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Biomedical subjects

H Kato

Publications and source records attributed to H Kato.

At least 109 records · Page 6Linked to original sources
PubMed2001

Regression of human T-cell leukemia virus type I (HTLV-I)-associated lymphomas in a rat model: peptide-induced T-cell immunity.

BACKGROUND: Human T-cell leukemia virus type I (HTLV-I) is etiologically linked to adult T-cell leukemia (ATL). The disease has a high mortality rate and is resistant to chemotherapy; therefore, immunologic approaches to treatment could be of interest. We have previously shown that athymic rats inoculated with a syngeneic (i.e., with the same genetic background) HTLV-I-infected T-cell line (FPM1-V1AX) develop ATL-like disease and that the transfer of T cells from normal syngeneic rats immunized with FPM1-V1AX cells prevents disease development. In this study, we further characterized the host antitumor immunity to explore the possibility of peptide-based vaccination against the ATL-like disease. METHODS: Immune T cells from rats immunized with FPM1-V1AX cells were analyzed for their phenotypes and cytotoxic properties. The epitope recognized by the T cells was analyzed by fine mapping. To evaluate the antitumor effects of a peptide-based vaccine, normal rats were immunized with synthetic oligopeptides corresponding to the epitope, the T cells were transferred to athymic rats inoculated with HTLV-I infected cells, and tumor size was monitored. RESULTS: Both CD4+ and CD8+ T-cell populations from rats immunized with FPM1-V1AX cells inhibited the growth of FPM1-V1AX cell-induced lymphomas in vivo. Long-term culture of splenic T cells from the immunized rats repeatedly resulted in establishment of CD8+ HTLV-I-specific cytotoxic T lymphocyte (CTL) lines restricted to the rat major histocompatibility complex class I molecule, RT1.A(l). The cytotoxicity of these lines was directed against the HTLV-I regulatory protein Tax and, specifically, against the epitope, amino acids 180-188 (GAFLTNVPY). Adoptive transfer of the Tax 180-188-specific CTL line or freshly prepared T cells from rats vaccinated with the Tax 180-188 oligopeptide prevented the development of FPM1-V1AX-cell induced lymphomas in athymic rats in comparison with control groups (two rats in each group). CONCLUSIONS: This study indicated a potential therapeutic effect of peptide-based vaccination against HTLV-I-induced lymphoproliferative disease.

Amino Acids↗
PubMed2001

Influence of angiogenetic factors and matrix metalloproteinases upon tumour progression in non-small-cell lung cancer.

We attempted to investigate immunohistochemical expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor (PD-ECGF), c-erbB-2, matrix metalloproteinase-2 (MMP-2), and MMP-9 using surgical specimens of 119 non-small-cell lung carcinoma (NSCLC) cases and to evaluate the relationship between the expression levels of each molecule and clinicopathological factors or prognosis. VEGF expression levels were significantly associated with the local invasion (P = 0.0001), lymph node involvement (pN-factor) (P = 0.0019), pathological stage (p-stage) (P = 0.0027) and lymphatic permeation (P = 0.0389). PD-ECGF expression levels were associated with pN-factor (P = 0.0347). MMP-2 expression levels were associated with pN-factor (P = 0.004) and lymphatic permeation (P = 0.0056). Also, MMP-9 expression levels showed a significant correlation to local invasion (P = 0.0012), pN-factor (P = 0.0093) and p-stage (P = 0.0142). Multivariate analysis showed VEGF to be the most related to local invasion (P = 0.0084), and MMP-2 was the only factor with significant independent impact on lymphatic permeation (P = 0.0228). Furthermore, log-rank analysis showed significant association with poor survival by VEGF, bFGF, MMP-2 and MMP-9. Especially, combined overexpression of VEGF and MMP-2 revealed poor prognosis, our study might provide a basis for the better evaluation of biological characteristics and a new therapeutic strategy based on chemotherapy.

Adult↗
PubMed2001

Syntheses and biological evaluations of alpha-D-mannosyl [60]fullerenols.

[60]Fullerenols carrying mono- and bis-alpha-D-mannosyl linkages on the surface were prepared via a [3+2]-cycloaddition reaction between 2-azidoethyl alpha-D-mannoside and C(60) followed by polyhydroxylation with aqueous NaOH. Their biological activity was evaluated in terms of binding affinity to lectins by hemagglutination assay and surface plasmon resonance. [60]Fullerenols without the mannosyl linkage caused aggregation of erythrocytes and binding to a beta-D-galactopyranoside specific lectin (RCA(120)). In contrast, mono- and bis-mannosyl fullerenols were found to decrease the activity for both aggregating erythrocytes and binding to RCA(120), and mono-mannosyl fullerenols turned to binding to alpha-D-mannose specific lectin (Con A).

Carbon↗
PubMed2001

Assessment of preferential Th1 or Th2 induction by low-molecular-weight compounds using a reverse transcription-polymerase chain reaction method: comparison of two mouse strains, C57BL/6 and BALB/c.

The aim of this study was to examine whether the RT-PCR method for various Th1/Th2 cytokines is appropriate for determination of response to allergens using C57BL/6 and Balb/c mice, which are known to preferentially demonstrate Th1 and Th2 responses, respectively. To this end, both strains of mice were sensitized by skin painting with the contact allergen dinitrochlorobenzene (DNCB) or the respiratory allergen trimellitic anhydride (TMA). We used the sensitizing protocol adopted by Kimber and coworkers (Toxicology 103, 63-73, 1995). At various time points after the last application, the levels of mRNA expression for Th1-type cytokines IFN-gamma, IL-18, and IL-12p40, as well as receptor IL-18R, and the Th2-type cytokine IL-4 and the receptor ST2L, in lymph nodes were measured. The results suggest that differential expression of IL-12p40 and IL-4 mRNA after 24 h allows clear discrimination between DNCB and TMA in C57BL/6 mice, more obviously than in Balb/c mice. Furthermore, to examine this method, C57BL/6 mice were exposed to OXA, DNFB, and TNCB (Th1-predominant allergens) or PA, TDI, and MDI (Th2-predominant allergens). Elevation of IL-12p40 expression was significant with the Th1 inducers, while the level of IL-4 was higher with Th2-predominant allergens. The results of the present study demonstrate, for the first time, that differential expression of IL-12p40 and IL-4 in C57BL/6 mice may be useful as a parameter for assessing influence of contact and respiratory allergens.

Allergens↗
PubMed2001

Neuroprotective effect of riluzole in MPTP-treated mice.

The neuroprotective effects of riluzole, a Na(+) channel blocker with antiglutamatergic activity, and MK-801, a blocker of N-methyl-D-aspartate (NMDA) receptors, were compared in the model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced depletion of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) levels in mice. The mice were injected intraperitoneally (i.p.) with four administrations of MPTP (10 mg/kg) at 1 h intervals and then the brains were analyzed 1, 3 and 7 days after the treatment. Dopamine and DOPAC levels were significantly decreased in the striatum from 1 day after MPTP treatment. A severe depletion in dopamine and DOPAC levels was found in the striatum 3 and 7 days after MPTP treatment. Riluzole antagonized the MPTP-induced decrease in dopamine, DOPAC and HVA levels in the striatum. On the other hand, MK-801 prevented the MPTP-induced decrease in DOPAC levels, but not in dopamine levels in the striatum. An immunohistochemical study indicated that riluzole can protect against MPTP-induced neuronal damage in the substantia nigra. These results suggest that riluzole is effective against MPTP-induced neurodegeneration of the nigrostriatal dopaminergic neuronal pathway.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2001

SERPINB12 is a novel member of the human ov-serpin family that is widely expressed and inhibits trypsin-like serine proteinases.

Members of the human serpin family regulate a diverse array of serine and cysteine proteinases associated with essential biological processes such as fibrinolysis, coagulation, inflammation, cell mobility, cellular differentiation, and apoptosis. Most serpins are secreted and attain physiologic concentrations in the blood and extracellular fluids. However, a subset of the serpin superfamily, the ov-serpins, also resides intracellularly. Using high throughput genomic sequence, we identified a novel member of the human ov-serpin gene family, SERPINB12. The gene mapped to the ov-serpin cluster at 18q21 and resided between SERPINB5 (maspin) and SERPINB13 (headpin). The presence of SERPINB12 in silico was confirmed by cDNA cloning. Expression studies showed that SERPINB12 was expressed in many tissues, including brain, bone marrow, lymph node, heart, lung, liver, pancreas, testis, ovary, and intestines. Based on the presence of Arg and Ser at the reactive center of the RSL, SERPINB12 appeared to be an inhibitor of trypsin-like serine proteinases. This hypothesis was confirmed because recombinant SERPINB12 inhibited human trypsin and plasmin but not thrombin, coagulation factor Xa, or urokinase-type plasminogen activator. The second-order rate constants for the inhibitory reactions were 2.5 +/- 1.6 x 10(5) and 1.6 +/- 0.2 x 10(4) M(-1) S(-1), respectively. These data show that SERPINB12 encodes for a new functional member of the human ov-serpin family.

Amino Acid Motifs↗
PubMed2001

Sodium butyrate induces growth arrest and senescence-like phenotypes in gynecologic cancer cells.

We demonstrated here the growth-suppressing effects of sodium butyrate (NaB) on human endometrial and ovarian cancer cells. The arrest of cells at the G1 checkpoint accounted for this effect. NaB-mediated p21 might arrest endometrial and ovarian cancer cells at the G0/G1 phase by eliciting pRb unphosphorylation. To demonstrate the role of pRb regulation by p21, we measured the sensitivity to NaB of cervical cancer cells in which pRb had been inactivated by HPV E7. The cervical cancer cells displayed a sensitivity in NaB-mediated G2/M arrest in addition to their sensitivity in G0/G1 arrest. Arrest at G0/G1 and G2/M accompanied induction of senescence-like phenotypes (SLPs). Most importantly, the effect of NaB on senescence induction was not coupled with the predominance of hypophosphorylated pRb forms in the cervical cancer cells. This suggested that NaB had the potential to elicit SLPs through p21-mediated withdrawal from cell cycle progression. The consequences of p21 induction were manifold. The effects of NaB on gynecologic cancer cell growth indicated its potential use in cancer treatment. NaB was effective even in the cancer cells with mutant p53 and/or Rb genes by eliciting cell senescence.

Animals↗
PubMed2001

Platelet-associated anti-GPIIb-IIIa autoantibodies in chronic immune thrombocytopenic purpura recognizing epitopes close to the ligand-binding site of glycoprotein (GP) IIb.

Localization of epitopes for platelet-associated (PA) anti-GPIIb-IIIa (alpha(IIb)beta(3)) autoantibodies in chronic immune thrombocytopenic purpura remains elusive. Previous studies suggest that PA antibodies recognize the tertiary structure of intact glycoprotein (GP) IIb-IIIa. To localize their epitopes using antigen-capture enzyme-linked immunosorbent assay (ELISA), the reactivity of 34 PA anti-GPIIb-IIIa antibodies was examined with recombinant GPIIb-IIIa having a defect in ligand-binding sites in either GPIIb or GPIIIa, and no major conformational change was induced: KO variant GPIIb-IIIa was attributed to a 2-amino acid insertion between residues 160 and 161 in the W3 4-1 loop in GPIIb, and CAM variant GPIIb-IIIa was attributed to D119Y in GPIIIa. In one third (11 of 34) of the patients, PA antibodies showed a marked decrease (less than 50%) in reactivity with KO compared with wild-type GPIIb-IIIa. Their reactivity was also impaired against GPIIbD163A-IIIa. In sharp contrast, they reacted normally with CAM GPIIb-IIIa. OP-G2, a ligand-mimetic monoclonal antibody, markedly inhibited their binding to GPIIb-IIIa in patients with impaired binding to KO GPIIb-IIIa, but small GPIIb-IIIa antagonists did not. In addition, a newly developed sensitive ELISA indicated that autoantibodies showing impaired binding to KO are more potent inhibitors for fibrinogen binding. The present data suggest that certain PA anti-GPIIb-IIIa autoantibodies recognize epitopes close to the ligand-binding site in GPIIb, but not in GPIIIa.

Adult↗
PubMed2001

Atypically enhancing hepatic cavernous hemangiomas: high-spatial-resolution gadolinium-enhanced triphasic dynamic gradient-recalled-echo imaging findings.

We retrospectively investigated the appearance and frequency of atypically enhancing cavernous hemangiomas with high-spatial-resolution (512x224 matrix) gadolinium-enhanced triphasic dynamic gradient-recalled-echo (GRE) MR images. Images of 132 hepatic cavernous hemangiomas (ranging in size from 4 to 72 mm; mean size 17.2 mm) in 95 patients (42 men and 53 women; age range 25-85 years; mean age 54 years) were retrospectively reviewed by two independent radiologists. Forty (30%) of 132 lesions atypically enhanced. Smaller hemangiomas (< or =15 mm) more frequently (29%) showed early entire enhancement with or without arterio-portal shunting in the hepatic arterial-dominant phase ( p<0.001); most of them showed hyperintense complete fill-in in the equilibrium phase and were readily characterized. "Bright dot" or minimal peripheral enhancement in the equilibrium phase was seen in a small number of lesions (6% each). With T2-weighted images, 130 (98%) lesions showed moderately to very high signal intensity and only 2 (2%) with minimal peripheral enhancement showed hyperintensity of slight degree. The high-spatial-resolution dynamic GRE images clearly revealed minute enhancement characteristics of hemangiomas. Although moderately to very high signal intensity with T2-weighted MR images is informative for the diagnosis of most cavernous hemangiomas, when a lesion shows minimal peripheral enhancement in the equilibrium phase and hyperintensity of slight degree with T2-weighted images, further follow-up or biopsy may be warranted to discriminate hypovascular metastases.

Adult↗
PubMed2001

Increased cytotoxic effects of photodynamic therapy in IL-6 gene transfected cells via enhanced apoptosis.

PDT has been reported to induce cancer cell expression of cytokines, such as IL-6 and TNF-alpha, but it has been unclear whether cytokine expression by cancer cells is directly related to the antitumor effect of PDT. We treated Lewis lung carcinoma (LLC) cells with a new photosensitizer, mono-L-aspartyl chlorin e6 (NPe6) and light from a diode laser and found that expression of the mRNA of IL-2, IL-6, and TNF-alpha was increased by NPe6-mediated-PDT 6 hr later. To elucidate the mechanism of the direct anti-tumor effect of cytokine expression, we examined the photosensitivity of cytokine-gene-transfected cells, namely LLC-IL-2, LLC-IL-6, and LLC-TNF-alpha cells, by MTT assay. The IL-6 gene transfected, LLC-IL-6 cells were significantly more sensitive to cytotoxic effects than the parent LLC cells and other cytokine gene-transfected cells. This finding indicates that IL-6 expression modulates cellular sensitivity to PDT and that IL-2 and TNF-alpha expressions does not. In addition, the apoptosis of LLC-IL-6 cells induced by NPe6-PDT was greater than in the other cells as determined by DNA fragmentation and staining of apoptotic nuclei. Because IL-6 has been reported to induce apoptosis by downregulating expression of Bcl-2, we analyzed the expression of apoptosis-related Bcl-2, Bax, and cytochrome C by Western blot analysis. Decreased expression of Bcl-2 and cytochrome C was observed in both LLC cells and LLC-IL-6 cells. Bax protein increased in a time-dependent manner, and the ratio of Bax to Bcl-2 rose markedly after PDT in LLC-IL-6 cells. These results suggest that the increased sensitivity of LLC-IL-6 cells to PDT-induced cytotoxicity results from the high ratio of Bax to Bcl-2 in the IL-6-dependent apoptotic pathway. In conclusion, IL-6 expression plays a role in cellular sensitivity to PDT, and combination of IL-6 and PDT may provide a new strategy for cancer treatment.

Animals↗
PubMed2001

The analysis of heparin-protein interactions using evanescent wave biosensor with regioselectively desulfated heparins as the ligands.

Evanescent wave biosensor has been recently employed as a powerful tool for analyses of macromolecular interactions. In the present study, evanescent wave biosensor analysis was developed to analyze the heparin-protein interaction using as ligands a series of heparin derivatives regioselectively desulfated by chemical methods, particularly to evaluate the effect of each sulfate group of heparin. The method for immobilizing heparin on the cuvette of the evanescent wave biosensor equipment was optimized to obtain the high response required for accurate measurement. The best result was achieved when the amino group introduced at the reducing end of heparin was coupled with carboxymethyl dextran on the surface of the cuvette using glycolchitosan as a multivalent linker. The established system appeared to describe well the interactions of heparin with such proteins as acidic and basic fibroblast growth factors and tissue factor pathway inhibitor.

Biosensing Techniques↗
PubMed2001

Crystallization and preliminary X-ray study of endopolygalacturonase from the pathogenic fungus Stereum purpureum.

Crystals of endopolygalacturonase I from Stereum purpureum have been obtained by the vapour-diffusion method. Prior to crystallization work, endopolygalacturonase I was deglycosylated with endo-beta-N-acetylglucosaminidase H. The crystal diffracts to ultrahigh (0.96 A) resolution using synchrotron radiation and belongs to space group P1, with unit-cell parameters a = 37.26, b = 46.34, c = 52.05 A, alpha = 67.17, beta = 72.44, gamma = 68.90 degrees.

Basidiomycota↗
PubMed2001

Overexpression of mitochondrial manganese superoxide dismutase protects against radiation-induced cell death in the human hepatocellular carcinoma cell line HLE.

We investigated the potential role of mitochondrial manganese superoxide dismutase (Mn-SOD) in protective activity against irradiation by analyzing cell viability by a colony formation assay and by detecting apoptosis in stably human Mn-SOD gene-transfected HLE, a hepatocellular carcinoma cell line. We found that overexpression of Mn-SOD reduced the levels of reactive oxygen species in the mitochondria and intracellular phospholipid peroxidation product (4-hydroxy-2-nonenal) and prevented cell death. The production of intracellular nitric oxide after irradiation was not changed by Mn-SOD overexpression. The results suggested that Mn-SOD might play an important role in protecting cells against radiation-induced cell death by controlling the generation of mitochondrial reactive oxygen species and intracellular lipid peroxidation.

Apoptosis↗
PubMed2001

Flexible loop of beta 2-glycoprotein I domain V specifically interacts with hydrophobic ligands.

Beta2-glycoprotein I (beta2-GPI), which consists of four complement control protein modules and a distinctly folded fifth C-terminal domain, is an essential cofactor for the binding to phospholipids of anti-cardiolipin antibodies, isolated from patients with anti-phospholipid antibody syndrome, and its fifth domain has attracted attention as a specific phospholipid-binding site. We focused on the fifth domain of beta2-GPI (Domain V) and examined the interaction of intact Domain V, Domains IV-V, and nicked Domain V with various hydrophobic ligands, as a model molecule of phospholipid. We found that electrostatic and hydrophobic interactions are important for Domain V binding to the ligand molecules. We also found that, while Domain IV has no significant effect on the interactions with ligands, the nicked Domain V with cleavage in the flexible loop decreases the affinity, indicating that the flexible loop region is the binding site of the hydrophobic ligands. The synthetic peptide corresponding to the loop region was disordered and interacted with bis-ANS, confirming the critical role of the loop region. To clarify the nature of the interaction between the loop region and hydrophobic compounds, we prepared the reduced and alkylated Domain V, which was denatured but was assumed to be a collapsed state. Alkylation by iodoacetic acid decreased the interaction of Domain V with bis-ANS, probably because the protein net charge was decreased by the six introduced carboxyl groups and consequently the electrostatic interactions were decreased. In contrast, Domain V alkylated by iodoacetamide, therefore retaining a high positive net charge, bound bis-ANS more strongly than the intact Domain V. These results suggested that the interaction of Domain V with hydrophobic compounds through the flexible loop is similar to the binding of hydrophobic compounds to the protein folding intermediate.

Alkylation↗
PubMed2001

Expression of p53 protein related to smoking and alcoholic beverage drinking habits in patients with esophageal cancers.

In esophageal squamous cell carcinoma (SCC), we used immunohistochemical analysis to further elucidate the correlation of p53 protein expression with clinicopathological factors, as well as with risk factors, such as tobacco smoking, alcohol consumption and a family history of cancer, using odds ratios (ORs). The expression of p53 protein was demonstrated in 55.1% of 89 esophageal SCC cases examined by immunohistochemistry. The expression of p53 protein did not correlate with gender, age, histological grading, lymph node metastasis, or TNM stage. The prevalence of p53 expression was significantly higher in patients with multiple primary esophageal cancers (P<0.05). p53 expression did not correlate with prognosis in univariate survival analysis. The esophageal SCC in either smokers or alcohol users was 4.67-5.83 times more likely to express p53 protein, while the likelihood of p53 expression in patients who use both tobacco and alcohol was more than 14.0 times. However, a significant association was not found between p53 expression and a family history of cancer, this having an OR as low as 1.85. The expression of p53 protein did not correlate with clinicopathological factors and prognosis in univariate and multivariate survival analyses. In contrast, tobacco smoking and alcohol consumption were shown to be strongly associated with p53 mutations in esophageal carcinogenesis.

Adult↗
PubMed2001

Novel forms of squamous cell carcinoma antigen transcripts produced by alternative splicing.

Squamous cell carcinoma antigen (SCCA) is a member of the ovalbumin serine protease inhibitor family, and the serum level of SCCA is a tumor marker of squamous cell carcinoma. Reverse transcription (RT)-PCR of the squamous cell carcinoma cell line showed the existence of a 156 base shorter transcript compared with that of SCCA1 cDNA. By inverse PCR, we cloned the full length cDNA of this SCCA (SCCA1b). Sequence analysis of the complete 1541 bp SCCA1b cDNA showed that it coded for 338 amino acids and had no typical signal sequence in the NH(2) terminus. The cDNA was expressed in Escherichia coli and the product was detected using Western blotting with antibodies against SCCA. Furthermore, RT-PCR of the full coding region of SCCA2 cDNA from cancer tissue showed the existence of a 63 base short transcript (SCCA2b). A comparison of SCCA1b and SCCA2b cDNA with the SCCA1 and SCCA2 genes showed that these messages were derived from each gene by an alternative splicing mechanism.

Alternative Splicing↗
PubMed2001

Neuronal plasticity in hippocampal mossy fiber-CA3 synapses of mice lacking the inositol-1,4,5-trisphosphate type 1 receptor.

In the present study, we used inositol-1,4,5-trisphosphate (IP3) type 1 receptor (IP3R1) knockout mice to examine the role of this receptor in the induction of LTP, LTD, and DP at mossy fiber-CA3 synapses. No difference in synaptically induced field-EPSPs was seen between the wild-type (IP3R1(+/+)) and IP3R1 knockout mice (IP3R1(-/-)), showing that basic synaptic transmission does not involve IP3R1 activation. Tetanus induced LTP in both wild-type and IP(3)R1(-/-) mice, but the magnitude of LTP was significantly greater in IP3R1(-/-) mice (149.8+/-3.5%, mean+/-S.E.M., n=15) than in wild-type mice (132.4+/-1.5%, n=17), suggesting that the IP3R1 has a suppressive effect on LTP induction. To determine whether this effect involved N-methyl-D-aspartate receptor (NMDAR)-dependent LTP, the effect of tetanus was tested in the present of the NMDAR antagonist, D,L-AP5 (50 microM); under these conditions, the LTP in both IP3R1(-/-) and IP3R1(+/+) mice was not significantly reduced. In addition, group I mGluR activation was shown to be necessary for LTP induction, as the LTP was almost blocked by the group I mGluR antagonist, RS-4CPG (500 microM) in both IP3R1(-/-) (117.6+/-1.7%, n=8) and IP3R1(+/+) (116.9+/-1.8%, n=5) mice. The IP3R1 also plays an essential role in LTD induction, as low-frequency stimulation (LFS) failed to induce LTD in the mutant mice (104.5+/-2.1%, n=10). DP was induced in both IP3R1(-/-) and wild-type mice.

Animals↗