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T Kawabata

Publications and source records attributed to T Kawabata.

At least 19 recordsLinked to original sources
PubMed2006

Spin correlations of strongly interacting massive fermion pairs as a test of Bell's inequality.

We report the results of the first-time test of the local hidden variable theories (Bell-Clauser-Horne-Shimony-Holt) involving strongly interacting pairs of massive spin 1/2 hadrons from the decay of short-lived (tau<10;-21sec) 2He spin-singlet state, populated in the nuclear reaction 2H+;1H-->;2He+n. The novel features of this experiment are (a) the use of an 'event-ready' [corrected] detector of nearly 100% efficiency to prepare an unbiased sample and (b) a focal-plane polarimeter of full 2pi sr acceptance with a random "post selection" of the reference axes. The spin-correlation function is deduced to be S[exp](pi/4)=2.83+/-0.24stat+/-0.07sys. This result is in agreement with nonlocal quantum mechanical prediction and it violates the Bell-CHSH inequality of |S|<or=2 at a confidence level of 99.3%.

Journal Article↗
PubMed2005

A defective Th1 response of the spleen in the initial phase may explain why splenectomy helps prevent a Listeria infection.

Listeria monocytogenes (Listeria) are known to grow and proliferate in the liver while a splenectomy induces host resistance against a Listeria infection despite the fact that a splenectomy inhibits the Th1 response. Therefore, the mechanism by which a splenectomy helps to prevent the growth of Listeria still remains to be elucidated. After an i.v. challenge of Listeria (1 x 10(6) CFU) in C57BL/6 mice, Listeria rapidly increased in the spleen but not in the liver until 48 h. However, after this initial phase, Listeria remarkably grew in the liver. In contrast, when the mice received a splenectomy beforehand, no remarkable growth of Listeria in the liver was observed after Listeria challenge despite the fact that serum IFN-gamma and IL-12 levels at 24 h after Listeria challenge were significantly lower than those in the sham mice. However, the liver leucocytes from mice by 6 h after infection produced a substantial amount of IFN-gamma while spleen MNC did not, whereas spleen leucocytes at 24 h after Listeria challenge did. Consistently, the IFN-gamma and IL-12 levels in the tissue homogenates of the spleen were significantly lower than in those of the liver until 6 h after infection. This defective spleen Th1 response in the early phase of Listeria infection was corrected by an IL-18 i.p. injection just after the Listeria challenge. Our findings suggest that Listeria exploit the defective Th1 environment of the spleen in the initial phase and afterwards overcome the host defense mechanism of the liver.

Animals↗
PubMed2005

Polymorphisms in PTCH1 affect the risk of ameloblastoma.

Ameloblastoma is the most common odontogenic tumor, but the genetic nature of the changes in the tumor cells has been unclear. Mutations of CTNNB1 or PTCH1 are observed in many human tumors. Both CTNNB1 and PTCH1 are important in tooth development and are expressed in ameloblastoma. The aim of this study was to investigate whether genetic alterations of CTNNB1 and PTCH1 are present in ameloblastoma. We investigated 14 cases of ameloblastoma. The polymorphisms found in the ameloblastoma patients were further examined in a subsequent case-control study. We found a CTNNB1 mutation in one case of plexiform-type ameloblastoma. CGG triplet repeat-number polymorphism (CGG7/CGG8) in the 5'-untranslated region of PTCH1 was observed. The proportion of CGG8 alleles was significantly higher in the ameloblastoma group. The results of this study indicate a possible relationship between the CGG8 allele in PTCH1 and the risk for ameloblastoma.

Adult↗
PubMed2005

[Left atrial thrombus in an 80-year-old woman scheduled to have an operation for uterus cancer; report of a case].

An 80-year-old woman was scheduled to have an operation for uterus cancer. Echocardiography revealed a giant mobile mass in the left atrium with a stalk at posterior wall of the left atrium. There was no significant mitral disease. Due to the risks of sudden circulatory collapse and systemic emboli, an emergency operation was indicated. Right side of the left atrium was opened under cardiopulmonary bypass following median sternotomy. The mass was attached to the posterior wall, 1.5 cm medial to the right upper pulmonary vein, with a thin stalk as diagnosed preoperatively. The mass (4.2 x 3.4 x 3.4 cm) was removed very easily. Pathological analysis revealed that the mass was a thrombus mixed with fibrin. A possible cause would be paroxysmal atrial fibrillation and/or hypercoagulative status due to malignancy. Anti-coagulation therapy was initiated postoperatively to prevent recurrence of thrombus. The patient recovered and discharged uneventfully.

Aged↗
PubMed2003

Excitation and decay of the isovector giant monopole resonances via the 208Pb(3He,t p) reaction at 410 MeV.

The excitation and subsequent proton decay of the isovector spin-flip giant monopole resonance (IVSGMR) is studied via the 208Pb(3He,t) reaction at 410 MeV. In the inclusive spectrum (60+/-5)% of the non-energy-weighted sum-rule strength for this 2 variant Planck's over 2h omega resonance was found in the region 29<Ex(208Bi)<51 MeV. The central excitation energy and width of the IVSGMR are 37+/-1 MeV and 14+/-3 MeV, respectively. It is found that the branching ratio for proton decay is (52+/-12)% and that the deep neutron-hole states in 207Pb are strongly fed.

Journal Article↗
PubMed2003

Development and validation of a radioligand binding assay to measure insulin specific IgG subclass antibodies in human serum.

The objective was to develop and validate a radioligand binding assay for insulin antibodies (IABs) of the IgG1, IgG2, IgG3, and IgG4 subclasses in human serum. The validation studies focused on determining specificity, capacity, linearity, sensitivity, and precision of each assay. It was seen that our assay for IAB IgG subclasses is specific and has sufficient capacity to measure each of the subclasses in human serum. Moreover, the linear region and limits of detection and quantitation for each assay are clearly determined.

Antibody Specificity↗
PubMed2002

kdsA mutations affect FtsZ-ring formation in Escherichia coli K-12.

No one has, as yet, addressed the relationship between the nature of the outer membrane and cell division. kdsA encodes 3-deoxy-D-manno-octulosonic acid (KDO) 8-phosphate synthetase which catalyses the first step in the synthesis of KDO, the linker between lipid A and oligosaccharide of lipopolysaccharide (LPS). Seven temperature-sensitive mutants containing missense mutations in kdsA were affected in the production of KDO and all mutants stopped dividing at 41 degrees C and formed filaments with either one or no FtsZ ring. All observed defects were reversed by the plasmid-borne wild-type kdsA gene. Western blotting analysis, however, demonstrated that the amount of FtsZ protein was not affected by the mutation. The mutants were more susceptible to various hydrophobic materials, such as novobiocin, eosin Y and SDS at 36 degrees C. Methylene blue, however, restored kdsA mutant growth. Plasmid-borne wild-type msbA, encoding a lipid A transporter in the ABC family, partially suppressed kdsA mutation. A mutation of lpxA, functioning at the first stage in lipid A biosynthesis, inhibited both cell division and growth, producing short filaments. These results indicate that the instability of the outer membrane, caused by the defect in KDO biosynthesis, affects FtsZ-ring formation.

Aldehyde-Lyases↗
PubMed2001

Energy dependence of nuclear transparency in C (p,2p) scattering.

The transparency of carbon for (p,2p) quasielastic events was measured at beam momenta ranging from 5.9 to 14.5 GeV/c at 90 degrees c.m. The four-momentum transfer squared (Q2) ranged from 4.7 to 12.7 (GeV/c)(2). We present the observed beam momentum dependence of the ratio of the carbon to hydrogen cross sections. We also apply a model for the nuclear momentum distribution of carbon to obtain the nuclear transparency. We find a sharp rise in transparency as the beam momentum is increased to 9 GeV/c and a reduction to approximately the Glauber level at higher energies.

Journal Article↗
PubMed2001

Preoperative serum interleukin-18 level as a postoperative prognostic marker in patients with gastric carcinoma.

BACKGROUND: Interleukin-18 (IL-18), a recently described cytokine produced mainly by macrophages, stimulates interferon-gamma (IFN-gamma) production by natural killer cells and T cells. Although it has been reported that serum IL-18 levels are higher in patients with advanced tuberculosis and acute graft-versus-host disease compared with normal controls, the authors found no reports regarding serum IL-18 levels in patients with malignant solid tumors. The purpose of this study was to determine serum IL-18 levels and their clinical significance in patients with gastric carcinoma. METHODS: Peripheral blood samples were obtained from 94 patients with gastric carcinoma who underwent curative surgery and from 50 healthy volunteers. The serum IL-18 level, the IFN-gamma, level, and the Helicobacter pylori (HP) serology status were determined in each sample with an enzyme-linked immunosorbent assay. RESULTS: The mean serum IL-18 level for all patients was significantly higher compared with the mean level in healthy volunteers (P < 0.01). IFN-gamma titers were below the level of detection in all samples tested. When the patients were subdivided into groups, it was found that the serum IL-18 level in patients with Stage II and III disease was significantly higher compared with the level found in healthy volunteers (P < 0.01). The serum IL-18 level decreased after patients underwent surgical resection. However, there was no significant difference in the serum IL-18 level between healthy controls and patients with Stage I or IV disease. Patients with IL-18 levels >or= 310 pg/mL (i.e., equal to or greater than the mean levels +/- 1 standard deviation in the healthy volunteers) experienced a significantly lower survival rate compared with patients who had IL-18 levels < 310 pg/mL after undergoing surgery (P < 0.05) despite a lack of any discernible difference in clinicopathologic factors between the two groups. The serum IL-18 level was identified as an independent postoperative prognostic factor in multivariate survival analysis using a Cox proportional hazards model (hazard ratio, 4.89; P = 0.01). There was no significant correlation between HP serology status and serum IL-18 levels. CONCLUSIONS: The preoperative serum IL-18 level may represent a significant postoperative prognostic determinant in patients with gastric carcinoma. Its function in the host immune system remains to be elucidated.

Aged↗
PubMed2001

Enhancement of learning capacity and cholinergic synaptic function by carnitine in aging rats.

The effects of a carnitine derivative, acetyl-L-carnitine (ALCAR), on the cognitive and cholinergic activities of aging rats were examined. Rats were given ALCAR (100 mg/kg) per os for 3 months and were subjected to the Hebb-Williams tasks and a new maze task, AKON-1, to assess their learning capacity. The learning capacity of the ALCAR-treated group was superior to that of the control. Cholinergic activities were determined with synaptosomes isolated from the cortices. The high-affinity choline uptake by synaptosomes, acetylcholine synthesis in synaptosomes, and acetylcholine release from synaptosomes on membrane depolarization were all enhanced in the ALCAR group. This study indicates that chronic administration of ALCAR increases cholinergic synaptic transmission and consequently enhances learning capacity as a cognitive function in aging rats.

Acetylcarnitine↗
PubMed2001

Polymerization of bisphenol A by purified laccase from Trametes villosa.

The metabolism of bisphenol A (BPA), an endocrine-disrupting chemical, was studied with a highly purified laccase from the basidiomycete Trametes villosa. The enzyme reaction products ranged widely from water-insoluble to -soluble compounds, one of which was previously identified as 4-isopropenylphenol. (1)H NMR and electron-impact mass spectrum analyses showed that one of the insoluble products was a BPA dimer, 5,5'-bis-[1-(4-hydroxy-phenyl)-1-methyl-ethyl]-biphenyl-2,2'-diol. Field-desorption mass spectrum analysis revealed BPA oligomers, some of which contained phenol, within the insoluble fraction. These results indicate that the laccase reaction may contain successive BPA polymerization, followed by either the addition of phenol to the formed oligomers or their decomposition to release 4-isopropenylphenol.

Benzhydryl Compounds↗
PubMed2001

Degradation of bisphenol A by purified laccase from Trametes villosa.

Degradation of bisphenol A (BPA), an endocrine-disrupting chemical, was studied with a purified laccase from the basidiomycete Trametes villosa. SDS--polyacrylamide gel electrophoresis of the purified laccase gave one single band with a mobility corresponding to MW 65 kDa. The absorption spectrum showed the characteristics of a blue copper protein with a maximum peak at 600 nm. HPLC analysis revealed that 2.2 micromol BPA were degraded by incubation with 1.5 units of the purified laccase in a total volume of 1.0 ml at pH 6.0 and 60 degrees C for 3 h. The enzyme reaction proceeded rapidly without requirement of mediators for the electron transfer. Isolation and identification of several reaction products are in progress, in which one product was identified as 4-isopropenylphenol by a gas chromatography--mass spectrophotometer.

Benzhydryl Compounds↗
PubMed2001

Single measurement of serum phospholipid fatty acid as a biomarker of specific fatty acid intake in middle-aged Japanese men.

OBJECTIVE: To assess the utility of serum phospholipid fatty acid (FA) levels as a biochemical indicator of habitual dietary fatty acid intake in Japanese, whose diet is characterized by low fat intake and high intake of n-3 polyunsaturated fatty acids (PUFA) of marine origin. SUBJECTS AND METHODS: Eighty-seven male volunteers from four public health center districts that were part of the Japan Public Health Center based Prospective Study (JPHC Study) cohort I, were included in this study. Habitual intake of fatty acid was obtained by 7 day weighed dietary records four times (in one area only twice) in 1994--1995. Blood was collected twice, in February and August of the same year, and the composition of FA in serum phospholipid was analyzed by gas chromatography. The correlation coefficient between serum phospholipid FA levels and fatty acid intake was calculated. RESULTS: High correlations were observed for eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA), which are marine origin n-3 PUFA (r=0.75, 0.49, 0.50, respectively). No significant correlation was observed for saturated fatty acid (SFA), although the monounsaturated fatty acid (MUFA), palmitoleic acid and oleic acid intake were moderately correlated (r=0.22, 0.35, respectively). The correlations for EPA, DPA and DHA were similar in both samples collected in February and August. CONCLUSIONS: These data suggest that in populations with a high and stable over time intake of n-3 PUFA of marine origin, a single measurement of serum phospholipids reflects the ranking of habitual intake of marine origin n-3 PUFA.

Biomarkers↗
PubMed2001

Cloning and nucleotide sequence of the mycodextranase gene from Streptomyces sp. J-13-3.

Mycodextranase (EC 3.2.1.61) is an alpha-glucanase that cleaves alpha-1,4-bonds of alternating alpha-1,3- and alpha-1,4-linked D-glucan (nigeran). The gene encoding mycodextranase from Streptomyces sp. J-13-3 was cloned by hybridization with a degenerate oligonucleotide probe from the amino-terminal amino acid sequence of the enzyme and its nucleotide structure was analyzed. The open reading frame consisted of 1,803 base pairs encoding a signal peptide of 60 amino acids and a mature protein of 540 amino acids with a calculated molecular weight of 56,078. The deduced amino acid sequence showed weak similality to a chitinase homolog from Streptomyces lividans and a chitinase from Xanthomonas sp.

Amino Acid Sequence↗
PubMed2001

In vitro transformation of rat renal cells by treatment with ferric nitrilotriacetate.

Administration of ferric nitrilotriacetate (Fe-NTA) in vivo causes acute renal tubular injury and finally induces renal cell carcinoma. There is accumulating evidence that these processes involve free radicals generated by Fe-NTA. To study the mechanism of renal carcinogenesis by Fe-NTA, we attempted to induce malignant transformation of primary cultured renal cells by treatment with Fe-NTA. When primary cultured renal cells (PRC) were treated continuously with Fe-NTA, all of the PRC died without transformation. On the other hand, when PRC were treated intermittently with Fe-NTA, transformed epithelial colonies were observed at 3 weeks after the first treatment. The established transformed cell line (RK523) showed drastic morphological transformation, grew in soft agar, and formed tumors when transplanted into athymic nude mice. These results indicate that the balance between cytotoxicity and mutagenecity is important for Fe-NTA induced transformation. The RK523 cell line may be a useful model for studying renal carcinogenesis in vitro.

Animals↗
PubMed2001

Role of blood volume in the age-associated decline in peak oxygen uptake in humans.

It has been reported that maximal oxygen uptake (VO(2 max)) is linearly correlated with blood volume (BV) in young people and that there is a reduction in VO(2 max) with aging. To examine the involvement of BV in the reduction of VO(2 max), we used an incremental cycle ergometer protocol in a semi-recumbent position to determine the relationship between peak oxygen uptake (VO(2 peak)) and BV in older subjects (69.1 +/- 1.0 years; n = 22), then compared that relationship with that in young subjects (22.3 +/- 0.5 years; n = 31). In the present study, VO(2 peak) and BV were significantly lower in the older subjects, compared with those in the young subjects. A linear correlation was demonstrated between the VO(2 peak) and BV in both the older (r = 0.705; p < 0.001) and the young (r = 0.681; p < 0.001) subjects within the groups. However, an analysis of covariance with BV as a covariate revealed that VO(2 peak) at a given BV was smaller in the older subjects than in the young subjects (p < 0.001), i.e., graphically, the regression line determined for the older subjects showed a downward shift. The decreased peak heart rate as a result of aging (153 +/- 3 beats/min in the older vs. 189 +/- 2 beats/min in the young subjects) contributed partly to this downward shift. These results suggest that the BV is an important determinant factor for VO(2 peak), especially within an age group, and that the age-associated decline of VO(2 peak) is also, to a relatively larger degree, because of factors other than BV and heart rate.

Adult↗
PubMed2001

Effects of oxygen concentrations on human fibroblasts treated with Fe(3+)-NTA.

Free radicals derived from the reaction of iron and oxygen are thought to be one of the causes of tissue injury. In order to identify whether oxygen concentrations are an important factor in iron-mediated damage to cells, cytotoxic effects of Fe(3+)-NTA on human fibroblasts (KMST-6 line) were studied under the conditions of 1% and 20% oxygen concentrations in an incubator. A comparison of the effects of Fe(3+)-NTA on cells cultured in 1% and 20% oxygen environments showed that the following features were more prominent under the usual culture concentrations of 20% oxygen: i) cytotoxicity, ii) increase in intracellular reactive oxygen species, iii) increase in H(2)O(2) production in the cells, and iv) formation of 8-hydroxydeoxyguanosine. To elucidate the roles of endogenous antioxidants, the levels of manganese superoxide dismutase (MnSOD) and catalase were measured by Western blotting. The increase in MnSOD in the presence of Fe(3+)-NTA was greater under the condition of 20% O(2) than under the condition of 1% O(2). The expression of catalase was significantly up-regulated at 20% O(2). However, when the cells were treated with Fe(3+)-NTA, the expression of catalase was markedly down-regulated under the condition of 20% O(2). Hydroxyl radical scavengers such as vitamin E, dimethyl-sulfoxide (DMSO) and mannitol reduced endogenous ROS generation and alleviated the cytotoxic effects of iron. On the other hand, superoxide dismutase (SOD), vitamin C and catalase did not show any protective effects against Fe(3+)-NTA. These findings suggest that enhanced cytotoxic effects of Fe(3+)-NTA at 20% O(2 )are due to endogenously produced hydroxyl radicals.

8-Hydroxy-2'-Deoxyguanosine↗