Biomedical subjects

T Taki

Publications and source records attributed to T Taki.

At least 163 records · Page 9Linked to original sources

PubMed1994

A new method for detecting beta 1,4-galactosyltransferase activity in sera of cancer patients.

A new method for assaying the activity of the enzyme that catalyzes the formation of a cancer-associated glycolipid, paragloboside (nLc4Cer), from lactotriaosylceramide (Lc3Cer) and UDP-galactose has been developed that is based on a time-resolved fluoroimmunoassay (TRFIA) with a Europium (Eu)-chelate-labeled antibody. The substrate, Lc3Cer, immobilized on a microtiter plate, was incubated with UDP-galactose, MnCl2, Triton CF-54, and the enzyme. The content of the incubation product, nLc4Cer, was determined by the TRFIA with anti-nLc4Cer monoclonal antibody H-11 as the first antibody and Eu-labeled anti-mouse IgM antibody as the second one. The lower limit of detection of nLc4Cer was estimated to be 0.2 pmol. This method was used to detect the galactosyltransferase activity in sera from patients with colorectal cancer or benign colorectal adenomas and from healthy subjects of a reference sample group. The reference interval was 0-0.25 pmol/25 microliters serum/2 h. Activity was significantly greater in patients with colorectal cancer than in those with colorectal benign adenoma (P < 0.05) and the subjects of the reference sample group (P < 0.01).

Adenoma↗

PubMed1994

Sulfate- and sialic acid-containing glycolipids inhibit DNA polymerase alpha activity.

The effects of various glycolipids on the activity of immunoaffinity-purified calf thymus DNA polymerase alpha were studied in vitro. Preincubation with sialic acid-containing glycolipids, such as sialosylparagloboside (SPG), GM3, GM1, and GD1a, and sulfatide (cerebroside sulfate ester, CSE) dose-dependently inhibited the activity of DNA polymerase alpha, while other glycolipids, as well as free sphingosine and ceramide did not. About 50% inhibition was achieved by preincubating the enzyme with 2.5 microM of CSE, 50 microM of SPG or GM3, and 80 microM of GM1. Inhibition was noncompetitive with both the DNA template and the substrate dTTP, as well as with the other dNTPs. Since the inhibition was largely reversed by the addition of 0.05% Nonidet P40, these glycolipids may interact with the hydrophobic region of the enzyme protein. Apparently, the sulfate moiety in CSE and the sialic acid moiety in gangliosides were essential for the inhibition since neither neutral glycolipids (i.e., glucosylceramide, galactosylceramide, lactosylceramide) nor asialo-gangliosides (GA1 and GA2) showed any inhibitory effect. Furthermore, the ceramide backbone was also found to be necessary for maximal inhibition since the inhibition was largely abolished by substituting the lipid backbone with cholesterol. Increasing the number of sialic acid moieties per molecule further enhanced the inhibition, while elongating the sugar chain diminished it. It was clearly shown that the N-acetyl residue of the sialic acid moiety is particularly essential for inhibition by both SPG and GM3 because the loss of this residue or substitution with a glycolyl residue completely negated their inhibitory effect on DNA polymerase alpha activity.

Animals↗

PubMed1994

Molecular mimicry between GQ1b ganglioside and lipopolysaccharides of Campylobacter jejuni isolated from patients with Fisher's syndrome.

We isolated Campylobacter jejuni from 2 patients with Fisher's syndrome subsequent to enteritis. Crude lipopolysaccharide fractions were extracted from the bacteria and separated by thin-layer chromatography. Monoclonal antibodies to GQ1b ganglioside (GMR13 and 7F5) reacted with both lipopolysaccharide fractions, indicating that the lipopolysaccharides bear the GQ1b epitope. This is the first report of molecular mimicry between neural tissue components and the antecedent infectious agents of Fisher's syndrome.

Antibodies, Monoclonal↗

PubMed1994

Blotting of glycolipids and phospholipids from a high-performance thin-layer chromatogram to a polyvinylidene difluoride membrane.

A simple method of blotting glycosphingolipids from a high-performance thin-layer chromatography (HPTLC) plate to a polyvinylidene difluoride (PVDF) membrane is described. The developed HPTLC plate is dipped in a solvent mixture (isopropanol/0.2% CaCl2/methanol, 40/20/7 by volume) for blotting, after which first a PVDF membrane and then a glass microfiber filter is placed on the plate. The assemblage then is pressed for 30 s with heating. Most of the glycosphingolipids that are separated on the HPTLC plate can be blotted quantitatively and detected with the reagents used on the plate. Detection of the glycosphingolipids on the membrane was confirmed to be more sensitive than that on the HPTLC plate by both chemical visualization and immunological staining. The glycosphingolipids blotted on the membrane could be reextracted. Blotting of phospholipids can be done by the same method. The results suggest that this method can be used in the purification and characterization of glycosphingolipids and in the detection of proteins which recognize glycosphingolipids and phospholipids.

Animals↗

PubMed1994

A simple and quantitative purification of glycosphingolipids and phospholipids by thin-layer chromatography blotting.

A new and simple method for purifying glycosphingolipids and phospholipids by using "TLC blotting" was established. Glycosphingolipids separated by two-dimensional thin-layer chromatography (TLC) were made visible with primuline reagent, and then bands were marked with a drawing colored pencil. The glycosphingolipids that separated on the HPTLC plate were transferred by TLC blotting to a polyvinylidene difluoride membrane together with the color marks. The marked areas were excised after which their glycosphingolipids were extracted and monitored by TLC. By this method, 20 glycosphingolipids showing homogeneous bands on a HPTLC plate were isolated from the neutral glycosphingolipid fraction of human meconium. Moreover, 10 kinds of acidic glycosphingolipids were purified as homogeneous bands from the bovine acidic glycosphingolipid fraction. The yields of glycosphingolipids (13 different ones) ranged from 68 to 92%, the mean value being 82.3%. The glycosphingolipids were confirmed to be purified as intact forms by mass spectrometric analysis and chromatographic mobilities on a HPTLC plate. The same procedure could also be used to purify phospholipids.

Animals↗

PubMed1994

Anti-proliferative effects of TNP-470 on human malignant glioma in vivo: potent inhibition of tumor angiogenesis.

A novel angiogenesis inhibitor TNP-470 was investigated for its anti-tumor activity against malignant gliomas both in vitro and in vivo. TNP-470 cytostatically inhibited the growth in all of the seven glioma cell lines in culture including anticancer drug resistant cells. The 50% inhibitory concentrations (IC50) of these glioma cell lines were 10 to 30 micrograms/ml and they were 10 to 20 times higher than IC50 of normal endothelial cells. TNP-470 (30 mg/kg, i.p., every other day) also significantly inhibited the tumor growth of T98G-transplanted nude mice. Microscopically, tumor vessels after the treatment of the tumor-bearing mice with TNP-470 became fewer in number and smaller in diameter than those without treatment. Furthermore, there appeared extensive necrotic areas in the tumor with TNP-470. These results indicate that TNP-470 is a potent angiogenesis inhibitor for malignant gliomas. In addition, the studies of labeling index of BrdU and Ki67 suggest that TNP-470 may act mainly on tumor endothelial cells, thus resulting in reduction of the tumor growth.

Animals↗

PubMed1994

Prevention of autoimmune insulin-dependent diabetes in non-obese diabetic mice by anti-LFA-1 and anti-ICAM-1 mAb.

Diverse adhesion molecules participate in many important responses and thus would be implicated in the pathogenesis of various autoimmune diseases. However, there is little evidence for the role of these molecules in autoimmune insulin-dependent diabetes mellitus. Here we present several lines of evidence suggesting that leukocyte function-associated antigen-1 (LFA-1) and its counter-receptor intercellular adhesion molecules (ICAM-1), one of the most important pairs among these adhesion molecules, are involved in the development of autoimmune diabetes in the non-obese diabetic (NOD) mouse. Immunohistochemical study showed the hyperexpression of ICAM-1 on islet-infiltrating mononuclear cells and vascular endothelium in NOD pancreas. In vivo administration of anti-LFA-1 or anti-ICAM-1 mAb from 5 to 30 (or 12) weeks of age exerted a very strong preventative effect on the development of spontaneous diabetes with a marked reduction of insulitis, whereas both antibodies, even combined to use simultaneously, could not prevent cyclophosphamide-induced diabetes. Adoptive transfer of insulitis and diabetes to young NOD mice following the injection of islet-derived mononuclear cells from diabetic donors was completely blocked by administration of both antibodies to recipients. The present study, therefore, provides the first evidence that immunointervention to LFA-1-ICAM-1 interaction has a strong prophylactic effect on autoimmune diabetes in NOD mice.

Animals↗

PubMed1994

Penner's serotype 4 of Campylobacter jejuni has a lipopolysaccharide that bears a GM1 ganglioside epitope as well as one that bears a GD1 a epitope.

The carbohydrate structures of lipopolysaccharides (LPSs) of Campylobacter jejuni strains belonging to Penner's serotypes (PEN) 1, 2, 4, 19, 23, and 36 were studied by thin-layer chromatography and immunostaining with several monoclonal antiganglioside antibodies. Anti-GM1 and anti-GD1a antibodies reacted with the LPSs of PEN 1, 4, and 19. Aspinall et al. (G. O. Aspinall, A. G. McDonald, T. S. Raju, H. Pang, A. P. Moran, and J. L. Penner. Eur. J. Biochem. 213:1017-1027, 1993) recently reported that the LPS of PEN 4 has a GD1a ganglioside-like structure rather than a GM1-like structure. We found that the LPS fraction of C. jejuni (PEN 4) has an LPS that bears a GM1 epitope as well as an LPS that bears a GD1a epitope.

Antibodies, Monoclonal↗

PubMed1994

[A study of prostatic tissue levels of cefodizime (CDZM)].

Twenty-four patients suffering from prostate hyperplasia were given venous injections of CDZM of either 1 or 2 g at specific intervals (30 min, 1, 2 and 4 hr) before surgery. Blood samples from the injected vein and tissue samples from the prostate were subsequently taken. In this study, the concentrations of CDZM in the prostate tissue (P) and in serum (S), as well as the ratio of the tissue to serum concentrations (P/S) were determined. In patients given 1 g injections, P ranged from 5.26-48.10 micrograms/g, while S ranged from 25.40-130.00 micrograms/ml and P/S ranged from 12.6-37.0%. In the patients given 2 g injections, P ranged from 9.40-49.20 micrograms/g, S ranged from 62.30-234.00 micrograms/ml and P/S ranged from 9.3-29.1%. CDZM exhibited excellent transmigration to the prostate tissue. Inflammatory bacteria present in prostatitis and urinary tract infections are generally those of E. coli, Proteus sp., but because the P range was much higher than the ratio of MIC, CDZM is expected to be useful against infections in the field of urology.

Aged↗

PubMed1993

A bacterium lipopolysaccharide that elicits Guillain-Barré syndrome has a GM1 ganglioside-like structure.

There is a strong association between Guillain-Barré syndrome (GBS) and Penner's serotype 19 (PEN 19) of Campylobacter jejuni. Sera from patients with GBS after C. jejuni infection have autoantibodies to GM1 ganglioside in the acute phase of the illness. Our previous work has suggested that GBS results from an immune response to cross-reactive antigen between lipopolysaccharide (LPS) of the Gram-negative bacterium and membrane components of peripheral nerves. To clarify the pathogenesis of GBS, we have investigated whether GM1-oligosaccharide structure is present in the LPS of C. jejuni (PEN 19) that was isolated from a GBS patient. After extraction of the LPS, the LPS showing the binding activity of cholera toxin, that specifically recognizes the GM1-oligosaccharide was purified by a silica bead column chromatography. Gas-liquid chromatography-mass spectrometric analysis has shown that the purified LPS contained Gal, GalNAc, and NeuAc, which are sugar components of GM1 ganglioside. 1H NMR methods [Carr-Purcell-Meiboom-Gill (CPMG), total correlation spectroscopy (TOCSY), and nuclear Overhauser effect spectroscopy (NOESY)] have revealed that the oligosaccharide structure [Gal beta 1-3 GalNAc beta 1-4(NeuAc alpha 2-3)Gal beta] protrude from the LPS core. This terminal structure [Gal beta 1-3GalNAc beta 1-4(NeuAc alpha 2-3)Gal beta] is identical to the terminal tetrasaccharide of the GM1 ganglioside. This is the first study to demonstrate the existence of molecular mimicry between nerve tissue and the infectious agent that elicits GBS.

Adult↗

PubMed1993

Human blood group B-active ganglio-glycosphingolipid in rat glioma.

A human blood group B-active glycosphingolipid, belonging to the ganglio-series, was isolated from rat glioma cell line RG2 subcutaneous isografts. The oligosaccharide structure of the glycosphingolipid was completely characterized as Gal alpha 1-3(Fuc alpha 1-2)Gal beta 1-3GalNAc beta 1-4Gal beta 1-4Glc beta 1- 1'ceramide by NMR spectrometry, negative fast atom bombardment-mass spectrometry, sequential degradation by glycosidases and methylation analysis. Human blood group B antigenicity and the activity of this glycosphingolipid were confirmed by immunostaining on thin-layer chromatography and the inhibition of hemagglutination, respectively. Although the lipid has been detected in rat granuloma, bone marrow cells, spleen, thymus, ascites hepatoma cells and gastric mucosa, this is the first report of the occurrence of the B-active lipid in glioma.

ABO Blood-Group System↗

PubMed1993

Glycosphingolipid compositions of human T-lymphotropic virus type I (HTLV-I) and human immunodeficiency virus (HIV)-infected cell lines.

Glycolipid compositions of cells infected by human retroviruses (human immunodeficiency virus, HIV and/or human T-cell lymphotropic virus type I, HTLV-I) have been studied. Eight cell lines, comprising two HTLV-I-infected T-cell lines (MT-2 and MT-4), two HTLV-I-negative T-cell lines (Jurkat and MF), a macrophage cell line (U937), and three HIV-infected counterpart cell lines (MT-4/HIV, Jurkat/HIV and U937/HIV) were used. The neutral glycolipids and gangliosides isolated from these cell lines were compared. Among them, the HTLV-I-infected T-cell lines, MT-2 and MT-4, showed similar patterns for both neutral glycolipids and gangliosides. Neutral glycolipids (GlcCer and LacCer) of MT-2 and MT-4 cells were markedly decreased, and a ganglioside, GM3, of theirs was decreased to only a trace amount compared to that in other cell lines. Gangliosides of MT-4 and MT-4/HIV were further separated on an Iatrobeads column, and were identified as GM2, GM1a and GD1a by methylation and liquid secondary ion mass spectrometric analyses. Since the patterns of neutral glycolipids and gangliosides of MT-2 and MT-4 are unique, as compared to those of HTLV-I-negative cells, it is suggested that these changes are related to HTLV-1 infection. No prominent differences in the ganglioside compositions between HIV-infected and non-infected cell lines could be observed. But it is noteworthy that the contents of asialo-GM2 in Jurkat/HIV and MT-4/HIV cells were increased as compared to those in the parental cell lines.

Carbohydrate Sequence↗

PubMed1993

Effect of T-cell receptor V beta-specific monoclonal antibodies on cyclophosphamide-induced diabetes mellitus in non-obese diabetic mice.

The expression of specific T-cell receptor gene segments by T lymphocytes appears to be critically important for the induction of several experimental autoimmune diseases mediated by these cells. We examined whether this situation also applied to non-obese diabetic mice by using various T-cell receptor V beta-specific monoclonal antibodies. No significant age- or sex-related differences were observed in V beta usage by peripheral and splenic T lymphocytes. CD8+ T lymphocytes among the islet-derived mononuclear cells isolated from 20-week-old female non-obese diabetic mice showed heterogeneity of their V beta gene usage. In order to examine the role of T lymphocyte subsets expressing specific T-cell receptor V beta segments in the development of diabetes mellitus, T-cell receptor V beta-specific monoclonal antibodies were administered to 10-week-old male non-obese diabetic mice treated with cyclophosphamide. None of the antibodies used could significantly diminish the incidence of cyclophosphamide-induced diabetes and the severity of insulitis [anti-V beta 3 (11 of 22 mice became diabetic, 50%), anti-V beta 5 (9 of 14, 64%), anti-V beta 8 (9 of 21, 43%), anti-V beta 11 (12 of 23, 52%), anti-V beta 14 (7 of 12, 58%), and anti-V beta 5 + anti-V beta 11 (6 of 12, 50%)] when compared with control mice (12 of 21, 57%). In addition, there were no significant differences in T-cell receptor V beta usage between diabetic and non-diabetic cyclophosphamide-treated mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Measurements and analyses of electrophoretic mobilities of RAW117 lymphosarcoma cells and their variant cells.

The electrophoretic mobilities of the cells of malignant lymphosarcoma cell line RAW117-P and its variant H10 with a highly metastatic property to the liver have been measured at various ionic strengths. The cells of parental cell line (RAW117-P) show higher mobility values in magnitude than those of its variant line (RAW117-H10) in the whole range of electrolyte concentration measured. We have also measured the sialic acid amount carried by cells of both lines. The content of sialic acids in RAW117-H10 cells is observed to be about 27% less than that in RAW117-P cells. The mobility data obtained have been analyzed by a novel mobility formula for colloidal particles with ion-penetrable surface charge layers. The observed mobility difference between RAW117-P cells and RAW117-H10 cells is found to be due to the difference in friction exerted by the cell surface layers on the liquid flow around the cells between these two types of cells and to the difference in fixed-charge density in their surface layers, which is caused by the 27% decrease in sialic acid content. A possible explanation for this mobility difference between these two types of cells is given.

Animals↗

PubMed1993

Glycosphingolipids of human peripheral nervous system myelins isolated from cauda equina.

Compositions of neutral and sulfated glucuronyl glycosphingolipids purified from human motor and sensory nerves and myelins were studied. Higher neutral glycosphingolipids (fraction B), which were separated from GalCer (fraction A), were analyzed by TLC and TLC-immunostaining. Both nerve myelins contained paragloboside (nLc4Cer) and nLc6Cer dominantly as major higher glycosphingolipids and very little globoside (Gb4Cer), whereas both nerves contained Gb4Cer and nLc4Cer. Besides these major glycosphingolipids, a neutral glycolipid containing asialoGM1 (Gg4Cer) epitope and other minor components such as ceramide trihexoside and ceramide dihexoside were detected in both nerves and their myelins. Furthermore, sulfated glucuronyl nLc4Cer and nLc6Cer, which were monoclonal antibody HNK-1 reactive glycolipids, were detected in both nerves and myelins.

Cauda Equina↗

PubMed1993

Studies on the differentiation inducers of myeloid leukemic cells from Citrus species.

An attempt was made to isolate differentiation inducers from Aurantii Nobilis Pericarpium and the fruit peel of Citrus reticulata Blanco (Rutaceae). Twenty-seven kinds of flavones, including five new flavones, were isolated after repeated chromatography from methanol extracts of these plants and their structures were established, from their physicochemical data, to be highly methoxylated flavones. Each compound, except for two flavone glucosides, showed the differentiation inducing activity toward mouse myeloid leukemia cells (M1), and the cells came to have phagocytic activity. Furthermore, differentiation inducing activity was tested using human acute promyelocytic leukemia cell line (HL-60).

Animals↗

PubMed1993

[Pharmacokinetics of MX2, a new morpholino anthracycline, in CSF following intravenous injection].

MX2 x HCl is a new morpholino anthracycline derivative with molecular weight 622.07, and highly lipophilic. In the animal experiments, MX2 was found to cross the blood brain barrier after i.v. injection. Its distribution into the brain was increased by intracarotid injection. In the present study, we examined the distribution of MX2 into the cerebrospinal fluid (CSF) after i.v. administration (5 mg/kg) in normal rabbits. Five min after injection, plasma concentration of MX2 reached to the maximum level (4344.5 ng/ml). CSF concentration of MX2 was at the highest level (75.8 ng/ml) 10 min after injection, and thereafter decreased gradually in parallel with plasma concentration. At 5 hrs after injection, CSF concentration became 26.7 ng/ml, AUC half time of elimination, and mean residence time were 3093.8 ng.hr/ml, 4.57 hrs and 5.10 hrs in plasma and 212.3 ng.h/ml, 5.23 hrs and 7.14 hrs in CSF, respectively. These results indicate that MX2 is able to distribute into CSF after i.v. injection, and expected to be a new anticancer drug for brain and leptomeningeal tumors.

Animals↗

PubMed1993

[In vitro ENU-induced carcinogenesis of rat fetal astroglia--biological character of mutant glial cell].

To investigate glial carcinogenesis in vitro, fetal rat brain cells were cultured and exposed to ENU (approximately 200 micrograms/ml). The cells were passaged weekly thereafter. Morphological changes were observed under the phase contrast microscope. When mutant colonies where the cells lost contact inhibition and grew in a multilayer fashion appeared, the cells were cloned. To assess the biological characters of cells, expression of GFAP, vimentin, A2B5 and p53 product were determined by immunohistochemistry and flow cytometry. Tumor forming ability of the cells was evaluated by both colony forming efficiency in low serum medium (LSM; 2% FBS, 300 cells/100 mm dish) and transplantability to nude mice. Both primary cultured and ENU-treated cells were positive for GFAP and vimentin, but population of A2B5 positive cells was less than 5%, thus indicating that these cells were astroglial in origin. The mutant colonies appeared 7 weeks after ENU treatment. These cells grew rapidly with cell doubling time ranging between 18 to 26 hours, while non-ENU-treated astroglias had a longer cell doubling time (48 to 55 hours). The cloned mutant glial cell lines formed large colonies in LSM (efficiency 20-40%), but astroglial cells did not. The mutant astroglial cells also developed tumors in nude mice. p53 protein was never detected in normal astroglia, however, some glial cells treated by ENU abruptly became p53 positive after several passages. These p53 positive cells formed stratified colonies thereafter. These results indicate that mutant astroglial cells can be induced by a single dose of ENU in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗