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T Ikehara

Publications and source records attributed to T Ikehara.

At least 19 recordsLinked to original sources
PubMed2002

Intracellular cytokine analysis of CD4-positive T cells predictive of sustained response to interferon therapy for patients with chronic hepatitis C.

We investigated whether the measurement of serum interleukin 18 (IL-18) and intracellular cytokine analysis of peripheral blood CD4-positive T cells (ICA-CD4+ Tc) of chronic hepatitis C (CH-C) patients before and two weeks after interferon (IFN) administration are useful for predicting sustained response to IFN. Twenty-nine CH-C patients received IFN every day for two weeks and three times a week for 22 weeks. Patients were divided into two groups: responders, in whom serum HCV-RNA was undetectable at the end of the follow-up (week 48), and nonresponders, in whom any other patterns were seen. Before and two weeks after IFN administration, serum IL-18 and ICA-CD4+ Tc as described by Jung et al were measured. Serum IL-18 and the relative prevalence of IFN-gamma+ and IL-4+, IFN-gamma+ and IL-4 (Th-1), and IFN-gamma- and IL-4+ cells in the responders were significantly increased, but only the relative prevalence of Th-1 cells in the nonresponders was increased two weeks after IFN therapy. In conclusion, ICA-CD4+ Tc and the measurement of serum IL-18 might be useful for predicting IFN therapy by comparing the results between before and two weeks after IFN.

CD4-Positive T-Lymphocytes↗
PubMed2001

Primary retroperitoneal pure yolk-sac tumor in an adult male.

Pure extragonadal tumors are rare in adult males. A 24-year-old male with an extremely high level of serum alpha-fetoprotein (32.795 ng/ml) was diagnosed by abdominal computed tomography as having a retroperitoneal tumor. A case of primary retroperitoneal pure yolk-sac tumor in an adult male is described.

Adult↗
PubMed2001

p300 forms a stable, template-committed complex with chromatin: role for the bromodomain.

The nature of the interaction of coactivator proteins with transcriptionally active promoters in chromatin is a fundamental question in transcriptional regulation by RNA polymerase II. In this study, we used a biochemical approach to examine the functional association of the coactivator p300 with chromatin templates. Using in vitro transcription template competition assays, we observed that p300 forms a stable, template-committed complex with chromatin during the transcription process. The template commitment is dependent on the time of incubation of p300 with the chromatin template and occurs independently of the presence of a transcriptional activator protein. In studies examining interactions between p300 and chromatin, we found that p300 binds directly to chromatin and that the binding requires the p300 bromodomain, a conserved 110-amino-acid sequence found in many chromatin-associated proteins. Furthermore, we observed that the isolated p300 bromodomain binds directly to histones, preferentially to histone H3. However, the isolated p300 bromodomain does not bind to nucleosomal histones under the same assay conditions, suggesting that free histones and nucleosomal histones are not equivalent as binding substrates. Collectively, our results suggest that the stable association of p300 with chromatin is mediated, at least in part, by the bromodomain and is critically important for p300 function. Furthermore, our results suggest a model for p300 function that involves distinct activator-dependent targeting and activator-independent chromatin binding activities.

Animals↗
PubMed2001

Heterochronous development of intrahepatic cholangiocellular carcinoma following hepatocellular carcinoma in a hepatitis B virus carrier.

A 68-year-old Japanese woman was admitted to our hospital in September 1995, because of a mass detected by ultrasonography during a follow-up examination for chronic hepatitis B. Hepatocellular carcinoma (HCC) in the right liver lobe was diagnosed based on imaging studies and elevated alpha-fetoprotein (AFP). Percutaneous ethanol injection therapy (PEIT) was performed. PEIT was repeated in November 1998, because the tumor had enlarged and serum AFP was re-elevated. Follow-up ultrasonography (US) demonstrated low echoic mass in the left liver lobe in August 1999; serum AFP was normal, but serum carbohydrate antigen 19-9 (CA19-9) was elevated to 420 U/ml. In October 1999, radiofrequency interstitial tissue ablation (RITA) was performed after tumor biopsy. Pathological findings revealed adenocarcinoma and pathological diagnosis was made as intrahepatic cholangiocellular carcinoma (ICC). Three weeks later, her serum CA19-9 was remarkably decreased (180 U/ml). The patient has been well for 5 months. Her latest AFP and CA19-9 in the serum were 2 ng/ml and 89 U/ml, respectively. The incidence of double cancer in the liver is rare. This is also the first case report to discuss ICC treated with RITA.

Aged↗
PubMed2000

p300-mediated acetylation facilitates the transfer of histone H2A-H2B dimers from nucleosomes to a histone chaperone.

We have used a purified recombinant chromatin assembly system, including ACF (Acf-1 + ISWI) and NAP-1, to examine the role of histone acetylation in ATP-dependent chromatin remodeling. The binding of a transcriptional activator (Gal4-VP16) to chromatin assembled using this recombinant assembly system dramatically enhances the acetylation of nucleosomal core histones by the histone acetyltransferase p300. This effect requires both the presence of Gal4-binding sites in the template and the VP16-activation domain. Order-of-addition experiments indicate that prior activator-meditated, ATP-dependent chromatin remodeling by ACF is required for the acetylation of nucleosomal histones by p300. Thus, chromatin remodeling, which requires a transcriptional activator, ACF and ATP, is an early step in the transcriptional process that regulates subsequent core histone acetylation. Glycerol gradient sedimentation and immunoprecipitation assays demonstrate that the acetylation of histones by p300 facilitates the transfer of H2A-H2B from nucleosomes to NAP-1. The results from these biochemical experiments suggest that (1) transcriptional activators (e.g., Gal4-VP16) and chromatin remodeling complexes (e.g., ACF) induce chromatin remodeling in the absence of histone acetylation; (2) transcriptional activators recruit histone acetyltransferases (e.g., p300) to promoters after chromatin remodeling has occurred; and (3) histone acetylation is important for a step subsequent to chromatin remodeling and results in the transfer of histone H2A-H2B dimers from nucleosomes to a histone chaperone such as NAP-1. Our results indicate a precise role for histone acetylation, namely to alter the structure of nucleosomes (e.g., facilitate the loss of H2A-H2B dimers) that have been remodeled previously by the action of ATP-dependent chromatin remodeling complexes. Thus, transcription from chromatin templates is ordered and sequential, with precise timing and roles for ATP-dependent chromatin remodeling, subsequent histone acetylation, and alterations in nucleosome structure.

Acetylation↗
PubMed2000

Effects on Rb(+)(K+) uptake of HeLa cells in a high K(+) medium of exposure to a switched 1.7 Tesla magnetic field.

Effects of a switched, time-varying 1.7 T magnetic field on Rb(+)(K+) uptake by HeLa S3 cells incubated in an isosmotic high K(+) medium were examined. The magnetic flux density was varied intermittently from 0.07-1.7 T at an interval of 3 s. K(+) uptake was activated by replacement of normal medium by high K(+) medium. A membrane-permeable Ca(2+) chelating agent (BAPTA-AM) and Ca(2+)-dependent K(+) channel inhibitors (quinine, charibdotoxin, and iberiotoxin) were found to reduce the Rb(+)(K+) uptake by about 30-40%. Uptake of K(+) that is sensitive to these drugs is possibly mediated by Ca(2+)-dependent K(+) channels. The intermittent magnetic field partly suppress ed the drug-sensitive K(+) uptake by about 30-40% (P < 0.05). To test the mechanism of inhibition by the magnetic fields, intracellular Ca(2+) concentration ([Ca(2+)]c) was measured using Fura 2-AM. When cells were placed in the high K(&plus;) medium, [Ca(2+)]c increased to about 1.4 times the original level, but exposure to the magnetic fields completely suppressed the increase (P < 0.01). Addition of a Ca(2+) ionophore (ionomycin) to the high K(+) medium increased [Ca(2+)]c to the level of control cells, regardless of exposure to the magnetic field. But the inhibition of K(+) uptake by the magnetic fields was not restored by addition of ionomycin. Based on our previous results on magnetic field-induced changes in properties of the cell membrane, these results indicate that exposure to the magnetic fields partly suppresses K(+) influx, which may be mediated by Ca(2+)-dependent K(+) channels. The suppress ion of K(+) fluxes could relate to a change in electric properties of cell surface and an inhibition of Ca(2+) influx mediated by Ca(2+) channels of either the cell plasma membrane or the inner vesicular membrane of intracellular Ca(2+) stores.

Calcium↗
PubMed2000

Hepatic abscess as a complication of the sump syndrome.

We report a case of hepatic abscess associated with the sump syndrome. The patient was a 66-year-old woman who had undergone cholecystectomy and side-to-side choledochoduodenostomy for a common bile duct (CBD) stone in 1983, and who presented with fever and right lower chest pain. A hepatic abscess was diagnosed; after it was drained, percutaneous transhepatic biliary drainage was performed. Bacteriological studies revealed the presence of Bacteroides fragilis and Streptococcus intermedius in the pus in the hepatic abscess cavity, and Klebsiella pneumoniae and Pseudomonas aeruginosa in the bile. The hepatic abscess and cholangitis rapidly resolved in response to two drainage procedures. At surgery, simple closure of the anastomosis was performed, because free drainage was observed from the distal CBD into the duodenum, despite the existence of a periampullary diverticulum.

Aged↗
PubMed2000

Amino acid sequences of hemoglobin from guinea fowl (Numida meleagri) and California quail (Lophortyx californica) with phylogenetic analysis of major groups of Galliformes.

We determined the complete amino acid sequences of the hemoglobin of two species, guinea fowl and California quail, in Galliformes from intact globin chain and chemical cleavage fragments in order to analyze the molecular evolution of hemoglobin for the classification of Galliformes. Galliformes have two types of hemoglobin components, HbA and HbD, which consist of identical beta chain and different alpha chains. The sequences are similar to globin chains of Galliformes reported previously. These sequences were compared with those of other Galliformes (Phasianidae, Meleagrididae) using duck and goshawk as out-groups. The phylogenetic tree of major groups of Galliformes based on hemoglobin was similar to the tree model produced based on the amino acid sequence of lysozyme c.

Amino Acid Sequence↗
PubMed1999

Stimulatory effect of enkephalins on calcium efflux from bovine adrenal chromaffin cells in culture.

The effects of leucine- and methionine-enkephalin, opiate peptides, on Ca2+ efflux from cultured bovine adrenal chromaffin cells were examined. These enkephalins stimulated the efflux of 45Ca2+ from cells in a concentration-dependent manner (10(-8) M-10(-6) M). Leucine-enkephalin did not increase the intracellular free Ca2+ level, 45Ca2+ uptake, catecholamine secretion, cAMP level or cGMP level. The peptide-stimulated 45Ca2+ efflux was not inhibited by incubation in Ca2+-free medium, but was inhibited by incubation in Na+-free medium. These results indicate that enkephalins stimulate extracellular Na+-dependent 45Ca2+ efflux from cultured bovine adrenal chromaffin cells, probably by stimulating membrane Na+/Ca2+ exchange.

Adrenal Medulla↗
PubMed1998

Effects of a time-varying strong magnetic field on transient increase in cytosolic free Ca2+ induced by bradykinin in cultured bovine adrenal chromaffin cells.

We tested the effects of exposure to a time-varying magnetic field changing between 0.07 and 1.7 T at an interval of 3 s on transient increase in intracellular Ca2+ stimulated by bradykinin in bovine adrenal chromaffin cells. Addition of bradykinin induced the increase in intracellular Ca2+ within a few minutes. The exposure to the magnetic field perfectly suppressed the increase in intracellular Ca2+ in Ca2+-free medium. The inhibition occurred for 15 min when the maximum magnetic flux density was more than 1.4 T. These results suggest that the exposure inhibits Ca2+ release from intracellular Ca2+ stores.

Animals↗
PubMed1998

Left acute scrotum associated with appendicitis.

A 10-year-old boy, who had a mild inguinal hernia in his left scrotum, was referred to our clinic because of redness of the scrotal skin and tenderness of the left scrotal contents. Scrotal echography showed a hypoechoic lesion around the normal testis and epididymis. Because torsion of either the testis or testicular appendage was suspected, the scrotum was opened and 1.5 mL of purulent fluid was observed in the tunica vaginalis with inflammatory tissue around the testis and epididymis. On the first postoperative day, a low grade fever and abdominal tenderness persisted, however, the abdomen was flat and soft. There was no marked tenderness over McBurney's point, but there was moderate tenderness over Lanz's point on deep palpation. Abdominal sonography and magnetic resonance imaging revealed abscess formation between the bladder and the sacrum. With a diagnosis of perforation of the appendix, a laparotomy was performed. The inguinal hernia sac could not be observed on inspection, and it was not possible to palpate the left side because of severe adhesion due to infection. Also, the neck of the right inguinal sac could not be seen. The appendix specimen was gangrenous. On the second postsurgical day, all symptoms and signs disappeared. We present this rare condition and discuss the difficulty in establishing a diagnosis.

Acute Disease↗
PubMed1998

Effects of electromagnetic fields on membrane ion transport of cultured cells.

We have studied the mechanisms of ion transport mediated by Na+/K(+)-pump and Na+,K+,Cl(-)-cotransport pathway of HeLa cells using Rb+ as an analog for K+, and proposed models of binding of ions for the transport pathways. Also, we clarified the relation between ion and water movements in the cells. Based on these findings, we have studied the effects of homogeneous and time-varying magnetic fields on the ion transport activity. The research presented here covers (i) brief explanations of our kinetic studies on the ion transport pathways for promoting understanding of the effects of magnetic fields on the pathways, (ii) our and other reports of the effects of magnetic fields on ion transport systems.

Carrier Proteins↗
PubMed1997

Overexpression of cyclin D1 and p53 associated with disease recurrence in colorectal adenocarcinoma.

Multiple genetic changes occur during the evolution of normal cells into cancer cells. It has been reported that both cyclin D1 and p53 genes play major roles in oncogenesis and/or cell cycle control in various cancers. In this study, we examined the overexpression of cyclin D1 and p53 by the immunohistochemical method and investigated the correlation between expression of these antigen and prognosis in patients with colorectal adenocarcinoma. Disease-free survival was significantly lower in the patients with cyclin D1-strongly positive tumors than in those with cyclin D1-negative tumors. Similarly, disease-free survival of the patients with p53-strongly positive tumors was significantly lower than that of those with p53-negative tumors. Moreover, multivariate analysis indicated that both cyclin D1 and p53 overexpression are independent prognostic factors in patients with colorectal adenocarcinoma. In conclusion, both cyclin D1 and p53 overexpression may be useful predictors of disease recurrence in patients with colorectal adenocarcinoma.

Adenocarcinoma↗
PubMed1997

Isolation and sequencing of two alpha-globin genes alpha(A) and alpha(D) in pigeon and evidence for embryo-specific expression of the alpha(D)-globin gene.

By screening a pigeon genomic DNA library, we isolated a recombinant phage clone containing the alpha(A)-globin gene. The DNA sequence of the approximately 6kbp-long insert fragment of the phage clone was determined. The sequence suggested the existence of pigeon alpha(D)-globin gene located 3.1 kbp upstream from the alpha(A)-globin gene. The expression of the alpha(D)-globin in late embryo was also shown by the N-terminal amino-acid sequence of the intact globin chain. These results show that two adult alpha-globin genes, alpha(A) and alpha(D), exist in the pigeon genome, and the alpha(D)-globin is expressed at the late embryo stage. The stage-specific expression suggests the existence of regulatory elements and factors interacting to inhibit transcription at the adult stage.

Amino Acid Sequence↗
PubMed1997

[Malignancy of colorectal cancer analyzed by expression of cyclin D1].

We evaluated the clinical significance of cyclin D1 expression in colorectal adenocarcinoma. One hundred twenty-three specimens resected from patients with colorectal cancers were investigated by staining with a monoclonal antibody against cyclin D1. The possible correlations among cyclin D1 expression, clinicopathologic factors and prognosis were studied. There was no significant association between cyclin D1 expression and various clinicopathological factors. However, disease-free survival was significantly worse in the patients with cyclin D1 strongly positive tumors than in those with cyclin D1 negative tumors. Cyclin D1 overexpression may be useful as a predictor of disease recurrence in patients with colorectal adenocarcinoma.

Adenocarcinoma↗
PubMed1996

Amino acid sequences of hemoglobin beta chains of five species of pinnipeds: Neophoca cinerea, Otaria byronia, Eumetopias jubatus, Pusa hispida, and Pagophilus groenlandica.

Pinnipeds (Otariidae, Odobenidae, and Phocidae) in the order Carnivora have one or two types (Hb I and Hb II) of hemoglobin components. These hemoglobins consist of identical beta chains and different alpha chains. We determined the complete amino acid sequences of the hemoglobin beta chain of three species of Otariidae (Australian sea lion, South American sea lion, and northern sea lion) and two species of Phocidae (ringed seal and harp seal) from intact beta chain and chemical cleavage fragments. The sequences are similar to beta chains of the already known sequences of pinnipeds. These sequences were compared with those of other carnivores (Mustelidae, Ursidae, Canidae, and Felidae) and adult human hemoglobin beta chain. Using Artiodactyla (pig) as an outgroup, we find that the tree constructed by means of phylogenetic analysis shows that Odobenidae is closest to Otariidae, and that Otariidae and Odobenidae are closer to Mustelidae than to Phocidae.

Amino Acid Sequence↗
PubMed1995

Blood flow velocity in the common carotid artery in humans during graded exercise on a treadmill.

Cerebral blood volume flow and flow velocity have been reported to increase during dynamic exercise, but whether the two increase in parallel and whether both increases occur as functions of exercise intensity remain unsettled. In this study, blood flow velocity in the common carotid artery was measured using the Doppler ultrasound method in eight healthy male students during graded treadmill exercise. The exercise consisted of stepwise progressive increases and decreases in exercise intensity. The peak intensity corresponded to approximately 85% of maximal oxygen consumption. During this exercise, the heart rate (fc), mean blood pressure (BP) in the brachial artery and mean blood flow velocity (vcc) in the common carotid artery increased as functions of exercise intensity. At the peak exercise intensity, fc, BP and vcc increased by 134.5%, 20.5% and 51.8% over the control levels before exercise (P < 0.01), respectively. The resistance index (RI) and pulsatility index (PI) were determined from the velocity profile and were expected to reflect the distal cerebral blood flow resistance. The RI and PI increased during the graded exercise, but tended to decrease at the highest levels of exercise intensity. As vcc increased with increases in exercise intensity it would be expected that cerebral blood flow would also increase at these higher intensities. It is also suggested that blood flow velocity in the cerebral artery does not proportionately reflect the cerebral blood flow during dynamic exercise, since the cerebral blood flow resistance changes.

Blood Flow Velocity↗