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Biomedical subjects

K Tsuda

Publications and source records attributed to K Tsuda.

At least 55 records · Page 3Linked to original sources
PubMed2000

US characterization of ovarian masses: a meta-analysis.

PURPOSE: To compare the effectiveness of current ultrasonographic (US) techniques for characterizing ovarian masses. MATERIALS AND METHODS: Through a MEDLINE literature search, articles with imaging-histopathologic correlation and data that allowed calculation of contingency tables were identified. Results of morphologic assessment, Doppler US, color Doppler flow imaging, and combined techniques were compared. RESULTS: Among 89 data sets from 46 included studies (5,159 subjects), 35 sets used morphologic information, 36 measured Doppler US indexes, 10 assessed tumor vascularity with color Doppler flow imaging, and eight used combined techniques. Summary receiver operating characteristic curves revealed significantly higher performance for combined techniques than for morphologic information (P: =.003), Doppler US indexes (P: =.003), or color Doppler flow imaging alone (P: =.001). The Q* point (and 95% CI) for combined techniques was 0.92 (0.87, 0.96) versus 0. 85 (0.83, 0.88) for morphology, 0.82 (0.78, 0.86) for Doppler US, and 0.73 (0.58, 0.87) for color Doppler flow imaging. Morphologic assessment showed a trend toward better performance than color Doppler flow imaging (P: =.09) or Doppler US indexes (P: =.07). Doppler US index results were better in earlier studies (P: =.005). CONCLUSION: Combined US techniques and a diagnostic algorithm perform significantly better than morphologic assessment, color Doppler flow imaging, or Doppler US indexes alone in characterizing ovarian masses.

Analysis of Variance↗
PubMed2000

Transition zone biopsy in the detection of prostate cancer.

OBJECTIVE: About 25% of all prostate cancers occur in the transition zone (TZ). We analyzed the impact of 4 systematic TZ and 2 systematic apex (AP) biopsies in addition to systematic sextant biopsies in an effort to establish the diagnostic importance of early prostate cancer. METHODS: One hundred and thirty patients underwent systematic transperineal multipoint prostate biopsy (biopsy of 12 sites, including 4 TZ and 2 AP biopsies). RESULTS: Forty-one of 130 men (31.5%) had biopsy specimens positive for cancer, and cancer originated in the TZ alone in 4 of these 41 patients (9.8%). Fourteen patients underwent radical retropubic prostatectomy. We compare the pathological findings of radical prostatectomy specimens and biopsy results. Prostate cancers predicted to be stage T(2c) by TZ biopsy were all classified as pT(2c) or greater. CONCLUSIONS: Routine TZ biopsy does not substantially increase the prostate cancer detection rate; however, it can be useful in patients who require repeat biopsy.

Aged↗
PubMed2000

Antihyperglycemic effect of T-1095 via inhibition of renal Na+-glucose cotransporters in streptozotocin-induced diabetic rats.

T-1095, a derivative of phlorizin, is an orally active inhibitor of Na+-glucose cotransporter (SGLT). We investigated the acute antihyperglycemic effect of T-1095 in streptozotocin-induced diabetic rats (STZ rats). T-1095 and its metabolite T-1095A inhibited the SGLT activity in brush border membranes prepared from kidneys of both normal and STZ rats, but the latter agent was approximately 10 times more potent than the former. Single oral administration of T-1095 (30-100 mg/kg) dose-dependently induced glycosuria in normal rats. The fed glucose levels in STZ rats were dose-dependently suppressed by single oral administration of T-1095 (3-100 mg/kg), whereas there was only marginal hypoglycemic effect in normal rats. Since there was no effect on blood glucose in nephrectomized STZ rats, inhibition of renal glucose reabsorption rather than intestinal glucose absorption mainly contributes to the antihyperglycemic effect of T-1095. In conclusion, T-1095 is the first orally active agent which has an acute antihyperglycemic action in the absence of endogenous insulin secretion with a low risk of hypoglycemia and has therapeutic potential for treatment of diabetes mellitus.

Animals↗
PubMed2000

Correction of hyperglycemia and insulin sensitivity by T-1095, an inhibitor of renal Na+-glucose cotransporters, in streptozotocin-induced diabetic rats.

We investigated the effects of T-1095 (3-(benzo[b]furan-5-yl)-2',6'-dihydroxy-4'-methylpropiophenone 2'-O-(6-O-methoxycarbonyl)-beta-D-glucopyranoside), an orally active inhibitor of Na+-glucose cotransporter, on hyperglycemia and insulin resistance in skeletal muscle of streptozotocin (STZ)-induced diabetic rats. Chronic (4 weeks) administration of T-1095 as food admixture (0.01 -0.1% wt/wt) suppressed the blood glucose level without affecting the food intake and body weight. In addition, the reduced 2-deoxyglucose uptake and lactate release in the soleus muscle of STZ rat was ameliorated by chronic treatment of T-1095. These data suggest that T-1095 improves insulin sensitivity in skeletal muscle through correction of hyperglycemia and has novel therapeutic potential for treatment of diabetes mellitus through removing glucose toxicity.

Animals↗
PubMed2000

New members of a cold-responsive group-3 Lea/Rab-related Cor gene family from common wheat (Triticum aestivum L.).

A Cor (cold-responsive) cDNA that belongs to the group-3 Lea (late embryogenesis abundant)/Rab (responsive to abscisic acid, ABA) family was isolated from a winter-hardy cultivar of common wheat (Triticum aestivum L.). Screening of a cold-acclimated cDNA library was performed using an ABA- and other stress-responsive barley cDNA clone, Hva1, as a probe. A wheat cDNA clone (designated as Wrab19) putatively encoded a basic (pI = 10.3) and hydrophobic protein with 179 amino acids. The deduced protein showed characteristics of the group-3 LEA/RAB protein family. In contrast to the single copy barley Hva1, Wrab19 belonged to a multigene family in the hexaploid wheat genome and six loci were assigned to the homoeologous group 1 chromosomes. Using Wrab19 as a probe, four homologous cDNAs (designated as Wrab17) were isolated that encoded acidic (pI = 4.6-4.7) and hydrophobic proteins, all with 166 amino acids. The deduced proteins showed high homology (a mean of 84% identity) with a barley gibberellic acid (GA3)-inducible protein, ES2A, and several other group-3 LEA/RAB proteins. Wrab17 was considered to be a three-copy gene and each copy was assigned to chromosome 5A, 4B or 4D of hexaploid wheat. Transcripts of both Wrab19 and Wrab17 accumulated within 1 day of cold acclimation at 4 degrees C. They were responsive to ABA and/or GA3, but showed some cultivar differences in their response to these plant hormones. We conclude that the two genes are new members of the group-3 Lea/Rab-related Cor gene family in wheat.

Abscisic Acid↗
PubMed2000

A cold-responsive wheat (Triticum aestivum L.) gene wcor14 identified in a winter-hardy cultivar 'Mironovska 808'.

A cDNA library was constructed from a cold-acclimated winter-hardy common wheat (Triticum aestivum L.) cultivar 'Mironovska 808'. Using this library and a cold- and light-responsive barley cDNA clone cor14b as a probe, cDNAs of a homologous wheat gene wcor14 were isolated. Two identical cDNAs designated as wcor14a had an open reading frame encoding an acidic (pI = 4.71) and hydrophobic polypeptide with 140 amino acids (MW = 13.5 kDa). The deduced WCOR14a polypeptide showed 70% identity with the barley chloroplast-imported COR14b and had a nearly identical N-terminal, putative chloroplast transit peptide of 51 amino acid residues. Another cDNA clone wcor14b was assumed to encode a polypeptide WCORb which had 5 substitutions and a frame shift in the C-terminal region as compared with WCOR14a. RACE PCR, genomic PCR and Southern blot analyses suggested that wcor14 and its related sequences constitute a small multigene family with and without an intron in the hexaploid wheat genome. Northern blot analysis showed that transcripts of wcor14 accumulated within 3-6 hours of cold acclimation at 4 degrees C and the level reached a maximum at day 3. The transcripts became non-detectable within 3 hours after de-acclimation at room temperature. Contrary to the barley cor14b, a similar level of wcor14 transcripts was detected under the continuous darkness. Neither treatment with NaCl, ABA nor dehydration induced its expression. Based on these results we conclude that wcor14 is a wheat orthologue of the barley cor14b and specifically induced by low temperature.

Amino Acid Sequence↗
PubMed2000

Single breath-hold T2-weighted MR imaging of the liver: value of single-shot fast spin-echo and multishot spin-echo echoplanar imaging.

OBJECTIVE: The objective of our study was to evaluate the efficacy of single breath-hold T2-weighted MR imaging for detection of focal hepatic lesions. MATERIALS AND METHODS: T2-weighted MR images were retrospectively reviewed from 51 patients with 85 solid and 59 nonsolid lesions using the following four sequences: conventional spin-echo, respiratory-triggered fast spin-echo, single-shot fast spin-echo, and multishot spin-echo echoplanar imaging. Images were reviewed on a hepatic segment-by-segment basis; T2-weighted images of a total of 408 hepatic segments were reviewed separately and independently for solid and nonsolid lesions by four radiologists. Quantitative, qualitative, and receiver operating characteristic analyses were performed. RESULTS: For solid lesions, no significant differences were seen among the lesion-to-liver contrast-to-noise ratios with the four sequences. In terms of solid lesion detection, no significant difference was seen between the diagnostic accuracy of multishot spin-echo echoplanar (Az = 0.90) and respiratory-triggered fast spin-echo (Az = 0.91) imaging, which showed the best performance of the four sequences. For nonsolid lesion detection, respiratory-triggered fast spin-echo and single-shot fast spin-echo imaging were judged the best (Az = 0.94). CONCLUSION: Breath-hold single-shot fast spin-echo and multishot spin-echo echoplanar sequences can be substituted for conventional spin-echo and respiratory-triggered fast spin-echo T2-weighted sequences.

Adult↗
PubMed2000

Activating transcription factor-2 is a positive regulator in CaM kinase IV-induced human insulin gene expression.

Insulin plays a crucial role in the regulation of glucose-homeostasis, and its synthesis is regulated by several stimuli. The transcription of the human insulin gene, enhanced by an elevated intracellular concentration of calcium ions, was completely blocked by Ca2+/calmodulin-dependent protein kinase inhibitor. The activity of the transcription factor activating transcription factor-2 (ATF-2), which binds to the cAMP responsive elements of the human insulin gene, was enhanced by Ca2+/calmodulin-dependent protein kinase IV (CaMKIV). Mutagenesis studies showed that Thr69, Thr71, and Thr73 of ATF-2 are all required for activation by CaMKIV. CaMKIV-induced ATF-2 transcriptional activity was not altered by activation of cJun NH2-terminal protein kinase (JNK) or p38 mitogen-activated protein (MAP) kinase. Furthermore, when transfected into rat primary cultured islets, ATF-2 enhanced glucose-induced insulin promoter activity, whereas cAMP response element-binding protein (CREB) repressed it. These results suggest a mechanism in which ATF-2 regulates insulin gene expression in pancreatic beta-cells, with the transcriptional activity of ATF-2 being increased by an elevated concentration of calcium ions.

Activating Transcription Factor 2↗
PubMed2000

Postoperative splanchnic perfusion following the reconstruction of thoracoabdominal aortic aneurysm involving abdominal visceral branches. Report of a case.

A 58-year-old man with thoracoabdominal aortic aneurysm involving visceral arteries underwent graft replacement of the thoracoabdominal aorta and associated reconstruction of abdominal visceral branches. Femoro-femoral extracorporeal bypass, intermittent selective visceral arterial perfusion and a staging cross-clamping method of the aorta were utilized at surgery. The total cross-clamping time of the aorta was 165 minutes. The patient's postoperative course was uneventful with no incidence of hepatic and renal failure or paraplegia. Although postoperative systemic blood pressure and cardiac output recovered to normal values within 7 hrs after the release of aortic clamping, it took 18 hrs for hepatic venous hemoglobin oxygen saturation (ShvO2) to recover. Base excess in arterial blood, lactic acid in arterial and hepatic venous blood, and ketone body ratio in arterial blood (AKBR) and hepatic venous blood (HVKBR) recovered to within normal ranges after 18 hrs of the release of aortic clamping. ShvO2 monitoring is a simple and may be a useful parameter in evaluating postoperative splanchnic perfusion and predicting abdominal organ failure at the time of thoracoabdominal aortic reconstruction involving visceral arteries.

Aortic Aneurysm, Abdominal↗
PubMed2000

[A case report of successful transcatheter arterial embolization therapy for osseous metastasis of hepatocellular carcinoma].

A 74-year-old man was admitted to our hospital with a chief complaint of severe local pain of the hip joint. Radiological findings showed a metastasized lesion on the left side of the pelvic wall originated from hepatocellular carcinoma (HCC) in the anterior segment of the liver. Transcatheter arterial embolization (TAE) therapy using epirubicin, Lipiodol and Spongel was successfully performed twice for primary HCC, and four times for osseous metastasis of HCC. After TAE therapy, the size of the metastasized lesion decreased with relief of pain, and an improvement in performance status of 4 to 2 was achieved. In conclusion, TAE therapy is thought to be very useful in the treatment of osseous metastasis of HCC with severe local pain.

Aged↗
PubMed2000

[Staging urinary bladder cancer with dynamic MR imaging].

This article reviews the magnetic resonance (MR) staging of bladder cancer. The multiplanar and soft-tissue characterization capabilities of MR imaging make it a valuable diagnostic tool to image the urinary bladder. Recent advances of MR imaging such as fast imaging, pelvic phased array coil, and dynamic imaging improve the image quality and diagnostic accuracy for staging bladder cancer. Some patient-related factors are also important for optimal imaging of the urinary bladder, especially motion artifacts from the gastrointestinal tract and the degree of bladder distension. An anticholinergic agent should be used for suppressing the motion artifacts. Optimal bladder filling can be achieved by asking patients to void and drink water 1 hour before examinations. Scanning perpendicular to the bladder wall is necessary for optimal evaluation for staging bladder cancer. Oblique scanning is needed in cases when a tumor is not located on the dome, base, anterior wall, posterior wall, or lateral walls. The early phase image of dynamic imaging is most useful for staging tumors. Better contrast between tumor and bladder wall on dynamic images provides high staging accuracy, especially in differentiation between superficial tumors and tumors with muscle invasion. MR imaging is comparable to computed tomography (CT) in the evaluation of lymph nodes. Although MR imaging currently is not appropriate for screening for bladder cancer and detecting small tumors, it has been proved to be most useful in the staging of bladder cancer.

Artifacts↗
PubMed1999

Glucose intolerance caused by a defect in the entero-insular axis: a study in gastric inhibitory polypeptide receptor knockout mice.

Mice with a targeted mutation of the gastric inhibitory polypeptide (GIP) receptor gene (GIPR) were generated to determine the role of GIP as a mediator of signals from the gut to pancreatic beta cells. GIPR-/- mice have higher blood glucose levels with impaired initial insulin response after oral glucose load. Although blood glucose levels after meal ingestion are not increased by high-fat diet in GIPR+/+ mice because of compensatory higher insulin secretion, they are significantly increased in GIPR-/- mice because of the lack of such enhancement. Accordingly, early insulin secretion mediated by GIP determines glucose tolerance after oral glucose load in vivo, and because GIP plays an important role in the compensatory enhancement of insulin secretion produced by a high insulin demand, a defect in this entero-insular axis may contribute to the pathogenesis of diabetes.

Administration, Oral↗
PubMed1999

Fluorescence Detection from Single Dendrimers with Multiple Chromophores.

The differences in the fluorescence behavior of a polyphenylene dendrimer with eight peryleneimides chromophores (1) and a single hexaphenylperyleneimide chromophore have been investigated at a single-molecule level through the combination of ultrasensitive fluorescence detection and microscopy.

Journal Article↗
PubMed1999

Refinement of crystal structural parameters using two-dimensional energy-filtered CBED patterns.

A new method to refine crystal structural parameters using convergent-beam electron diffraction (CBED), which is applicable to nanometre-size crystal structure analysis, is proposed. This method is based on the fitting between theoretical calculations and experimental intensities of energy-filtered two-dimensional CBED patterns containing higher-order Laue-zone (HOLZ) reflections. The use of HOLZ reflections is essential for the method because small displacements of atoms can be sensitively detected using HOLZ reflections with large reciprocal vectors. For this purpose, a new Omega-filter transmission microscope (JEM-2010FEF), which can take energy-filtered CBED patterns up to a high angle with a small distortion, and a new analysis program to refine structural parameters, which is based on many-beam Bloch-wave calculations and nonlinear least-squares fitting, have been developed. As a test example, a positional parameter and isotropic and anisotropic Debye-Waller factors of CdS have been refined. Two-dimensional CBED patterns calculated with the refined parameters show very good agreement with the experimental ones, and the refined values of the parameters also agree well with the result of a single-crystal X-ray diffraction experiment. Important problems of the analysis procedure are discussed item by item.

Journal Article↗
PubMed1999

The cyclic AMP response element modulator family regulates the insulin gene transcription by interacting with transcription factor IID.

We analyzed a mechanism of transcriptional regulation of the human insulin gene by cyclic AMP response element modulator (CREM) through four cyclic AMP response elements (CREs). We isolated two novel CREM isoforms (CREMDeltaQ1 and CREMDeltaQ2), which lack one of the glutamine-rich domains, Q1 and Q2 respectively, and six known isoforms (CREMtaualpha, CREMalpha, inducible cyclic AMP early repressor (ICER) I, ICER Igamma, CREM-17X, and CREM-17) from rat pancreatic islets and the RINm5F pancreatic beta-cell line. CREM isoforms functioned as efficient transcriptional activators or repressors to modulate insulin promoter activity by binding to all of the insulin CREs. The binding activity of repressors is higher than that of activators and suppressed not only basal activity but also activator-induced activities. Furthermore, CREM activator interacted directly with the transcription factor IID components hTAF(II)130 and TATA box-binding protein (TBP). These results suggest that the activation of the insulin gene transcription by CREM activator is mediated by not only direct binding to the CREs but also by recruiting transcription factor IID to the insulin promoter via its interaction with hTAF(II)130 and TBP. On the other hand, the CREM repressor ICER competitively interrupts the binding of the activators to CREs and does not interact with either TBP or hTAF(II)130; therefore, it might fail to stabilize the basal transcriptional machinery and repress transactivation.

Animals↗
PubMed1999

Cisplatin-induced toxicity in LLC-PK1 kidney epithelial cells: role of basolateral membrane transport.

Cytotoxicity of cisplatin was evaluated after apical and/or basolateral treatment of LLC-PK1 cell monolayers grown on porous membrane filters with 300 microM cisplatin. When LLC-PK1 cells were exposed from basolateral side for 0.5-4 h, lactate dehydrogenase (LDH) release into culture medium was markedly stimulated. However, apical treatment of the cells with cisplatin for 0.5 h did not stimulate LDH release. gamma-Glutamyltransferase activity and amount of protein in the cell homogenate were markedly decreased by basolateral treatment with cisplatin. However, in the apical treatment with cisplatin, these changes were relatively small, suggesting that degrees of the toxicities were different between basolateral and apical treatment with cisplatin. Cellular platinum level after basolateral treatment with cisplatin was higher compared to that following apical treatment. Furthermore, both accumulation and toxicity of cisplatin in LLC-PK1 cells were decreased by treatment with cisplatin at 4 degrees C. These results suggested that there were specific mechanisms mediating cisplatin uptake at the basolateral membranes of LLC-PK1 cells.

Animals↗
PubMed1999

The MH1 domains of smad2 and smad3 are involved in the regulation of the ALK7 signals.

The biological responses of the transforming growth factor beta (TGF-beta) superfamily are induced by activation of a receptor complex and Smad proteins. We surveyed the TGF-beta superfamily receptors using the degenerate PCR strategy, and found activin receptor-like kinase 7 (ALK7) to be abundantly expressed in fetal rat pancreatic islets. ALK7 is also expressed in adult rat islets and pancreatic beta-cell-derived MIN6 cells. The constitutively active form of ALK7, ALK7(T194D), activated Smad3 and a chimeric Smad protein, Smad3-2, containing the MH1 domain of Smad3 and the MH2 domain of Smad2, and translocated them to nuclei and then induced activation of the human PAI-1 promoter. However, neither Smad2 nor Smad2-3 protein, containing the MH1 domain of Smad2 and the MH2 domain of Smad3 were activated. These results indicate that the ALK7 signal regulates nuclear localization and activation of Smad2 and Smad3, and the MH1 domain of Smad2 has inhibitory effects on the nuclear localization.

Activin Receptors↗