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K Sato

Publications and source records attributed to K Sato.

At least 19 recordsLinked to original sources
PubMed2006

Optical mapping of spatiotemporal emergence of functional synaptic connections in the embryonic chick olfactory pathway.

In order to understand the functional maturation of the CNS, it is essential to first describe the functional maturation of sensory processing. We have approached this topic by following the ontogenetic patterning of neural circuit formation related to cranial and spinal sensory input using voltage-sensitive dye imaging. In previous studies, we have described the functional maturation of synapses in brainstem/midbrain neural circuits. Here, we elucidate the functional maturation of forebrain circuits by investigating neural networks related to the olfactory nerve (N. I) of chicken embryo. In the isolated N. I-olfactory bulb-forebrain preparation, application of electrical stimulation to N. I elicited excitatory postsynaptic potential (EPSP)-related slow optical signals in the olfactory bulb. The slow signal was mainly mediated by glutamate, and was easily fatigued with repetitive stimuli because of the immaturity of synapses in the embryonic CNS. Ontogenetically, the slow signal was detected from the 6-day embryonic stage, suggesting that functional synaptic connections between N. I and olfactory bulb emerge around this stage. In addition, from the 8-day embryonic stage, another response area was discriminated within the forebrain, which corresponded to the higher-ordered nucleus of the olfactory pathway. In comparison with our previous studies concerning the functional development of other cranial nerve-related sensory nuclei in the embryonic brainstem and midbrain, these results suggest that the olfactory pathway is functionally generated in the early stages of development when neural networks related to other visceral and somatic sensory inputs are also in the process of developing.

Aging↗
PubMed2006

A third-generation bisphosphonate, minodronic acid (YM529), successfully prevented the growth of bladder cancer in vitro and in vivo.

Minodronic acid (YM529) is a third-generation bisphosphonate (BP) that has been shown to directly and indirectly prevent proliferation, induce apoptosis, and inhibit metastasis of various types of cancer cells. In this study, we have investigated the therapeutic efficacy of YM529 against bladder cancer, both in vitro and in vivo. YM529 inhibited geranylgeranylation as well as farnesylation and reduced the growth of all seven bladder cancer cell lines in a dose- and time-dependent manner in vitro. YM529 demonstrated a good synergistic or additive antiproliferative effect when administered in combination with cisplatin or paclitaxel. Immunohistochemical study revealed YM529 inhibited the prenylation of Rap1A in vivo. YM529 administered systemically did not markedly inhibit the growth of visceral metastases but it showed a significant anticancer effect on bone metastases monitored by an in vivo imaging system. Moreover, intravesical YM529 demonstrated significant growth inhibition in a bladder cancer orthotopic model. No adverse effects were associated with the systemic as well as the intravesical treatment regimens. In conclusion, our study suggests that YM529 may be a potent anticancer agent for bladder cancer. The efficacy and safety of this BP as an agent for combination chemotherapies against bladder cancer should be verified by early-phase clinical trials.

Animals↗
PubMed2006

Effect of pH and hydration on the normal and lateral interaction forces between alumina surfaces.

Interaction forces between alumina surfaces were measured using an AFM-colloid probe method at different pHs. For an alpha-alumina-sapphire system at acidic pH, the force curve exhibited a well-defined repulsive barrier and an attractive minimum. At basic pH, the interactive force was repulsive at all separations with no primary minimum. Lateral force measurements under the same conditions showed that frictional forces were nearly an order of magnitude smaller at basic pH than those observed at acidic pH. This behavior was attributed to the hydration of the alumina surface. Normal and lateral force measurements with the strongly hydrated rho-alumina surfaces supported these findings.

Journal Article↗
PubMed2006

Finasteride 1 mg has no inhibitory effect on omeprazole metabolism in extensive and poor metabolizers for CYP2C19 in Japanese.

OBJECTIVE: To examine the inhibitory effect of finasteride 1 mg on the metabolism of omeprazole in genetically determined extensive (EMs) and poor metabolizers (PMs) for CYP2C19 in young healthy Japanese male subjects. METHODS: Twenty-four volunteers participated in this study, among whom 12 were homozygous EMs and 12 were PMs for CYP2C19. A single center, controlled, randomized, open, crossover study with a 5 day washout between the two study periods was performed. Each of the six EMs and PMs received a single oral 20 mg dose of omeprazole on day 1 (treatment I). After a 5 day washout period, these subjects received 1 mg of finasteride once a day for three consecutive days, and a single oral 20 mg dose of omeprazole was co-administered on day 3 (treatment II). The 12 other EMs and PMs received treatments I and II in reverse. Plasma samples were collected for up to a 12 hours postdose of omeprazole, and the pharmacokinetic parameters of omeprazole were determined. RESULTS: The geometric mean ratio (GMR) for the AUC((0-12 hr)) of omeprazole when co-administered with finasteride/omeprazole alone is 1.13 (90%CI, 1.03, 1.25) and 0.96 (0.88, 1.05) in EMs and PMs, respectively. Finasteride did not significantly alter C(max), T(max) and t(1/2) in both genotypes. CONCLUSION: Finasteride 1 mg, widely used for the treatment of androgenetic alopecia in men, did not meaningfully increase omeprazole exposure (20 mg) in both EMs and PMs for CYP2C19. These results indicate that finasteride does not meaningfully inhibit CYP2C19 activity in vivo at the dose of 1 mg.

Adult↗
PubMed2006

Japanese adult male voxel phantom constructed on the basis of CT images.

A Japanese adult male voxel (volume pixel) phantom (hereinafter referred to as the JM phantom) was constructed on the basis of CT images of a healthy Japanese adult male volunteer. Body characteristics of the JM phantom were compared with those of a voxelised MIRD5 type phantom and a Japanese adult male voxel phantom which was previously developed. The voxel size of the JM phantom is 0.98 x 0.98 x 1 mm(3). The shapes of the organs of the JM phantom, even for small or complicated organs, such as thyroid and stomach, are more realistically reproduced as compared with the previous Japanese voxel phantom (voxel size: 0.98 x 0.98 x 10 mm(3)). Photon self-absorbed fractions (self-AFs) for brain, kidneys, spleen, pancreas, thyroid and urinary bladder wall of JM were evaluated and were compared with those of the other phantoms. In consequence, it was suggested that the mass, shape and thickness of organs are important factors for the determination of self-AFs.

Adult↗
PubMed2006

Positronium formed by recombination of positron-electron pairs in polymers.

In nonpolar polymers, positronium (Ps) is dominantly formed by fast intraspur reactions of the energetic positron, but its formation is partially contributed by recombination of weakly bound Mott-Wannier-like positron-electron pairs and is susceptible to electric field and positron irradiation induced perturbations. The average initial energy of para-Ps (p-Ps) formed by recombination is found to be about half the energy of ordinary p-Ps dominantly formed by the fast intraspur reactions.

Journal Article↗
PubMed2006

Surgical closure of the larynx for intractable aspiration, using double hinged flaps of the vocal folds and false vocal folds.

We report a new surgical procedure to treat intractable aspiration: closure of the larynx, using double hinged flaps of the vocal folds and false vocal folds. The anterosuperior portion of the thyroid cartilage is ablated. A small horizontal incision is made just above the anterior commissure and is continued posteriorly along the laryngeal ventricle; these incisions are continued across the posterior wall of the glottis. Incisions are made into the bilateral vocal folds and false vocal folds in order to create the hinged flaps. The glottis and the supraglottis are closed by approximating the bilateral vocal folds and false vocal folds hinged flaps. Superiorly or inferiorly based sternohyoid muscle pedicles are then inserted into the dead space between the approximated bilateral vocal folds and false vocal folds hinged flaps. The removed lamina of the thyroid cartilage is obliterated between both sternohyoid muscle flaps to enforce the closure of the larynx.

Aphonia↗
PubMed2006

Heating by an electron Bernstein wave in a spherical tokamak plasma via mode conversion.

The first successful high power heating of a high dielectric constant spherical tokamak plasma by an electron Bernstein wave (EBW) is reported. An EBW was excited by mode conversion (MC) of an mode cyclotron wave injected from the low magnetic field side of the TST-2 spherical tokamak. Evidence of electron heating was observed as increases in the stored energy and soft x-ray emission. The increased emission was concentrated in the plasma core region. A heating efficiency of over 50% was achieved, when the density gradient in the MC region was sufficiently steep.

Journal Article↗
PubMed2006

Certified reference material for radionuclides in fish flesh sample IAEA-414 (mixed fish from the Irish Sea and North Sea).

A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides (40K, 137Cs, 232Th, 234U, 235U, 238U, 238Pu, 239+240Pu and 241Am) were certified for this material. Information on massic activities with 95% confidence intervals is given for six other radionuclides (90Sr, 210Pb(210Po), 226Ra, 239Pu, 240Pu 241Pu). Less frequently reported radionuclides (99Tc, 129I, 228Th, 230Th and 237Np) and information on some activity and mass ratios are also included. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. The material is available from IAEA, Vienna, in 100 g units.

Animals↗
PubMed2006

Expression of Golf in the rat placenta: Possible implication in olfactory receptor transduction.

Olfactory receptors are G-protein coupled receptors and are encoded by an extremely large and diverse family of genes in mammals. There is increasing evidence that olfactory receptors are widely distributed in many organs, suggesting that olfactory receptors do not only recognize airborne odorants but also play important roles in chemotaxis or organ construction in embryo. In this study, we investigated whether olfactory receptors and their transduction molecule, Golf are expressed in the rat placenta. By RT-PCR, we identified 11 different olfactory receptor genes, which are all members of class II, in the rat placenta cDNAs, and our results suggested that particular members of the olfactory receptor gene family might be preferentially expressed in the placenta. By western blot analysis, we demonstrated that Golf protein is expressed in the placenta and its expression levels are developmentally regulated. We found that Golf immunoreactivity is exclusively localized to giant cell trophoblasts and spongiotrophoblast cells. These findings raised a possibility that a particular subset of olfactory receptors might be coupled with Golf and function in giant cell trophoblasts and spongiotrophoblast cells.

Animals↗
PubMed2006

Continuous low-dose human atrial natriuretic peptide promotes diuresis in oliguric patients after living donor liver transplantation.

Human atrial natriuretic peptide (ANP) is beneficial for the prophylaxis of acute renal failure (ARF) after liver transplantation (OLT). We evaluated renal function in OLT patients with or without ARF, describing cases unresponsive to loop diuretics successfully treated with continuous low-dose ANP infusion without hemodialysis. Twenty-seven consecutive adult-to-adult living donor liver transplantations (LDLTs) were performed in 26 patients. One case was excluded due to the need for continuous hemodialysis (HD) during the operation. Of the 26 cases, 6 (23%, group 2) developed ARF in the first 30 days after LDLT; the other 20 were ARF-free (group 1). The median follow-up was 24 months. No patient required either continuous or intermittent HD. Only one patient died due to multiple liver abscesses. Mean preoperative serum creatinine (sCr) value and intraoperative blood loss in group 2 were significantly higher than those in group 1. Three cases in group 2 failed to improve on high-dose loop diuretics with low-dose dopamine, exhibiting fluid overload. The remaining three cases in group 2 responded to conventional diuretic treatments. Continuous low-dose ANP was started 2, 4, or 5 days after LDLT, and urine output significantly increased after ANP administration. The serum creatinine values were 1.1, 1.2, and 1.1 at 1 month and 1.0, 0.9, and 0.6 mg/dL at 6 months after LDLT. Massive blood loss during the operation caused ARF, but did not affect renal function after LDLT. Continuous low-dose ANP improved renal function and diuresis for oliguric ARF patients, preventing the need for HD or continuous venovenous hemodialysis.

Adult↗
PubMed2006

Acute heat stress stimulates mitochondrial superoxide production in broiler skeletal muscle, possibly via downregulation of uncoupling protein content.

Acute heat stress (34 degrees C for 18 h) resulted in increased levels of reactive oxygen species (ROS) in mitochondria isolated from the skeletal muscle of broilers. This occurred when glutamate-requiring complexes I, III, and IV of the electron transport chain or succinate-requiring complexes II, III and IV were used as the substrate. This result confirms our previous observation that exposure of broilers to 34 degrees C for 18 h results in increased superoxide production in skeletal (pectoralis) muscle, and extends this finding by showing that substrate-independent ROS generation occurs during the heat stress period. When broilers were exposed to heat stress, the levels of avian uncoupling protein (avUCP) mRNA in skeletal muscle were significantly decreased, to 28% of the levels found in untreated controls. This was accompanied by a significant decrease in the levels of the avUCP protein, to 37% of control levels. In contrast, avian adenine nucleotide translocator mRNA levels were not affected by exposure to heat stress. This finding is consistent with previous studies which showed that the increases in superoxide production that are observed in the presence of carboxyatractylate, a specific inhibitor of adenine nucleotide translocator, were the same for skeletal muscle mitochondria from both control and heat-stressed chickens. Taken together, these results suggest that acute heat stress stimulates mitochondrial superoxide production in broiler skeletal muscle, possibly via downregulation of avUCP. The present study provides the first evidence that synthesis of avUCP protein is downregulated in heat-stressed broilers.

Animals↗
PubMed2006

Role of TNF-alpha in muscularis inflammation and motility disorder in a TNBS-induced colitis model: clues from TNF-alpha-deficient mice.

Macroscopic and histological analysis revealed that the colonic inflammation induced by 2,4,6-trinitrobenzenesulphonic acid (TNBS) was of lower grade in tumour necrosis factor-alpha (TNF-alpha)(-/-) mice than in wild-type mice. Myeloperoxidase activity, an indicator of neutrophilic infiltration, was also low in both the mucosal and smooth muscle layer of the TNF-alpha(-/-) mouse colon. After the induction of inflammation with TNBS, the levels of proinflammatory cytokines, such as TNF-alpha, interleukin-1beta and interleukin-6, were elevated both in the inflamed mucosa and muscle layers in the wild-type mice; however, the productions of these cytokines were greatly reduced in the TNF-alpha(-/-) mouse colon. The contractions of isolated colonic smooth muscle strips induced by several stimulatory agents were significantly decreased after treatment with TNBS in wild-type mice; however, these contractions were scarcely affected in TNF-alpha(-/-) mice. Finally, using the organ culture method, we found that TNF-alpha directly (independent of mucosal inflammation) disturbs the smooth muscle function. These results suggest that TNF-alpha plays an essential role not only in mucosal inflammation but also in muscularis inflammation in the colon of mice with TNBS-induced colitis, and that TNF-alpha directly induces motor dysfunctions by acting on the smooth muscle.

Animals↗
PubMed2006

Dissecting Ascaris glycosphingolipids for immunomodulatory moieties--the use of synthetic structural glycosphingolipid analogues.

We have previously shown glycosphingolipids of Ascaris suum to have phosphorylcholine (PC) and non-PC immunomodulatory moieties. In the present study we further investigated the nature of the immunomodulatory moieties by employing three synthetic glycosphingolipids each possessing features of the original molecule to examine effects on macrophage and dendritic cell (DC) cytokine production and surface co-stimulatory molecule expression. Compound 2, which lacked PC but contained ceramide, had no effect on either macrophages or DCs. Surprisingly however, Compound 1, which contained PC and hence arguably most resembled the native material, had, with the exception of a small increase in surface antigen expression, no immunomodulatory properties. Conversely, Compound 3, which contained PC but was otherwise least like the native molecule, demonstrated a number of effects on both macrophages and DCs, including induction of Th-1/pro-inflammatory cytokines, inhibition of such cytokines induced by IFN-gamma/LPS and increased expression of co-stimulatory molecules. Taken together these results indicate: (i) that although PC is an immunomodulatory component of the native molecule other structural feature are necessary to allow it to act; (ii) that carbohydrate rather than ceramide is likely to represent a non-PC immunomodulatory moiety; and (iii) that synthetic PC-containing molecules have the potential to act as immunomodulatory drugs.

Animals↗
PubMed2006

CLOCK is involved in obesity-induced disordered fibrinolysis in ob/ob mice by regulating PAI-1 gene expression.

BACKGROUND: An increased level of obesity-induced plasma plasminogen activator inhibitor-1 (PAI-1) is considered a risk factor for cardiovascular disease. AIM: The present study investigates whether the circadian clock component CLOCK is involved in obesity-induced PAI-1 elevation. METHODS: We examined plasma PAI-1 and mRNA expression levels in tissues from leptin-deficient obese and diabetic ob/ob mice lacking functional CLOCK protein. RESULTS: Our results demonstrated that plasma PAI-1 levels were augmented in a circadian manner in accordance with the mRNA expression levels in ob/ob mice. Surprisingly, a Clock mutation normalized the plasma PAI-1 concentrations in accordance with the mRNA levels in the heart, lung and liver of ob/ob mice, but significantly increased PAI-1 mRNA levels in adipose tissue by inducing adipocyte hypertrophy in ob/ob mice. The Clock mutation also normalized tissue PAI-1 antigen levels in the liver but not in the adipose tissue of ob/ob mice. CONCLUSION: These observations suggest that CLOCK is involved in obesity-induced disordered fibrinolysis by regulating PAI-1 gene expression in a tissue-dependent manner. Furthermore, it appears that obesity-induced PAI-1 production in adipose tissue is not closely related to systemic PAI-1 increases in vivo.

Adipose Tissue↗
PubMed2006

Composite large cell neuroendocrine carcinoma and adenocarcinoma of the common bile duct.

Large cell neuroendocrine carcinoma (LCNEC) is a high grade type of neuroendocrine tumour with an aggressive clinical course. This report describes the first case of LCNEC combined with an adenocarcinoma component in the common bile duct. A 68 year old man presented with jaundice. Severe stenosis of the bile duct was revealed by endoscopic retrograde cholangiography, and adenocarcinoma cells were detected by brush cytology. Pancreaticoduodenectomy was performed, and the patient died of disease three months after surgery. A tumour measuring 2.0 cm in diameter was located in the intrapancreatic portion of the bile duct. Histologically, the tumour consisted of a LCNEC component and a well differentiated adenocarcinoma component. There were transitional areas between the two components. Immunohistochemically, LCNEC cells were reactive for neuroendocrine markers, but no specific hormonal expression was found. Chromogranin A positive cells were found in some areas of the adenocarcinoma component. These findings are consistent with the theory that both of the carcinoma components originated from a common pluripotent stem cell.

Adenocarcinoma↗
PubMed2006

Reactive lymphoid hyperplasia of the liver in a patient with multiple carcinomas: a case report and brief review.

A rare case of reactive lymphoid hyperplasia (RLH) of the liver in a 75-year-old woman admitted to hospital for surgical treatment of gastric, caecal and colon carcinomas is described here. Two nodular lesions in the left and right lobes of the liver were clinically diagnosed as metastatic tumours by computed tomography of the abdomen. A demarcating grey-white mass of size 1.4 cm was observed in a partially resected liver specimen. On examining the lesion microscopically, it was found to be composed of hyperplastic lymphoid follicles, lymphocytes, plasma cells, other inflammatory cells and interlaced hyalinised fibrous tissues. In the portal tracts around the lesion, chronic inflammatory cell infiltrates were seen, but no interface hepatitis or lymphoid follicle was observed. No evidence of monoclonality was observed by immunohistochemistry for B and T cell markers, in situ hybridisation for kappa and lambda light chains, and polymerase chain reaction analysis of immunoglobulin heavy chains or T cell receptor beta and gamma gene rearrangements. Bcl-2 immunoreactivity was not observed in the germinal centre. Epstein-Barr virus (EBV) antigen (latent membrane protein-1) and EBV-encoded small RNAs were not detected. A proliferation neither of myofibroblasts nor of cells positive for follicular dendritic cell markers was observed. RLH, formerly known as pseudolymphoma, has been reported of the liver in only 14 cases and is considered to be a differential diagnosis of small nodular lesions of the liver. That RLH has an inflammatory reactive nature, not a neoplastic disposition, and that EBV does not participate in the pathogenesis of RLH is supported by this case.

Adenocarcinoma↗