Biomedical subjects

T Ishikawa

Publications and source records attributed to T Ishikawa.

At least 73 records · Page 4Linked to original sources

PubMed2003

The effect of rebamipide on Helicobacter pylori extract-mediated changes of gene expression in gastric epithelial cells.

BACKGROUND: Recent studies have shown that Helicobacter pylori affects intracellular signal transduction in host cells, leading to the activation of transcriptional factors and the induction of pro-inflammatory cytokines. On the other hand, rebamipide, an anti-gastritis and anti-ulcer agent, could scavenge reactive oxygen species and reduce interleukin-8 (IL-8) expression in gastric epithelial cells induced by H. pylori-stimulation through the attenuated activation of nuclear factor-kappaB (NF-kappaB). AIMS: In this study, we investigated the effects of rebamipide on gene expression in H. pylori-stimulated epithelial cells using DNA chip. METHODS: H. pylori water extract (HPE) was prepared from NCTC11637, the type strain of H. pylori. Total RNA was extracted from MKN45 cells, a human gastric cancer cell line, following HPE-stimulation with and without rebamipide for 3 h, and differences in gene expression profiles were observed using GeneChip and Human 6800 probe array. RESULTS: The GeneChip analysis demonstrated that 132 up-regulated genes and 873 down-regulated genes, such as growth factors, chemokines and transcription factors, were detected in MKN45 cells 3 h after stimulation of H. pylori. Among them, several genes, including bFGF, RANTES and MIP-2beta, were previously unknown to be expressed in H. pylori-stimulated human gastric cells. Rebamipide reduced expression of 119 genes encoding cytokines, growth factors and their receptors and transcription factors. CONCLUSIONS: These findings suggest that rebamipide could inhibit inflammatory reactions and tumour progression by modifying H. pylori infection-induced gene expression in gastric epithelial cells.

Alanine↗

PubMed2003

Inhibitory effects of interferon-gamma on the heterologous desensitization of beta-adrenoceptors by transforming growth factor-beta 1 in tracheal smooth muscle.

BACKGROUND: Transforming growth factor-beta1 (TGF-beta 1) is generally considered to play an important role in the pathogenesis of chronic inflammation and fibrosis. OBJECTIVE AND METHODS: This study was designed to determine mechanisms of reduced responsiveness of guinea-pig tracheal smooth muscle to beta-adrenoceptor agonists by TGF-beta 1, using isometric tension records and tissue cAMP measurement. Moreover, we examined the involvement of the signal transduction processes of TGF-beta superfamily in the desensitization of beta-adrenoceptors. RESULTS: After exposure to 0.2-2000 pm TGF-beta 1 for 4-8 h, the inhibitory effects of 1 microm isoprenaline (ISO) and 10 microm forskolin on 1 microm MCh-induced contraction were markedly reduced in a concentration-dependent fashion. The desensitization by TGF-beta 1 was greater against ISO than for forskolin. The values of EC75 for the curves for ISO after exposure to the normal bathing solution and TGF-beta 1 were 0.039 +/- 0.02 and 0.38 +/- 0.28 microm, respectively. The values of EC50 for the curves for forskolin under these conditions were 0.50 +/- 0.12 and 0.89 +/- 0.21 microm, respectively. On the other hand, the inhibitory effects of phosphodiesterase inhibitors such as theophylline and rolipram were not attenuated after exposure to TGF-beta 1. Concentration-inhibition curve for ISO was shifted to the right after exposure to 2000 pm TGF-beta 1 for 8 h more than that curve for forskolin. In contrast, the curve for theophylline was not shifted to the right by TGF-beta 1. When the tissues were incubated with TGF-beta 1 in the presence of IFN-gamma, an intracellular antagonist of TGF-beta signalling, IFN-gamma inhibited the reduced response to ISO and forskolin after exposure to TGF-beta 1 in a concentration-dependent fashion. After exposure to TGF-beta 1, the effects of cAMP accumulation of ISO was significantly reduced, however, neither forskolin-nor theophylline-induced cAMP accumulation was affected. IFN-gamma had no significant effect on cAMP accumulation either to ISO or forskolin. CONCLUSIONS: Impairment of the beta-adrenoceptors/adenylyl cyclase pathway are involved in heterologous desensitization of beta-adrenoceptors induced by TGF-beta 1 in airway smooth muscle. IFN-gamma functionally suppresses this phenomenon via cAMP-independent processes. Phosphodiesterase is still intact under this condition.

Adrenergic beta-Agonists↗

PubMed2003

Deposition and clearance for radon progeny in the human respiratory tract.

In vivo counting of 214Pb was conducted to estimate the deposition and retention of radon progeny in the human respiratory tract. Two volunteer subjects were exposed to high radon concentrations. After the exposures, activity deposited in the extrathoracic (ET) region for each subject was measured using a NaI(Tl) detector. According to the International Commission on Radiological Protection (ICRP) model, a reference value for particle transport rate from ET2 to the GI tract is 100 d(-1) (half-time, 10 min). The effective half-time of 214Pb deposited in the ET region was calculated for pure nose and mouth breathers, using the ICRP reference transport rate. While the measured half-times for nose breathers were generally consistent with the calculated values, those for mouth breathers were significantly larger than the calculated values. The results indicated that the particle transport rate from ET2 to the GI tract was much smaller than the reference value in the ICRP model.

Absorption↗

PubMed2003

Bio-kinetics of radon ingested from drinking water.

Previous studies have identified the stomach as the most significant organ for the dose from ingested radon. An important factor in dosimetric modelling is the rate of radon loss from the stomach. In the present study, two subjects who ingested radon-rich water were measured using a NaI(Tl) detector fixed over the stomach. The counting rates for 214Pb and 214Bi peak regions were plotted as a function of time after ingestion. These data were interpreted using a compartment model that expressed biokinetics of radon and its progeny. The model was fitted to the experimental data by changing biokinetic parameters such as the rate of radon loss from the stomach. Previous models for dosimetric purposes often assumed that the half-time for radon loss from the stomach is below 20 min. The present results, however, suggest that a part of radon stayed longer in the stomach than expected in the previous models.

Administration, Oral↗

PubMed2003

Quantitative assessment of the total myocardial uptake ratio of 123I-BMIPP by using the Ishii-MacIntyre method is useful for predicting cardiac complications in patients with mitochondrial encephalomyopathy or myotonic dystrophy.

We evaluated the usefulness of the total myocardial uptake ratio (TMUR) of 15-(p-[123I]iodophenyl)-3(R,S)-methyl-pentadecanoic acid (123I-BMIPP) for predicting cardiac complications in patients with mitochondrial encephalomyopathy or myotonic dystrophy. Six patients with mitochondrial encephalomyopathy, four with myotonic dystrophy, and 10 control subjects were studied. Quantitative assessment of 123I-BMIPP dynamic myocardial imaging was performed, and the TMUR of 123I-BMIPP was calculated according to the Ishii-MacIntyre method. Then, the TMUR was compared in the 10 patients and 10 healthy controls, and all patients were followed for 56.1+/-22.1 months to evaluate cardiac complications. TMUR in patients (2.69+/-0.64) was significantly (P =0.01) lower than that in controls (3.28+/-0.25). Three patients in whom the TMUR value was above 3.00 had no cardiac complications. On the other hand, all patients in whom TMUR was below 3.00 had some kind of cardiac complication during the follow-up period. Two patients showed progressive conduction abnormality and underwent pacemaker implantation, one patient had sick sinus syndrome and underwent pacemaker implantation, another patient showed non-sustained ventricular tachycardia and paroxysmal atrial fibrillation, and four of seven patients, including one with a pacemaker, showed an increased cardiothoracic ratio value over 50%. In conclusion, measurement of the TMUR by the Ishii-MacIntyre method is useful for evaluating the development of cardiac complications in patients with mitochondrial encephalomyopathy or myotonic dystrophy.

Adult↗

PubMed2003

[Off-pump coronary artery bypass grafting using donut and SPY].

Off-pump coronary artery bypass grafting (OPCAB) has been rapidly increased, because of its less invasiveness with low complications. However, graft patency rate highly depends on operators' capability due to technical difficulties. In this article, detail operative procedures are introduced to perform OPCAB in 100% for isolated coronary patients. Selecting better stabilizer may be a key of success. Donut Heart Stabilizer can make a still and stable operative field to anastomose less than 1 mm coronary artery. It is very useful to achieve complete revascularization for all stenosed coronary branches. OPCAB with 9 arterial grafts could be done using Donut. SPY Intra-operative Imaging System is also important to get 100% patency rate of the grafts. Using SPY, we can avoid graft trouble during operation in operation room (OR). SPY image is the best key information for operators to decide revision of the failed grafting. Donut 2 Heart Stabilizer has been improved to make more wide and stable operative field. Donut and SPY is the best combination for OPCAB.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2003

[Coronary endarterectomy and on-lay patch anastomosis in a case with unstable angina due to diffusely diseased coronary artery].

A 76-year-old woman with unstable angina due to diffusely diseased coronary artery successfully underwent coronary artery bypass grafting (CABG) using endarterectomy and on-lay patch anastomosis. She had triple vessel disease in the coronary artery and all of them were diffusely stenotic. It was impossible to undertake simple CABG. We were able to perform 3 coronary artery bypass grafting using endarterectomy and on-lay patch anastomosis. The postoperative course was uneventful and postoperative angiogram revealed well patent 3 grafts. Coronary endarterectomy and on-lay patch anastomosis were effective procedure in a patient with diffusely diseased coronary artery.

Aged↗

PubMed2003

[Left superior segmental resection for lung cancer with anomalous branching of the left A4 + 5; report of 2 cases].

We experienced with two cases of left superior segmental resection for lung cancer with the left A4 + 5 which arose from pars mediastinalis. Left superior segmental resection was performed on a 67-year-old female and an 81-year-old male. In both cases we divided A4 + 5 temporarily and anastomosed to pars interlobaris of the left pulmonary artery. As a result, it was able to perform safe division of bronchus. In cases with A4 + 5 arising from pars mediastinalis, operation is difficult and risky because A4 + 5 locates in front of the left upper lobe bronchus. It is safer to reconstruct A4 + 5 on pars interlobaris of the left pulmonary artery in such cases.

Adenocarcinoma↗

PubMed2002

Hyperfine structure of antiprotonic helium revealed by a laser-microwave-laser resonance method.

Using a newly developed laser-microwave-laser resonance method, we observed a pair of microwave transitions between hyperfine levels of the (n,L)=(37,35) state of antiprotonic helium. This experiment confirms the quadruplet hyperfine structure arising from the interaction of the antiproton orbital angular momentum, the electron spin and the antiproton spin as predicted by Bakalov and Korobov. The measured frequencies of nu(+)(HF)=12.895 96+/-0.000 34 GHz and nu(-)(HF)=12.924 67+/-0.000 29 GHz agree with recent theoretical calculations on a level of 6x10(-5).

Journal Article↗

PubMed2002

Differential gene expression profiles of gastric cancer cells established from primary tumour and malignant ascites.

Advanced gastric cancer is often accompanied by metastasis to the peritoneum, resulting in a high mortality rate. Mechanisms involved in gastric cancer metastasis have not been fully clarified because metastasis involves multiple steps and requires a combination of altered expressions of many different genes. Thus, independent analysis of any single gene would be insufficient to understand all of the aspects of gastric cancer peritoneal dissemination. In this study, we performed a global analysis of the differential gene expression of a gastric cancer cell line established from a primary main tumour (SNU-1) and of other cell lines established from the metastasis to the peritoneal cavity (SNU-5, SNU-16, SNU-620, KATO-III and GT3TKB). The application of a high-density cDNA microarray method made it possible to analyse the expression of approximately 21 168 genes. Our examinations of SNU-5, SNU-16, SNU-620, KATO-III and GT3TKB showed that 24 genes were up-regulated and 17 genes down-regulated besides expression sequence tags. The analysis revealed the following altered expression such as: (a) up-regulation of CD44 (cell adhesion), keratins 7, 8, and 14 (epitherial marker), aldehyde dehydrogenase (drug metabolism), CD9 and IP3 receptor type3 (signal transduction); (b) down-regulation of IL2 receptor gamma, IL4-Stat (immune response), p27 (cell cycle) and integrin beta4 (adhesion) in gastric cancer cells from malignant ascites. We then analysed eight gastric cancer cell lines with Northern blot and observed preferential up-regulation and down-regulation of these selected genes in cells prone to peritoneal dissemination. Reverse transcriptase-polymerase chain reaction confirmed that several genes selected by DNA microarray were also overexpressed in clinical samples of malignant ascites. It is therefore considered that these genes may be related to the peritoneal dissemination of gastric cancers. The results of this global gene expression analysis of gastric cancer cells with peritoneal dissemination, promise to provide a new insight into the study of human gastric cancer peritoneal dissemination.

Animals↗

PubMed2002

Thoracoscopic internal mammary sentinel node biopsy for breast cancer.

Sentinel node (SN) biopsy has changed the management of breast cancer. This pilot study assessed the utility of lymphatic mapping and thoracoscopic SN biopsy for internal mammary node (IMN) staging. Forty-nine breast cancer patients underwent lymphatic mapping using 99mTc-tin colloid. Patients with IMSNs underwent thoracoscopic biopsy. Lymphoscintigraphy showed IMSNs in 15 of 49 cases (31%). The incidence of IMN drainage was relationed to age and tumor location; 50% of patients younger than age 40 and 43% with tumors located in inner quadrants had IMN drainage. The thoracoscopic procedure was performed in 11 of 15 patients, and 18 IMSNs were removed; the time of the procedure ranged from 20 to 60 min. No patients had complications from the procedure. Two of 11 patients (18%) had IMSN metastasis, and one of them had only IMN metastasis. Lymphatic mapping and the thoracoscopic approach were useful for IMSN biopsy. They may enable the physician to make an appropriate treatment decision for breast cancer.

Adult↗

PubMed2002

The analysis of the usefulness of laparoscopic microwave coagulation therapy for hepatocellular carcinoma in patients with poor hepatic reserve by serial measurements of IL-6, cytokine antagonists, and C-reactive protein.

BACKGROUND: Little is known about the effectiveness of laparoscopic microwave coagulation therapy (L-MCT) for hepatocellular carcinoma (HCC) in patients with liver cirrhosis and poor hepatic reserve. Here, we analyzed the usefulness of laparoscopic MCT by comparing the serum levels of IL-6, cytokine antagonists, and C-reactive protein (CRP) following L-MCT with those following MCT with the open method (O-MCT). METHODS: Sixteen patients with hepatocellular carcinoma (HCC) were separated into L-MCT and O-MCT groups according to ICGR15 (ICGR15 30%<:L-MCT, 30%> :O-MCT). Nine patients with poorer hepatic reserve received L-MCT, while seven patients with relatively good hepatic reserve received O-MCT. Serum levels of cytokine antagonists (interleukin-6, IL-6; interleukin-1 receptor antagonist, IL-1ra; soluble tumor necrosis factor receptor type I, sTNF-R55) and C-reactive protein (CRP) were simultaneously measured on serial postoperative days (POD) by immunoassay. RESULTS: Postoperative serum levels of IL-6, IL-1ra, and CRP were significantly elevated on POD-1 and returned to the preoperative levels on POD-7 in both L-MCT and O-MCT groups. In contrast, no significant elevation of sTNF-R55 was found during the period in both groups. In addition, no statistical differences were found in the levels of IL-6, IL-1ra, sTNF-R, and CRP between the groups, except that the level of IL-6 on POD-1 in L-MCT group was significantly lower than that in the O-MCT group. CONCLUSION: These results suggested that the surgical stress by L-MCT in patients with poorer hepatic reserve were almost equal to that by O-MCT in patients with relatively good hepatic reserve, indicating the usefulness of L-MCT for HCC patients with poorer hepatic reserve. We recommend the laparoscopic approach for future patients with the criterion that ICGR15 is over 30%.

C-Reactive Protein↗

PubMed2002

SK4/IK1-like channels mediate TEA-insensitive, Ca2+-activated K+ currents in bovine parotid acinar cells.

Although Ca(2+)-activated K(+) (K(Ca)) channels distinct from maxi-K(+) channels have been suggested to contribute to muscarinically stimulated K(+) currents in salivary acinar cells, the molecular nature of the channels is unclear. Using electrophysiological and RT-PCR techniques, we have now investigated the involvement of SK4/IK1-like channels in native K(Ca) currents in bovine parotid acinar (BPA) cells. Ca(2+)-dependent K(+) efflux from perfused bovine parotid tissues was not inhibited by a maxi-K(+) channel blocker, tetraethylammonium (TEA). Whole cell recordings from BPA cells showed a TEA-insensitive K(Ca) conductance, which was highly permeable to Rb(+). In inside-out macropatches, TEA-insensitive Rb(+) currents were activated by Ca(2+) with half-maximal values of 0.4 microM. 1-Ethyl-2-benzimidazolinone (1-EBIO) increased the Ca(2+) sensitivity of the currents. The calmodulin antagonists trifluoperazine, calmidazolium, and W-7 inhibited the Ca(2+)-activated Rb(+) currents. In outside-out macropatches, Ca(2+)-activated Rb(+) currents were inhibited by Ba(2+), quinine, clotrimazole, and charybdotoxin but not by d-tubocrarine or apamin. RT-PCR analysis showed transcripts of SK4/IK1 in BPA cells. These results collectively suggest that SK4/IK1-like channels mediate the native K(Ca) currents in BPA cells.

Animals↗

PubMed2002

Primary populations of metastable antiprotonic (4)He and (3)He atoms.

Initial distributions of metastable antiprotonic (4)He and (3)He atoms over principal (n) and angular momentum (l) quantum numbers have been deduced using laser spectroscopy experiments. The regions n = 37-40 and n = 35-38 in the two atoms account for almost all of the observed fractions [(3.0 +/- 0.1)% and (2.4 +/- 0.1)%] of antiprotons captured into metastable states.

Journal Article↗

PubMed2002

Deterministic retrieval of surface waviness by means of topography with coherent X-rays.

A surface profile retrieval technique from multiple X-ray total reflection images taken at various distances with full coherent illumination is demonstrated. An experiment was performed using the 1 km-long BL29XU beamline at the SPring-8 facility, Japan. Obtained results are compared with results from the optical metrology technique (Fizeau's interferometer). Good agreement between X-ray and optical methods proves the validity of the current approach. Meanwhile, the sensitivity of the X-ray technique is several times higher than that of the standard one. This technique is well suited to the needs of characterizing grazing optics for new-generation X-ray sources.

Journal Article↗

PubMed2002

Measurement of x-ray pulse widths by intensity interferometry.

The pulse width of hard undulator radiation (32 ps width, energy 14 keV) was determined by intensity interferometry. The method, in combination with various x-ray monochromators, enables measurements to be taken over a wide range of time frames, from ns to fs. The applicable target includes measurements of ultrafast x-ray pulse widths from fourth generation synchrotron light sources.

Calibration↗

PubMed2002

X-ray interferometry with multicrystal components using intensity correlation.

A theoretical relation between intensity correlation and interference was experimentally verified for the case of a large-separation skew-symmetric bicrystal interferometer. The intensity correlation was enhanced in the angular range where the interference fringes were clearly observed. An application investigating the interference condition of the interferometer is presented using the intensity-correlation technique.

Journal Article↗

PubMed2002

Non-Fermi-liquid spin dynamics in CeCoGe3-xSi(x) for x = 1.2 and 1.5.

Muon spin relaxation has been measured in CeCoGe3-xSi(x) at the magnetic/nonmagnetic boundary compositions of x = 1.2 and x = 1.5. Both the alloys are found to exhibit an ordered region and a disordered region. At x = 1.2, short-range magnetic ordering is observed below 0.86 K in the ordered region. The disordered region is paramagnetic and the muon spin-lattice relaxation rate lambda2 in this region displays non-Fermi-liquid (NFL) spin dynamics, i.e., the power law lambda2 proportional to T0.72 which shows the formation of Griffiths phase. lambda2 in the x = 1.5 alloy displays logarithmic (NFL) scaling below 1 K, in agreement with the theory of a T = 0 K magnetic transition.

Journal Article↗