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T Kawai

Publications and source records attributed to T Kawai.

At least 55 records · Page 3Linked to original sources
PubMed2001

Problems with peritoneal cytology in second-look laparotomy performed in patients with epithelial ovarian carcinoma.

BACKGROUND: The recurrence rate of ovarian carcinoma is high even when a second-look laparotomy (SLL) is negative. In the current study, the accuracy of peritoneal cytology as an evaluation method of SLL was examined. METHODS: The positive SLL rate and the diagnostic accuracy of peritoneal cytology were evaluated in 101 patients with epithelial ovarian carcinoma. RESULTS: Twenty-three of the 101 patients (23%) were positive based on SLL. The factors considered to be high risk factors for a positive SLL were advanced disease (Stages III and IV by the International Federation of Gynecology and Obstetrics [FIGO] classification), serous adenocarcinoma, and maximum residual tumor > 2 cm after primary surgery (P < 0.05). Of the 23 patients found to be positive on SLL, peritoneal cytology was positive in 6 patients, in whom the percentage was low (26%). The remaining 17 patients (74%) demonstrated false-negative cytology. Of these 17 patients, the tumor tissues were found to be capsulated completely with connective tissues in all biopsy specimens from 9 patients (53%) and in all but 1 biopsy specimen in 6 patients (35%), together accounting for a capsulation rate of 88%. Conversely, clear exposure of the tumor tissues was observed in at least two biopsy specimens in those patients demonstrating positive cytology (P < 0.01). CONCLUSIONS: Peritoneal cytology in SLL was found to result in a high false-negative rate. One of the reasons for this was considered to be capsulation of the lesions with proliferated connective tissues, which may have been the result of by chemotherapy.

Adult↗
PubMed2001

Lipopolysaccharide stimulates the MyD88-independent pathway and results in activation of IFN-regulatory factor 3 and the expression of a subset of lipopolysaccharide-inducible genes.

Bacterial lipopolysaccharide (LPS) triggers innate immune responses through Toll-like receptor (TLR) 4, a member of the TLR family that participates in pathogen recognition. TLRs recruit a cytoplasmic protein, MyD88, upon pathogen recognition, mediating its function for immune responses. Two major pathways for LPS have been suggested in recent studies, which are referred to as MyD88-dependent and -independent pathways. We report in this study the characterization of the MyD88-independent pathway via TLR4. MyD88-deficient cells failed to produce inflammatory cytokines in response to LPS, whereas they responded to LPS by activating IFN-regulatory factor 3 as well as inducing the genes containing IFN-stimulated regulatory elements such as IP-10. In contrast, a lipopeptide that activates TLR2 had no ability to activate IFN-regulatory factor 3. The MyD88-independent pathway was also activated in cells lacking both MyD88 and TNFR-associated factor 6. Thus, TLR4 signaling is composed of at least two distinct pathways, a MyD88-dependent pathway that is critical to the induction of inflammatory cytokines and a MyD88/TNFR-associated factor 6-independent pathway that regulates induction of IP-10.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Observation of a (6)(LambdaLambda)He double hypernucleus.

A double-hyperfragment event has been found in a hybrid-emulsion experiment. It is identified uniquely as the sequential decay of ( 6)(LambdaLambda)He emitted from a Xi(-) hyperon nuclear capture at rest. The mass of ( 6)(LambdaLambda)He and the Lambda-Lambda interaction energy DeltaB(LambdaLambda) have been measured for the first time devoid of the ambiguities due to the possibilities of excited states. The value of DeltaB(LambdaLambda) is 1.01+/-0.20(+0.18)(-0.11) MeV. This demonstrates that the Lambda-Lambda interaction is weakly attractive.

Journal Article↗
PubMed2001

Electrical conduction through poly(dA)-poly(dT) and poly(dG)-poly(dC) DNA molecules.

We report direct measurements of electrical transport through poly(dA)-poly(dT) and poly(dG)-poly(dC) DNA molecules containing identical base pairs. The observed experimental results suggest that electrical transport through DNA molecules occurs by polaron hopping. We have also investigated the effect of gate voltage on the current-voltage curve. It demonstrates the possibility of a DNA field-effect transistor operating at room temperature. Moreover, the gate-voltage dependent transport measurements show that poly(dA)-poly(dT) behaves as an n-type semiconductor, whereas poly(dG)-poly(dC) behaves as a p-type semiconductor.

DNA↗
PubMed2001

The membrane-type collectin CL-P1 is a scavenger receptor on vascular endothelial cells.

Collectins are a family of C-type lectins that have collagen-like sequences and carbohydrate recognition domains (CRD). They are involved in host defense through their ability to bind to carbohydrate antigens of microorganisms. The scavenger receptors type A and MARCO are classical type scavenger receptors that have internal collagen-like domains. Here we describe a new scavenger receptor that is a membrane-type collectin from placenta (collectin placenta 1 (CL-P1)), which has a typical collectin collagen-like domain and a CRD. The cDNA has an insert of about 2.2 kilobases coding for a protein containing 742 amino acid residues. The deduced amino acid sequence shows that CL-P1 is a type II membrane protein, has a coiled-coil region, a collagen-like domain, and a CRD. It resembles type A scavenger receptors because the scavenger receptor cysteine-rich domain is replaced by a CRD. Northern analyses, reverse transcription-polymerase chain reaction, and immunohistochemistry show that CL-P1 is expressed in vascular endothelial cells but not in macrophages. By immunoblotting and flow cytometry CL-P1 appears to be a membrane glycoprotein of about 140 kDa in human umbilical vein or arterial endothelial cells, placental membrane extracts, and CL-P1 transfected Chinese hamster ovary cells. We found that CL-P1 can bind and phagocytose not only bacteria (Escherichia coli and Staphylococcus aureus) but also yeast (Saccharomyces cerevisiae). Furthermore, it reacts with oxidized low density lipoprotein (OxLDL) but not with acetylated LDL (AcLDL). These binding activities are inhibited by polyanionic ligands (polyinosinic acid, polyguanylic acid, dextran sulfate) and OxLDL but not by polycationic ligands (polyadenylic acid or polycytidylic acid), LDL, or AcLDL. These results indicate that CL-P1 might play important roles in host defenses that are different from those of soluble collectins in innate immunity.

Amino Acid Sequence↗
PubMed2001

Long-term islet allograft function in the absence of chronic immunosuppression: a case report of a nonhuman primate previously made tolerant to a renal allograft from the same donor.

UNLABELLED: Development of mixed chimerism by donor bone marrow transplantation (DBMT) has led to long-term tolerance of solid organ allografts in nonhuman primates. As an initial attempt to extend this approach to cellular transplant, islet transplant from the same donor was attempted in the recipient previously made tolerant to a kidney allograft. METHODS: After the conditioning with ATG, total body irradiation, thymic irradiation, and splenectomy, DBMT was performed followed by 4 weeks of cyclosporine. Kidney transplantation and native nephrectomies were subsequently performed on day 89. After 2.8 years of DBMT, diabetes was induced by streptozocin (STZ) and islets from bone marrow and kidney donor were transplanted without immunosuppression. RESULTS: After DBMT, the recipient developed chimerism and no evidence of kidney rejection for more than 1000 days. STZ induced diabetes was reversed after the islet transplantation. Islet biopsies demonstrated insulin staining without rejection. Although the recipient became diabetic 300 days after islet transplantation, viable transplanted islets were found in the liver and under the kidney capsule without any evidence of rejection. CONCLUSION: Tolerance with a nonmyeloablative conditioning can allow successful pancreatic islet transplantation without immunosuppression. Because no histological evidence of rejection was identified, recurrent diabetes is presumed to be inadequate islet mass.

ABO Blood-Group System↗
PubMed2001

Endotoxin-induced maturation of MyD88-deficient dendritic cells.

LPS, a major component of the cell wall of Gram-negative bacteria, can induce a variety of biological responses including cytokine production from macrophages, B cell proliferation, and endotoxin shock. All of them were completely abolished in MyD88-deficient mice, indicating the essential role of MyD88 in LPS signaling. However, MyD88-deficient cells still show activation of NF-kappaB and mitogen-activated protein kinase cascades, although the biological significance of this activation is not clear. In this study, we have examined the effects of LPS on dendritic cells (DCs) from wild-type and several mutant mice. LPS-induced cytokine production from DCs was dependent on MyD88. However, LPS could induce functional maturation of MyD88-deficient DCs, including up-regulation of costimulatory molecules and enhancement of APC activity. MyD88-deficient DCs could not mature in response to bacterial DNA, the ligand for Toll-like receptor (TLR)9, indicating that MyD88 is differentially required for TLR family signaling. MyD88-dependent and -independent pathways originate at the intracytoplasmic region of TLR4, because both cytokine induction and functional maturation were abolished in DCs from C3H/HeJ mice carrying the point mutation in the region. Finally, in vivo analysis revealed that MyD88-, but not TLR4-, deficient splenic CD11c(+) DCs could up-regulate their costimulatory molecule expression in response to LPS. Collectively, the present study provides the first evidence that the MyD88-independent pathway downstream of TLR4 can lead to functional DC maturation, which is critical for a link between innate and adaptive immunity.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Physicochemical and immunological characterization of hepatitis B virus envelope particles exclusively consisting of the entire L (pre-S1 + pre-S2 + S) protein.

The hepatitis B virus (HBV) envelope (env) protein is composed of three regions; the 108- or 119-residue pre-S1 region involved in the direct interaction with hepatocytes, the 55-residue pre-S2 region associated with the polymerized albumin-mediated interaction, and the major 226-residue S protein region. Thus, to improve the immunogenic potency of conventional HB vaccines, development of a new vaccine containing the entire pre-S1 region in addition to pre-S2 and S is desired. We previously reported the efficient production of the HBV env L (pre-S1 + pre-S2 + S) protein in the recombinant yeast cells [J Biol Chem 267 (1992) 1953]. In this study, the HBV env L protein produced as nano-particles in yeast has been purified and characterized. By equilibrium sedimentation, an average molecular weight of L particle was estimated to be approximately 6.4 x 10(6), indicating that about 110 molecules of L proteins are assembled into an L particle. By atomic force microscopy in a moist atmosphere, the L particles were observed as large spherical particles with a diameter of 50-500 nm. The L particles were stable on short-time heating at a high temperature and long-time storage at a low temperature but rather unstable on repeated freezing and thawing and treatment with dithiothreitol. When immunized in mice, L particles elicited efficiently and simultaneously the anti-S, anti-pre-S2, and anti-pre-S1 antibodies. The ED(50) values in mice for the anti-S and anti-pre-S2 antibodies were similar to those elicited by the M (pre-S2 + S) particles. Furthermore, the anti-pre-S1 rabbit antibodies were found to recognize various segments of the pre-S1 region, including the pre-S1 (21-47) segment. These results show the high ability of L particles to induce all antibodies against HBV env proteins, hence promising the future application of L particles for the next generation HB vaccine.

Animals↗
PubMed2001

Orbit-related long-term climate cycles revealed in a 12-Myr continental record from Lake Baikal.

Quaternary records of climate change from terrestrial sources, such as lake sediments and aeolian sediments, in general agree well with marine records. But continuous records that cover more than the past one million years were essentially unavailable until recently, when the high-sedimentation-rate site of Lake Baikal was exploited. Because of its location in the middle latitudes, Lake Baikal is highly sensitive to insolation changes and the entire lake remained uncovered by ice sheets throughout the Pleistocene epoch, making it a valuable archive for past climate. Here we examine long sediment cores from Lake Baikal that cover the past 12 million years. Our record reveals a gradual cooling of the Asian continental interior, with some fluctuations. Spectral analyses reveal periods of about 400 kyr, 600 kyr and 1,000 kyr, which may correspond to Milankovitch periods (reflecting orbital cycles). Our results indicate that changes in insolation were closely related to long-term environmental variations in the deep continental interior, over the past 12 million years.

Journal Article↗
PubMed2001

Iodine L-edge XAFS study of linear polyiodide chains in amylose and alpha-cyclodextrin.

We performed iodine L edge XAFS measurements on blue-black amylose-iodine complex to obtain information about the electronic and geometrical structures of polyiodide chain included in amylose helix. Measurements were also carried out on crystalline alpha-cyclodextrin-iodine complex (alpha-cyclodextrin)2 x Cd0.5 x I5 x 27H2O, in which the polyiodide chain is known to consist of I(5)- unit. It was found that the XANES spectra of these complexes have similar line shapes except for some minor differences, indicating that there are close similarities in the nature of polyiodide chains in these complexes. Besides their similarity, difference in the intensity of the peak at the L1 absorption edge was observed. Its implication for the electronic and geometrical structures is also discussed.

Journal Article↗
PubMed2001

EXAFS analysis of the zinc-binding domain of boar spermatidal transition protein 2.

Boar Spermatidal Transition Protein 2 (TP2; 137 amino acid residues) is supposed to play an important role in initiation of chromatin condensation and cessation of transcriptional activity during mammalian spermniogenesis. Boar TP2 has three potential zinc finger motifs and binds three atoms of zinc per molecule. However the structure of the zinc-binding domain of boar TP2 has not been completely determined. To elucidate the local structure around the zinc atoms of boar TP2, we performed an X-ray absorption fine structure (XAFS) measurement on the zinc-binding domain of TP2(TP2Z)(residues 1-103) in the fluorescence mode. By EXAFS analyses we have demonstrated that each of the three zinc atoms is coordinated by approximately two sulfur and two nitrogen atoms on average. The average Zn-S and Zn-N distances were found to be 2.36 and 2.01 A, respectively. The sulfur and nitrogen atoms are attributed to cysteine and histidine residues, respectively, from comparison of the EXAFS spectra with model compounds ZnS and ZnTPP zinc(II) tetraphenylporphyrin).

Amino Acid Sequence↗
PubMed2001

IkappaB kinase alpha is essential for mature B cell development and function.

IkappaB kinase (IKK) alpha and beta phosphorylate IkappaB proteins and activate the transcription factor, nuclear factor (NF)-kappaB. Although both are highly homologous kinases, gene targeting experiments revealed their differential roles in vivo. IKKalpha is involved in skin and limb morphogenesis, whereas IKKbeta is essential for cytokine signaling. To elucidate in vivo roles of IKKalpha in hematopoietic cells, we have generated bone marrow chimeras by transferring control and IKKalpha-deficient fetal liver cells. The mature B cell population was decreased in IKKalpha(-/-) chimeras. IKKalpha(-/-) chimeras also exhibited a decrease of serum immunoglobulin basal level and impaired antigen-specific immune responses. Histologically, they also manifested marked disruption of germinal center formation and splenic microarchitectures that depend on mature B cells. IKKalpha(-/-) B cells not only showed impairment of survival and mitogenic responses in vitro, accompanied by decreased, although inducible, NF-kappaB activity, but also increased turnover rate in vivo. In addition, transgene expression of bcl-2 could only partially rescue impaired B cell development in IKKalpha(-/-) chimeras. Taken together, these results demonstrate that IKKalpha is critically involved in the prevention of cell death and functional development of mature B cells.

Animals↗
PubMed2001

Ionic Strength Effects of Electrolytes on Solubilized States of Water in AOT Reversed Micelles.

The limiting amounts of solubilized aqueous NaCl, NaNO(3), MgCl(2), and AlCl(3) in sodium 1,2-bis-(2-ethylhexyloxycarbonyl)-1-ethanesulfonate (aerosol OT)/isooctane solutions have been measured as a function of the ionic strength of the electrolytes. In any system, the limiting amounts increased up to the optimal ionic strength (Io(opt)), and afterward, as ionic strength increased, they decreased and were followed by a constant. These increased and decreased curves of water solubilization below and above Io(opt), called, respectively, salting-in and salting-out curves, could be interpreted, respectively, from the counteracting effects of attractive intermicellar interaction and interfacial bending stress. The effects of electrolytes on the solubilized states of water by micelles were examined using NMR and near-infrared spectroscopic techniques. Consequently, two types of waters, i.e., water bound directly to the ionic head groups of the surfactant in reversed micelles and water interacting with the hydrated head groups in swollen micelles through hydrogen bonds, were almost unaffected by any electrolytes, whereas much greater effects were observed for bulklike water in W/O microemulsions. The order of the degree of lowering of salting-out curves in W/O microemulsion regions in each system was found to agree with the Hofmeister series. Copyright 2001 Academic Press.

Journal Article↗
PubMed2001

Increased sensitivity to thyroid hormone in mice with complete deficiency of thyroid hormone receptor alpha.

Only three of the four thyroid hormone receptor (TR) isoforms, alpha1, beta1, and beta2, bind thyroid hormone (TH) and are considered to be true TRs. TRalpha2 binds to TH response elements on DNA, but its role in vivo is still unknown. We produced mice completely deficient in TRalpha (TRalpha(o/o)) that maintain normal serum thyroid-stimulating hormone (TSH) concentration despite low serum thyroxine (T(4)), suggesting increased sensitivity to TH. We therefore examined the effects of TH (L-3,3',5-triiodothyronine, L-T3) given to TH-deprived and to intact TRalpha(o/o) mice. Controls were wild-type (WT) mice of the same strain and mice resistant to TH due to deficiency in TRbeta (TRbeta(-/-)). In liver, T3 produced significantly greater responses in TRalpha(o/o) and smaller responses in TRbeta(-/-) as compared with WT mice. In contrast, cardiac responses to L-T3 were absent or reduced in TRalpha(o/o), whereas they were similar in WT and TRbeta(-/-) mice, supporting the notion that TRalpha1 is the dominant TH-dependent TR isoform in heart. 5-Triiodothyronine (L-T3) given to intact mice produced a greater suppression of serum T(4) in TRalpha(o/o) than it did in WT mice and reduced by a greater amount the TSH response to TSH-releasing hormone. This is an in vivo demonstration that a TR deficiency can enhance sensitivity to TH. This effect is likely due to the abrogation of the constitutive "silencing" effect of TRalpha2 in tissues expressing the TRbeta isoforms.

Animals↗
PubMed2001

Development of control serum for microbial antibody tests.

Control sera are an essential component of in-vitro clinical diagnostic reagents. We have developed a control serum for HBsAg, anti-HCV, anti-HIV and anti- Treponema pallidum testing. Since this control serum is prepared from human plasma, we paid special attention to viral safety. We incorporated three viral inactivation methods into the manufacturing process that maintain the necessary characteristics of a stable control serum.

Antibodies, Bacterial↗
PubMed2001

Effects of low-level occupational exposure to styrene on color vision: dose relation with a urinary metabolite.

To investigate the threshold effects of chronic low-level occupational exposure to styrene on color vision, we examined color discrimination in 105 male workers exposed to styrene (mean age 37.7 years; mean length of exposure 6.2 years; mean urinary concentration of mandelic acid 0.21 g/L) and in 117 referents (mean age 37.7 years). We also assessed the effects of styrene by examination of the nature of the relation between disorders of nervous function and age, alcohol consumption, and other variables. A standardized questionnaire was adopted to collect information about work history, occupational or nonoccupational solvent exposure, alcohol consumption, and drug use. Color vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the color confusion index (CCI). There was a dose-dependent relationship between the urinary concentration of mandelic acid and color vision loss. The CCIs of the subgroups whose urinary mandelic acid levels were 0.1-0.2 and >0.2 g/L were significantly higher than those of each referent group (P<0.05 and P<0.01, respectively), but not in the subgroup whose urinary mandelic acid level was lower than 0.1 g/L. Our study suggests that a low level of styrene, presumably 0.1-0.2 g/L, involves the risk of inducing adverse effects on color vision. After confounding factors were adjusted for, the urinary mandelic acid level had a significant positive relationship with color vision.

Adult↗