Biomedical subjects

H Tanaka

Publications and source records attributed to H Tanaka.

At least 55 records · Page 3Linked to original sources

PubMed2006

A functional MRI study: cerebral laterality for lexical-semantic processing and human voice perception.

BACKGROUND AND PURPOSE: Language dominance research using functional neuroimaging has made important contributions to clinical applications. Nevertheless, although recent neuroimaging studies demonstrated right-lateralized activation by human voice perception, the influence of voice perception in terms of language dominance has not been adequately studied. We aimed to accurately clarify language dominance for lexical-semantic processing in the temporal cortices by focusing on human voice perception. METHODS: Thirty normal right-handed subjects were scanned by functional MR imaging while listening to sentences (SEN), reverse sentences (rSEN), and identifiable nonvocal sounds (SND). We investigated cerebral activation and the distribution of individual Laterality Index under 3 contrasts: rSEN-SND, SEN-SND, and SEN-rSEN. RESULTS: The rSEN-SND contrast, including human voice perception, revealed right-lateralized activation in the anterior temporal cortices. Both SEN-SND and SEN-rSEN contrasts, including lexical-semantic processing, showed left-lateralized activation in the inferior and middle frontal gyrus and middle temporal gyrus. The SEN-rSEN contrast, without the influence of human voice perception, showed no temporal activation in the right hemisphere. Symmetrical or right-lateralized activation was observed in 22 of 27 subjects (81.4%) under the rSEN-SND contrast in the temporal cortices. Although 9 of 27 subjects (33.3%) showed symmetrical or right-lateralized activation under the SEN-SND contrast in the temporal cortices, all subjects showed left-lateralized activation under the SEN-rSEN contrast. CONCLUSION: Our results demonstrated that right-lateralized activation by human voice perception could mask left-lateralized activation by lexical-semantic processing. This finding suggests that the influence of human voice perception should be adequately taken into account when language dominance is determined.

Adult↗

PubMed2006

Relationship between variations in the circle of Willis and flow rates in internal carotid and basilar arteries determined by means of magnetic resonance imaging with semiautomated lumen segmentation: reference data from 125 healthy volunteers.

BACKGROUND AND PURPOSE: Volume flow rates in the feeding arteries of the brain are measured to evaluate blood flow dynamics in vascular disease. Although these flow values are thought to be effected by anatomic variations in the circle of Willis, few reports have described the effect. This study reports on the relationship between variations in the circle of Willis and volume flow rates in the bilateral internal carotid and basilar arteries of normal volunteers. METHODS: We prospectively examined 125 healthy volunteers by MR imaging. Variations in the circle of Willis were classified as "textbook" type, hypoplasia of the precommunicating segment of the anterior cerebral artery (A1), hypoplasia of the precommunicating segment of the posterior cerebral artery (P1), or "other." Volume flow rates were measured by 2D cine phase-contrast MR imaging. Lumen boundaries and volume flow rates were semiautomatically determined by pulsatility-based segmentation. RESULTS: Of the 117 subjects (61 men, 56 women; mean age, 23.6 years) considered suitable for flow measurement, 105 showed textbook type, and 6 each showed A1 hypoplasia and P1 hypoplasia. Total flow rates for the 3 variations were 781 +/- 151 mL/min (mean +/- SD), 744 +/- 119, and 763 +/- 129, respectively. Relative contributions by flow rates of the internal carotid arteries and the basilar artery for the 3 variations were 39.8%:38.9%:21.3%, 31.8%:49.1%:19.0%, and 46.6%:41.6%:11.7%, respectively, showing statistically significant differences. CONCLUSIONS: Variations in the circle of Willis correlate significantly with relative contributions by the flow rates of the bilateral internal carotid and basilar arteries.

Adult↗

PubMed2006

Promotive effects of hyperthermia on the inhibition of DNA synthesis in ehrlich ascites tumor cells by eicosapentaenoic and docosahexaenoic acids.

AIM: To evaluate inhibitory effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on DNA synthesis in combination with hyperthermia in vitro. METHODS: A suspension of Ehrlich ascites tumor cells (EAT) was mixed with DHA or EPA in a glass tube, heated at 37 degrees C, 40 degrees C, or 42 degrees C for 1 h in a water bath, and cultured at 37 degrees C for 19 or 96 h. DNA synthesis was assayed by monitoring of the incorporation of [3H]-thymidine into the acid-insoluble fraction. DHA or EPA incorporated into EAT cells was extracted and measured by thin-layer chromatography and gas-liquid chromatography. RESULTS: The inhibition of DNA synthesis by EPA or DHA increased markedly upon the treatment at 42 degrees C and 40 degrees C compared to that at 37 degrees C. At 37 degrees C, inhibitory action of EPA was more potent than that of DHA at low concentrations (at 50 microM -- DNA synthesis level: EPA, 63.1%; DHA, 87.9%), whereas inhibitory action of DHA was higher at 150 muM (16.7%, 4.4%, ibid.). The effect of DHA compared to EPA was more marked at 40 degrees C (29.0%, 19.2% at 100 microM) or 42 degrees C (19.7%, 10.6% at 100 microM). Evaluation of DNA synthesis rate in the cells treated for 1 h by EPA or DHA with the next culturing of EAT cells for 19 h resulted in the enhanced inhibitory activity of EPA even at concentrations as low as 50 microM at either 37 degrees C (0.5%, 11.3%) or 42 degrees C (0.6%, 4.5%), which in these conditions was higher than that of DHA. At the same time the rate of incorporation of EPA in EAT cells at 37 degrees C or 42 degrees C was lower than that of DHA. CONCLUSION: Administration of DHA or EPA in vitro significantly inhibit DNA synthesis, and such effect is enhanced by combination of PUFAs with hyperthermia.

Animals↗

PubMed2006

[Multiple recurrence of cardiac myxoma in a Carney complex patient 4 years after the first operation].

Carney complex is a rare syndrome which includes cardiac myxoma, hyperactive endocrine neoplasm, spotty pigmented skin, and extracardiac myxomatous tumors. We report a case of a 26-year-old woman with Carney complex in whom recurrent multiple cardiac myxomas were resected 4 years after the first operation for left atrial (LA) myxoma. She had a history of left adrenalectomy in 1997 for Cushing syndrome due to primary pigmented nodular adrenocortical disease (PPNAD). In February 2001, she was diagnosed with Carney complex because of evidence of LA myxoma, her spotty pigmented skin lesions, her past history and family history of cardiac myxoma in her mother. Then, LA myxoma was successfully resected through the superior trans-septal approach and has been followed-up by ultrasound cardiography (UCG) every 6-month after discharge. In January 2005, UCG revealed 2 masses in the LA and the right ventricle outflow tract. The 2nd surgery was performed in February 2005. We found the 3rd myxoma during surgery, resembling a flat polyp in the LA just at the inflow of the right upper pulmonary vein. All 3 myxomas were successfully resected. Sixteen months after the 2nd operation, she has been doing well without any sign of recurrence of myxoma.

Adult↗

PubMed2005

Symmetry-resolved absorption spectra of vibrationally excited CO2 molecules.

Symmetry-resolved x-ray absorption spectroscopy has been first carried out on high-temperature molecules. From the angle-resolved ion yield spectra of CO2 both at room temperature and at 430 degrees C, symmetry-resolved absorption profiles of the C 1s(-1) 2pi(u) and O 1s(-1) 2pi(u) resonances have been extracted for the vibrational ground state molecules and bending-vibration excited ones. The profiles change dramatically between them, and the Renner-Teller effect becomes more evident for the vibrationally excited molecules. The effects of the multimode vibronic coupling are suggested for the O 1s(-1) 2pi(u) and O 1s(-1) 3s sigma(g) resonances.

Journal Article↗

PubMed2005

Violation of the Franck-Condon principle due to recoil effects in high energy molecular core-level photoionization.

Carbon 1s photoelectron spectra of methane are measured over a photon energy range between 480 eV and 1200 eV. Additional components appear between the individual symmetric stretching vibrational components and are attributed to the excitations of asymmetric stretching and bending vibrations due to recoil of the high-energy photoelectron emission. This recoil effect is the evidence for the violation of the Franck-Condon principle which states that neither the positions nor the momenta of the nuclei change during the ionization event.

Journal Article↗

PubMed2005

Metastases-related genes in the classification of liver and peritoneal metastasis in human gastric cancer.

INTRODUCTION: With the aim of identifying metastases-related genes in gastric cancer, we performed a broad analysis of differential gene expression between low-metastatic parental cell lines and established highly metastatic sublines. MATERIALS AND METHODS: We established novel cell lines, AZ-H5c, NUGC-3H5, and TMK-1H7, with a high potential of liver metastasis, and AZ-P7a, NUGC-3P4T, and TMK-1P4a, with a high potential of peritoneal metastasis. These cell lines were derived from low-metastatic parental AZ-521, NUGC-3, and TMK-1 cell lines, respectively. Furthermore, to investigate different levels of gene expression implicated in metastatic potentials in gastric cancer, we investigated approximately 2000 expressed genes in each cell line using a DNA microarray. RESULTS: Varieties of genes were up-regulated or down-regulated in highly metastatic liver and peritoneal cell lines. Fifty-eight genes, including the transferrin receptor, ras-related rho, and osteopontin, and 22 genes, including apolipoprotein E and inhibin A-submit, were up-regulated and down-regulated in two or three liver metastatic sublines. On the other hand, 19 genes, the transferrin receptor, c-fos, and RANTES, and 26 genes, including MAC25, PISSLRE, and RNA polymerase, were up-regulated and down-regulated in two or three peritoneal metastatic sublines. CONCLUSION: How gene expression is implicated in gastric cancer metastasis has never been thoroughly explained, and further studies are necessary to understand the involvement of genes in cancer metastasis more thoroughly. We hope that our highly metastatic liver and peritoneal experimental models are helpful for further study and gene therapy of human gastric cancer.

Cell Line, Tumor↗

PubMed2005

Magnetoelastic coupling in the spin-dimer system TlCuCl3.

Based on high-resolution measurements of the thermal expansion and the magnetostriction we analyze the magnetoelastic coupling of TlCuCl3. We find that the phase boundary between the low-field spin liquid phase and the magnetic-field-induced Néel phase is extremely sensitive to pressure and would change by about +/-185%/GPa depending on the direction of uniaxial pressure. This drastic effect can unambiguously be traced back to the pressure dependencies of the intradimer coupling, whereas changes of the interdimer couplings under pressure play a minor role. The observed strong decrease of the interdimer coupling, when Tl is substituted by K, is therefore not a consequence of chemical pressure.

Journal Article↗

PubMed2005

New and reliable MRI diagnosis for progressive supranuclear palsy.

OBJECTIVE: To evaluate the area of the midbrain and pons on mid-sagittal MRI in patients with progressive supranuclear palsy (PSP), Parkinson disease (PD), and multiple-system atrophy of the Parkinson type (MSA-P), compare these appearances and values with those of normal control subjects, and establish diagnostic MRI criteria for the diagnosis of PSP. METHODS: The authors prospectively studied MRI of 21 patients with PSP, 23 patients with PD, 25 patients with MSA-P, and 31 age-matched normal control subjects. The areas of the midbrain tegmentum and the pons were measured on mid-sagittal MRI using the display tools of a workstation. The ratio of the area of the midbrain to the area of the pons was also evaluated in all subjects. RESULTS: The average midbrain area of the patients with PSP (56.0 mm2) was significantly smaller than that of the patients with PD (103.0 mm2) and MSA-P (97.2 mm2) and that of the age-matched control group (117.7 mm2). The values of the area of the midbrain showed no overlap between patients with PSP and patients with PD or normal control subjects. However, patients with MSA-P showed some overlap of the values of individual areas with values from patients with PSP. The ratio of the area of the midbrain to the area of pons in the patients with PSP (0.124) was significantly smaller than that in those with PD (0.208) and MSA-P (0.266) and in normal control subjects (0.237). Use of the ratio allowed differentiation between the PSP group and the MSA-P group. CONCLUSION: The area of the midbrain on mid-sagittal MRI can differentiate PSP from PD, MSA-P, and normal aging.

Aged↗

PubMed2005

Angular distribution of different vibrational components of the X and B states reached after resonant Auger decay of core-excited H2O: experiment and theory.

Vibrationally resolved spectra have been obtained for the lowest-lying cationic states X (2)B(1), A (2)A(1), and B (2)B(2) of the water molecule reached after participator resonant Auger decay of core-excited states. The angular distribution has been measured of the first four vibrational components of the X state in the photon energy regions including the O 1s-->4a(1) and the O 1s-->2b(2) core excitations, and for different portions of the vibrational envelope of the B state in the photon energy region including the O 1s-->2b(2) core excitation. For the X state, a large relative spread in beta values of the different vibrational components is observed across both resonances. For the B state, a very different trend is observed for the high binding energy side and the low binding energy side of the related spectral feature as a function of photon energy. A theoretical method based on the scattering K matrix has been used to calculate both the photoabsorption spectrum and the beta values, by taking both interference between direct and resonant photoemission and vibrational/lifetime interference into account. The numerical results show qualitative agreement with the trends detected in the experimental values and explain the conspicuous variations of the beta values primarily in terms of coupling between direct and resonant photoemission by interaction terms of different sign for different final vibrational states.

Journal Article↗

PubMed2005

Surface processes during sorption of aromatic molecules on medium pore zeolites.

The elementary steps of sorption and transport of benzene, toluene, and o- and p-xylene from the gas phase to hydroxy groups of zeolite H/ZSM-5 on the outer surface (SiOH groups) and in the pores (SiOHAl groups) were studied using pressure modulations followed by fast time-resolved IR spectroscopy. Sorption on these acid sites occurs via a common physisorbed state on the outer surface. The equilibration of the molecules in this state is fast compared to the sorption rates on SiOH and SiOHAl groups. The relative rates of equilibration of functional groups with the aromatic molecules suggest that the aromatic molecules move freely on the surface of the outer surface before reversibly binding to OH groups, entering the micropores or desorbing. Molecules able to enter into the pores (benzene, toluene, p-xylene) adsorb faster on SiOHAl groups than on SiOH groups. If the access of the molecules into the pores is sterically constrained (o-xylene), the rate of adsorption on the remaining accessible SiOH groups is strongly enhanced.

Journal Article↗

PubMed2005

Horizontal and vertical distribution of estrogenic activities in sediments and waters from Tokyo Bay, Japan.

Endocrine-disrupting chemicals with estrogenic activity (e.g., alkylphenols) have been detected in coastal Japan. We aimed to determine estrogenic activity in extracts of river water, seawater, sediments, and sediment cores from Tokyo Bay by in vitro gene expression assay. Fifty-one of 57 extracts had some estrogenic activity. E2 equivalents (ng E2 equivalents per gram dry weight or per liter above the limit of detection) in river water samples ranged from 0.70 to 4.01 ng/L; in seawater samples from 0.34 to 2.52 ng/L; and in surface sediments from 2.07 to 12.1 ng/g. The relationship between salinity and estrogenic activity in water samples suggested that fresh water is one source of environmental estrogens in Tokyo Bay. Fractionation of sediment extracts showed that the highest estrogenic activity was observed in the midpolar fraction. The observed activities were compared with activities mediated by known concentrations of nonylphenol, bisphenol-A, estrone, and 17beta-estradiol. In sediment collected near the sewage treatment plants, the estrogenic activity of the midpolar fraction could be explained about 34% by nonylphenol and estrone contained in this fraction. Core sediment measurements detected estrogenic activity from as far back as the 1960s. The regulations on the industrial wastewater in early 1970s would be one of the main reasons for the lower estrogenic activity in the upper section of the sediment core. The high estrogenic activities as measured in water and sediment samples from Tokyo might be restricted to certain coastal areas.

Biological Assay↗

PubMed2005

Individual fundamental mode dependence of H2O vibrational excitation in the 6-8 eV resonance region by electron impact.

Resonance phenomena in the bending (010), symmetric (100), and asymmetric (001) stretching vibrational modes in water (H(2)O) molecules have been investigated by measuring differential cross sections (DCSs) at fixed energy losses of 0.43, 0.46, 0.49, and 0.51 eV while sweeping the impact energies from 1.6 to 10 eV, at angles 60 degrees and 90 degrees, using a crossed-beam method. No resonancelike enhanced features have been observed in the study of the (010) mode. In the DCSs for the combined (100+001) mode, a single broad hump was observed at each angle, whose position shifts towards the higher energy side with increasing scattering angle, a feature typical of the interference profiles previously observed in a study of the (301) vibrational mode. DCSs for the (001) mode exhibited a rather isotropic angular distribution with no evidence of resonances. However, enhancement of DCSs were indeed observed for the (100) mode, at the energy loss of 0.46 eV, which is attributable to the A(1) symmetry resonance that was studied by Seng and Linder [J. Phys. B 9, 2539 (1976)], with a typical s-wave characteristic angular distribution. Theoretical analysis based on the continuum multiple-scattering approach has been carried out to provide rationale to the experimental results.

Journal Article↗

PubMed2005

Gene expression in spermiogenesis.

Germ cells convey parental genes to the next generation, and only germ cells perform meiosis, which is a mechanism that preserves the parental genes. The fusion of the products of germ cell meiosis, the haploid sperm and egg, creates the next generation. Sperm are the haploid germ cells that contribute genes to the egg. In preparation for this, the haploid round spermatids produced by meiosis undergo drastic morphological changes to become sperm. During this process of spermiogenesis, the nuclear form of the haploid germ cell takes shape, the mitochondria are rearranged in a specific manner, the flagellum develops and the acrosome forms. Spermatogenesis is supported by precise and orderly regulation of gene expression during the changes in chromatin structure, when protamine replaces histone. In this report, we summarize the molecular mechanisms involved in spermiogenesis.

Animals↗

PubMed2005

Changes in serum and red blood cell membrane lipids in patients treated with interferon ribavirin for chronic hepatitis C.

One of the side effects by interferon ribavirin (I/R) treatment is haemolytic anemia, causing some patients to discontinue I/R treatment. The exact mechanism of I/R-induced anemia is unknown. The aim of this study is to evaluate the effects of I/R treatment on the serum lipid and red blood cell (RBC) membrane lipid profiles of patients with chronic hepatitis C (CHC) and the association between changes of RBC membrane lipids and haemolytic anemia by I/R treatment. Fourteen patients with CHC were treated with I/R and their serum lipid profiles were studied. In addition, in seven of the 14 patients, the RBC membrane lipid profiles were analysed. In the RBC membrane lipid composition, the total cholesterol, total phospholipids and cholesterol/phospholipids (C/PL) ratio were significantly increased. Phosphatidylcholine (PC) and the phosphatidylcholine/ sphingomyelin (PC/SM) ratio were significantly decreased and other phospholipid fractions were significantly increased. Changes in the serum lipids and RBC membrane lipid profiles of patients with CHC treated with I/R were shown. Especially, a decrease in the RBC deformability and membrane fluidity by changes in these RBC membrane lipids was supposed and it is suggested that those changes may result in haemolytic anemia by I/R treatment.

Adult↗

PubMed2005

Light/dark cyclic movement of algal culture (Synechocystis aquatilis) in outdoor inclined tubular photobioreactor equipped with static mixers for efficient production of biomass.

Synechocystis aquatilis SI-2 was grown outdoors in a 12.5 cm diam. tubular photobioreactor equipped with static mixers. The static mixers ensured that cells were efficiently circulated between the upper (illuminated) and lower (dark) sections of the tubes. The biomass productivity varied from 22 to 45 g m-2 d-1, with an average of 35 g m-2 d-1, etc which corresponded to average CO2 fixation rate of about 57 g CO2 m-2 d-1. The static mixers not only helped in improving the biomass productivities but also have a high potential to lower the photoinhibitory effect of light during the outdoor cultures of algae.

Biomass↗

PubMed2005

Assessment of talus deformity by three-dimensional MRI in congenital clubfoot.

PURPOSE: To evaluate the morphological deformity of talus in congenital clubfoot by three-dimensional MRI. MATERIAL AND METHOD: Subjects were five patients (two male, three female, mean age 5 months) with unilateral congenital clubfoot. Magnetic resonance imaging was performed of both feet using 1.5 T magnet. Based on the resulting magnetic resonance imaging volume data, a three-dimensional surface bone model was reconstructed by the Marching Cubes method. The long axis of the reconstructed model was determined, and in relation to the standard planes including this axis, the degree of talar head and neck deviation, and the relative positioning of the talus and navicular in the talonavicular joint were compared between normal foot and clubfoot. RESULT: The talar head and neck angle in relation to the talus exhibited significant medial deviation in the clubfoot, but the degree of plantar deviation of the talar head and neck did not show significance. The navicular was located more medially in clubfoot than in normal foot. The volume of the total talar and of the ossific nucleus for the clubfoot was smaller than that for the normal foot. CONCLUSION: The assessment technique presented herein was shown to be useful in ascertaining the various pathological characteristics associated with clubfoot.

Ankle Joint↗

PubMed2005

Recurrence rate and transplantability after liver resection in patients with hepatocellular carcinoma who initially met transplantation criteria.

To understand the recurrence rate and transplantability after liver resection (LR), which are essential factors to predict the prognosis of initial resection and salvage transplantation for hepatocellular carcinoma (HCC), we reviewed the clinical records of 279 consecutive HCC patients who met the Milan criteria and underwent LR between 1990 and 2000. Recurrence-free survival rates after 1, 2, 3, 5, and 10 years following LR were 84%, 62%, 49%, 29%, and 17%, respectively. Multivariate analysis using clinical factors such as age, sex, histological differentiation, serum levels of alpha-fetoprotein and 7S domain of type IV collagen (7S collagen), platelet counts, indocyanin green retention test after 15 minutes, and type of LR (resection of one or more segments, or less than one segment) revealed 7S collagen to be a independent factor that significantly affects recurrence-free survival. Yearly recurrence rates up to 5 years after resection ranged from 14% to 27%, averaging 20%. Concerning 169 patients who underwent tests for 7S collagen, the average yearly recurrence rate (27%) in patients with 7S collagen levels 8.0 ng/mL or higher was remarkably greater than that in the patients with levels less than 8.0 ng/mL (16%). The transplantability rate at the time of recurrence meeting the Milan criteria was roughly 60%. There were no pre-LR factors that significantly predicted transplantability. This result indicates that patients with lower 7S collagen levels are more eligible for initial LR and then salvage LT rather than primary LT.

Adult↗