism of the anticoagulant activity of sulfatide revealed that it was specific to sulfatide and that the galactose-bound sulfate group is essential for this activity. The activity of clusters of sulfatide molecules was much more pronounced than that of single molecules.

Animals↗
PubMed1990

Effects of various lysosphingolipids on cell growth, morphology and lipid composition in three neuroblastoma cell lines.

The cell numbers of three mouse neuroblastoma cell lines were decreased upon incubation with lysosphingolipids in the following order of effectiveness: lysosulfatide (lysoCS) greater than psychosine (Ps) greater than sphingosylphosphocholine (SPC). The different cell lines showed characteristic sensitivities to various concentrations of lysolipids less than 150 microM. Interestingly, only SPC induced neurite outgrowth and changed the lipid composition, modifying the amounts of cholesterol, sphingomyelin (SM) and ganglioside GM3 in all cell lines. The effect of SPC on these cell lines was comparable to the effect of N-acetyl SPC (NAcSPC) rather than that of SM.

Animals↗
PubMed1990

New approach for characterization of lysosulfatide by TLC, fast atom bombardment mass spectrometry and NMR spectroscopy.

Thin layer chromatography of lysosulfatide showed anomalous Rf-values in contrast with such lysosphingolipids as glucopsychosine and galactopsychosine with neutral, acidic, and alkaline developing solvents. This was thought to be due to the presence of oppositely charged sulfate and amino groups in the lysosulfatide. In the negative mode of fast atom bombardment mass spectrometry, the lysosulfatide showed the pseudo molecular ion (M-H)- peak at m/z 540 and sulfate ion peak at m/z 97, whereas in the positive mode, it showed not only the pseudo molecular ion (M+H)+ peak at m/z 542, but also the major peaks of protonated psychosine at m/z 462 and fragment ions of dehydrated sphingosine at m/z 282 and 264, 13C-NMR signals of all carbons of lysosulfatide were determined by using distortionless enhancement by polarization transfer. The difference in chemical shifts of ring carbons of galactose residue between lysosulfatide and galactopsychosine was largest at C-3 (downfield shift), thereby indicating the location of the sulfate group to be at C-3 of galactose. This conclusion is supported by the 1H-NMR spectra of the lysosulfatide and galactopsychosine. Thus, the chemical structure of lysosulfatide was confirmed by fast atom bombardment mass spectrometry and 13C- and 1H-NMR spectroscopy. Furthermore, 13C-NMR signals of C-1 to C-5 of the sphingosine moiety showed significantly different chemical shifts between the lysosulfatide and galactopsychosine. These differences suggested that C-1 to C-5 of sphingosine might be influenced by intramolecular or intermolecular interaction between the sulfate group of the galactose residue and the amino group of sphingosine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Effect of an inhibitor of glucosylceramide synthesis on cultured rabbit skin fibroblasts.

1-Phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), an effective inhibitor of UDP-glucose:ceramide glucosyltransferase, caused growth inhibition of cultured rabbit skin fibroblasts in a dose-dependent manner. At 50 microM both threo and erythro isomers of PDMP completely suppressed the cell growth. Major gangliosides of the fibroblasts, GM3 and GD3, were greatly reduced in amounts in the presence of threo-PDMP and accumulation of ceramides was observed. Surface labeling with galactose oxidase and [3H]NaBH4 demonstrated that neural glycosphingolipids with four or more sugars present on the surface of control cells were not detectable when the fibroblasts were grown in medium containing threo-PDMP. Metabolic labeling of cellular glycosphingolipids with [14C]-galactose showed reduced incorporation of radioactivity into gangliosides and neutral glycosphingolipids when threo-PDMP was present in the medium. In contrast, the erythro isomer of PDMP did not affect the biosynthesis of glycosphingolipids, a result suggesting that the inhibitory effect of erythro-PDMP on cell growth was due to a mechanism other than the inhibition of glucosyltransferase.

Animals↗
PubMed1990

Characterization and change of phospholipids in the aorta of Watanabe hereditable hyperlipidemic rabbit.

The characterization and change of lipids in aorta with the progression of atherosclerosis were elucidated in Watanabe hereditable hyperlipidemic (WHHL) rabbit, an animal model for human familial hypercholesterolemia as compared with those of normal rabbits. The amount of total phospholipids in the aorta of WHHL rabbit increased about 6-fold that of normal level. Sphingomyelin showed the largest increase and phosphatidylcholine the second in the aorta of WHHL rabbit. The fatty acid composition of sphingomyelin was characteristic of higher content of unsaturated fatty acids. It was suggested that the specific increase in both sphingomyelin and its unsaturated fatty acid content might be ascribed to regulation mechanism to recover the membrane fluidity which was reduced by the marked accumulation of cholesterol in the aorta of WHHL rabbit. Glycerophospholipids in the aorta of WHHL rabbit also contained more unsaturated fatty acids than those in normal ones. It was suggested that the higher amounts of unsaturated fatty acids of glycerophospholipids might be derived from those of serum lipoproteins and that they also might help to restore or recover membrane fluidity in the cholesterol-accumulated aorta of WHHL rabbit. Phosphatidylcholine in the aorta of WHHL rabbit contained a large amount of alkylacyl type-homologue (25-fold normal level) which was a precursor of platelet-activating factor (PAF). The increase of lysophosphatidylcholine, a potent chemotactic factor for monocyte, was also observed in WHHL rabbit. The increase of these chemical mediators indicated severe pathologic state in the atherosclerotic lesions of the aorta of WHHL rabbit.

Animals↗
PubMed1989

Effect of long-term treatment with sulfatide on hyperlipidemia and progression of atherosclerosis in WHHL rabbits.

Changes in serum lipids and lipoproteins and progression of atherosclerosis with age were examined in Watanabe heritable hyperlipidemic (WHHL) rabbits with or without treatment with sulfatide. The injection of sulfatide solution caused a reduction of serum triacylglycerols for five months including the period of treatment, but afterwards, failed to lower the level of total cholesterol, triacylglycerols and phospholipids, and to suppress the progression of atherosclerosis. Concentrations of LDL as a major serum lipoprotein in WHHL rabbits with or without the treatment with sulfatide were found to be about 64-fold those of normal rabbits by immunological assay using anti-LDL antiserum, whereas the contents of total cholesterol, triacylglycerols, and phospholipids in WHHL rabbit sera were found to be about 10-fold those of normal rabbits. All WHHL rabbits with or without the treatment with sulfatide contained very small amounts of HDL. Types of apoproteins of isolated LDL and VLDL fractions suggested that the former seemed to be derived from VLDL remnant, and the latter to be derived from chylomicron remnant. It was noted that all WHHL rabbit sera had a significant increased amount of lysophosphatidylcholine, and that the fatty acid composition of total serum lipids had almost no change except for slight decrease in arachidonic acid with age. Pathological examination showed that severe atherosclerotic lesions were not so different between WHHL rabbits with or without treatment with sulfatide at age over 22 months.

Aging↗
PubMed1989

Expression of Forssman glycolipid and blood group-related antigens A, Le(x), and Le(y) in human gastric cancer and in fetal tissues.

The expression of Forssman glycolipid antigen in human gastric cancers was investigated by thin-layer chromatogram immunostaining of glycolipid fractions. Incompatible blood group A antigen, Le(x) and Le(y) antigen were also studied in comparison with Forssman antigen. Forssman glycolipid as the pentaglycosylceramide was demonstrated in nine out of 12 gastric cancers, and in three out of 10 adjacent uninvolved tissues. In most cases the content of Forssman glycolipid was increased in the cancers compared with that in the uninvolved counterparts. Forssman pentaglycosylceramide was also detected in some normal gastric mucosae (two out of four), and in a fetal gastrointestinal tract tissue. In immunohistochemical examination of gastric cancer tissues, sialidase treatment revealed a positive staining with anti-Forssman antibody. Some cancer tissues from patients with blood group O were found to contain blood group A-active glycolipids, which could be distinguished from Forssman glycolipid by thin-layer chromatogram immunostaining. The incidence of incompatible A-active glycolipids was two out of 10 cancers from patients with blood group O or B. Le(x)- and Le(y)-active glycolipids were detected in most of the preparations and were not accumulated consistently in the cancers.

Adult↗
PubMed1988

Differences in neuronal lipid composition between superior cervical ganglia and nodose ganglia of the rat.

The lipid content and composition of rat superior cervical ganglia containing sympathetic motor neurons and nodose ganglia containing parasympathetic sensory neurons were studied for the first time to elucidate the mechanism of the different effects of exogenous gangliosides on these neurons in the culture medium. The ganglioside content of the superior cervical ganglia was almost 3-times that of the nodose ganglia. Although both ganglia contained GM3, GD3, GD1b and GT1b as major gangliosides, the nodose ganglia additionally contained a significant amount of sialosyllactoneotetraosylceramide LM1 (10% of total sialic acids). Contrasting with nodose ganglia, vagus fiber and dorsal root ganglia of rats, superior cervical ganglia had a higher content of sulfatide than galactosylceramide. The phospholipid content was lower in superior cervical ganglia than in nodose ganglia. Superior cervical ganglia contained less ethanolamine plasmalogen and more phosphatidylcholine than nodose ganglia. Sphingomyelin in superior cervical ganglia contained mainly medium-chain fatty acids, while that in nodose ganglia contained mainly longer-chain fatty acids. Differences in the fatty acid composition of glycerophospholipids were also observed. The results indicate that the properties of neuronal cell membranes from superior cervical ganglia and nodose ganglia are quite different, and that the differences may reflect the physiological roles of these ganglia.

Animals↗