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Biomedical subjects

S Kawabata

Publications and source records attributed to S Kawabata.

At least 73 records · Page 4Linked to original sources
PubMed1999

Human interleukin-12 enhances interferon-gamma-producing influenza-specific memory CD8+ cytotoxic T lymphocytes.

Interferon (IFN)-gamma synthesis of CD45RO+ (memory) and CD45RA+ (naive) CD8+ cytotoxic T lymphocytes (CTLs) and the role of interleukin (IL)-12 in the regulation of human CTL functions in virus-specific immunity were investigated. After culture with influenza virus, CD45RO+ CD8+ T cells from human peripheral blood mononuclear cells increased in frequency and exhibited significant major histocompatibility complex class I-mediated CTL activity, whereas CD45RA+ CD8+ T cells did not. Influenza virus-stimulated CD45RO+ CD8+ T cells contained significantly higher levels of IFN-gamma-producing cells and IFN-gamma-specific mRNA than did CD45RA+ CD8+ T cells. Recombinant human IL-12 further enhanced CTL activity and IFN-gamma production by CD45RO+ CD8+ T cells. These data clearly show that human virus-specific CTL activity and coproduction of IFN-gamma are associated with the CD45RO+ CD8+ T cells that are modulated by the cell-mediated, immunity-inducible cytokine IL-12 in humans.

Adult↗
PubMed1999

Cloning, sequencing, and functional expression in Escherichia coli of chaperonin (groESL) genes from Vibrio cholerae.

Using a series of oligonucleotides synthesized on the basis of conserved nucleotide motifs in heat-shock genes, the groESL heat-shock operon from a Vibrio cholerae TSI-4 strain has been cloned and sequenced, revealing that the presence of two open reading frames (ORFs) of 291 nucleotides and 1,632 nucleotides separated by 54 nucleotides. The first ORF encoded a polypeptide of 97 amino acids, GroES homologue, and the second ORF encoded a polypeptide of 544 amino acids, GroEL homologue. A comparison of the deduced amino acid sequences revealed that the primary structures of the V. cholerae GroES and GroEL proteins showed significant homology with those of the GroES and GroEL proteins of other bacteria. Complementation experiments were performed using Escherichia coli groE mutants which have the temperature-sensitive growth phenotype. The results showed that the groES and groEL from V. cholerae were expressed in E. coli, and groE mutants harboring V. cholerae groESL genes regained growth ability at high temperature. The evolutionary analysis indicates a closer relationship between V. cholerae chaperonins and those of the Haemophilus and Yersinia species.

Amino Acid Sequence↗
PubMed1999

Targeted salivary gland immunization with plasmid DNA elicits specific salivary immunoglobulin A and G antibodies and serum immunoglobulin G antibodies in mice.

For the development of vaccines against oral and pharyngeal pathogens invading the mucosal epithelia, both secretory and serum immunoglobulin A (IgA) and IgG antibodies and cytotoxic T lymphocytes (CTL) have been induced. We used a novel approach, targeted salivary gland (TSG) immunization, using plasmid pcDNA3/fimA, coding for Porphyromonas gingivalis fimbriae. Expression of subunit protein, fimbrillin, was observed in eukaryotic cells growing in vitro following transfection with pcDNA3/fimA. In this study, we obtained good humoral and cell-mediated immune responses in BALB/c mice by TSG administration using the above-mentioned DNA vaccine. The production of fimbria-specific IgA and IgG antibodies in saliva and serum IgG antibody was significantly stimulated by TSG immunization. Injection of DNA vaccine into salivary gland elicited high-level production of antigen-specific IgG antibody, similar to that induced following intramuscular immunization. The major IgG subclass that recognized fimbriae was IgG2a in serum from pcDNA3/fimA-immunized mice. Reverse transcription-PCR analysis of mononuclear cells from salivary glands showed that levels of Th2 cytokine-specific mRNA were higher in the immunized group than in the nonimmunized group. In addition, TSG DNA immunization resulted in the generation of antigen-specific CTL in spleen. These results indicate that TSG immunization with plasmid DNA may represent a genetic immunization strategy against infection by oral and pharyngeal pathogens that may invade local, mucosal surfaces.

Animals↗
PubMed1999

Molecular interactions of Porphyromonas gingivalis fimbriae with host proteins: kinetic analyses based on surface plasmon resonance.

Fimbriae of Porphyromonas gingivalis are thought to play an important role in the colonization and invasion of periodontal tissues. In this study, we analyzed the interactions of P. gingivalis fimbriae with human hemoglobin, fibrinogen, and salivary components (i.e., proline-rich protein [PRP], proline-rich glycoprotein [PRG], and statherin) based on surface plasmon resonance (SPR) spectroscopy with a biomolecular interaction analyzing system (BIAcore). The real-time observation showed that the fimbriae interacted more quickly with hemoglobin and PRG than with other proteins and more intensely with fibrinogen. The significant association constant (ka) values obtained by BIAcore demonstrated that the interactions between fimbriae and these host proteins are specific. These estimated Ka values were not too different; however, the Ka values for hemoglobin (2.43 x 10(6)) and fibrinogen (2.16 x 10(6)) were statistically greater than those for the salivary proteins (1.48 x 10(6) to 1.63 x 10(6)). The Ka value of anti-fimbriae immunoglobulin G for fimbriae was estimated to be 1. 22 x 10(7), which was 6.55-fold higher than the mean Ka value of the host proteins. Peptide PRP-C, a potent inhibitor of PRP-fimbriae interaction, dramatically inhibited fimbrial association to PRP and PRG and was also inhibitory against other host proteins by BIAcore. The binding of fimbriae to these proteins was also evaluated by other methods with hydroxyapatite beads or polystyrene microtiter plates. The estimated binding abilities differed considerably, depending on the assay method that was used. It was noted that the binding capacity of PRP was strongly diminished by immobilization on a polystyrene surface. Taken together, these findings suggest that P. gingivalis fimbriae possess a strong ability to interact with the host proteins which promote bacterial adherence to the oral cavity and that SPR spectroscopy is a useful method for analyzing specific protein-fimbriae interactions.

Amino Acid Sequence↗
PubMed1999

Secretion of functional salivary peptide by Streptococcus gordonii which inhibits fimbria-mediated adhesion of Porphyromonas gingivalis.

Porphyromonas gingivalis, a putative periodontopathogen, can bind to human salivary components with its fimbriae. We have previously shown that fimbriae specifically bind to a peptide domain shared by a major salivary component, i.e., proline-rich (glyco)proteins (PRPs). The synthetic domain peptide PRP-C (pPRP-C) significantly inhibits the fimbrial binding to PRPs. In this study, a recombinant strain of Streptococcus gordonii secreting pPRP-C was generated as a model of a possible approach to prevent the oral colonization by the pathogen. A duplicate DNA fragment (prpC) encoding pPRP-C was obtained by self-complementary annealing of synthetic oligonucleotides. prpC was connected downstream to a promoter and a gene encoding a signal peptide of Streptococcus downei glucosyltransferase I in frame. The linked fragments were inserted into the plasmid pMNK-4 derived from pVA838. The constructed plasmid was inserted to produce the transformant S. gordonii G9B, which then successfully secreted recombinant pPRP-C (r-pPRP-C) of the expected size. The concentrated bacterial culture supernatant containing r-pPRP-C inhibited the binding of P. gingivalis cells and fimbriae to PRP1 in a dose-dependent manner up to 72 and 77%, respectively. The r-pPRP-C concentrate also inhibited the coaggregation of P. gingivalis with various streptococcal strains as effectively as synthetic pPRP-C in a dose-dependent manner. Collectively, pPRP-C was found to be able to prevent P. gingivalis adherence to salivary receptor protein and plaque-forming bacteria. These results suggest that this recombination approach with a nonperiodontopathic bacterium may be suitable for the therapeutic prevention of P. gingivalis adherence to the oral cavity.

Bacterial Adhesion↗
PubMed1999

Inhibitory effects of protamines on proteolytic and adhesive activities of Porphyromonas gingivalis.

Protamines (salmine prepared from sperm DNA of salmon and clupeine from herring sperm), which are basic peptides rich in arginine, were found to inhibit the proteolytic activity of arginine-specific cysteine protease (RC-protease) from Porphyromonas gingivalis. Lineweaver-Burk plot analysis revealed that the protamines competitively inhibited proteolytic activity with cleavage of benzoyl-L-arginine-p-nitroanilide, a synthetic substrate of RC-protease. Furthermore, the protamines were capable of binding strongly to P. gingivalis fimbriae and inhibited fimbrial interaction with immobilized fibronectin. These results clearly show that protamines are potent inhibitors of the proteolytic and adhesive activities of P. gingivalis.

Adhesins, Bacterial↗
PubMed1999

[A case of neuro-Behcet's disease with transient cerebral ischemia evoked by smoking].

We present a 63-year-old male case of neuro-Behçet's disease with transient cerebral ischemia evoked by smoking. He first noticed genital ulcer after the operation of colon cancer, and then recurrent oral aphtha and skin erythema. From these symptoms and other laboratory data, we diagnosed him as suffering from Behçet's disease. He also showed dysbasia, dysarthria, pseudo-bulbar palsy, and changes in character, characteristic to neuro-Behçet's disease. After smoking, he showed disturbance of consciousness, dysequilibrium, and bilateral adynamia in upper and lower extremities, so we performed SPECT study. Compared with routine SPECT, less blood perfusion in frontal lobe, temporal lobe, and basal ganglia was observed after smoking. Mild vasculitis was observed in skin biopsy, but no such signs were observed in cerebral angiography. After steroid therapy, these symptoms evoked by smoking faded away. Previous studies reported that vasculitis is an important predisposing cause of vasospasm, and that smoking causes transient cerebral ischemia by vasospastic mechanisms. In this case, mild vasculitis was thought to be predisposed to vasospasm by smoking.

Behcet Syndrome↗
PubMed1999

[Simulation study on parent artery occlusion therapy for basilar head giant aneurysms: hemodynamic efficacy of additional bypass on enhancing aneurysmal thrombosis].

Parent artery occlusion therapy has been used as an alternative for directly untreatable basilar head giant aneurysms. However, some aneurysms still require additional technique to further induce intraaneurysmal stagnation and thrombosis. Using a hydraulic model, half-life of the dye in the model aneurysm was measured as an index of the intraaneurysmal stagnation. The ratio of diameters (D1, D2) of the two posterior communicating arteries (PCom) is defined as diameter ratio (DR) (D1/D2, D1 < D2). Occlusion therapy was simulated in 4 different sites. The most distal site was at the distal BA (Type A) and the most proximal site at the bilateral VA (Type D). The additional technique investigated was bypass placement to the P2 segment of the posterior cerebral artery (PCA) on the smaller PCom side. The half-life was 2.5 +/- 0.2 (mean +/- 2SD) sec before occlusion. Occlusion therapy significantly increased the half-life depending on the occlusion site and DR values with the maximum values of infinite in Type A and 25 sec in Type D. Placement of the bypass decreased the tangential flow volume to the aneurysmal neck, and increased the time markedly in Types A and B, considerably in Type C and slightly in Type D. Parent artery occlusion therapy has been considered less beneficial for patients with a diameter ratio of less than 0.70 since aneurysmal stagnation depends on the diameter ratio. Bypass placement additional to the occlusion therapy is very useful in enhancing the aneurysmal stagnation, which would make those patients indicated for the therapy.

Basilar Artery↗
PubMed1999

[Microsurgical results of paraclinoid aneurysms of the internal carotid artery: microsurgery versus intravascular surgery].

Since paraclinoid aneurysms exhibit considerable variations in the surrounding skull base structures, some skill and experience are considered essential for their microsurgical treatment. On the other hand, intravascular coil embolization would be free from these extravascular factors. Fifty-two aneurysms in 48 patients were treated microsurgically. They were divided into an early series treated before 1995 and a late series treated after 1996. Three aneurysms in 3 patients were treated by intravascular surgery. Preoperative neuroimages, topographic anatomy and surgical results were compared retrospectively. The results in the microsurgical late series were better than those in the early series. While 89% of the patients exhibited excellent results with two patients left with partial visual field defect (7%) and one death (3%) in the early series, the rates in the late series were 95%, 5% and 0%, respectively. Complications and failure in neck clipping were considered to be due to such topography as, 1) C3 aneurysms extending into the anterior clinoid process, 2) multiple aneurysms, 3) ophthalmic artery originating near the dome, 4) atheroma or calcification at the neck, 5) marked medical shift of C2 segment, and 6) tight adhesion of the dural ring to the dome. Coil embolization was successful in two aneurysms, while it was given up in one. We currently propose that intravascular surgery is indicated for cases 1), 4), 5) and 6), and microsurgery would be more advantageous for cases where the neck is broad and where the topography concerning aneurysmal multiplicity or the branching site of the ophthalmic artery is not fully understood by preoperative imaging.

Aneurysm↗
PubMed1999

Phase I study of irinotecan combined with carboplatin in previously untreated solid cancers.

Irinotecan (CPT-11) and carboplatin have broad anti-tumor activities. We conducted a Phase I study of CPT-11 combined with carboplatin in previously untreated solid cancers, especially advanced lung cancer. The aim of the study was to determine the maximum tolerated dose (MTD) and the dose-limiting toxicities in this regimen. In addition, we prospectively evaluated the Chatelut formula for predicting carboplatin clearance. Patients with advanced cancer were treated with CPT-11 (days 1, 8, and 15) and carboplatin (day 1) of a fixed-target area under the concentration-time curve (AUC) of 5 mg x min/ml. Carboplatin dose was determined by multiplying the AUC by the clearance predicted using the Chatelut formula. The CPT-11 dose was escalated from 40 mg/m2 to the MTD by 10 mg/m2. A total of 27 patients, 26 lung cancer patients and 1 colon cancer patient, were enrolled in this study. Dose-limiting leukoneutropenia, thrombocytopenia, and diarrhea, including one treatment-related death, were observed at 60 mg/m2 CPT-11, indicating that this level was the MTD. In 11 patients, the actual AUCs of carboplatin almost achieved the target AUC of 5. Fifteen (60%) of 25 evaluable patients showed an objective response, with an 85% response rate [11 of 13 patients (complete response, 31%; partial response, 54%)] in small cell lung cancers and a 36% response rate (4 of 11 patients) in non-small cell lung cancers. Neutropenia, thrombocytopenia, and diarrhea were the dose-limiting toxicities in this regimen. CPT-11 (50 mg/m2) under the carboplatin target AUC of 5 using the Chatelut formula was the recommended dose for further Phase II study, and this regimen seems to be active for small cell lung cancer.

Adult↗
PubMed1998

A leukotriene receptor antagonist, ONO-1078, modulates drug sensitivity and leukotriene C4 efflux in lung cancer cells expressing multidrug resistance protein.

ONO-1078 is a new class of peptide leukotriene receptor antagonist, and multidrug resistance protein (MRP) is a membrane tranporter of multiple anticancer drugs and endogenous leukotriene C4 (LTC4). We investigated the effects of ONO-1078 on drug sensitivity and LTC4-efflux in MRP-expressing lung cancer cells. Drug sensitivity, intracellular vincristine accumulation, and intracellular and extracellular LTC4 concentrations were measured with or without ONO-1078. The effect of ONO-1078 on MRP-mediated calcein-efflux was determined by flow cytometry. ONO-1078 (1 to 10 microM) dose-dependently enhanced the sensitivity of NCI-H520 cells to vincristine with the reduced accumulation, and also enhanced the sensitivity to doxorubicin and etoposide. ONO-1078 inhibited both LTC4- and calcein-efflux from the cells with increased intracellular accumulations. Our findings indicate that ONO-1078 modulates multidrug resistance and inhibits LTC4-efflux in lung cancer cells, by inhibition of MRP function.

ATP-Binding Cassette Transporters↗
PubMed1998

Evolution and phylogeny of defense molecules associated with innate immunity in horseshoe crab.

This short review describes the molecular evolution and phylogeny of various defense molecules participating in the host defense of horseshoe crab. It is well known that invertebrate animals, which lack adaptive immune systems, have developed various defense systems, so called innate immunity, that respond to common antigens on the surface of potential pathogens. The systems include hemolymph coagulation, melanization, cell agglutination, antimicrobial action, active oxygen formation, and phagocytic action. Among them, hemolymph coagulation and phenoloxidase-mediated melanization, in addition to cell agglutination, are directly induced by foreign substances, that result in the engulfment of invading microbes. The immobilized invaders are finally killed by antimicrobial substances released mainly from many kinds of hemocytes. In the past two decades, we have investigated biochemically various defense molecules, using horseshoe crab as a model animal, and established extensively their molecular structures. These results now make it possible to discuss evolution and phylogeny of the defense molecules at a molecular level, in comparison with those derived from vertebrate animals. Here, the authors will describe the present state of our knowledge concerning molecules mainly associated with innate immunity.

Amino Acid Sequence↗
PubMed1998

Diversity of calcium signaling by metabotropic glutamate receptors.

During prolonged application of glutamate (20 min), patterns of increase in intracellular Ca2+ concentration ([Ca2+]i) were studied in HEK-293 cells expressing metabotropic glutamate receptor, mGluR1alpha or mGluR5a. Stimulation of mGluR1alpha induced an increase in [Ca2+]i that consisted of an initial transient peak with a subsequent steady plateau or an oscillatory increase in [Ca2+]i. The transient phase was largely attributed to Ca2+ mobilization from the intracellular Ca2+ stores, but the sustained phase was solely due to Ca2+ influx through the mGluR1alpha receptor-operated Ca2+ channel. Prolonged stimulation of mGluR5a continuously induced [Ca2+]i oscillations through mobilization of Ca2+ from the intracellular Ca2+ stores. Studies on mutant receptors of mGluR1alpha and mGluR5a revealed that the coupling mechanism in the sustained phase of Ca2+ response is determined by oscillatory/non-oscillatory patterns of the initial Ca2+ response but not by the receptor identity. In mGluR1alpha-expressing cells, activation of protein kinase C selectively desensitized the pathway for intracellular Ca2+ mobilization, but the mGluR1alpha-operated Ca2+ channel remained active. In mGluR5a-expressing cells, phosphorylation of mGluR5a by protein kinase C, which accounts for the mechanism of mGluR5a-controlled [Ca2+]i oscillations, might prevent desensitization and result in constant oscillatory mobilization of Ca2+ from intracellular Ca2+ stores. Our results provide a novel concept in which oscillatory/non-oscillatory mobilizations of Ca2+ induce different coupling mechanisms during prolonged stimulation of mGluRs.

Calcium↗
PubMed1998

Molecular analyses of glucosyltransferase genes among strains of Streptococcus mutans.

Three glucosyltransferase (GTase) genes (gtfB, gtfC and gtfD) were cloned and sequenced from clinically isolated strains of Streptococcus mutans MT8148 (serotype c), MT4239 (c), MT4245 (e), MT4467 (e) and MT4251 (f), respectively. Comparison of the gtf genes revealed that interstrain difference of gtfB and gtfD was limited, while gtfC showed significant interstrain variations. Similar to gtfB and gtfD, gtfC possessed five direct repeats composed of homologous unit in the carboxyl-terminal portion. The repeating unit consisted of 63-65 amino acid residues and is responsible for glucan binding. The gtfC gene from S. mutans MT4245 lacked the fourth unit. Multiple alignment with the gtf sequence of strain GS-5 (c) revealed several changes in these gtf genes due to frameshift mutations. The peptides encoded by the gtfB, gtfC and gtfD genes of GS-5 were 1, 80, and 32 amino acid residues shorter than those of the test strains except strain MT4245.

Bacterial Proteins↗
PubMed1998

Two hevein homologs isolated from the seed of Pharbitis nil L. exhibit potent antifungal activity.

Two antifungal peptides (Pn-AMP1 and Pn-AMP2) have been purified to homogeneity from seeds of Pharbitis nil. The amino acid sequences of Pn-AMP1 (41 amino acid0 residues) and Pn-AMP2 (40 amino acid residues) were identical except that Pn-AMP1 has an additional serine residue at the carboxyl-terminus. The molecular masses of Pn-AMP1 and Pn-AMP2 were confirmed as 4299.7 and 4213.2 Da, respectively. Both the Pn-AMPs were highly basic (pI 12.02) and had characteristics of cysteine/glycine rich chitin-binding domain. Pn-AMPs exhibited potent antifungal activity against both chitin-containing and non-chitin-containing fungi in the cell wall. Concentrations required for 50% inhibition of fungal growth were ranged from 3 to 26 micrograms/ml for Pn-AMP1 and from 0.6 to 75 micrograms/ml for Pn-AMP2. The Pn-AMPs penetrated very rapidly into fungal hyphae and localized at septum and hyphal tips of fungi, which caused burst of hyphal tips. Burst of hyphae resulted in disruption of the fungal membrane and leakage of the cytoplasmic materials. To our knowledge, Pn-AMPs are the first hevein-like proteins that show similar fungicidal effects as thionins do.

Amino Acid Sequence↗
PubMed1998

Targeted lymph-node immunization with whole inactivated simian immunodeficiency virus (SIV) or envelope and core subunit antigen vaccines does not reliably protect rhesus macaques from vaginal challenge with SIVmac251.

OBJECTIVE: Sexual transmission of HIV is the most common route of HIV transmission throughout the world. To prevent sexually transmitted HIV infection, a vaccine is urgently needed. A previous report demonstrated the targeted immunization of the iliac lymph nodes with simian immunodeficiency virus (SIV) subunits protects rhesus macaques from rectal challenge with SIV. We sought to determine whether this immunization strategy could protect rhesus macaques from vaginal challenge with SIV. DESIGN: Macaques were immunized with either whole-killed SIV or envelope and core subunit antigen vaccines. Using three independent groups, with three macaques in each group, macaques were immunized by the targeted iliac lymph-node (TILN) route, injecting the vaccine close to the iliac lymph nodes that drain the genital tract. RESULTS: The TILN immunization procedure induced high-titer SIV-specific immunoglobulin (Ig) G antibodies in serum in all animals and anti-SIV IgG and IgA antibodies in the cervicovaginal secretions of most animals. After a series of three or four TILN immunizations, the animals were intravaginally challenged with SIVmac251. All animals became virus isolation-positive, except one animal immunized with SIV p27 and gp120. This animal was virus isolation-negative but SIV DNA proviral sequences were detected in peripheral blood mononuclear cells. CONCLUSIONS: In this series of studies, reliable protection from vaginal transmission of SIV was not achieved by the TILN immunization procedure.

Animals↗
PubMed1998

Diagnostic potential and pitfalls of ultrasound-guided fine-needle aspiration cytology for breast lesions.

Ultrasound (US)-guided fine-needle aspiration cytology (FNAC) is now widely accepted as a diagnostic procedure for breast lesions. Along with its advantages, US-guided FNAC also has some pitfalls. The recognition of these pitfalls for this procedure is extremely important for the strict management of the disease. We retrospectively investigated the diagnostic potential and pitfalls of US-guided FNAC in the diagnosis of breast lesions. This study consisted of 348 aspirated samples from 274 breast tumors. The rate of sufficient aspirates was 74% after a single aspiration, while sufficient materials were finally obtained from 93% of the tumors by repeated aspirations. The rate was lower in tumors measuring less than 10 mm in diameter (62%), and in sclerosing adenosis (25%). The sensitivity of FNAC was 65%, the specificity was 75%, the border diagnosis rate was 18%, and the positive predictive value was 92%. The false-negative rate was higher in noninvasive carcinoma (45%). The border diagnosis rate was also higher in scirrhous carcinoma (29%). There were also five false-positive cases. Limited to nonpalpable lesions, the sufficient aspirates rate was 70% and the accuracy was 67%.

Adenocarcinoma, Scirrhous↗