Search PubMed⌕ Search

Biomedical subjects

H Tani

Publications and source records attributed to H Tani.

At least 37 records · Page 2Linked to original sources
PubMed2000

Zygosporin D and two new cytochalasins produced by the fungus Metarrhizium anisopliae.

Zygosporin D (3) and two new cytochalasins (4 and 5) were isolated from the culture filtrate of the fungus Metarrhizium anisopliae and characterized on the basis of their spectral data and chemical conversions. The new cytochalasins, 4 and 5, were determined to be deacetylcytochalasin C and (6R,16S,18R,21R)-18,21-dihydroxy-16, 18-dimethyl-10-phenyl[11]cytochalasa-13(E),19(E)-diene-1,7,17-trio ne, respectively. Of these three cytochalasins, only zygosporin D is an effective inhibitor of shoot elongation of rice seedlings.

Cytochalasins↗
PubMed2000

Real-time ultrasonographic assessment of antroduodenal motility after ingestion of solid and liquid meals by patients with functional dyspepsia.

BACKGROUND AND AIMS: Although antroduodenal motility has usually been studied by using manometric or scintigraphic methods, ultrasonography is an established, non-invasive method to evaluate duodenogastric motility. We used ultrasonography to evaluate gastric motility in patients with functional dyspepsia. METHODS: Sixty-four patients with functional dyspepsia and 36 asymptomatic healthy subjects were given liquid and solid test meals. We investigated the gastric emptying rate, motility index, and duodenogastric reflux for the liquid meal and gastric emptying time, half-emptying time, and motility index for the solid meal. RESULTS: After the liquid meal, the gastric emptying rate and motility index were significantly lower and the duodenogastric reflux was significantly higher in functional dyspepsia patients than in healthy subjects. After the solid meal, gastric emptying time, half-emptying time and the motility index were significantly lower in the patients than in the healthy subjects. Delayed gastric emptying of both meals occurred in only 20.3% of patients. Delayed emptying of the liquid or solid meal occurred in 62.5% of patients. In both groups, gastric emptying time of the solid meal was positively correlated with the motility index at 15 min post-ingestion. CONCLUSION: In functional dyspepsia patients, delayed gastric emptying of a solid meal was related to antral hypomotility during the early postprandial phase. Ultrasonographic assessment of gastric motility in both liquid and solid meals may provide a better understanding of the pathogenesis of functional dyspepsia.

Adult↗
PubMed2000

Expression of human herpesvirus 6B rep within infected cells and binding of its gene product to the TATA-binding protein in vitro and in vivo.

We have characterized the human herpesvirus 6B (HHV-6B) rep gene, which is a homologue of the adeno-associated virus type 2 rep and is unique in the herpesvirus family. Three transcripts, 9.0, 5.0, and 2. 7 kb (the major transcript), were detected by Northern blotting using an HHV-6B rep probe under late conditions. We investigated the expression kinetics of the rep gene using cycloheximide (CHX) and phosphonoformic acid (PFA), which are inhibitors of protein synthesis and viral DNA synthesis, respectively. The 5.2-kb transcript was mainly detected in the absence of protein biosynthesis upon infection, and none of the 9.0-, 5.0-, and 2.7-kb transcripts detected under the late conditions were detected in the presence of CHX and PFA. Sequences obtained from a cDNA library showed that the 5.0- and 2.7-kb transcripts were spliced from two and three exons, respectively, and the 2.7-kb transcript was more abundant. Immunohistochemistry using an antibody raised against the HHV-6 rep gene product (REP) revealed that REP was mainly present in the nucleus of MT-4 cells within 24 h after infection with HHV-6B. Using pull-down assays, coimmunoprecipitation, and a mammalian two hybrid system, we showed that HHV-6 REP binds to a transcription factor, human TATA-binding protein, through its N-terminal region.

Animals↗
PubMed2000

Role of reactive oxygen species in gallic acid-induced apoptosis.

We earlier demonstrated that gallic acid (3,4,5-trihydroxybenzoic acid) induced apoptosis in promyelocytic leukemia HL-60RG cells, which was inhibited by catalase and intracellular Ca2+ chelator. In this study, we further studied the involvement of reactive oxygen species (ROS) and intracellular Ca2+ in gallic acid-induced apoptosis. The enhancement of intracellular ROS in HL-60RG cells was detected dose-dependently as early as 5 min after stimulation with gallic acid by using 5,6-carboxy-2',7'-dichlorofluorescin diacetate (DCFH-DA). Further studies that used various antioxidants and ROS scavengers showed that the intracellular peroxide level was well correlated with the potency to induce apoptosis and that the increased intracellular peroxides after gallic acid treatment seemed likely to result from the influx of H2O2 derived from superoxide which were generated extracellularly. In addition, gallic acid, HX/XO, and H2O2-induced apoptosis was completely inhibited by pretreatment with intracellular Ca2+ chelator 1,2-bis(2-aminophenoxyethane)-N,N,N'-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA-AM), but increase of intracellular peroxide levels by gallic acid were suppressed only slightly. It is suggested that intracellular ROS induced by gallic acid plays an important role in eliciting an early signal in apoptosis. Especially, H2O, which is derived from superoxide anion generated extracellularly may increase intracellular Ca2+ levels or cooperate with intracellular Ca2+, thus resulting in apoptosis induction.

Antioxidants↗
PubMed2000

Study of lipid in the ear canal in canine otitis externa with Malassezia pachydermatis.

An epidemiological investigation of 120 canine otitis externa cases in 1,370 dogs was done on the incidence rate, ear pinna shapes, breeds and their relationships. Eighty-five cases (12.6%) in 672 dogs with pendulous ears and 35 cases (5.0%) in 698 dogs with erect ears had otitis externa, and the difference between them was significant (P<0.05). Ninety-five auditory cerumen specimens were cultured for Malassezia pachydermatis (M. pachydermatis) and analyzed for concentrations of major fatty acids. Although rates of cases positive for M. pachydermatis in both ear pinna shapes were almost the same, i.e. 55.2% in the pendulous group and 53.6% in the erect group, the average total fatty acid level of the pendulous ear group was significantly (P<0.05) higher than that in the erect ear group after dismissing extraordinary levels in the Siberian husky. Isolated M. pachydermatis strains were examined for the effects of fatty acid supplementation on their growth. The majority of the strains utilized fatty acids and grew faster in fatty acid supplemented broth. These results suggest that M. pachydermatis, the predominant causative agent of canine otitis externa, prefers the auditory canal of dogs with lipid-rich earwax and grows fast, but growth strongly depends upon the canine breed.

Animals↗
PubMed1999

Oncogenic osteomalacia presenting as bilateral stress fractures of the tibia.

We report on a patient with bilateral stress fractures of the tibia who subsequently showed classic biochemical features of oncogenic osteomalacia. Conventional radiographs were normal. MR imaging revealed symmetric, bilateral, band-like low-signal lesions perpendicular to the medial cortex of the tibiae and corresponding to the only lesions subsequently seen on the bone scan. A maxillary sinus lesion was subsequently detected and surgically removed resulting in prompt alleviation of symptoms and normalization of hypophosphatemia and low 1,25-(OH)2 vitamin D3. The lesion was pathologically diagnosed as a hemangiopericytoma-like tumor. Patients with oncogenic osteomalacia may present with stress fractures limited to the tibia, as seen in athletes. The clue to the real diagnosis lies in paying close attention to the serum phosphate levels, especially in patients suffering generalized symptoms of weakness and not given to unusual physical activity.

Adult↗
PubMed1999

Oxytocin gene expression and action in goat testis.

Gene expression, immunohistochemical localization, binding and effects of oxytocin (OT) on androgen production in the testis of adult goats were studied. Using polymerase chain reaction (PCR) analysis we were able to detect OT gene transcripts in the goat testis. Immunohistochemistry revealed that both OT and neurophysin epitopes were expressed together in the intratubular regions, especially in the Sertoli cells, suggesting the production of OT in these cells. However, enzyme immunoassay found no difference in OT concentration between testicular arterial and venous plasma. Saturable, specific [3H]-OT binding sites were present in membrane fractions of the goat testis. Scatchard analysis indicated an apparent affinity of 42 +/- 7 L/nmol and binding capacity of 24 +/- 4 fmol OT bound/mg DNA. In vitro treatment of goat testes for 6 h with 100 nM OT led to a 3.5-fold increase (P < 0.001) in 5 alpha-dihydrotestosterone (DHT) production in spite of the induced decrease in testosterone, suggesting that OT not only affects testosterone production but also modulates its conversion to DHT. These results indicate that the goat testis produces OT, which may be involved in the local control of androgen biosynthesis.

Animals↗
PubMed1999

Increased LH pulse frequency and estrogen secretion associated with termination of anestrus followed by enhancement of uterine estrogen receptor gene expression in the beagle bitch.

The relationships among pulsatile LH secretion pattern, estrogen secretion, and expression of the uterine estrogen receptor gene were examined throughout the estrous cycle in beagle bitches. In Experiment 1, blood samples were collected from 30 bitches every 10 min for 8 h from a cephalic vein during different phases of the estrous cycle. An increase in the mean plasma levels of LH occurred from mid to late anestrus (P < 0.01). The LH pulse frequency increased (P < 0.01) from late anestrus to proestrus, and was strongly correlated (r = 0.96, P < 0.001) with the mean plasma level of estradiol-17 beta (E2). In Experiment 2, middle uterine samples, including the myometrium and endometrium, from 18 bitches were taken at 6 stages of the estrous cycle. The total number of estrogen receptors and nuclear estrogen receptor and its mRNA levels in the uterus also increased (P < 0.01) from late anestrus to proestrus. Mean plasma E2 level and the number of uterine estrogen receptor were positively correlated (r = 0.81, P < 0.05). In Experiment 3, nine bitches were ovariectomized in mid anestrus. Two weeks later they received a single injection of 10 or 50 micrograms/kg, i.m., estradiol benzoate. The number of uterine estrogen receptor and their mRNA levels for ovariectomized bitches were low, but increased (P < 0.05) after treatment with a low dose of estradiol benzoate. These results suggest that increases in LH pulse frequency and estrogen secretion are associated with termination of anestrus and that subsequent enhancement of uterine estrogen receptor expression may be up-regulated by estradiol.

Anestrus↗
PubMed1999

Development and validation of an ultrasonographic activity index of Crohn's disease.

OBJECTIVES: We developed and validated an ultrasonographic index of intestinal inflammatory activity for patients with Crohn's disease. METHODS: Fifty-five patients with Crohn's disease were examined by transabdominal ultrasonography. The pathological findings were classified into three types (A-C) on the basis of wall thickness and wall stratification. To calculate the index, we divided the intestine into eight segments, and the scores for each segment were summed to calculate the index (ultrasonographic activity index of Crohn's disease) as follows: 1 point for type A lesions, [wall thickness (mm) -2] x 2 for type B lesions, and [wall thickness (mm) -2] x 4 for type C lesions. Endoscopic or barium contrast findings were also scored in a similar fashion, with the following parametric scores: 10 for cobblestoning, 5 for longitudinal ulcers, 3 for aphthoid ulcers, and 1 for chronic inflammatory changes. RESULTS: A strong correlation (r2 = 0.62, P<0.01) was found between the ultrasound index and the endoscopic/radiological score, while weak correlations were found between the endoscopic/radiological score and the Crohn's disease activity index or biological indices of inflammation. CONCLUSIONS: Our results show that the ultrasonographic activity index of Crohn's disease can be of value in the ongoing assessment and treatment of patients.

Adolescent↗
PubMed1999

Characterization of an outer membrane protein gene, pgmA, and its gene product from Porphyromonas gingivalis.

A gene upstream from fimA, the gene encoding fimbrilin, on the chromosome of Porphyromonas gingivalis was sequenced and shown to be the gene encoding an outer membrane protein in this organism based on homology and biochemical analyses. Therefore, the gene (formerly ORF5) was designated pgmA, the P. gingivalis outer membrane protein A gene. The gene product, PgmA, was sensitive to protease, and was detected as a 60-kDa protein from wild-type strains with trichloroacetic acid treatment, which was carried out to destroy intrinsic proteases, and from protease-deficient mutants without this treatment prior to electrophoresis. PgmA was indeed present in the membrane fraction. Its nature was determined to be that of outer membrane proteins in gram-negative bacteria based on attempts at differential extraction of inner membrane proteins with detergents. No evidence has been found thus far from functional analyses that this protein is related to fimbrial morphogenesis and functions or to serum resistance of this organism.

Amino Acid Sequence↗
PubMed1999

Interaction of hepatitis C virus core protein with viral sense RNA and suppression of its translation.

To clarify the binding properties of hepatitis C virus (HCV) core protein and its viral RNA for the encapsidation, morphogenesis, and replication of HCV, the specific interaction of HCV core protein with its genomic RNA synthesized in vitro was examined in an in vivo system. The positive-sense RNA from the 5' end to nucleotide (nt) 2327, which covers the 5' untranslated region (5'UTR) and a part of the coding region of HCV structural proteins, interacted with HCV core protein, while no interaction was observed in the same region of negative-sense RNA and in other regions of viral and antiviral sense RNAs. The internal ribosome entry site (IRES) exists around the 5'UTR of HCV; therefore, the interaction of the core protein with this region of HCV RNA suggests that there is some effect on its cap-independent translation. Cells expressing HCV core protein were transfected with reporter RNAs consisting of nt 1 to 709 of HCV RNA (the 5'UTR of HCV and about two-thirds of the core protein coding regions) followed by a firefly luciferase gene (HCV07Luc RNA). The translation of HCV07Luc RNA was suppressed in cells expressing the core protein, whereas no significant suppression was observed in the case of a reporter RNA possessing the IRES of encephalomyocarditis virus followed by a firefly luciferase. This suppression by the core protein occurred in a dose-dependent manner. The expression of the E1 envelope protein of HCV or beta-galactosidase did not suppress the translation of both HCV and EMCV reporter RNAs. We then examined the regions that are important for suppression of translation by the core protein and found that the region from nt 1 to 344 was enough to exert this suppression. These results suggest that the HCV core protein interacts with viral genomic RNA at a specific region to form nucleocapsids and regulates the expression of HCV by interacting with the 5'UTR.

Binding Sites↗
PubMed1998

A human liver cell line exhibits efficient translation of HCV RNAs produced by a recombinant adenovirus expressing T7 RNA polymerase.

An in vitro system that supports the efficient growth of hepatitis C virus (HCV) and reflects its complete in vitro replication cycle has not yet been established. The establishment of a minigene RNA of HCV in mammalian cells could facilitate the study of virus-cell interactions and the molecular pathogenesis of this virus. We constructed a replication-deficient recombinant adenovirus expressing bacteriophage T7 RNA polymerase under the control of CAG promoter (AdexCAT7). A high level of T7 RNA polymerase was detectable for at least 11 days after inoculation. Cells infected with AdexCAT7 were then transfected with plasmids carrying the authentic T7 promoter, the 5' untranslated region (UTR) of encephalomyocarditis virus, a luciferase gene, and a T7 terminator (pT7EMCVLuc) or carrying the modified T7 promoter, the 5'UTR of HCV, a luciferase gene, the coding region of C-terminal of NS5B and the 3'UTR of HCV, a ribozyme of hepatitis D virus and a T7 terminator (pT7HCVLuc). Most of the cell lines examined supported a higher expression of luciferase by transfection with pT7EMCVLuc than with pT7HCVLuc. However, one cell line, FLC4, derived from a human hepatocellular carcinoma, exhibited very high reporter gene expression with pT7HCVLuc. In this cell line, transfection with RNA synthesized in vitro from pT7HCVLuc induced a higher level of reporter gene expression than RNA from pT7EMCVLuc. The T7-adenovirus system for the synthesis of HCV minigenes in vivo provides useful information on the molecular mechanisms of HCV translation in human liver cells.

3' Untranslated Regions↗
PubMed1998

Role of IQGAP1, a target of the small GTPases Cdc42 and Rac1, in regulation of E-cadherin- mediated cell-cell adhesion.

The small guanosine triphosphatases (GTPases) Cdc42 and Rac1 regulate E-cadherin-mediated cell-cell adhesion. IQGAP1, a target of Cdc42 and Rac1, was localized with E-cadherin and beta-catenin at sites of cell-cell contact in mouse L fibroblasts expressing E-cadherin (EL cells), and interacted with E-cadherin and beta-catenin both in vivo and in vitro. IQGAP1 induced the dissociation of alpha-catenin from a cadherin-catenin complex in vitro and in vivo. Overexpression of IQGAP1 in EL cells, but not in L cells expressing an E-cadherin-alpha-catenin chimeric protein, resulted in a decrease in E-cadherin-mediated cell-cell adhesive activity. Thus, IQGAP1, acting downstream of Cdc42 and Rac1, appears to regulate cell-cell adhesion through the cadherin-catenin pathway.

Animals↗
PubMed1998

Separation of microsomal cytochrome b5 via phase separation in a mixed solution of Triton X-114 and charged dextran.

The successful introduction of a charged dextran into the Triton X-114 phase separation system for the selective extraction of cytochrome b5 (cyt. b5) in liver microsomes is described. In the absence of charged dextran, 55% of total microsomal proteins and 84% of cyt. b5 were extracted into the surfactant-rich phase. In the presence of anionic dextran sulfate, the extractability of total microsomal proteins was greatly reduced while that of cyt. b5 was increased. After triplicate extraction, cyt. b5 was purified more than 10-fold from microsomes with a recovery of 91% in the surfactant-rich phase. In view of its operational simplicity, this method provides a good means for the partial purification of cyt. b5 prior to chromatographic separations.

Animals↗
PubMed1998

Induction of fertile estrus in bitches using a sustained-release formulation of a GnRH agonist (leuprolide acetate).

A single subcutaneous injection of a sustained-release formulation of a potent GnRH agonist, leuprolide acetate (LA; [D-Leu6, Pro9NEt]-GnRH), was evaluated as a method of inducing fertile estrus in 12 mature anestrous and 6 prepubertal beagle bitches. The bitches were treated with microencapsulated LA (100 micrograms/kg, s.c.) at 120 or 150 d post partum, or at 1 yr of age, followed by a GnRH-analogue (fertirelin; [Pro9NEt]-GnRH, 3 micrograms/kg, i.m.) on the first day of induced estrus. Signs of estrus were seen within 10.3 +/- 0.9 d after LA administration in all bitches. The interestrous interval in 120- and 150-d post-partum bitches was shortened (P < 0.05) to 191 +/- 3 and 222 +/- 3 d, respectively, compared with 264 +/- 11 d in control bitches. All LA treated dogs demonstrated behavioral estrus and mated. Three of 6 (50%) at 120 d post partum, 6 of 6 (100%) at 150 d post partum and 5 of 6 (83%) of prepubertal (1-yr old) bitches then became pregnant and produced a mean litter size of 4.1 +/- 0.8 pups. A normal circulating estrogen and progesterone response pattern was observed in mature anestrous bitches. A prepubertal bitch that failed to become pregnant had a similar estrogen response pattern but an insufficient progesterone profile. The results suggest that microencapsulated LA can be useful in inducing fertile estrus in the domestic dogs.

Anestrus↗
PubMed1998

Involvement of CD14 on human gingival fibroblasts in Porphyromonas gingivalis lipopolysaccharide-mediated interleukin-6 secretion.

The lipopolysaccharides (LPS) of Porphyromonas gingivalis are implicated in the initiation and development of periodontal diseases. However, the mechanisms underlying P. gingivalis LPS-mediated periodontal destruction are still unknown. Here, it was found that P. gingivalis LPS activates human gingival fibroblasts (HGF) to release interleukin 6 (IL-6) via CD14. Flow-cytometric analysis showed that HGFs bind to fluorescein-isothiocyanate (FITC)-labelled LPS, and express CD14 on their surfaces. The binding of FITC LPS was competitively suppressed by unlabelled synthetic lipid A as well as by LPS. LPS-induced IL-6 production was inhibited by anti-CD14 monoclonal antibody in a dose-dependent manner. The binding of FITC LPS to HGF was abrogated by anti-CD14 monoclonal antibody. Engagement of LPS initiated the protein tyrosine phosphorylation of several intracellular proteins including extracellular signal-regulated kinase (ERK) 1 and 2, and these events were suppressed by the anti-CD14 monoclonal. These results suggest that CD14 is a cell surface binding site for LPS and is involved in the LPS-mediated activation of HGF.

Antibodies, Monoclonal↗
PubMed1998

Evaluation of the colorectal wall in normal subjects and patients with ulcerative colitis using an ultrasonic catheter probe.

BACKGROUND: Ulcerative colitis is usually evaluated by barium enema and colonoscopy, methods of imaging that are limited to the mucosal surface. Endoscopic ultrasonography (EUS) is the best modality for the evaluation of transmural changes in the bowel wall. We therefore evaluated the colorectal wall in normal control subjects and patients with ulcerative colitis using an ultrasonic catheter probe. METHODS: Endoscopic ultrasound with a catheter probe was performed on 36 normal control subjects (36 examinations) and 72 patients (111 examinations) with documented ulcerative colitis. RESULTS: In normal control subjects, the total wall, mucosa, submucosa, and muscularis propria were significantly thicker in the rectum than in the colon. There was no significant difference in the thickness of the colon and rectum among different age groups or between men and women. In ulcerative colitis, we classified the boundary of each layer into three patterns (smooth, irregular, and blurred) and then classified the wall into six types. In Matts grade 2 and 3 ulcerative colitis lesions, the total wall and each layer were significantly thicker than lower grade lesions and normal control subjects. For grade 1 and most of the grade 2 lesions, the boundary of each layer was smooth. In some of the grade 3 lesions, the mucosa-submucosa and submucosa-muscularis propria layer borders were abnormal. In all grade 4 cases, the mucosa-submucosa boundary was blurred. There was some correlation between the Matts grade and EUS findings except for Matts grade 3 lesions which had various EUS patterns. CONCLUSION: Endoscopic ultrasound with a catheter probe is a useful modality for the transmural assessment of the colorectal wall and, when used in conjunction with the many clinical and endoscopic parameters currently available, may contribute to the diagnosis and treatment of ulcerative colitis.

Adult↗