Biomedical subjects

S Hayakawa

Publications and source records attributed to S Hayakawa.

At least 37 records · Page 2Linked to original sources

PubMed2001

Characterization of NKT cells in human peripheral blood and decidual lymphocytes.

PROBLEM: To examine whether natural killer (NKT) cells are present in human pregnancy decidua. METHOD OF STUDY: We calculated the percentage of CD3+CD161+Valpha 24+-NKT cells in peripheral blood and early pregnancy decidua, and analyzed intracellular cytokines, interleukin (IL)-4 and interferon (IFN)gamma in NKT cells using flow cytometry. RESULTS: A distinct subset of CD3+ CD161+ lymphocytes expressing an invariant antigen receptor encoded by the Valpha24 and Vbeta11 segment was accumulated in the decidua. In pregnant subjects the percentages of NKT cells were significantly increased in the decidua compared with peripheral blood. Both NKT cells in the decidua and the peripheral blood had an ability to rapidly produce cytokine associated with Th1 (IFNgamma) and Th2 (IL-4). Interestingly, the percentages of IL-4 and IFNgamma producing NKT cells were significantly higher in the decidua compared with the peripheral blood. CONCLUSIONS: These findings suggest that NKT cells might control the Th1/Th2 balance by producing IL-4 and IFNgamma at the feto-maternal interface.

Adult↗

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

Sequential comparison of peptides containing half-cystine residues from ovalbumins of six avian species.

Hen ovalbumin contains one cystine disulfide (Cys73-Cys120) and four cysteine sulfhydryl groups (Cys11, Cys30, Cys367, and Cys382) in a single polypeptide chain of 385 amino acid residues. To investigate whether or not such a structure is shared by related avian species, the contents of disulfide-involved half-cystine residues and their positions in the primary structure of ovalbumins from five species were compared with those of hen ovalbumin. Ovalbumins were alkylated with a fluorescent dye, IAEDANS, under disulfide-reduced and disulfide-intact conditions and digested with a number of proteolytic enzymes. The sequences were deduced from peptides containing half-cystine residues labeled with the fluorescent dye. The results showed that the number of free cysteine sulfhydryl groups of ovalbumins was different among the species, three for guinea fowl and turkey (Cys11, Cys367, and Cys382); and two for Pekin duck, mallard duck, and Emden goose (Cys11 and Cys331). On the other hand, a single intrachain disulfide bond could be identified from ovalbumins of five species using a combination of peptide mapping and N-terminal amino acid sequencing analysis under reduced and non-reduced conditions, in which the intrachain disulfide bond was like that of hen ovalbumin (Cys73-Cys120). The results also indicated that the variations in amino acid sequences on these peptides containing half-cystine residues bear a close relationship with the phylogeny of the six species.

Amino Acid Sequence↗

PubMed2001

Apoptosis-inducing activity of high molecular weight fractions of tea extracts.

High molecular weight fractions of green tea, black tea, oolong tea, and pu-erh tea were found to induce apoptosis in human monoblastic leukemia U937 cells by examination of their ability to inhibit cell proliferation and to induce apoptotic body formation and DNA ladder formation. These tea fractions were also shown to induce apoptosis in stomach cancer MKN-45 cells. In addition to known antitumor-promoting activity of tea high molecular weight fractions, their apoptosis-inducing activity may contribute to cancer chemopreventive effects of tea.

Apoptosis↗

PubMed2001

[Long-term outcome after extracorporeal shock wave lithotripsy for gallstones].

We retrospectively reviewed 289 cases followed for a long time after extracorporeal shock wave lithotripy (ESWL) for gallstones. Follow-up periods ranged from 0.5 years to 9.2 years, with a median of 4.1 years. The complete resolution rate was 45.6%. A solitary gallstone, non-calcified gallstones on CT, and Tsuchiya's sonographic type Ia and Ib gallstones were found to be statistically significant variable for resolution of the disease. With a maximum follow-up period of 9 years, the cumulative recurrence rate was 30.7%. Among the 156 patients whose gallstones did not resolve, 70 were symptomatic and the other 86 were asymptomatic. Thirty-eight of the symptomatic patients (54.3%) became symptom-free, while 23 asymptomatic patients (29.1%) became symptomatic. The cumulative rate of occurrence of colic attacks and/or acute cholecystitis was significantly higher in the cases with lithotripsy fragments 4 mm or more in size than in the cases wih fragments 3 mm or less in size (51.8% vs. 16.7%; p < 0.05). ESWL was followed by surgery in 23.1% because symptoms developed or became aggravated after ESWL in 58.3% of them. Gallbladder cancer was discovered in one case. Patients undergoing ESWL should be followed by focusing on postoperative recurrence, symptoms, and gallbladder cancer.

Adult↗

PubMed2000

Diphenyleneiodonium prevents reactive oxygen species generation, tyrosine phosphorylation, and histamine release in RBL-2H3 mast cells.

Mast cells play a central role in immediate allergic reactions mediated by immunoglobulin E. It has recently been reported that mast cells generate intracellular reactive oxygen species (ROS) in response to stimulation with divergent physiologically relevant stimulants. However, the physiological role of ROS is poorly understood. Here we demonstrate that mast cell model rat basophilic leukemia (RBL-2H3) cells generate ROS in response to antigen and the calcium-ionophore A23187 via activation of diphenyleneiodonuim (DPI)-sensitive enzyme and that blockade of ROS generation by DPI suppresses histamine release induced by either stimulant. Increased tyrosine phosphorylation of pp125(FAK) and a 77-kDa protein coprecipitating specifically with the kinase occurred in parallel with the secretion, and blockade of ROS generation by DPI also suppressed the tyrosine phosphorylation of both proteins. These findings suggest that ROS generated by a flavoenzyme-dependent mechanism may be involved in histamine release through the pp125(FAK) pathway.

Animals↗

PubMed2000

Epigallocatechin gallate inhibits histamine release from rat basophilic leukemia (RBL-2H3) cells: role of tyrosine phosphorylation pathway.

Some tea polyphenolic compounds including (-)-epigallocatechin gallate (EGCG) have been shown to inhibit histamine release from mast cells through poorly understood mechanisms. By using a mast cell model rat basophilic leukemia (RBL-2H3) cells we explored the mechanism of the inhibition. EGCG inhibited histamine release from RBL-2H3 cells in response to antigen or the calcium-ionophore A23187, while (-)-epicatechin (EC) had little effect. Increased tyrosine phosphorylation of several proteins including approximately 120 kDa proteins occurred in parallel with the secretion induced by either stimulation. EGCG also inhibited tyrosine phosphorylation of the approximately 120-kDa proteins induced by either stimulation, whereas EC did not. The tyrosine kinase-specific inhibitor piceatannol inhibited the secretion and tyrosine phosphorylation of these proteins induced by either stimulation also. Further analysis showed that the focal adhesion kinase pp125(FAK) was one of the approximately 120-kDa proteins. These findings suggest that EGCG prevents histamine release from mast cells mainly by inhibiting tyrosine phosphorylation of proteins including pp125(FAK).

Animals↗

PubMed2000

Improvement of bioactivity of H(2)O(2)/TaCl(5)-treated titanium after subsequent heat treatments.

Commercially pure titanium was treated with a H(2) O(2)/3mM TaCl(5) solution at 80 degrees C for various periods and a titania gel layer was formed on the surface. This gel remained amorphous when heating for 1 h below 200 degrees C and transformed to anatase after heating between 300 degrees and 600 degrees C. The anatase titania gel layers were found to be bioactive as to deposit carbonate ion-incorporated apatite within 1 day of immersion in the Kokubo solution, whereas the amorphous layers did not deposit apatite within 7 days. The apatite particles were found to nucleate preferentially inside the cracks prevailing in the thicker gel layers of 1-h chemically treated specimens. After immersing for 2 days, the titanium specimens were almost completely covered by apatite. Elimination of peroxide radicals from the titania gel and formation of anatase upon subsequent heating are considered to be responsible for the enhanced ability of apatite deposition.

Apatites↗

PubMed2000

Tea catechins and related polyphenols as anti-cancer agents.

Epigallocatechin gallate (EGCg) and theaflavins, a major constituent of green tea infusion and the constituents of black tea, respectively, were found to inhibit matrix metalloproteinases (MMPs) which are intimately associated with tumor invasion and metastasis. EGCg and related polyphenols exhibited apoptosis-inducing activity for several cancer cell lines including human stomach and colon cancer cells. Comparison of the activity of these compounds revealed the importance of the number and the steric disposition of hydroxyl groups. A pyrogallol-type structure in a molecule is a minimum requirement for apoptosis induction of catechin compounds and that in the B ring has an important role in the activity. These data would provide useful information for designing anti-cancer agents on the basis of anti-inhibitory activity for MMPs and/or apoptosis-inducing activity.

Anticarcinogenic Agents↗

PubMed2000

Transpapillary biopsy in gallbladder disease.

BACKGROUND: Endoscopic biopsy is routine in gastrointestinal disease; similarly, histopathologic diagnosis is desirable in gallbladder disease. In this study we examined the clinical usefulness and the problems associated with transpapillary gallbladder biopsy. METHODS: Transpapillary gallbladder biopsy was attempted in 9 patients with gallbladder disease. After inserting a catheter sheath into the gallbladder using a guidewire via the transpapillary route without sphincterotomy, we inserted a biopsy forceps into the lumen of the sheath up to the gallbladder lumen and obtained specimens. RESULTS: We could obtain sufficient specimens for histopathologic diagnosis in 8 of 9 cases (88.9%). Of the 8 successful cases, targeted specimens were obtained in 7 (87.5%). Diagnostic accuracy with respect to malignant versus benign disease was 100% (2 of 2) and 83.3% (5 of 6), respectively. There were no complications. CONCLUSION: Transpapillary gallbladder biopsy is a clinically useful technique because it facilitates histopathologic diagnosis and therefore guides the choice of therapy.

Biopsy↗

PubMed2000

Importance of a pyrogallol-type structure in catechin compounds for apoptosis-inducing activity.

Several catechin compounds were examined for their ability to induce apoptosis in human histiocytic lymphoma U937 cells. Catechins with a pyrogallol-type structure in a B-ring induced apoptosis and a 3-O-gallate group in cis-relationship to the B ring enhanced the activity. Catechins without a pyrogallol-type structure in a molecule lacked activity. These data suggest the important role of the 5'(3')-hydroxyl group in the B-ring and that a pyrogallol-type structure in a molecule is a minimum requirement for apoptosis induction by catechin compounds.

Apoptosis↗

PubMed2000

Murine fetal resorption and experimental pre-eclampsia are induced by both excessive Th1 and Th2 activation.

It has been proposed that immune responses in mammalian normal pregnancy are Th2-like, thereby protecting the fetus and placenta from being rejected. Administration of exogenous Th1 cytokines into pregnant mice is reported to induce feto-placental resorption. However, the effects of exogenous Th2 cytokines and Th2 directed responses in pregnant animals have not been well studied. In this study, we examined IL-4 and IL-12, which play decisive roles in the development of Th2 and Th1 responses, respectively, in the induction of fetal resorption and development of experimental pre-eclampsia. Transfer of either IL-4 and/or IL-12 stimulated splenocytes from BALB/C virgin female mice into BALB/C pregnant mice mated with either C57BL/6 or BALB/C male mice resulted in fetal resorption and glomerular nephritis associated with hypertension and proteinuria. In mice treated with IL-12 stimulated splenocytes, fatty liver degeneration associated with bile retention was observed. These results indicate that both excessive Th1 and Th2 activation contribute to the development of fetal resorption and pre-eclampsia, but that Th1 is critical to the development of liver degeneration.

Adoptive Transfer↗

PubMed2000

Immunochemical and structural analysis of pepsin-digested egg white ovomucoid.

Ovomucoid, an egg protein comprising approximately 10% egg white, was digested using the enzyme pepsin, and fragments were isolated by anion-exchange and reverse phase HPLC. Four distinct fragments were identified by analysis with SDS-PAGE, including three large fragments with molecular weights of around 24, 18, and 14 kDa. N- and C-terminal and amino acid sequencing analyses identified the fragments as V134-C186 (domain 3), V21-A133, and A1-A133 (domain 1+2). Further separation and sequencing of the fraction composed of small peptides, to determine their exact makeup and location in the protein, remained to be carried out and identified a peptide G51-Y73. All four fragments showed IgE-binding activity, as measured by ELISA, using human sera from egg-allergic individuals. Little change in the digestibility of ovomucoid by trypsin and chymotrypsin was observed following digestion with pepsin, indicating that pepsin-digested ovomucoid retains its trypsin (protease) inhibitor activities. Reduced carboxymethylated ovomucoid was prepared, and digestion with pepsin produced significantly more peptides than did the digestion of the native ovomucoid, indicating that the disulfide bonds play a significant role in the digestive resistance of ovomucoid. The reduction of ovomucoid enhanced its digestibility and lower allergenicity of the protein.

Digestion↗

PubMed2000

Possible involvement of endothelium-derived hyperpolarizing factor (EDHF) in the depressor responses to platelet activating factor (PAF) in rats.

1. In anaesthetized rats, platelet activating factor (PAF; 1 microg kg(-1)) decreased mean arterial blood pressure by around 60 mmHg (n=18). This depressor response was completely blocked by the PAF antagonist, CV-6209 (1 mg kg(-1)), indicating the role of PAF-specific receptor in the response. 2. N(G)-nitro-L-arginine methyl ester (L-NAME; 50 mg kg(-1)), an NO synthase inhibitor, profoundly elevated systemic blood pressure (n=19), indicating an important role of NO in the basal blood pressure regulation. The depressor response to PAF (1 microg kg(-1)) normalized against that to sodium nitroprusside (SNP) (10 microg kg(-1)) was not substantially different between rats treated without and with L-NAME (n=4). In contrast, the depressor effect of acetylcholine (0.03 - 1.0 microg kg(-1)) normalized against that of SNP (10 microg kg(-1)) was significantly attenuated by L-NAME (n=5). 3. Charybdotoxin (0.4 mg kg(-1)) plus apamin (0.2 mg kg(-1)) significantly attenuated the depressor response to PAF (1 microg kg(-1)) (n=5) without affecting the blood pressure change due to SNP (1 mg kg(-1)) (n=3). Charybdotoxin (0.4 mg kg(-1)) (n=4) or apamin (0.2 mg kg(-1)) (n=4) alone did not affect the PAF-induced depressor response. 4. These findings suggest that EDHF may make a significant contribution to the depressor response to PAF in rats. Although NO plays the determinant role in the basal blood pressure regulation, its contribution to PAF-produced depressor response seems to be less as compared with that to the depressor response to acetylcholine.

Animals↗

PubMed2000

Frequent presence of Helicobacter pylori genome in the saliva of patients with hyperemesis gravidarum.

Recently, possible involvement of Helicobacter pylori (H. pylori) in hyperemesis gravidarum have been reported based on serological studies and the therapeutic effects of antibiotics. In this study, we examined for the presence of H. pylori genome [by (PCR) of saliva] in combination with serological techniques. Thirty-four patients with hyperemesis and 29 normal pregnant subjects were examined for serum anti-H. pylori IgG antibodies and PCR of saliva. By serum antibody test, 16 of 34 hyperemesis patients (47.5%) were positive for anti-H. pylori IgG antibody, while 6 of 29 control subjects (20.6%) were positive (chi2 p < 0.0005). PCR revealed positive H. pylori genome in 21 cases out of 34 hyperemesis (61.8%, 14 of 16 patients positive for H. pylori antibody and 7 of H. pylori-antibody-negative 18 patients) and 8 of 29 control subjects (27.6%) (chi2 p < 0.000001). We suggest chronic infection of H. pylori as one of the important factors on the pathogenesis of hyperemesis gravidarum even though it may not be the single cause of the disorder.

Adult↗

PubMed2000

Apoptosis-inducing activity of galloyl monosaccharides in human histiocytic lymphoma U937 cells.

Three galloyl monosaccharides contained in medicinal plants were examined for apoptosis-inducing activity in human histiocytic lymphoma U937 cells. Tetragalloyl glucose (TgG) induced apoptosis as found by chromatin condensation, DNA ladder formation, and inhibition by a caspase inhibitor. Digalloyl hamamelose had moderate activity, while monogalloyl glucose was only marginally active. These findings suggest that the number and disposition of their phenolic groups are important for apoptosis induction. TgG induced apoptosis in human colon and stomach cancer cell lines as well, indicating it is potentially useful as an anti-cancer agent.

Antineoplastic Agents, Phytogenic↗

PubMed2000

Peritoneal and peripheral B-1-cell populations in patients with endometriosis.

OBJECTIVE: The purpose of this study was to investigate the frequency of B-1 cells in the peritoneal cavity and peripheral blood of patients with endometriosis. MATERIALS AND METHODS: We examined 31 patients with endometriosis and 14 normal nonpregnant women. Peripheral blood cells and peritoneal exudate cells (PECs) were stained with FITC or PE-labeled anti-CD5/CD19 monoclonal antibodies. Immunofluorescence analysis was performed using a flow cytometer. The significance of differences between the patient and control groups was determined by the non-parametric Mann-Whitney test. RESULTS: There was no significant difference in the percentages of B-1 cells in the peripheral blood of women with and without endometriosis (median, 22.7%; range, 4.7-92.3% vs median, 20.05%; range, 11.1-12.6%, respectively). Endometriosis patients with antinuclear antibodies (ANAs) demonstrated significantly elevated B-1 cells compared to both endometriosis patients without ANAs and normal controls (p < 0.005 and p < 0.05, respectively). Endometriosis patients demonstrated significantly higher B-1 cell populations (B-1 cells/total B-cell ratio) in PECs than did non-endometriosis patients (p < 0.05). CONCLUSIONS: The peripheral B-1-cell population in patients with endometriosis is related to ANA production. B-1 cells might play important roles in the development of endometriosis through autoantibody production.

Adult↗

PubMed2000

Effects of paternal lymphocyte immunization on peripheral Th1/Th2 balance and TCR V beta and V gamma repertoire usage of patients with recurrent spontaneous abortions.

PROBLEM: The mechanism of immunotherapy for patients with recurrent spontaneous abortions is not well understood. In order to investigate the suppressor mechanism of paternal lymphocyte immunization, we examined peripheral blood lymphocyte subpopulations and the repertoire of T-cell receptor (TCR) gene segments. METHOD OF STUDY: Twelve patients with recurrent miscarriage were treated with immunization with paternal lymphocyte vaccinations three times during 12-14 weeks. Before and 2 weeks after the final inoculation, lymphocyte subsets and intra-cellular interferon (IFN)-gamma and/or interleukin (IL)-4 production were examined by flow cytometry. TCR V beta and V gamma repertoires were examined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: We found no significant difference in CD4/CD8 ratios, prevalence of CD56+CD3+ or CD57+CD3+ cells (possible extrathymic T cells), gamma(delta)T cells, and CD5+ CD19+ (B-1) cells. However, by in vitro activation with phorbol 12-myristate 13-acetate (PMA) and ionomycin, peripheral CD4 cells demonstrated a significant decrease of IFN-gamma-producing T helper 1 (Th1) cells and an increase of IL-4-producing T helper 2 (Th2) cells after immunotherapy. Seven of nine patients who exhibited remarkable decreases in Th1/Th2 ratios became pregnant within 6 months after three courses of immunotherapy, and four women delivered healthy babies, while none of the three patients who exhibited an increased or unchanged Th1/Th2 ratio had full-term pregnancies (chi2 < 0.0001). Further, changes in usage of TCR V beta and V gamma gene segments were observed after immunotherapy in six patients examined. CONCLUSION: Our findings suggest a shift of Th1-dominant to Th2-dominant status by vaccination might play important roles in maintaining successful pregnancies. Induction of some T cells that utilize different TCR repertoires possibly suppresses maternal rejection reactions.

Abortion, Habitual↗