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Biomedical subjects

K Tsuji

Publications and source records attributed to K Tsuji.

At least 307 records · Page 17Linked to original sources
PubMed1995

Reliable and sensitive method for determination of microcystins in complicated matrices by frit-fast atom bombardment liquid chromatography/mass spectrometry.

A reliable and sensitive method for determination of hepatotoxic microcystins in complicated matrices by frit-fast atom bombardment liquid chromatography/mass spectrometry (Frit-FAB LC/MS) is described. Immonium ions of constituent amino acids, which were obtained together with molecular ion species by FAB mass spectral analysis of standard microcystins RR, YR, LR, and [D-Asp3] and [Dha7]microcystins LR using flow injection system composed of Frit-FAB probe, showed potential for reliable identification of microcystins by Frit-FAB LC/MS. Frit-FAB LC/MS using a microbore column provided not only the baseline separation of standard microcystins RR, YR, and LR but 200-fold higher sensitivity than that using conventional column. Furthermore, when a selected ion monitoring (SIM) technique was used, the detection limits of microcystins RR, YR, and LR were 300, 350, and 400 pg, respectively, at a signal-to-noise ratio of 5:1, and calibration curves of each microcystin showed a linear relationship from 2 ng to 50 ng. Finally, identification and quantitative analyses of microcystins in water samples were carried out.

Chromatography, Liquid↗
PubMed1995

Transforming growth factor-beta 1 has both promoting and inhibiting effects on induction of DNA synthesis in human fibroblasts.

Growth-arrested human normal fibroblasts, TIG-1, initiated DNA synthesis following addition of epidermal growth factor (EGF). Transforming growth factor-beta 1 (TGF-beta 1) by itself had no effect on induction of DNA synthesis. When EGF and TGF-beta 1 were added simultaneously to growth-arrested TIG-1 cells, induction of DNA synthesis was enhanced compared with that by EGF alone. Contrarily, when TGF-beta 1 was added earlier than 2 h or later than 2 h of EGF addition, induction of DNA synthesis was prevented. Induction of DNA synthesis by EGF was insensitive to pertussis toxin (PT, an inhibitor of Gi protein) and to staurosporine (a protein kinase inhibitor). The promoting effect of TGF-beta 1 on DNA synthesis was PT-insensitive and staurosporine-insensitive. Contrarily, inhibitory activity of TGF-beta 1 on DNA synthesis was PT-sensitive and staurosporine-insensitive. These studies suggest that the effect of TGF-beta 1 is to promote or to inhibit induction of DNA synthesis by EGF expressed through different signal transduction processes in the same cell.

Alkaloids↗
PubMed1995

The breakpoint on 7p in a patient with t(6;7) and craniosynostosis is spanned by a YAC clone containing the D7S503 locus.

We previously reported a patient with an apparently balanced t(6;7) translocation and craniosynostosis. We now demonstrate, by fluorescence in situ hybridization, that the yeast artificial chromosome clone 933-e-1 from the Centre d'Etude du Polymorphisme Humain library harbouring the D7S503 locus spans the breakpoint on distal 7p. Recent reports have defined a candidate region for a Saethre-Chotzen craniosynostosis locus between the loci D7S513 and D7S516, a region that includes the D7S503 locus. Since the translocation carrier shows only some of the symptoms characteristic for the Saethre-Chotzen syndrome, it remains unresolved whether the gene disrupted by the translocation event is the only one causing craniosynostosis in this chromosomal region.

Child, Preschool↗
PubMed1995

A possible mechanism for the hypoxia-hypoglycemia-induced release of excitatory amino acids from cultured hippocampal astrocytes.

In order to elucidate the mechanism of release of excitatory amino acid (EAA) induced by hypoxia-hypoglycemia (in vitro ischemia) from cultured hippocampal astrocytes, we compared the EAA release by in vitro ischemia with those by other treatments. The EAA release induced by in vitro ischemia treatment was rapid and reversible. The amount of released aspartate was comparable to that of glutamate, although the endogenous content of aspartate was one sixth that of glutamate. High-K (100 mM) treatment and the addition of 5 mM NaCN induced a rapid EAA release and the glutamate release was much greater than aspartate. Addition of 5 mM iodoacetate, a glycolysis inhibitor, induced a slow EAA release, and the amount of released aspartate was much higher than that of glutamate. On the other hand, the in vitro ischemia treatment and the addition of 5 mM NaCN induced only 20% reduction in ATP content for initial 5 min, whereas the addition of 5 mM iodoacetate induced a marked reduction. Our data suggest that ischemia-induced EAA release from astrocytes is a complex process in which local energy failure, inhibition of glycolysis, and depolarization of the cell membrane are involved.

Adenosine Triphosphate↗
PubMed1995

Novel agonists for metabotropic glutamate receptors: trans- and cis-2-(2-carboxy-3-methoxymethylcyclopropyl)glycine (trans- and cis-MCG-I).

New derivatives of 2-(carboxycyclopropyl)glycine (CCG), (2S,1'S,2'R,3'S)- and (2S,1'S,2'R,3'R)-2-(2-carboxy-3-methoxymethylcyclopropyl) glycine (trans- and cis-MCG-I), effectively inhibited forskolin-stimulated cyclic AMP formation in a concentration dependent manner in cultured spinal neurones of rats. They effectively depressed monosynaptic excitation in the spinal reflex of newborn rats with IC50 values of 0.3 and 3 microM, respectively, which was sensitive to (+)-MCPG. They did not cause any depolarization even when the concentration was increased up to 0.3 mM. However, after treatment with quisqualate, cis-MCG-I caused a depolarization of motoneurones in the newborn rat spinal cord in a concentration dependent manner with a threshold concentration of 1 microM (quisqualate effect). The depolarizing activity developed after quisqualate treatment gradually decreased but lasted for more than 2 hr. The depolarization induced by cis-MCG-I seemed pharmacologically similar to that of phosphonate-containing analogues of glutamate such as L-AP4 or L-AP6 under the "quisqualate effect". These novel CCG derivatives would be expected to provide useful probes for elucidating the physiological function of mGluRs.

Animals↗
PubMed1995

Stability of microcystins from cyanobacteria--II. Effect of UV light on decomposition and isomerization.

Microcystins are very potent hepatotoxins and strong liver tumor promoters produced by cyanobacteria, and their occurrence has been reported all over the world. They could threaten human health when toxic Microcystis occurs in water supply reservoirs. In this study, we examined the stability of microcystins during photolysis with UV light. The toxins were easily decomposed by UV light at wavelengths around the absorption maxima of the toxins and the decomposition depended on the intensity of the light. The half-life of microcystin LR by 147 microW/cm2 UV irradiation was 10 min, and the toxin was completely decomposed by 2550 microW/cm2 UV after 10 min. When the toxins were irradiated with weaker UV light, isomerization was also observed by a different mechanism from that during photolysis by sunlight and pigment, and several products including three geometrical isomers of the conjugated diene of Adda were detected. Microcystin RR showed almost the same behavior as that of microcystin LR under the same conditions. Since no noxious products were formed in the present study, a water treatment including UV irradiation is very possible for removing microcystins from raw water.

Chromatography, High Pressure Liquid↗
PubMed1995

HLA and tumor necrosis factor beta gene polymorphisms in Okinawa lung cancer patients: comparative study with mainland Japan lung cancer patients.

The frequencies of HLA class I and II antigens and TNF-beta polymorphism in lung cancer patients were investigated in two areas with different immunogenetic backgrounds, in Okinawa and in mainland Japan (Honshu). In Okinawa frequencies of HLA-Cw3 in squamous cell lung carcinoma patients were higher and those of HLA-DR, both in all lung cancer and in adeno lung carcinoma patients, were lower compared to those of normal controls. Among serologic HLA-DR4-positive individuals, no difference of DRB1*04 gene allele frequency was shown between patients and controls. In Honshu no statistically significant difference of HLA-class I and II alleles frequencies was found; however, the frequency of TNF-beta 10.5-kb homozygote in lung cancer patients was lower than that of controls. For 2-year survival, there was no difference between DR4-positive and -negative individuals and also between each TNF-beta type in Okinawa. In contrast, Honshu patients with 10.5-kb homozygote showed an improved 5-year survival ratio compared to those with heterozygote. We postulate that different immunogenetic backgrounds or environments might have caused the varying HLA or TNF-beta association in the predisposition to or prognosis of lung cancer.

Adenocarcinoma↗
PubMed1995

Microsatellite polymorphism between the tumor necrosis factor and HLA-B genes in Behçet's disease.

Behçet's disease is associated with the HLA-B51 antigen. However, it has not yet been clarified if the HLA-B51 gene itself is the susceptibility gene related to this disease or if it is some other non-HLA gene in linkage disequilibrium with HLA-B51. Therefore, we screened one of the HSP70 genes, HUM70t (HSP70-Hom), around the class III region and the microsatellite sequence located between the HLA-B and TNF genes for genetic polymorphism in BD. A comparison between patients with BD and healthy controls revealed no significant difference in the frequency of the HUM70t polymorphism. In the microsatellite sequence, Tau-a, in the region between the HLA-B and TNF genes, the frequency of 14 repetitions of GT was increased significantly and that of 11 repetitions was decreased significantly in the patient group. Further, the allelic distributions of the B51 antigen-associated microsatellite polymorphism differed significantly between patients and healthy controls, and in the B51 antigen-negative subjects, analysis of the microsatellite polymorphism also revealed a significant difference in the haplotype frequency between the patient and control groups. These results suggest that the HLA-B51 gene may not be the primary locus responsible for BD, and implicate some other gene(s) located between the TNF and HLA-B genes.

Base Sequence↗
PubMed1995

Neurotoxicity of acromelic acid in cultured neurons from rat spinal cord.

Acromelic acid A, which contains the kainic acid structure in its molecule, is known to cause selective damage of interneurons in the rat lower spinal cord. In the present study, the potent neurotoxicity of acromelic acid A was demonstrated in cultured rat spinal neurons in terms of the activity of lactate dehydrogenase that was released from degenerated neurons into the culture medium. Acromelic acid A increased the lactate dehydrogenase activity in time- and concentration-dependent manners, and its EC50 was about 2.5 microM, which was much lower than that of kainic acid (70 microM) and (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (EC50; 11 microM). The maximum level of lactate dehydrogenase released by acromelic acid A was quite similar to that by kainic acid, but was about twice the level produced by (RS)-alpha-3-hydroxy-5-methyl-4-isoxazolepropionic acid. Exposure to acromelic acid A caused release of L-glutamate from the cells into the medium; however, the concentration of L-glutamate released was far below the level for inducing the neurotoxic effects. The neurotoxicity of 10 microM acromelic acid A was almost completely inhibited by 30 microM 6-nitro-7-sulphamoylbenzo(F)quinoxaline-2,3-dione and 6-cyano-7-nitroquinoxaline-2,3-dione, potent antagonists for non-N-methyl-D-aspartate receptors, but was partly (35%) reduced by 30 microM dizocilpine maleate. In cultured hippocampal neurons, the toxicity of acromelic acid A was significantly less effective (EC50: 18 microM) than that in spinal neurons, whereas the toxicity of kainic acid was almost the same in both neurons. These results suggest that acromelic acid A directly activates non-N-methyl-D-aspartate receptors on the cultured spinal neurons to induce neuronal death. A new type of non-N-methyl-D-aspartate receptors which is specific to acromelic acid A is suggested to be present at least in spinal neurons.

Amino Acids↗
PubMed1995

Synergistic action of interleukin-10 (IL-10) with IL-3, IL-4 and stem cell factor on colony formation from murine mast cells in culture.

We examined the effects of interleukin-10 (IL-10) on colony formation from two different types of murine mast cells, bone marrow-derived mast cells (BMMC) and serosal mast cells (SMC), using a methylcellulose culture method. IL-10 alone did not induce colony formation from either phenotype. However, BMMC and SMC produced colonies in the presence of IL-10 in combinations with IL-3, IL-4 or stem cell factor (SCF), but they responded in different manners. IL-10 enhanced the IL-3-dependent colony formation from BMMC and induced the colony formation from BMMC synergistically with IL-4 or SCF dose-dependently, although IL-4 and SCF were not active alone. The most significant synergism was observed between IL-10 and IL-4. The addition of IL-10 to the cultures of BMMC in the presence of two or three factors enhanced the colony formation induced by IL-3 plus IL-4, and inhibited the colony formation induced by IL-3 plus SCF or IL-3, IL-4 plus SCF. In the colony formation from SMC, IL-10 synergized with IL-3 but not with IL-4 or SCF. IL-10 in combination with two or three factors enhanced the colony formation from SMC induced by IL-3 plus IL-4, but did not affect the colony formation induced by other combinations among IL-3, IL-4 and SCF. These findings indicate that IL-10 plays an important role in the proliferation of murine mast cells.

Animals↗
PubMed1995

Analysis of survival of allogeneic fetal liver fragments in rats.

The survival of allogeneic fetal liver fragments in the omentum was analyzed in rats. The lymphocyte subsets of the spleen and peripheral blood were also examined. When the fetal liver fragments were transplanted into the omentum, they survived for 2 wk, whereas adult liver fragments survived only 1 wk. In fetal liver fragments transplantation, the CD8 positive lymphocyte percentage in peripheral blood decreased significantly 3 wk after transplantation in comparison with that in adult liver fragment transplantation. The skin graft of the donor party showed a longer median survival time in rats receiving fetal liver fragment transplants than that in recipients of adult liver fragments. Although further study is needed, allogeneic fetal liver fragments survived longer in the omentum than reported elsewhere, and the decrease of CD8 positive peripheral blood lymphocytes may have been the reason for this.

Animals↗
PubMed1995

Transient increase of cyclic AMP induced by glutamate in cultured neurons from rat spinal cord.

We demonstrated that glutamate increased the cyclic AMP level in cultured neurons from rat spinal cord. A bath application of glutamate (300 microM) elicited a rapid increase of the cyclic AMP concentration reaching a level three times as high as the basal level in approximately 3 min, and its content then decreased to the control level in 15 min. The increase was not observed in a Ca(2+)-free medium and was inhibited by an antagonist of NMDA receptors or a voltage-sensitive Ca2+ channel blocker. Preincubation with W7 also inhibited the glutamate-evoked cyclic AMP increase. NMDA, aspartate, and high-K+ conditions also induced a cyclic AMP increase; however, a decreasing phase did not follow. The decreasing phase was observed when (2S,1'S,2'S)-2-(carboxycyclopropyl)-glycine, a potent agonist for metabotropic glutamate receptors, was combined with NMDA. These results suggest that the cyclic AMP increase is mediated by a Ca2+ influx via both NMDA receptors and voltage-sensitive Ca2+ channels followed by an activation of the Ca2+/calmodulin system, and the decreasing phase observed in the case of glutamate exposure is due to the activation of the metabotropic glutamate receptors.

Animals↗
PubMed1995

Determination of HLA class II alleles by genotyping in a Manchu population in the northern part of China and its relationship with Han and Japanese populations.

The genetic polymorphism of the HLA class II loci was investigated in a Manchu population resident in the northern part of China and compared with those of other Asian populations including Japanese and Han. In 8 DQA1 alleles, the most frequent allele was DQA1*03 with the gene frequency of 25.5%. Of 15 DQB1 alleles tested, 11 were observed and the most common allele was DQB1*0301 with the gene frequency of 24.5%. Among 19 DPB1 alleles, 11 were detected and DPB1*0501 (43.8%) was the most frequent allele as observed in other Asian populations such as Japanese, Chinese and Korean. Of 43 DRB1 alleles tested, 21 were detected and DRB1*0901 (14.0%), *1501 (11.0%), *1201 (11.0%), *07 (9.0%) and *1401 (9.0%) were highly predominant and account for the high frequencies of DR9, DR2, DR5, DR7 and DR6. In the DRB3 gene (DR52), DRB3*0202 (18.0%) was the most frequent. With respect to the DRB4 gene (DR53), the gene frequency of DRB4*0101 was 35.0%. Of 3 DRB5 alleles detected, DRB5*0101 (11.0%) was highly predominant. Comparison of HLA class II allele frequencies in Manchu with those in Japanese and Han Chinese populations (South & North) detected some significant differences and genetic divergence between these Oriental populations. The dendrogram constructed by the neighbor-joining (NJ) method based on the allele frequencies of DQA1, DQB1, DPB1 and DRB1 of 10 representative populations over the world suggested that Manchu is the closest, but at the same genetic distance to both Northern and Southern Han Chinese.

Alleles↗
PubMed1995

Synthesis and antibacterial activities of optically active substituted 1,2-dihydro-6-oxo-6H-pyrrolo[3,2,1-ij]quinoline-5-carboxylic acids.

A series of optically active substituted 1,2-dihydro-6-oxo-pyrrolo[3,2,1-ij]quinoline-5-carboxylic acids was prepared via optically active 2-methyl-4,5-difluoroindoline (10) and tested for antibacterial activities. Among them, (2S)-9-[(3R,1'S)-3-(1'-amino)ethyl-1-pyrrolidinyl]-8-fluoro-1,2-dihydro- 2- methyl-6-oxo-6H-pyrrolo[3,2,1-ij]-quinoline-5-carboxylic acid (19) showed potent activity against gram-positive bacteria and (2S)-8-fluoro-1,2-dihydro-2-methyl-9-(3-methyl-1-piperazinyl)-6-oxo-6H- pyrrolo[3,2,1-ij]quinoline-5-carboxylic acid (16) exhibited well balanced in vitro activity, good intravenous efficacy, and high aqueous solubility.

Anti-Bacterial Agents↗
PubMed1995

Acute myelomonocytic leukemia in a patient with multiple myeloma: evidence for different clonal origin.

A case of 77-year-old female with multiple myeloma (IgG-k) developed acute myelomonocytic leukemia (AMMoL) following a myelodysplastic stage after chemotherapy with melphalancyclophosphamide combinations for 6 years. The leukemic blast cells expressed both myeloid antigens (CD11b, CD13, CD14, CD15, CD33 and CD34) and T/B lymphoid antigens (CD2, CD4, CD22 and PCA1). Cytogenetic analysis revealed a chromosome deletion -7. Analysis of immunoglobulin genes showed the heavy chain genes in germ line configuration. These findings indicate that the AMMoL was a therapy-related stem cell leukemia and was a clonal origin genetically different from multiple myeloma irrespective of plasma cell phenotype.

Aged↗
PubMed1995

[Preferential proliferation of natural killer cells with bone marrow mononuclear cells in multiple myeloma].

We examined proliferation of natural killer (NK) cells in 10 day mixed culture of peripheral blood mononuclear cells (PBMC) from healthy subjects with irradiated bone marrow mononuclear cells (BMMC) with multiple myeloma. In culture, NK cells increased with 9.5-fold. However, no increase was observed in T cells. The NK cell proliferating activity of PBMC stimulated with BMMC was higher than that of IL-2. NK cells at a purity of 90% or higher purity were collected from 10 day culture. Proliferation of these NK cells was stimulated by the addition of IL-2 but was suppressed by the addition of antibody coated erythrocyte (EA). IFN-gamma production was negligible in cultures of these NK cells alone but was marked in cultures with EA stimulate IFN-gamma production. Next, the NK cell obtained as above showed marked NK activity against K 562 cells, and this activity was further enhanced by the addition of IL-2. Also, while NK cells, these NK cells had some activity against Daudi cells and it was enhanced by the addition of IL-2. These results also suggest the presence of unknown cytokines with NK cell proliferating activities in the bone marrow of patients with multiple myeloma.

Bone Marrow Cells↗