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H Tezuka

Publications and source records attributed to H Tezuka.

At least 19 recordsLinked to original sources
PubMed2001

A factor of inducing IgE from a filarial parasite is an agonist of human CD40.

Immune responses to parasitic helminth are usually characterized by quite mysterious phenomena: dominance of Th2-like immunity and antigen-nonspecific IgE secretion. We previously purified a factor from Dirofilaria immitis that induces antigen-nonspecific IgE in rats and named it DiAg. In the presence of IL-4, DiAg induces mouse B cells to secrete IgE, which is antigen-nonspecific polyclonal antibody. We investigated the biochemical characteristics of DiAg as a factor of inducing IgE in this study. Recombinant DiAg (rDiAg) with interleukin (IL)-4 induced IgE synthesis in highly purified human normal B cells in vitro cell culture systems. The addition of recombinant human soluble CD40 IgG fusion protein (rsCD40-Ig) inhibited induction of IgE synthesis by rDiAg with IL-4. Monocyte cells were stimulated with rDiAg and recombinant human soluble CD40L (rsCD40L); IL-12 and TNF-alpha were induced. The addition of rsCD40-Ig to THP-1 cells activated with rDiAg and rsCD40L inhibited the production of IL-12. rDiAg bound to the monocyte cell membrane fraction and recombinant human soluble CD40; this binding of rDiAg was competitively inhibited by addition of rsCD40L. Moreover, in CD40-deficient mice, IgE production and MLN-B cell proliferation by rDiAg were completely absent. Based on these results, we concluded that DiAg is an agonist of CD40.

Animals↗
PubMed2001

A factor of inducing IgE from a filarial parasite prevents insulin-dependent diabetes mellitus in nonobese diabetic mice.

Parasitic helminth infections are characterized by eosinophilia and markedly elevated levels of circulating antigen-nonspecific immunoglobulin E (IgE), responses from which concern helminth protection. We previously purified a factor from Dirofilaria immitis that induces antigen-nonspecific IgE in mice and rats. Recombinant DiAg (rDiAg) has various biological activities. It is also known that parasitic helminth infection generates tremendous Th2 responses. The nonobese diabetic (NOD) mouse spontaneously develops Th1 cell-dependent autoimmune diabetes. Here we investigated the effects of rDiAg on the initiation and progression of this disease. rDiAg treatment of 6-week-old NOD females (the age at which insulitis typically begins) completely prevented insulitis and diabetes. Thus, rDiAg impaired the islet Ag-specific Th1 cell response in vivo, and the prevention of diabetes by rDiAg was associated with switching of the response from a Th1 to a Th2 profile. Since rDiAg clearly prevented insulitis by inhibiting the development and further accumulation of pathogenic Th1 cells to islets of Langerhans, we conclude that DiAg is a native Th2 inducer in filarial helminth and that Th1 responses are required for early events in the development of spontaneous autoimmune diabetes. In conclusion, the presence of parasitic helminth infections may play an important role as an immunomodulator in some autoimmune diseases or allergies.

Amino Acid Sequence↗
PubMed2001

Functional correlation between the nuclear localization of Fht1p and its flocculation and heat tolerance activities in budding yeast Saccharomyces cerevisiae.

Fht1p is involved in the flocculation and heat tolerance machinery of budding yeast Saccharomyces cerevisiae. Despite knowledge of its involvement in those phenotypes, a precise mechanism has yet to be discovered. To this end, we monitored the relationship between subcellular localization of Fht1p and its flocculation or heat tolerance function using newly developed expression vectors with a recombinant green fluorescent protein (GFP; S65T/S147P) of Aequorea victoria added at both the N- and C-terminus of Fht1p. The main fluorescent signal of the GFP tagged with either a wild-type Fht1p or mutants which preserve their flocculation function was detected in the nucleus, whereas signals of functionless mutants were dispersed to the cytoplasm.

Cell Nucleus↗
PubMed2001

Recombinant Dirofilaria immitis-derived antigen can suppress passive cutaneous anaphylaxis reactions.

BACKGROUND: High levels of antigen-nonspecific IgE are produced in animals infected with helminth parasites. Generally, the increase in IgE is thought to exacerbate allergic reactions. However, high levels of antigen-nonspecific IgE may alter some features of anaphylactic reactions. To investigate the molecular mechanisms of antigen-nonspecific IgE production induced during filarial infections, we previously constructed rDiAg (recombinant Dirofilaria immitis-derived antigen) in Escherichia coli. In the present study, we examined the effect of rDiAg on the production of antigen-nonspecific IgE and on allergic cutaneous reactions in rats. METHODS: Osmotic pumps filled with 200 microg of rDiAg or with 200 microl of PBS (control) were subcutaneously implanted in Wistar rats, and plasma samples were collected weekly thereafter. IgE levels were determined by ELISA. Homologous passive cutaneous anaphylaxis (PCA) reactions with anti-DNP-As IgE were examined 21 days after implantation. (125)I-IgE binding assays were examined on peritoneal mast cells from rDiAg-infused rats and control rats. RESULTS: Antigen-nonspecific IgE production was induced in rDiAg-infused rats. PCA reactions were suppressed in rDiAg-infused rats in spite of high levels of IgE and a markedly increased expression of Fc epsilon RI. (125)I-IgE did not bind to mast cells derived from rDiAg-infused rats, but it bound dose dependently to mast cells derived from control rats. CONCLUSION: The present data support the hypothesis that antigen-nonspecific IgE might protect against antigen-specific IgE by means of competition for mast cell receptors. rDiAg is an essential factor to induce antigen-nonspecific IgE in helminth infections.

Animals↗
PubMed2001

Enhancement of foot formation in Hydra by a novel epitheliopeptide, Hym-323.

During the course of a systematic screening of peptide signaling molecules in Hydra magnipapillata, a novel peptide, Hym-323, which enhances foot regeneration was identified. The peptide is 16 amino acids long, and is encoded in the precursor protein as a single copy. Northern blot analysis, in situ hybridization analysis and immunohistochemistry showed that it was expressed in both ectodermal and endodermal epithelial cells throughout the body, except for the basal disk and the head region. The peptide enhanced foot regeneration by acting on epithelial cells. Lateral transplantation experiments indicated that the foot activation potential was increased in the peptide-treated tissue. These results suggest that Hym-323 is a peptide involved in a foot-patterning process in Hydra.

Amino Acid Sequence↗
PubMed2000

Alkali and alkaline-earth metal ketyl complexes: isolation, structural diversity, and hydrogenation/protonation reactions

The use of hexamethylphosphoric triamide (HMPA) as a stabilizing ligand allowed successful isolation of a series of structurally characterizable alkali metal and calcium ketyl complexes. Reaction of lithium and sodium with one equivalent of fluorenone and reaction of sodium with one equivalent of benzophenone in THF, followed by addition of two equivalents of HMPA, yielded the corresponding ketyl complexes 1, 2, and 11, respectively, as microketyl-bridged dimers. If one equivalent of HMPA was used in the reaction of sodium with fluorenone, a further aggregated complex, the mu3-ketyl-bridged tetramer 3, was isolated, whereas analogous reaction of benzophenone with sodium afforded the trimeric ketyl complex 13, rather than a simple benzophenone analogue of 3. In the reaction of potassium with fluorenone, the use of two equivalents of HMPA gave the tetramer 4, rather than a dimeric complex analogous to 1 or 2. Compared to the tetrameric sodium complex 3, there is an extra HMPA ligand that bridges two of the four K atoms in 4. When 0.5 equiv of HMPA was used in the above reaction, complex 5, a THF-bridged analogue of 4, was isolated. In the absence of HMPA, the reaction of sodium with an excess of fluorenone yielded the tetrameric ketyl complex 6, in which two of the four Na atoms are each terminally coordinated by a fluorenone ligand, and the other two Na atoms are coordinated by a THF ligand. Two bridging THF ligands are also observed in 6. Reaction of 1,2-bis(biphenyl-2,2'-diyl)ethane-1,2-diol (7) with two equivalents of LiN(SiMe3)2 or NaN(SiMe3)2 in the presence of four equivalents of HMPA easily afforded 1 or 2, respectively, via C-C bond cleavage of a 1,2-diolate intermediate. The reaction of calcium with two equivalents of fluorenone or benzophenone in the presence of HMPA gave the corresponding complexes that bear two independent ketyl ligands per metal ion. In the presence of 3 or four equivalents of HMPA, the fluorenone ketyl complex was isolated in a six-coordinate octahedral form (10), while the benzophenone ketyl complex was obtained as a five-coordinate trigonal bipyramid (13). The radical carbon atoms in both benzophenone ketyl and fluorenone ketyl complexes are still in an sp2-hybrid state. However, in contrast with the planar configuration of the whole fluorenone ketyl unit, the radical carbon atom in a benzophenone ketyl species is not coplanar with any of the phenyl groups; this explains why benzophenone ketyl is more reactive than fluorenone ketyl. Hydrolysis of 2 or 11 with 2N HCI yielded the corresponding pinacol-coupling product, while treatment of 2 or 11 with 2-propanol, followed by hydrolysis, gave the pairs fluorenone and fluorenol or benzophenone and benzhydrol, respectively. A possible mechanism for these reactions is proposed.

Journal Article↗
PubMed2000

Changes of in vivo gastrointestinal motor pattern in pacemaker-deficient (WsRC-Ws/Ws) rats.

In vitro studies on pacemaker-deficient W-mutants have revealed a disappearance of rhythmic contraction in their gastrointestinal tracts. Their contractile force has not been diminished, however. In contrast, W-mutants often present dysmoility-like symptoms with distension of the gastrointestinal tract in vivo. Gastrointestinal motility of W-mutant rats was examined in vivo by an extraluminal strain-gauge force transducer method. We examined a normal gastrointestinal motor pattern in the rats with two distinct motor phases, digestive and interdigestive. Moreover, we detected a failure to form an interdigestive contractile complex in pacemaker-deficient rats. The interdigestive motor activity of the gastrointestinal tract is important for cleaning gastrointestinal tract in preparation for the next meal. The impairment of the interdigestive contractile complex may be related to the dysmoility-like symptoms of W-mutant rats in vivo.

Animals↗
PubMed1995

A human CD4- CD8- T-cell receptor alpha beta + T leukemic cell line undergoing phytohemagglutinin-induced apoptosis.

A human CD4- CD8- alpha beta T-cell receptor (TCR alpha beta)+ T leukemic cell line, L-KAW, was established from the peripheral blood of a 6-year-old male patient with T-cell acute lymphoblastic leukemia. Its phenotype was found to be CD7+CD2+CD3+CD4-CD8- TCR alpha beta +. The cell line proved susceptible to killing by exposure to a mitogenic concentration of phytohemagglutinin (PHA) within several hours, with biochemical analyses demonstrating extensive degradation of DNA to oligonucleosomal bands characteristic of apoptosis. Chromatin condensation and cell shrinkage features of apoptotic cells could also be clearly identified under the electron microscope. The apoptosis-related Fas antigen was expressed on L-KAW cells and DNA fragmentation was induced by incubation with anti-Fas monoclonal antibody. The c-myc mRNA levels declined within 15 min to 3 h after the addition of PHA. These results suggest that L-KAW cells are specifically sensitive to induction of apoptosis in response to PHA without preactivation. They may, therefore, be considered an analog of activated T-cells and prove useful as a model system for characterizing biochemical and molecular mechanisms underlying the process of this type of cell death.

Antibodies↗
PubMed1995

Endoscopic polypectomy for pacemaker patients.

Endoscopic polypectomy using high frequency voltage is contraindicated in patients with cardiac pacemakers. Recently, highly advanced pacemakers have enabled us to perform endoscopic polypectomy on these patients by taking appropriate cautions. We successfully removed 10 colonic polyps and one gastric polyp in patients with pacemakers by endoscopic polypectomy. No complication and dysfunction of the pacemaker occurred before, during or after the polypectomy.

Aged↗
PubMed1993

Diagnostic difficulty in a case of heterotopic pancreatic tissue of the ileum.

We describe a case of heterotopic pancreatic tissue of the ileum causing acute gastrointestinal tract bleeding. It was initially clearly demonstrated as an ileal polyp preoperatively by radiologic means. Exploratory surgery was performed, and the segment of ileum containing the mass was resected. Histopathologic examination of the lesion revealed heterotopic pancreatic tissue of Heinrich type II. There was no histological evidence of acute or chronic pancreatitis, but erosion was confirmed at the tip of the mass. Even symptomatic heterotopic pancreatic tissue of the ileum may give difficult diagnostic problems. The present case is reported to show the possibility of diagnosing rare abnormalities of the ileum.

Choristoma↗
PubMed1992

Different modifications by vanillin in cytotoxicity and genetic changes induced by EMS and H2O2 in cultured Chinese hamster cells.

The modifying effects of vanillin on the cytotoxicity and 6-thioguanine (6TG)-resistant mutations induced by two different types of chemical mutagens, ethyl methanesulfonate (EMS) and hydrogen peroxide (H2O2), were examined using cultured Chinese hamster V79 cells. The effects of vanillin on H2O2-induced chromosome aberrations were also examined. Vanillin had a dose-dependent enhancing effect on EMS-induced cytotoxicity and 6TG-resistant mutations, when cells were simultaneously treated with vanillin. The post-treatment with vanillin during the mutation expression time of cells after treatment with EMS also showed an enhancement of the frequency of mutations induced by EMS. However, vanillin suppressed the cytotoxicity induced by H2O2 when cells were post-treated with vanillin after H2O2 treatment. Vanillin showed no change in the absence of activity of H2O2 to induce mutations. Post-treatment with vanillin also suppressed the chromosome aberrations induced by H2O2. The differential effects of vanillin were probably due to the quality of mutagen-induced DNA lesions and vanillin might influence at least two different kinds of cellular repair functions. The mechanisms by which vanillin enhances or suppresses chemical-induced cytotoxicity, mutations and chromosome aberrations are discussed.

Animals↗
PubMed1992

[Clinical characteristics and prognosis of secondary amyloidosis in patients with rheumatoid arthritis--renal involvement and therapy].

Secondary amyloidosis is an important complication that may have a strong influence on the prognosis of patients with rheumatoid arthritis (RA). We studied 21 RA patients with secondary amyloidosis. The two major initial signs were gastrointestinal symptoms and renal involvement. When 15 of the 21 patients were diagnosed as having secondary amyloidosis, they displayed renal involvement including proteinuria, hematuria and hypercreatininemia. The 15 patients with amyloidosis were either subjected to dialysis or died within 35 months on the average. The causes of death in 13 patients were cardiac failure, gastrointestinal bleeding and infection, which were strongly implicated with renal failure. Dialysis was applied to seven patients. Three of them were maintained with chronic dialysis. We discussed the induction-time and the method of dialysis in patients with amyloidosis secondary to RA.

Adolescent↗
PubMed1991

CD4+CD45RA+ cells (suppressor-inducer T cells) in thyroid tissue from patients with Graves' disease.

Previously, we used dual immunofluorescent analysis and showed that the thyroid gland from patients with Graves' disease had a reduced number of CD4+CD45RA+ cells, but an increased number of complementary CD4+CDw29+ cells. An immunohistochemical study, however, produced opposite results; interstitial lymphocytes predominantly expressed the CD45RA+ rather than the CDw29+ phenotype. Because the difference in findings may be due to differences in the techniques used, we did the following experiments: Mononuclear cells were treated with various amounts of collagenase (50-1000 mg/l) which had no effect on the cell surface antigens CD3, CD4 and CD45RA. A dual immunofluorescent study showed that the numbers of CD4+CD45RA+ and CD8+CD45RA+ cell population among CD45RA+ cell population were markedly decreased in the thyroid tissue, and that the CD45RA antigen on the intrathyroidal mononuclear cells was mainly expressed on the CD20+ cells. As the thyroid section had been fixed with acetone before immunohistochemical staining, CD45RA- cells were treated with acetone and stained with anti-CD45RA monoclonal antibody using an avidin-biotin peroxidase complex method. The results of this experiment suggest that there are cell surface molecules which react with anti-CD45RA monoclonal antibody after treatment with acetone in CD45RA- cells. The above findings confirm our previous results which showed that the thyroid glands of patients with Graves' disease have decreased numbers of suppressor-inducer T cells. Also, several problems exist in the detection of CD45RA+ cells when using an immunohistochemical method.

Acetone↗
PubMed1991

[A case of adrenomyeloneuropathy with marked spinal cord atrophy on magnetic resonance imaging].

A 29-year-old man complained of increasing paraplegia and sphincter disturbances. On admission, he was 23 years old. He had moderate pigmentation of the skin, and his neurological examinations revealed spastic paraplegia, hyperreflexia of both legs with Babinski's signs, a pinprick sensation deficit below the L-1 level, loss of vibration sense in the lower extremities and horizontal nystagmus on lateral gaze. Endocrinological examinations revealed adrenocortical insufficiency. CSF, EEG, EMG, brain-CT and myelography did not show any abnormalities, but metrizamide CT myelography at the low thoracic spinal cord revealed decreased cord diameter. Nerve conduction velocities showed impairment in the tibial and peroneal motor fibers. Auditory brain-stem response revealed elongated III-V interval. A cystometrogram disclosed a reflex neurogenic bladder. In the analysis of the fatty acid component of plasma sphingomyelin, the C26/C22, C25/C22, C24/C22 ratios were found to be increased, and the diagnosis of adrenomyeloneuropathy (AMN) was confirmed. The patient's mother was also found to be asymptomatic carrier of AMN on the basis of long chain fatty acid plasma levels. The MRI performed in his age of 29 years, showed marked spinal atrophy from low cervical to low thoracic regions and mild cerebellar atrophy. This findings seems to correspond with chronic progressive demyelination of spinal white matter such as pyramidal tract and fasciculus gracilis.

Adrenoleukodystrophy↗