Biomedical subjects

T Sasaki

Publications and source records attributed to T Sasaki.

At least 55 records · Page 3Linked to original sources

PubMed2005

Clinico-pathological features of squamous cell carcinoma of the oral cavity in patients <40 years of age.

BACKGROUND: Considerable controversy exists in the literature regarding the clinical course of young patients with oral squamous cell carcinoma (SCC). The purpose of this study was to evaluate the clinico-pathological features of oral SCC among young people. METHODS: From a cohort of 529 patients diagnosed with SCC, 35 (6.6%) were under the age of 40 years. This group was compared to a control group of 110 cases aged over 40 to determine if there were any differences in clinicopathological features between the two groups. RESULTS: In the young group there were 20 males and 15 females. The site was most frequently the tongue (51.3%), followed by the floor of the mouth, the buccal mucosa, and the upper and lower alveolus and gingiva. The local and regional control rate was 64.8% which was similar to that of older patients in this series. CONCLUSIONS: The prognosis of oral SCC in the young patients does not appear to be different from that of the older population. Univariate analysis showed that clinical stage and the mode of invasion were the most significant prognostic factors in both younger and older patients.

Adult↗

PubMed2005

Interleukin-15 and transforming growth factor alpha are associated with depletion of tumor-associated macrophages in colon cancer.

We examined the effects of IL-15 and TGF-alpha on the inhibition of macrophage infiltration into colon cancer tissue, and secretion of amphoterin from colon cancer cells. Production of IL-15 and/or TGF-alpha was associated with depletion of tumor-associated macrophages (TAMs) in both Dukes' B and C tumors (P = 0.0324 and 0.0051, respectively). Production of IL-15 and/or TGF-alpha was also associated with amphoterin mRNA expression in colon cancer tissues with TAM depletion in both Dukes' B and C tumors (P = 0.0167 and P = 0.0062, respectively). WiDr human colon cancer cells treated with IL-15 and/or TGF-alpha induced reduction of nucleus-localized amphoterin and an increase in cytosolic and membranous amphoterin. Moreover, IL-15 and/or TGF-alpha treatment increased amphoterin secretion by WiDr cells. Most notably, IL-15 and TGF-alpha treatment induced the increase of cytosol/membrane localization and secretion of amphoterin and the most pronounced effect among the treatments carried out. These results suggested that IL-15/TGF-alpha promotes depletion of TAMs and secretion of amphoterin in colon cancer.

Antigens, CD↗

PubMed2005

[Infective endocarditis with splenic abscess and cerebral hemorrhage].

A 65-year-old man was admitted with ataxic gait and high fever. Brain magnetic resonance imaging (MRI) showed multiple cerebral hemorrhages and echocardiogram showed vegetations attached to the mitral valve and moderate mitral regurgitation. No microorganisms were identified by blood culture examination. Despite adequate treatment with antibiotics, large multiple splenic abscesses were detected by computed tomography (CT), the patient complained of fever and the value of CRP was increased again. We decided to first perform splenectomy, followed by mitral valve repair and maze operation. The pathology of the spleen showed findings consistent with large abscesses due to septic emboli. The postoperative course was uneventful.

Abscess↗

PubMed2005

High concentration of deoxycholic acid abrogates in vitro transformation of IEC6 intestinal cells by azoxymethane.

In this study, we designed an in vitro azoxymethane (AOM)-induced carcinogenesis model and analyzed the effect of deoxycholic acid (DCA) on growth, apoptosis, genotoxicity, and transformation of IEC6 intestinal cells. CYP2E1 production was confirmed in IEC6 cells. The growth of IEC6 cells was enhanced by DCA (100 microg/ml). However, IEC6 cells treated with DCA (200 microg/ml) were inhibited and disappeared at 48 hrs after treatment. Apoptotic cells increased 11.2 times by treatment with DCA (200 microg/ml) as compared to cells with no treatment. DNA injury detected by comet assay was found in cells treated with AOM, but not in cells treated with DCA (100 microg/ml) and AOM. The number of colony formation in soft agar increased by AOM treatment. However, the number of foci treated with DCA (100 microg/ml) plus AOM was 69% that of cells treated with AOM alone. Two out of the 6 mice subcutaneously injected with AOM-treated IEC6 cells showed tumorigenesis, whereas IEC6 cells treated with DCA (100 microg/ml) plus AOM or DCA (100 microg/ml) alone did not form any tumor. Reduced protein expression of MLH1, Bcl-2 was detected in IEC6 cells treated with DCA (100 microg/ml). Production of Bax, pJNK, TGF-beta, TGFBRI, TGFBRII, and beta-catenin were higher in IEC6 cells treated with DCA (100 microg/ml) than that in cells with no treatment. These results suggest that high-dose DCA induced apoptosis and inhibited AOM-induced in vitro transformation of IEC6 cells.

Animals↗

PubMed2004

Study on optimization for current distribution in magnetic stimulation therapy for urinary incontinence.

It has been reported that magnetic stimulation effectively eliminates urinary incontinence. However, this type of therapy has not been established as a practical treatment for urinary incontinence because of its poor power conversion efficiency and the leakage of current to regions other than that of the target of stimulation. It is therefore necessary to develop magnetic stimulators that are more efficient in stimulating the sphincter muscles and the peripheral nerves, and are more convenient than those presently available. By using a large-diameter coil, the magnetic stimulation method offers a larger current distribution over a wider area of the target region than electrical stimulation method, and the placement of the coil can be relatively easily changed to obtain better therapeutic results. We attempted, with a computer simulation model of the female abdomen, to simulate the distribution of the induced current density on the basis of biological tissue conductivity. We determined which method of stimulation is the most efficient by varying the stimulator coil location and size. A genetic algorithm (GA) was used for optimization.

Computer Simulation↗

PubMed2004

Evidence for an oscillatory signature in atmospheric neutrino oscillations.

Muon neutrino disappearance probability as a function of neutrino flight length L over neutrino energy E was studied. A dip in the L/E distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed L/E distribution constrained nu(micro)<-->nu(tau) neutrino oscillation parameters; 1.9x10(-3) 0.90 at 90% confidence level.

Journal Article↗

PubMed2004

Observation by an air-shower array in Tibet of the multi-TeV cosmic-ray anisotropy due to terrestrial orbital motion around the Sun.

We report on the solar diurnal variation of the galactic cosmic-ray intensity observed by the Tibet III air shower array during the period from 1999 to 2003. In the higher-energy event samples (12 and 6.2 TeV), the variations are fairly consistent with the Compton-Getting anisotropy due to the terrestrial orbital motion around the Sun, while the variation in the lower-energy event sample (4.0 TeV) is inconsistent with this anisotropy. This suggests an additional anisotropy superposed at the multi-TeV energies, e.g., the solar modulation effect. This is the highest-precision measurement of the Compton-Getting anisotropy ever made.

Journal Article↗

PubMed2004

Search for electron neutrino appearance in a 250 km long-baseline experiment.

We present a search for electron neutrino appearance from accelerator-produced muon neutrinos in the K2K long-baseline neutrino experiment. One candidate event is found in the data corresponding to an exposure of 4.8 x 10(19) protons on target. The expected background in the absence of neutrino oscillations is estimated to be 2.4+/-0.6 events and is dominated by misidentification of events from neutral current pi(0) production. We exclude the nu(micro) to nu(e) oscillations at 90% C.L. for the effective mixing angle in the 2-flavor approximation of sin((2)2theta(microe)( approximately 1/2sin((2)2theta(13))>0.15 at Deltam(2)(microe)=2.8 x 10(-3) eV(2), the best-fit value of the nu(micro) disappearance analysis in K2K. The most stringent limit of sin((2)2theta(microe)<0.09 is obtained at Deltam(2)(microe)=6 x 10(-3) eV(2).

Journal Article↗

PubMed2004

Limits on the neutrino magnetic moment using 1496 days of Super-Kamiokande-I solar neutrino data.

A search for a nonzero neutrino magnetic moment has been conducted using 1496 live days of solar neutrino data from Super-Kamiokande-I. Specifically, we searched for distortions to the energy spectrum of recoil electrons arising from magnetic scattering due to a nonzero neutrino magnetic moment. In the absence of a clear signal, we found micro(nu)</=(3.6x10(-10))micro(B) at 90% C.L. by fitting to the Super-Kamiokande day-night spectra. The fitting took into account the effect of neutrino oscillation on the shapes of energy spectra. With additional information from other solar neutrino and KamLAND experiments constraining the oscillation region, a limit of micro(nu)</=(1.1x10(-10))micro(B) at 90% C.L. was obtained.

Journal Article↗

PubMed2004

Imaging phase separation near the Mott boundary of the correlated organic superconductors kappa-(BEDT-TTF)2X.

Electronic phase separation consisting of the metallic and insulating domains with 50-100 microm in diameter is found in the organic Mott system kappa-[(h8-BEDT-TTF)(1-x)(d8-BEDT-TTF)x]2Cu[N(CN)2]Br by means of scanning microregion infrared spectroscopy using the synchrotron radiation. The phase separation appears below the critical end temperature 35-40 K of the first-order Mott transition. The observation of the macroscopic size of the domains indicates a different class of the intrinsic electronic inhomogeneity from the nanoscale one reported in the inorganic Mott systems such as high-Tc copper and manganese oxides.

Journal Article↗

PubMed2004

The gibberellic-acid insensitive dwarfing gene sdw3 of barley is located on chromosome 2HS in a region that shows high colinearity with rice chromosome 7L.

In this study, comparative high resolution genetic mapping of the GA-insensitive dwarfing gene sdw3 of barley revealed highly conserved macrosynteny of the target region on barley chromosome 2HS with rice chromosome 7L. A rice contig covering the sdw3-orthologous region was identified and subsequently exploited for marker saturation of the target interval in barley. This was achieved by (1) mapping of rice markers from the orthologous region of the rice genetic map, (2) mapping of rice ESTs that had been physically localized on the rice contig, or (3) mapping of barley ESTs that show strong sequence similarity to coding sequences present in the rice contig. Finally, the sdw3 gene was mapped to an interval of 0.55 cM in barley, corresponding to a physical distance of about 252 kb in rice, after employing orthologous EST-derived rice markers. Three putative ORFs were identified in this interval in rice, which exhibited significant sequence similarity to known signal regulator genes from different species. These ORFs can serve as starting points for the map-based isolation of the sdw3 gene from barley.

Blotting, Southern↗

PubMed2004

Dome-shaped magnetic phase diagram of thermoelectric layered cobaltites.

Using muon spin spectroscopy we have found that, for both NaxCoO(2) (0.6<or=x<or=0.9) and three- and four-layer cobaltites, a common low temperature magnetic state (which in some cases is manifest as an incommensurate spin density wave) forms in the CoO(2) planes. Here we summarize those results and report an almost dome-shaped relation between the transition temperature into the low-T magnetic state and the composition x for NaxCoO(2) and/or the high-temperature asymptotic limit of thermopower in the more complex three- and four-layer cobaltites. This behavior is explained using the Hubbard model on a two-dimensional triangular lattice in the CoO(2) plane.

Journal Article↗

PubMed2004

New proposal for T classification of gingival carcinomas arising in the maxilla.

When the current T classification of the UICC (1987 and 1997) is used to stage carcinomas arising the upper alveolus and gingival and hard palate, most cases are classified as T4 because of their anatomic characteristics, similar to carcinomas arising in the lower alveolus and gingiva. This study compared the following two methods for classifying the T stage of maxillary carcinomas: (1) the original T classification criteria proposed by the UICC (1987 and 1997), and (2) a new T classification criteria, called the sinus and nasal floor (SNF) criteria. We found that the SNF criteria were more closely related to tumor control and survival than were the UICC criteria in patients with carcinomas arising in the upper alveolus and gingival and hard palate. Increased use of the SNF criteria is expected to improve staging of gingival tumors arising in the maxilla and increase the accuracy of diagnosis, especially of T4 tumors.

Adenocarcinoma↗

PubMed2004

Functional analysis of the tumour suppressor gene PTEN in murine B cells and keratinocytes.

To investigate the roles of the PTEN (phosphatase and tensin homologue deleted from chromosome 10)/PI3K (phosphoinositide 3-kinase) signalling pathway in vivo, we have generated a series of mutant mice with null or tissue-specific gene-targeted deletions of Pten. Here we present our investigations of Pten function in B cells and keratinocytes in mice. Mice with a B cell-specific mutation of Pten showed increased serum autoantibodies and elevated numbers of B1a cells. Among conventional B (B2) cells in mutant spleens, numbers of marginal zone B cells were significantly increased, while those of follicular B cells were reciprocally decreased. Immunoglobulin class switch recombination was defective and associated with impaired induction of activation-induced cytidine deaminase. Mice with a keratinocyte-specific mutation of Pten exhibited epidermal hyperplasia, hyperkeratosis and accelerated skin morphogenesis. Within 3 weeks of birth, 90% of these animals died of malnutrition, possibly caused by hyperkeratosis of the oesophageal epithelia. Surviving mutant mice developed spontaneous skin tumours within 8.5 months of birth, and chemical treatment accelerated the onset of tumours. Our data show that PTEN is an important regulator in B cells and keratinocytes.

Animals↗

PubMed2004

Effect of sample thickness on bite force studied with a multiple-point sheet sensor.

The aim of this study was to investigate the relationship between thickness of sample food and bite force. We designed a new sensor that can detect the pressure distribution between the incisor and molar teeth on one side, and the contact area between the food samples and the teeth. The force and contact area were directly measured in real time using the multiple-point sheet sensor, which is a very thin and flexible pressure-sensing device. Silicone rubber blocks were used as a sample food and were chewed with incisors and molars by 10 healthy women. The peak force, contact area, duration and impulse were greater between the incisors for a thicker specimen. The active pressure, defined as the ratio of the force to contact area, at peak was similar for different thicknesses. In contrast, with a 2 mm thick sample, the peak force and force related parameters were greatest in molar chewing. The force, contact area and duration were greater for molar chewing cycles than incisor ones. We verified that the thickness of samples influenced the chewing force of humans and the effects differed between incisors and molars.

Adult↗

PubMed2004

Dieulafoy's lesion of the esophagus correctly diagnosed and successfully treated by the endoscopic injection of N-butyl-2-cyanoacrylate.

Dieulafoy's lesion is an arterial malformation in the subumucosal layer of the gastrointestinal tract that can cause massive bleeding. The esophagus is not a common location for this lesion. We present here a first report of Dieulafoy's lesion of the esophagus correctly diagnosed and successfully treated by the endoscopic injection of N-butyl-2-cyanoacrylate.

Aged↗

PubMed2004

Human airway submucosal glands augment eosinophil chemotaxis during rhinovirus infection.

BACKGROUND: Asthma exacerbations are frequently associated with rhinovirus (RV) infections. However, the contribution of airway submucosal gland (SMG) to exacerbations of asthma in RV respiratory infection has not been studied. OBJECTIVE: This study was undertaken to examine whether RV-infected human respiratory SMG cells produce pro-inflammatory cytokines and chemokines for eosinophils, and augment eosinophil transmigration across human airway epithelium. METHODS: We infected cultured human tracheal SMG cells with RV14, collected culture media at 1, 3, and 5 days after infection, and measured the chemotactic activity for eosinophils in the culture supernatant using a 48-well microchemotaxis chamber and a (51)Cr-labelled eosinophil transmigration assay. RESULTS: Exposing a confluent human tracheal SMG cell monolayer to RV14 consistently led to infection. Human SMG cells with RV infection secreted soluble factors activating human eosinophil chemotaxis into the culture supernatant in a time-dependent manner, and the culture supernatant significantly augmented the transmigration of (51)Cr-labelled eosinophils through human airway epithelial cell layers from the basal to mucosal side. These effects were completely abolished by a mixture of a monoclonal antibody regulated on activation, normal T cells expressed and secreted (RANTES) and an antibody to granulocyte macrophage-colony stimulating factor (GM-CSF). CONCLUSION: These results suggest that human respiratory SMG cells may augment eosinophil transmigration across the airway epithelium through the secretion of RANTES and GM-CSF after RV infection, and may contribute to exacerbations of asthma.

Adult↗

PubMed2004

Unusual hypersensitivity to warfarin in a critically ill patient.

A patient was admitted to the intensive care unit because of respiratory failure, and warfarin therapy was started at 2 mg/day for the treatment of pulmonary embolism, together with other medications. Despite the low dosage of warfarin, international normalized ratio (INR) was markedly elevated from 1.15 to 11.28 for only 4 days, and bleeding symptoms concurrently developed. Vitamin K2 was infused along with discontinuation of warfarin. One day later, the INR was found to have decreased, and bleeding was also improved. An objective causality assessment indicated a probable relationship between clotting abnormality and warfarin administration, although the degree of elevation of the INR was unusual in the light of the daily warfarin dose and duration of its exposure. Based on the clinical status of the patient, it was suspected that several conditions contributed to the abnormal hypersensitivity to warfarin. Contributory factors probably included pharmacokinetic interactions with co-administrated drugs, vitamin K deficiency caused by decreased dietary intake, reduced gut bacterial production, impaired intestinal absorption and hepatic synthetic capacity, and increased consumption of clotting factors. In view of our experience in the present case, it should be stressed that close monitoring of coagulation capacity is necessary in critically ill patients in order to avoid fatal haemorrhage after initiating warfarin therapy regardless of the dosage.

Aged↗