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Biomedical subjects

S Takagi

Publications and source records attributed to S Takagi.

At least 19 recordsLinked to original sources
PubMed2006

Effectiveness of an 'half elemental diet' as maintenance therapy for Crohn's disease: A randomized-controlled trial.

BACKGROUND: Although thiopurines have a proven role in maintenance therapy for Crohn's disease, an alternative therapy is needed for patients intolerant or resistant to thiopurines. AIM: To evaluate the effectiveness of home enteral nutrition as a maintenance therapy regimen in which half of the daily calorie requirement is provided by an elemental diet and the remaining half by a free diet. We refer to this home enteral nutrition therapy as 'half elemental diet'. METHODS: Between 2002 and 2005, 51 patients in remission from two hospitals were randomly assigned to a half elemental diet group (n = 26) or a free diet group (n = 25). The primary outcome measure of this study was the occurrence of relapse over the 2-year period. RESULTS: The relapse rate in the half elemental diet group was significantly lower [34.6% vs. 64.0%; multivariate hazard ratio 0.40 (95% CI: 0.16-0.98)] than that in the free diet group after a mean follow-up of 11.9 months. Compliance was similar in the two groups. No adverse event occurred in any of the patients throughout the study. CONCLUSION: This randomized-controlled trial shows the effectiveness of an half elemental diet, which is a promising maintenance therapy for Crohn's disease patients.

Adult↗
PubMed2006

Possible association of actin filaments with chloroplasts of spinach mesophyll cells in vivo and in vitro.

In palisade mesophyll cells of spinach (Spinacia oleracea L.) kept under low-intensity white light, chloroplasts were apparently immobile and seemed to be surrounded by fine bundles of actin filaments. High-intensity blue light induced actin-dependent chloroplast movement concomitant with the appearance of a couple of long, straight bundles of actin filaments in each cell, whereas high-intensity red light was essentially ineffective in inducing these responses. The actin organization observed under low-intensity white light has been postulated to function in anchoring chloroplasts at proper intracellular positions through direct interaction with the chloroplasts. Intact chloroplasts, which retained their outer envelopes, were isolated after homogenization of leaves and Percoll centrifugation. No endogenous actin was detected by immunoblotting in the final intact-chloroplast fraction prepared from the leaves kept under low-intensity white light or in darkness. In cosedimentation assays with exogenously added skeletal muscle filamentous actin, however, actin was detected in the intact-chloroplast fraction precipitated after low-speed centrifugation. The association of actin with chloroplasts was apparently dependent on incubation time and chloroplast density. After partial disruption of the outer envelope of isolated chloroplasts by treatment with trypsin, actin was no longer coprecipitated. The results suggest that chloroplasts in spinach leaves can directly interact with actin, and that this interaction may be involved in the regulation of intracellular positioning of chloroplasts.

Actin Cytoskeleton↗
PubMed2006

Low-temperature spin diffusion in a highly ideal S=1/2 Heisenberg antiferromagnetic chain studied by muon spin relaxation.

The organic radical-ion salt DEOCC-TCNQF4 contains linear chains of stacked molecules with significant Heisenberg antiferromagnet interactions along the chain and extremely weak interactions between the chains. Zero-field muSR has confirmed the absence of long-range magnetic order down to 20 mK and field-dependent muSR is found to be consistent with diffusive motion of the spin excitations. The anisotropic spin dynamics and the upper boundary for magnetic ordering temperature both indicate interchain magnetic coupling /J'/<7 mK. As the intrachain coupling J is 110 K, /J'/J/ is significantly less than 10(-4). This system therefore provides one of the most ideal examples of the one-dimensional S=1/2 Heisenberg antiferromagnet yet discovered.

Journal Article↗
PubMed2006

Blood vessel density correlates with the effects of targeted intra-arterial carboplatin infusion with concurrent radiotherapy for squamous cell carcinomas of the oral cavity and oropharynx.

Our aim was first to evaluate the association between blood vessel density (BVD) and free platinum concentration in experimentally induced tumours in rabbits. We also investigated the association between tumour BVD and the clinical response of patients who had undergone targeted carboplatin intra-arterial (i.a.) chemoradiotherapy. VX2 carcinoma cells were transplanted into 46 inbred female Japanese white rabbits. In the i.a. group, carboplatin was infused into the lingual artery, and in the intravenous (i.v.) group, carboplatin was infused through the auricular vein. In the clinical study, we evaluated 19 patients with squamous cell carcinomas of the oral cavity and oropharynx, who had undergone targeted carboplatin i.a. chemoradiotherapy and had been administered i.a. tegafur/uracil chemotherapy before surgery. We quantified angiogenesis in both studies. Increased BVD was associated with a higher free platinum concentration in the tumour region in the i.a. group of rabbits. In the clinical study, using multivariate logistic regression analysis, only the BVD was related independently to the treatment effect. Therefore, BVD is a valid predictor of the effects of i.a. targeted carboplatin chemotherapy and concurrent radiotherapy for treating human oral and oropharyngeal squamous cell carcinomas.

Animals↗
PubMed2006

Clinical pharmacokinetics of anti-angiogenic photodynamic therapy with benzoporphyrin derivative monoacid ring-A in dogs having naturally occurring neoplasms.

The aim of this study was to examine the pharmacokinetics of clinically applied benzoporphyrin derivative monoacid ring-A (BPD-MA; Verteporfin), a second-generation photosensitizer, during a trial of photodynamic therapy (PDT) in nine dogs having naturally occurring neoplasms. After injecting BPD-MA at 0.5 mg/kg intravenously, its mean half-life (t1/2) was found to be 8.14 +/- 5.34 h, mean clearance (Cl) 35.13 +/- 9.62 ml/(h kg), the mean value of the volume of distribution (Vc) 0.08 +/- 0.01 l/kg and the mean steady state volume of distribution (Vss) 0.38 +/- 0.31 l/kg respectively. With the exception of a transitional increase in serum alkaline phosphatase activity, no other clinical abnormalities were observed. The t1/2 in dogs with naturally occurring tumours was longer than that in humans, but similar to that in rats. The values of Cl and Vss in dogs having naturally occurring neoplasms were lower than those in humans. It is suggested that the pharmacokinetics of BPD-MA in tumour-bearing dogs would be helpful in determining the protocol of a short drug-light interval PDT with BPD-MA that mainly targets the tumour vasculature.

Animals↗
PubMed2006

Effect of a calcium prerinse on salivary fluoride after a 228-ppm fluoride rinse.

The objective of this study was to determine if a concentrated calcium prerinse given before a fluoride rinse would cause an increase in the post rinse sali vary fluoride (F). A panel of 5 subjects used a 30, 150 or 300 mmol/l calcium lactate prerinse followed by a 1-min NaF rinse. All calcium prerinses significantly increased the 1-hour saliva F relative to the NaF control without a prerinse. The maximum increase was produced by the 150 mmol/l calcium lactate prerinse and was about ninefold higher than the NaF control.

Calcium Compounds↗
PubMed2006

Salivary fluoride from fluoride dentifrices or rinses after use of a calcium pre-rinse or calcium dentifrice.

The low concentration of available calcium (Ca) in oral fluids limits the formation of Ca-mediated fluoride deposits that maintain oral fluoride (F) after a topical F treatment. The purpose of this study was to examine if a high concentration of Ca would increase salivary F when used before a F rinse or dentifrice. We found that a Ca pre-rinse (150 mmol/l Ca lactate) or Ca dentifrice (0.084 g Ca glycerolphosphate per gram dentifrice) used immediately before a 60 s 228-ppm F rinse (12 mmol/l NaF) produced a 4.6x or 3.6x increase (p < 0.05) respectively in the 1 h salivary F concentrations over the F rinse alone. Reducing the post-Ca F rinse to 10 s still produced a significant 2.2x increase in salivary F compared to the 60 s F rinse alone. Used with a conventional 1,100 ppm F (i.e. 1,100 microg F per gram) NaF dentifrice (Crest), the above Ca pre-rinse increased 1 h salivary F levels by 2.3x over the F dentifrice alone. However, a F rinse given before a Ca rinse produced no increase in 1 h salivary F concentrations. Although the persistence of these increases requires further study, these results suggest that a moderately high concentration of Ca given shortly before a F rinse or F dentifrice may increase the cariostatic effect of the F product.

Biological Availability↗
PubMed2006

Nano DCPA-whisker composites with high strength and Ca and PO(4) release.

The main challenges facing composite restorations are secondary caries and bulk fracture. The objective of this study was to develop nano DCPA (dicalcium phosphate anhydrous)-whisker composites with high strength and Ca and PO(4) ion release to combat caries. Flexural strength for the nano DCPA-whisker composites at a nano DCPA:whisker mass ratio of 1:2 ranged from (148 +/- 9) MPa to (167 +/- 23) MPa, significantly higher than the (103 +/- 32) MPa of an inlay/onlay commercial control composite without Ca-PO(4) release. The nano DCPA-whisker composite released PO(4) to a concentration of (1.95 +/- 0.13) mmol/L and Ca of (0.68 +/- 0.05) mmol/L. Compared with previous conventional Ca- and PO(4)-releasing composites, the nano DCPA-whisker composites had strengths two-fold higher, and released comparable or higher levels of Ca and PO(4). In conclusion, combining nano-DCPA with whiskers yielded novel composites that released high levels of Ca and PO(4) requisite for remineralization. These high-strength composites may provide a unique combination of stress-bearing and caries-inhibiting capabilities.

Analysis of Variance↗
PubMed2005

Vasodilative effect of perillaldehyde on isolated rat aorta.

The vasodilative effect of perillaldehyde, one of the major oil components in Perilla frutescens BRITTON, was studied using isolated rat aorta. Perillaldehyde at final concentrations of 0.01 to 1 mM showed dose-dependent relaxation of the aorta contracted by treatment with prostaglandin F2alpha or norepinephrine. Neither the presence of NG-nitro-L-arginine methyl ester nor removal of the aortic endothelium affected the vasodilatation, suggesting that perillaldehyde exerts a direct effect on vascular smooth muscle cells. The vasodilative effect of perillaldehyde was not inhibited by pretreatment with a beta-adrenergic receptor blocker (propranolol), an inhibitor of phosphodiesterase (theophylline), a delayed rectifier K+ channel blocker (tetraethylammonium chloride), or an ATP-sensitive K+ channel blocker (glibenclamide). However, perillaldehyde showed contrasting effects on vasodilatation of the aorta contracted by an influx of extracellular Ca2+ - perillaldehyde caused little vasodilatation on the aorta contracted by the Ca2+ ionophore A23187, while it inhibited the vasoconstriction induced by treatment with high-concentration K+, which dominantly opened the voltage-dependent Ca2+ channel. These results suggest that the vasodilative effect of perillaldehyde is derived from blocking the Ca2+ channels.

Animals↗
PubMed2005

Significance of colonoscopy in patients with intestinal graft-versus-host disease after hematopoietic stem cell transplantation.

BACKGROUND AND STUDY AIMS: Patients with intestinal graft-versus-host disease (GVHD) are generally in poor clinical condition. In this study we aimed to establish the clinical significance of endoscopic diagnosis of this condition, observing only the distal section of the large intestine. PATIENTS AND METHODS: Endoscopic and pathological findings at colonoscopy were evaluated retrospectively in 12 patients who were diagnosed with intestinal GVHD after undergoing hematopoietic stem cell transplantation. RESULTS: The main mucosal changes observed at endoscopy were granular change, edema, "spotty redness", and sloughing. These were clearly displayed after enhancement with Indigo carmine staining, and with insertion of the colonoscope only as far as the distal section of the large intestine. A histological diagnosis of intestinal GVHD was made in 50 % of the patients, whose intestinal epithelium specimens showed numerous apoptotic bodies. It was possible to perform total colonoscopy in two patients who were in relatively good condition clinically, but there were no remarkable differences in the endoscopic findings throughout the large intestine, from the terminal ileum to the rectum. In terms of clinical outcomes of the 12 patients, their prognosis was poor in that they all either went on to suffer from chronic GVHD or died. CONCLUSIONS: Endoscopic and histological findings on distal colonoscopy are clinically significant in the diagnosis of intestinal GVHD, and limiting this examination to the distal section of the large intestine avoids causing further clinical deterioration in patients who are already in very poor general condition and the possibility of causing endoscopy-related complications.

Adolescent↗
PubMed2005

Incidence of insulin resistance in obese subjects in a rural Japanese population: the Tanno and Sobetsu study.

OBJECTIVES: Although it is well known that obesity is closely related to insulin resistance, the incidence of the development of insulin resistance in people with obesity is not known. In this study, we investigated the incidence of insulin resistance in citizens of two rural communities in Japan. SUBJECTS AND METHODS: The subjects were 102 men and 126 women over the age of 30 years selected from 1035 citizens who had undergone medical examinations in the towns of Tanno and Sobetsu, Hokkaido, in 1991 and 1998. Those who were on medication for hypertension, diabetes, hyperlipidaemia, coronary heart disease and cerebral vessel disease were excluded. The simple index to determine insulin resistance [i.e. homeostasis model assessment (HOMA-R) > or = 1.73] was used, and subjects who were determined to be positive for insulin resistance according to this index in 1991 were also excluded in order to determine the incidence of insulin resistance in subjects who had no abnormalities other than obesity. The systolic blood pressure (SBP), diastolic blood pressure, body mass index (BMI), triglyceride level, high-density lipoprotein level, blood sugar level, serum insulin value and HOMA-R were measured in all subjects in 1991 and in 1998. Moreover, the subjects were divided into two groups according to BMI, a normal group consisting of subjects with BMI < 25 and an obesity group consisting of subjects with BMI > or = 25. We also compared the incidences of insulin resistance in normal and obesity groups of subjects who were newly determined to be positive for insulin resistance on the basis of data obtained from medical examinations conducted in 1998. RESULTS: The incidence of insulin resistance was significantly higher in the obesity group than in the normal group (25.0 vs. 4.5%). The results of logistic regression analysis showed that obesity was closely related to insulin resistance and that the relative risk of development of insulin resistance adjusted for age, sex, SBP, FPG and HDL was 3.193 (95% CI 1.085-9.401). CONCLUSIONS: The incidence of insulin resistance was significantly higher in the obesity group than in the normal group in this study, suggesting that improvement in obesity is important for prevention of the occurrence of type 2 diabetes or atherosclerotic disease based on insulin resistance.

Adult↗
PubMed2005

Urethral transitional cell carcinoma in a cat.

A 15-year-old, male neutered cat was referred for investigation of dysuria. A retrograde urethrography was performed which showed two space-occupying masses within the lumen of the mid-to-proximal urethra. Exploratory coeliotomy revealed two urethral masses. Segmental urethrectomy was performed to resect the mass, and the lower urinary tract was reconstructed by vesico-urethral anastomosis. Histopathology showed the mass to be a transitional cell carcinoma with incomplete surgical margins. Tumour regrowth was suspected when dysuria was found approximately 318 days after surgery. Clinical signs were palliated by radiation using weekly fractions of 6 Gy for three weeks. The cat died of unknown causes 386 days postoperatively.

Anastomosis, Surgical↗
PubMed2004

Inhibition of endotoxin- and antigen-induced airway inflammation by fudosteine, a mucoactive agent.

We evaluated the effect of a mucoactive agent (-)-(R)-2-amino-3-(3-hydroxypropylthio) propionic acid (fudosteine), on airway inflammation using endotoxin- and antigen-induced models. Time courses of growth related oncogene/cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1) production, neutrophil migration and goblet cell hyperplasia were examined in endotoxin-induced rat airway inflammation. GRO/CINC-1 in bronchoalveolar lavage fluid (BALF) increased in response to intratracheal instillation of endotoxin and peaked within 4 h. Neutrophils in BALF and goblet cells on trachea peaked 24 and 96 h after endotoxin instillation, respectively. Fudosteine significantly inhibited increases in GRO/CINC-1 at 10-100 mg/kg, and neutrophils and goblet cells at 30 and 100 mg/kg. These results suggest that inflammatory events including neutrophil chemoattractant production and neutrophil migration play important roles for goblet cell hyperplasia in endotoxin-induced airway inflammation, and fudosteine inhibits goblet cell hyperplasia by inhibiting GRO/CINC-1 production and/or neutrophil migration. Furthermore, fudosteine (100 mg/kg) inhibited ovalbumin-induced eosinophil infiltration into BALF, suggesting it attenuates asthmatic inflammation.

Animals↗
PubMed2004

A physical approach to remove anatomical reentries: a bidomain study.

Controlling cardiac chaos is often achieved by applying a large damaging electric shock-defibrillation. It removes all waves, without differentiating reentries and normal waves, anatomical and functional reentries. Anatomical reentries can be removed by anti-tachycardia pacing (ATP) as well. But ATP requires the knowledge of the position of the reentry, and an access to it with an invasive stimulating electrode. We show that the physics of electric field distribution between cardiac cells permits one to deliver an electric pulse exactly to the core of an anatomical reentry, without knowing its position and even to locations where access with a stimulating electrode is not possible. The energy needed is two orders of magnitude less than defibrillation energy. The results are insensitive to both a detailed ionic model and to the geometry of the fibers.

Arrhythmias, Cardiac↗
PubMed2004

Unpinning and removal of a rotating wave in cardiac muscle.

Rotating waves in cardiac muscle may be pinned to a heterogeneity, as it happens in superconductors or in superfluids. We show that the physics of electric field distribution between cardiac cells permits one to deliver an electric pulse exactly to the core of a pinned wave, without knowing its position, and even to locations where a direct access is not possible. Thus, unpinning or removal of rotating waves can be achieved. The energy needed is 2 orders of magnitude less than defibrillation energy. This opens a way to new manipulations with pinned vortices both in experiments and in cardiac clinics.

Animals↗