Search PubMed⌕ Search

Biomedical subjects

K Taniguchi

Publications and source records attributed to K Taniguchi.

At least 19 recordsLinked to original sources
PubMed2006

Ferroelectric polarization flop in a frustrated magnet MnWO4 induced by a magnetic field.

The relationship between magnetic order and ferroelectric properties has been investigated for MnWO4 with a long-wavelength magnetic structure. Spontaneous electric polarization is observed in an elliptical spiral spin phase. The magnetic-field dependence of electric polarization indicates that the noncollinear spin configuration plays a key role for the appearance of the ferroelectric phase. An electric polarization flop from the b direction to the a direction has been observed when a magnetic field above 10 T is applied along the b axis. This result demonstrates that an electric polarization flop can be induced by a magnetic field in a simple system without rare-earth 4f moments.

Journal Article↗
PubMed2006

Dynamical behavior of the motions associated with the nonlinear periodic regime in a laboratory plasma subject to delayed feedback.

Time-delayed feedback is applied to the motions associated with the nonlinear periodic regime generated due to current-driven ion acoustic instability; this is a typical instability in a laboratory plasma, and the dynamical behavior is experimentally investigated using delayed feedback. A time-delayed autosynchronization method is applied. When delayed feedback is applied to the nonlinear periodic orbit, the periodic state changes to various motions depending on the control parameters, namely, the arbitrary time delay and the proportionality constant. Lyapunov exponents are calculated in order to examine the dynamical behavior.

Journal Article↗
PubMed2006

Analysis of genetic factors related to preferential selection of the NSP1 gene segment observed in mixed infection and multiple passage of rotaviruses.

Reassortment is one of the major evolutionary mechanisms of the rotavirus genome. Preferential selection (assortment) of the NSP1 gene segment from either of the parental viruses after coinfection of these viruses has been reported as a notable finding in reassortment. To analyze genetic factors which are associated with preferential selection of the rotavirus NSP1 gene segment into progeny viruses, mixed infection and multiple passages were performed using two panels of rotaviruses, i.e., bovine rotavirus A5 clones, and simian rotavirus SA11 and five strains of SA11-based single NSP1 gene-substitution reassortants. In the first experiment, three A5 clones (A5-10, A5-13, and A5-16) that had genetically distinct NSP1 genes in the same genetic background were used. In coinfection of these A5 clones, it was noted that the A5-10 NSP1 gene, which encodes an incomplete protein product due to presence of a nonsense codon at an unusual position, was selected more preferentially than the A5-13 NSP1 gene with intact length and structure. The A5-16 NSP1 gene, with a deletion of 500 bp, was least efficiently selected. In the second experiment, we prepared two reassortants, SOF and SRF, which have NSP1 genes from rotavirus strains OSU and RRV, respectively, in the genetic background of SA11, which were used together with previously prepared reassortants SKF, SDF, and SNF, which had NSP1 genes from strains KU, DS1, and K9, respectively. Among the 6 NSP1 genes analyzed, the NSP1 gene from SKF was most preferentially selected, followed by SNF, SOF, SDF, SA11, and SRF, in that order. Although SOF exhibited less growth efficacy than SA11, the growth rates of other reassortants were similar to that of SA11. These findings suggest that for the occurrence of preferential selection of the NSP1 gene, production of the intact NSP1 protein may not be involved, but the presence of intact length of the NSP1 gene may be required. Furthermore, it was also found that genetic similarity based on primary structure of this gene is not related to the selectivity of the NSP1 gene.

Animals↗
PubMed2005

Significance of lymph node micrometastasis in pN0 hilar bile duct carcinoma.

AIMS: To examine micrometastasis in node-negative hilar bile duct carcinoma (HBDC) using an immunohistochemical method and evaluated the clinical significance. METHODS: Four hundred and twenty three regional lymph nodes from 28 patients with node-negative HBDC who had undergone a resection were immunostained with an antibody against cytokeratins eight and 18 (CAM 5.2). RESULTS: Lymph node micrometastasis was detected in 11 of the 28 patients and 14 of the 423 lymph nodes. Lymph node micrometastasis was significantly correlated with the pT classification (p=0.03), the histopathological grading (p=0.01) and venous invasion (p=0.05). The 5-year survival rate of the patients with lymph node micrometastasis was 21.8%, as opposed to 66.5% in the patients without micrometastasis. Patients with micrometastasis showed a significantly poorer survival rate than those without micrometastasis (p=0.02). CONCLUSION: The results suggest that immunohistochemically detected lymph node micrometastasis has an impact on the outcome in HBDC.

Adult↗
PubMed2005

Expression of tandem P domain K+ channel, TREK-1, in the rat carotid body.

TREK-1 is one of the important potassium channels for regulating membrane excitability. To examine the distribution of TREK-1 in the rat carotid body, we performed RT-PCR for mRNA expression and in situ hybridization and immunohistochemistry for tissue distribution of TREK-1. RT-PCR detected mRNA expression of TREK-1 in the carotid body. Furthermore, in situ hybridization revealed the localization of TREK-1 mRNA in the glomus cells. TREK-1 immunoreactivity was mainly distributed in the glomus cells and nerve fibers in the carotid body. TREK-1 may modulate potassium current of glomus cells and/or afferent nerve endings in the rat carotid body.

Animals↗
PubMed2005

Experimental surveillance using data on sales of over-the-counter medications--Japan, November 2003-April 2004.

OBJECTIVES: This report describes a study to explore the possibility of using data on sales of over-the- counter (OTC) medications as part of a routine syndromic surveillance system aimed at early detection of infections of public health concern. A retrospective evaluation was conducted of sales of OTC medications used to treat the common cold. This report discusses the correlation of these data to influenza activity in Japan during the 2003-04 influenza season and evaluates the potential of using such data to predict influenza epidemics. METHODS: Data from approximately 1,100 pharmacies throughout Japan collected during November 2003-April 2004 were analyzed. OTC sales data were compared with influenza incidence data (one weekly and two daily data sets) to determine correlations and predictability. Adjusted R-square was used as an index of goodness of-fit in the estimation. Data reflecting daily influenza activity were obtained from the National Surveillance of Daily Influenza Outpatients and the Mailing List-Based Influenza Epidemic Database. National sentinel surveillance data for influenza from approximately 5,000 sites nationwide also were analyzed. RESULTS: Although a correlation was demonstrated between sales of OTC medications used to treat the common cold and concurrent influenza activity, analysis of sales data alone was not sufficient to determine influenza activity in advance even when sales promotion effects were excluded from the analysis. CONCLUSION: Because visiting a health-care provider costs more than purchasing OTC medications, the hypothesis was formed that an ill person will purchase OTC medications first and visit a physician only if the condition does not resolve or worsens. The results of this study do not provide any clear evidence to support this hypothesis. For this reason, OTC sales do not appear to be a good candidate for a national real-time detection system for influenza epidemics in Japan.

Commerce↗
PubMed2005

Morphological changes in the rat endocrine pancreas within 12 h of intravenous streptozotocin administration.

We examined early morphological changes in pancreatic endocrine cells within 12 h of intravenous streptozotocin (STZ) administration (60 mg/kg). Thirty rats were allocated either to a control group (vehicle alone) or to one of four experimental groups tested after 3, 6, 9 and 12 h. Karyopyknosis and cytoplasmic vacuoles were first observed in beta-cell cytoplasm 3 h after STZ administration (STZ-3 h), and the most severe damage was found in beta cells at STZ-12 h. Insulin-positive non-islet cells were observed near the intercalated duct (ICD) and/or centroacinar (CA) cells at STZ-6 h and their numbers peaked at STZ-6 h. The distribution patterns of the insulin-positive cells and those of nestin and insulin-like growth factor-1 were similar and their nuclei were positive for proliferating cell nuclear antigen. Thus, ICD cells and/or CA cells reacted immediately to transform into insulin-secreting cells to replace injured beta cells (or to compensate for the lack of beta cells) within 12 h of STZ administration.

Animals↗
PubMed2005

Cell proliferation activity of proliferating bile duct after bile duct ligation in rats.

The cell proliferation activity of proliferating bile ducts produced by bile duct ligation (BDL) in rats was examined histologically, immunohistochemically, and ultrastructurally. Proliferating bile ducts, which were similar to normal bile ducts, increased with time after BDL. The cell proliferation activity of proliferating bile ducts, measured using proliferating-cell nuclear antigen and 5-bromo-2'-deoxyuridine antibodies, tended to be high at 1 and 3 days after BDL and decreased progressively at 2 to 4 weeks after BDL. On the other hand, alpha-smooth muscle actin-positive myofibroblast-like cells increased continuously after BDL. These findings indicate that there is a negative correlation between the cell proliferation activity of proliferating bile ducts and that of myofibroblast-like cells.

Animals↗
PubMed2005

The gene expression level of transforming growth factor-beta (TGF-beta) as a biological prognostic marker of hepatocellular carcinoma.

The question that transforming growth factor-beta (TGF-beta) provides a tumor-suppressive or a tumor promoting role is still unknown in hepatocellular carcinoma (HCC). In the present study, we quantitatively investigated the gene expression levels of TGF-beta in liver tissues from patients with HCC. We also evaluated the prognostic importance of TGF-beta gene in HCC patients. A total of 59 patients with primary HCC who underwent hepatectomy between 1993 and 2001 were enrolled. TGF-beta gene expression levels of tumors and of noncancerous livers were analyzed by real-time reverse transcriptase polymerase chain reaction (RT-PCR). The percentage of apoptotic cells in tumor cells (apoptotic index: AI) was evaluated with immunohistochemistry. Also the expression of survivin protein (apoptosis inhibitor) in tumors was detected by immunohistochemistry. TGF-beta gene expression levels of tumors were compared with clinicopathological findings of patients. The relative expression level of TGF-beta mRNA of 59 tumor tissues did not differ from those of 8 normal liver tissues or 59 noncancerous liver tissues. The mean AI of 29 tumors with normal expression levels of TGF-beta gene (4%) was significantly higher than that of 30 tumors with low expression levels of TGF-beta gene (2.5%, p = 0.03). Thirteen out of 30 tumors (43%) with low expression level of TGF-P gene showed survivin positive, while only 4 out of 29 tumors (14%) with preserved expression of TGF-beta gene showed survivin positive. This difference was significant (p = 0.012). The overall 5-year survival rate of 29 patients with tumors with preserved TGF-beta gene prolonged to 72% compared with that of 30 patients who had tumors with suppressed TGF-beta gene (58%, p = 0.156). In HCC, TGF-beta gene may play a defensive role against tumor progression by regulating survivin protein expression and by controlling occurrence of spontaneous apoptosis in tumors.

Adult↗
PubMed2005

Methotrexate-induced acute lung injury in a patient with rheumatoid arthritis.

Methotrexate (MTX)-induced acute lung injury developed in a female patient with rheumatoid arthritis. She was successfully treated with high-dose glucocorticoid therapy. During her hospital stay, the serum concentration of surfactant protein (SP)-D, which was markedly elevated on admission, was finally normalized and the disease resolved. However, the serum concentration of Klebs von den Lungen (KL)-6 remained high. Although the mechanisms of lung injury by MTX have not been well defined, serial measurements of serum SPD might be useful for the clinical evaluation of drug-induced acute lung injury.

Acute Disease↗
PubMed2005

Induction of mononuclear cell infiltration into liver by Japanese herbal medicine.

Juzen-Taiho-To (JTT) is a Japanese herbal medicine that has been administered mainly to patients weakened by long illness. Currently, it has also been used for cancer patients and showed antitumor effects that have been reported as phagocytosis enhancement, cytokine induction and antibody production. In this study, we examined the effect of oral administration of JTT in mice on the immunological restoration of the liver, especially focused on natural killer (NK) T-cell induction. Mice were grouped to receive JTT or placebo orally for a period of 1, 3 and 7 days. After sacrifice, the liver tissue was fixed, embedded and stained with hematoxylineosin and some antibodies by common staining methods. Transmission electron microscope (TEM) observation was also carried out. Although the JTT-treated mice had the same appearance as the non-JTT-treated mice, their livers were infiltrated by massive mononuclear cells, some of which were aggregated in clusters. Immunohistochemical staining revealed that there was abundant cytokine expression of interleukin (IL)-12 and massive infiltration of mononuclear cells with large granules in the liver of JTT-treated mice. Oral administration of JTT may induce the expression of IL-12 and be followed by immunological restoration such as NK T-cell induction in liver

Animals↗
PubMed2004

Daily omega-3 fatty acid intake and depression in Japanese patients with newly diagnosed lung cancer.

The aim of the present study was to examine the association between daily omega-3 fatty acid intake and depression in Japanese cancer patients. Omega-3 fatty acid intake in 771 patients with newly diagnosed primary lung cancer was evaluated using a food-frequency questionnaire, and the prevalence of depression was examined using the cutoff values for the depression subscale included in the Hospital Anxiety and Depression Scale. After adjustment for potential confounding factors, the odds ratio (OR) for depression among patients in the highest quartile of the total eicosapentaenoic acid- (C20:5n-3) and docosapentaenoic acid (C22:6n-3)-intake group compared with patients in the lowest quartile was not significantly different. On the other hand, the OR among the highest quartile of alpha-linolenic acid (C18:3n-3) intake (adjusted OR=0.50, 95% CI: 0.31-0.71, P for trend=0.004) and the highest quartile of total omega-3 fatty acid intake (adjusted OR=0.55, 95% CI: 0.35-0.88, P for trend=0.022) were significantly different. These results suggest that total eicosapentaenoic acid and docosapentaenoic acid intake might not be associated with depression in Japanese patients with newly diagnosed lung cancer, but that alpha-linolenic acid intake and total omega-3 fatty acid intake might be.

Aged↗
PubMed2004

Polymorphisms in the taste receptor gene (Tas1r3) region are associated with saccharin preference in 30 mouse strains.

The results of recent studies suggest that the mouse Sac (saccharin preference) locus is identical to the Tas1r3 (taste receptor) gene. The goal of this study was to identify Tas1r3 sequence variants associated with saccharin preference in a large number of inbred mouse strains. Initially, we sequenced approximately 6.7 kb of the Tas1r3 gene and its flanking regions from six inbred mouse strains with high and low saccharin preference, including the strains in which the Sac alleles were described originally (C57BL/6J, Sac(b); DBA/2J, Sac(d)). Of the 89 sequence variants detected among these six strains, eight polymorphic sites were significantly associated with preferences for 1.6 mm saccharin. Next, each of these eight variant sites were genotyped in 24 additional mouse strains. Analysis of the genotype-phenotype associations in all 30 strains showed the strongest association with saccharin preference at three sites: nucleotide (nt) -791 (3 bp insertion/deletion), nt +135 (Ser45Ser), and nt +179 (Ile60Thr). We measured Tas1r3 gene expression, transcript size, and T1R3 immunoreactivity in the taste tissue of two inbred mouse strains with different Tas1r3 haplotypes and saccharin preferences. The results of these experiments suggest that the polymorphisms associated with saccharin preference do not act by blocking gene expression, changing alternative splicing, or interfering with protein translation in taste tissue. The amino acid substitution (Ile60Thr) may influence the ability of the protein to form dimers or bind sweeteners. Here, we present data for future studies directed to experimentally confirm the function of these polymorphisms and highlight some of the difficulties of identifying specific DNA sequence variants that underlie quantitative trait loci.

Animals↗
PubMed2004

Testicular atrophy after bile duct ligation in chickens.

Testicular atrophy associated with biliary obstruction in chickens, produced by the ligation of both extrahepatic bile ducts, was examined grossly, histologically, immunohistochemically, and ultrastructurally. Grossly, reduction in testicular size and volume was evident in chickens that underwent bile duct ligation (BDL). Histologically, there was marked reduction in tubular diameter, peritubular fibrosis, loss of spermatogenic cells, and tubules lined only by Sertoli cells. In addition, Leydig cells, which accumulated in the interstitium of the testes, contained numerous large lipid vacuoles, as determined by electron microscopy. These features suggest that BDL in chickens causes hypogonadism and low serum testosterone.

Animals↗
PubMed2003

Mapping sentinel nodes in patients with early-stage gastric carcinoma.

BACKGROUND: Nodal status in gastric carcinoma is related not only to prognosis but also to the extent of nodal dissection. However, a method for accurate assessment of nodal status during operation has not been established. This study aimed to map the sentinel nodes of gastric carcinoma and to estimate the clinical usefulness of sentinel node biopsy. METHODS: Following laparotomy, a vital dye (0.2 ml 2 per cent patent blue) was injected through a gastroscope into the submucosal layer at four sites around a clinical T1 gastric carcinoma. The dye immediately appeared at the serosal surface and stained lymphatic vessels and nodes. The stained nodes were removed and examined by frozen sectioning. RESULTS: The assay was successful in mapping the lymphatic basins in 203 (96.2 per cent) of 211 patients. The dye stained one or more metastatic nodes in 31 patients, but failed to indicate a metastatic node in four patients with a large involved node. Meticulous postoperative examination of all resected nodes in the standard paraffin slices revealed no new metastases. The accuracy of the assay was 98.0 per cent. CONCLUSION: The method was accurate in predicting nodal status in patients with early-stage gastric carcinoma.

Adult↗
PubMed2003

Serologic and genomic characterization of a G12 human rotavirus in Thailand.

The G and P type specificity of the human rotavirus strain T-152 (G12P[9]) isolated in Thailand was serologically confirmed with G12-specific monoclonal antibodies prepared in this study by using a reference G12 strain, L26, as an immunizing antigen and a P[9]-specific monoclonal antibody, respectively. The genomic relationship of strain T-152 with representative human rotavirus strains was examined by means of Northern blot analysis. The results showed that T152 is closely related to strain AU-1 (G3P[9]). Gene 5 (NSP1 gene) of T152, which did not hybridize with those of any other strains examined, was characterized by sequence determination. The T152 NSP1 gene is 1,652 nucleotides in length, encodes 493 amino acids, and exhibits low identity to those of representative human and animal rotaviruses.

Animals↗