Biomedical subjects

T Takeda

Publications and source records attributed to T Takeda.

At least 181 records · Page 10Linked to original sources

PubMed2000

Immunologic evaluation of an Escherichia coli O157-infected pregnant woman. A case report.

BACKGROUND: To the best of our knowledge, this is the first case of pregnancy complicated by hemorrhagic enterocolitis due to Escherichia coli O157. CASE: A woman with hemorrhagic enterocolitis due to E coli O157 was seen at 32 weeks of gestation. We investigated her immune response to 0157 lipopolysaccharide and to Shiga toxin in the sera and breast milk. CONCLUSION: IgM and IgA to 0157 lipopolysaccharide in the breast milk of this patient might protect her infant after the disappearance of serum IgM.

Adult↗

PubMed2000

[Efficacy of cibenzoline for chest oppression and ventricular arrhythmia during effort and alcohol consumption in a patient with hypertrophic obstructive cardiomyopathy: a case report].

A 67-year-old man presented with chest oppression and palpitation during effort and alcohol consumption. Echocardiography demonstrated asymmetric septal hypertrophy and systolic anterior motion of the anterior mitral leaflet with a pressure gradient of 80 mmHg across the left ventricular outflow tract (LVOT), leading to the diagnosis of hypertrophic obstructive cardiomyopathy. During the treadmill exercise test, blood pressure decreased with electrocardiographic ST-segment depression and subsequent frequent premature ventricular contractions. Holter-electrocardiographic monitoring also showed ST-segment depression with premature ventricular contractions during effort and alcohol consumption. Coronary angiography showed no abnormalities and cardiac catheterization at baseline showed a systolic pressure gradient of only 2 mmHg across the LVOT. However, the gradient increased to 33 mmHg after premature ventricular contraction, 27 mmHg at Valsalva maneuver and 75 mmHg with dobutamine infusion (5 micrograms/kg/min) and disappeared with 70 mg of intravenous cibenzoline. Medication with cibenzoline (300 mg/day) for one month reduced the LVOT gradient at rest to 53 mmHg and strikingly improved symptoms and exercise tolerance and also suppressed premature ventricular contractions during exercise and alcohol consumption. We conclude that cibenzoline was effective for reduction of LVOT gradient both at rest and during exercise and alcohol consumption.

Administration, Oral↗

PubMed2000

[Biweekly low-dose cisplatin and 5-fluorouracil combination chemotherapy for advanced gastrointestinal carcinoma].

Biweekly intravenous infusions of low-dose cisplatin (CDDP) and 5-fluorouracil (5-FU) were evaluated in 80 patients with advanced or recurrent gastric, colorectal, pancreatic or gallbladder adenocarcinoma. CDDP was given biweekly at a dose of 15 mg/m2 infused for 30 minutes, and 5-FU 375 mg/m2 was infused for 2 hours as many times as possible. The response rate among patients with gastric cancer was 26%, colorectal cancer 10%, pancreatic cancer 7.7%, and gallbladder cancer 42.9%. The response rates were not so high, but the median survival time of patients with recurrent gastric cancer was 17.3 months, pancreatic cancer 6.7 months, and gallbladder cancer 10.7 months. A patient with unresected advanced pancreatic head cancer with liver and para-aortic lymph node metastases received this therapy 38 times, and lived for 54 months. No severe side effects occurred in any of these cases. Thus, this chemotherapy could well be effective for the outcome of cases of advanced gastrointestinal carcinoma.

Adenocarcinoma↗

PubMed2000

[Metallic stent placement for iliac artery occlusive disease].

Since 1991, we have performed stent placement for 35 iliac artery lesions in 31 patients. The etiologic diseases were atherosclerotic in 34 patients and traumatic dissection in one. The indications of placement were total occlusion in 3, late restenosis after angioplasty in 5, dissection in 5, and residual stenosis due to inadequate angioplasty in 21. We also performed direct stent placement for one traumatic dissection. The stents used were Wallstents in 10, Palmaz stents in 14, Strecker stents in 9, and Memotherm stents in 2 lesions. Follow-up was performed clinically or angiographically with measurement of the ankle/arm pressure index. Stent placement was successful in all cases, and relief or improvement of symptoms was achieved. The follow-up period ranged from 6-85 months (mean, 37.3 months). Late stent stenosis or occlusion occurred in 6 cases, among which 4 occluded lesions were successfully recanalized by thrombolytic therapy with angioplasty or second stent placement. In total, the primary patency rates were 88% and 77% at two and four years, respectively, while the secondary patency rates were 94% and 94%. In conclusion, metallic stent placement may offer extended application of intravascular treatment for iliac artery occlusive disease, and good long-term patency rates can be expected.

Adult↗

PubMed2000

New types of X-ray computed tomography (CT) with synchrotron radiation: fluorescent X-ray CT and phase-contrast X-ray CT using interferometer.

New types of X-ray computed tomography (CT), fluorescent X-ray CT and phase-contrast X-ray CT are being developed for biomedical research. While fluorescent scanning X-ray CT (FXCT) can detect specific contrast elements, or endogenous iodine, at very low content (less than 400 pg iodine of tissue in a volume of 8 x 10(-6) ml), the phase-contrast X-ray CT (PCCT) is a highly sensitive imaging technique to differentiate between different biological tissue types (based on their specific gravity variation) without the use of a contrast agent. Therefore, we can expect functional diagnosis with FXCT, and high contrast, high resolution biological imaging with PCCT. In this paper, a human thyroid gland imaged by FXCT, and a metastatic human cancerous lesion depicted using PCCT are presented. The latter method used a newly manufactured, large, monolithic, X-ray interferometer, which is described in this paper in detail.

Colonic Neoplasms↗

PubMed2000

Escherichia coli Shiga toxin.

The Stx family contains two types called Stx1 (verotoxin 1: VT1 or Shiga-like toxin: SLT1) and Stx2 (VT2, SLT2); both toxins are encoded by bacteriophages. Stx1 is identical to Shiga toxin produced by Shigella dysenteriae type I. Stx2 is heterogeneous and immunologically different from Stx1. Although many variations are found in Stx family, all Stx has an A-B structure: the A subunit has N-glycosidase activity and the B subunit binds to a membrane glycolipid, globotriaosylceramide (Gb3). The A subunit cleaves a single adenine residue from the 28S rRNA component of eukaryotic ribosomes, resulting in inhibition of protein synthesis. Stx-producing Escherichia coli (STEC) is known to cause hemorrhagic enterocolitis and hemolytic-uremic syndrome (HUS). Stx plays a role in the occurrence of blood in the feces and in the HUS by their action on the endothelial cells of blood vessels in the intestinal submucosa and in the renal glomeruli. Epidemiologically, Stx2 seems to be more important than Stx1 in development of HUS. The action of Stx is not limited to inhibition of protein synthesis. Stx induces macrophages to express tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and interleukin-6 (IL-6) in vitro. These cytokines and lipopolysaccharide (LPS) are reported to increase the susceptibility of cells to Stx. A variety of cells such as tubular epithelial cells, may be targets for Stx-mediated apoptosis. Apoptosis is considered to contribute to the pathogenesis of HUS caused by STEC. In this review, recent progress in Stx-related research is summarized.

Apoptosis↗

PubMed2000

Outcomes of dysplastic nodules in human cirrhotic liver: a clinicopathological study.

The number of dysplastic nodules detected clinically has increased since patients with hepatitis virus-associated cirrhosis, who are at increased risk for hepatocellular carcinoma (HCC), began to undergo regular cancer surveillance. Although it is potentially important to determine which type(s) of nodule may be prone to progress to HCC, outcomes of dysplastic nodules have not been fully investigated. This prompted us to examine the outcomes of dysplastic nodules in cirrhotic patients clinicopathologically. We studied 33 dysplastic nodules of <20 mm in maximum diameter, diagnosed by fine needle aspiration biopsy under ultrasonography (US). These nodules were clinically followed, mainly by US examination, for up to 70 months. When the nodules enlarged or exhibited changes on US, they were histologically reexamined by second biopsy. Surprisingly, 15 of the 33 nodules (45.5%) disappeared, 14 nodules (42.4%) remained unchanged, and only 4 nodules (12.1%) progressed to HCC. The latter 4 nodules were all hyperechoic on US and were composed of clear cells with fatty change or small cells with increased nuclear density, and in all 4 patients serum was positive for hepatitis C virus antibody. Univariate analyses revealed that, although not significant, the hyperechoic nodules or nodules with small cell change showed a higher HCC progression rate in comparison with the hypoechoic nodules or the nodules without small cell change. In summary, most of the dysplastic nodules we followed disappeared or remained unchanged, but some progressed to HCC. Hyperechoic nodules in patients with hepatitis C virus-associated cirrhosis, which show small cell change with increased nuclear density, may be prone to progress to HCC.

Adult↗

PubMed1999

Activation of Src family kinase yes induced by Shiga toxin binding to globotriaosyl ceramide (Gb3/CD77) in low density, detergent-insoluble microdomains.

Shiga toxin (Stx) is an enterotoxin produced by Shigella dysenteriae serotype 1 and enterohemorrhagic Escherichia coli, which binds specifically to globotriaosylceramide, Gb3, on the cell surface and causes cell death. We previously demonstrated that Stx induced apoptosis in human renal tubular cell line ACHN cells (Taguchi, T., Uchida, H., Kiyokawa, N., Mori, T., Sato, N., Horie, H., Takeda, T and Fujimoto, J. (1998) Kidney Int. 53, 1681-1688). To study the early signal transduction after Stx addition, Gb3-enriched microdomains were prepared from ACHN cells by sucrose density gradient centrifugation of Triton X-100 lysate as buoyant, detergent-insoluble microdomains (DIM). Gb3 was only recovered in DIM and was associated with Src family kinase Yes. Phosphorylation of tyrosine residues of proteins in the DIM fraction increased by 10 min and returned to the resting level by 30 min after the addition of Stx. Since the kinase activity of Yes changed with the same kinetics, Yes was thought to be responsible for the hyperphosphorylation observed in DIM proteins. Unexpectedly, however, all of the Yes kinase activity was obtained in the high density, detergent-soluble fraction. Yes was assumed to be activated and show increased Triton X-100 solubility in the early phase of retrograde endocytosis of Stx-Gb3 complex. Since Yes activation by the Stx addition was suppressed by filipin pretreatment, Gb3-enriched microdomains containing cholesterol were deeply involved in Stx signal transduction.

Animals↗

PubMed1999

CDC7 kinase complex as a molecular switch for DNA replication.

Cdc7 kinase and its activator Dbf4 protein, originally identified in budding yeast Saccharomyces cerevisiae, are widely conserved in eukaryotes including fission yeast and human. Dbf4-related activators bind and stimulate kinase activity of Cdc7-like catalytic subunit. Its kinase activity is cell cycle-regulated, mainly through availability of the activation subunit whose level increases at G1/S boundary and is maintained at a high level throughout S phase. MCM2 protein is among physiologically important substrates. Genetic studies in fission yeast indicate that Cdc7-related kinase complex also functions in meiosis, uninduced mutagenesis, DNA replication checkpoint signaling and maintenance of chromatin structures during S phase.

Animals↗

PubMed1999

Automatic activation in the human primary motor cortex synchronized with movement preparation.

The human primary motor cortex during a unilateral finger reactive movement to visual stimuli was examined by magnetoencephalography (MEG) measurement. The brain activity related to movement execution (the motor activity contralateral to the movement side) was estimated based on movement onset conditions and reaction times. The movement onset conditions were: (1) a simple reaction time task with a visual stimulus, (2) a Go/NoGo task with different colored stimuli and (3) a Go/NoGo task with different position stimuli. Dipole source estimation was done, and the time course of the motor activity was calculated. The results showed that not only the visual response but also the contralateral motor activity was evoked by the stimulus in all cases, and even when the NoGo stimulus was given. The motor activity in the primary motor cortex was conjectured to consist of two dominant components: the first component for the movement preparation and the second component for the movement execution. Because the first component happened with a constant delay time from the stimulus even in the NoGo case, the first component, coming through a fast pathway for signals from visual stimulus processing to the motor cortex without any intervening cognitive processing, was conjectured to make the motor cortex prepare for the forthcoming movement onset automatically regardless of the stimulus instruction.

Adult↗

PubMed1999

Telomerase activity in malignant ovarian tumors with deregulation of cell cycle regulatory proteins.

Using a semiquantitative telomeric repeat amplification protocol assay, telomerase-positive frequencies and enzyme levels were measured. Out of 95% of 49 human ovarian tumors, the highest level of telomerase activity was observed in malignant tumors. Furthermore, by immunohistochemical staining of cell cycle regulatory proteins (pRB, p16, cyclin D1, cyclin E and p53) at the G1 checkpoint, we evaluated the relation between each protein alterations and the levels of telomerase activity. We could not demonstrate a clear relation with each molecule except for cyclin E, but suggesting that aberrant accumulation of these proteins was considered as a reason for telomerase deregulation, which may play an essential role in the pathway of telomerase regulation.

Adult↗

PubMed1999

Mudskipper periophthalmodon schlosseri can repay oxygen debts in air but not in water

We determined aerial and aquatic oxygen uptake rates (&Mdot;o(2)) of Periophthalmodon schlosseri at rest and after exhaustive exercise at 30 degrees C. Resting &Mdot;o(2) in air (3.16 +/- 0.10 [SE] &mgr;mol/g/hr) was significantly higher than that in air saturated water (2.41 +/- 0.06 &mgr;mol/g/hr). When the fish was placed in air after 2 min exhaustive exercise, &Mdot;o(2) immediately increased about 2.5 times, thereby repaying oxygen debt of 5.0 &mgr;mol/g. In contrast, &Mdot;o(2) failed to show any significant elevation from the resting level as long as the fish was confined in water after exercise. However, when the fish was subsequently emerged, &Mdot;o(2) did increase above the resting level, amounting to an excess oxygen uptake of 5.5 &mgr;mol/g. These results demonstrated that the gas transport system of P. schlosseri is better adapted to air breathing and the mode of adaptation limited the capability for water breathing. J. Exp. Zool. 284:265-270, 1999. Copyright 1999 Wiley-Liss, Inc.

Journal Article↗

PubMed1999

A novel human CC chemokine, eotaxin-3, which is expressed in IL-4-stimulated vascular endothelial cells, exhibits potent activity toward eosinophils.

IL-4 has been shown to be involved in the accumulation of leukocytes, especially eosinophils, at sites of inflammation by acting on vascular endothelial cells. To identify novel molecules involved in the IL-4-dependent eosinophil extravasation, cDNA prepared from HUVEC stimulated with IL-4 was subjected to differential display analysis, which revealed a novel CC chemokine designated as eotaxin-3. The human eotaxin-3 gene has been localized to chromosome 7q11.2, unlike most other CC chemokine genes. The predicted mature protein of 71 aa showed 27-42% identity to other human CC chemokines. The recombinant protein induced a transient increase in the cytosolic Ca2+ concentration and in vitro chemotaxis on eosinophils. Furthermore, in cynomolgus monkeys, the accumulation of eosinophils was observed at the sites where the protein was injected. Eotaxin-3 inhibited the binding of 125I-eotaxin, but not 125I-macrophage inflammatory protein-1alpha, to eosinophils and acted on cell lines transfected with CCR-3, suggesting that eotaxin-3 recognized CCR-3. IL-13 as well as IL-4 up-regulated eotaxin-3 mRNA in HUVEC, whereas neither TNF-alpha, IL-1beta, IFN-gamma, nor TNF-alpha plus IFN-gamma did. The expression profile of eotaxin-3 is different from those of eotaxin, RANTES, and monocyte chemoattractant protein-4, which are potent eosinophil-selective chemoattractants and are induced by either TNF-alpha or TNF-alpha plus IFN-gamma. These results suggest that eotaxin-3 may contribute to the eosinophil accumulation in atopic diseases.

Amino Acid Sequence↗

PubMed1999

Functional interaction between Oct-1 and retinoid X receptor.

The retinoid X receptor (RXR) is a member of the nuclear hormone receptor superfamily and heterodimerizes with a variety of other family members such as the thyroid hormone receptor (TR),1 retinoic acid receptor, vitamin D receptor, and peroxisome proliferator-activated receptor. Therefore, RXR is supposed to play a key role in a ligand-dependent regulation of gene transcription by nuclear receptors. In this study, we have identified the octamer-binding transcription factor-1 (Oct-1) as a novel interaction factor of RXR. In vitro pull-down assays using RXR deletion mutants showed that the interaction surfaces were located in the region encompassing the DNA binding domain (C domain) and the hinge domain (D domain) of RXR. We also showed that RXR interacted with the POU homeodomain but not with the POU-specific domain of Oct-1. Gel shift analysis revealed that Oct-1 reduced the binding of TR/RXR heterodimers to the thyroid hormone response element (TRE). In transient transfection assays using COS1 cells, Oct-1 repressed the T3-dependent transcriptional activity of TR/RXR heterodimers, consistent with in vitro DNA binding data; however, transcriptional activation by Gal4-TR(LBD) (LBD, ligand binding domain), which lacks its own DNA binding domain but retains responsiveness to T3, was not influenced by Oct-1. These results suggest that Oct-1 functionally interacts with RXR and negatively regulates the nuclear receptor signaling pathway by altering the DNA binding ability of the receptors.

Animals↗

PubMed1999

Assessment of DNA-protein crosslinks in the course of aging in two mouse strains by use of a modified alkaline filter elution applied to whole tissue samples.

Two different mouse strains have been used for determination of age dependence of DNA-protein crosslinks by alkaline filter elution: a long lived laboratory strain, NMRI and an accelerated senescence-prone, short lived strain, SAMP1. Five organs were selected: Brain, kidney, lung, heart and liver. Remarkably in all five organs of short lived SAMPI mice crosslinks increased significantly with age. In NMRI however only in brain and heart a significant rise in old age has been observed, while in the other organs there was no increase in DNA-protein crosslinking. Appreciable mitotic activity which is lacking in brain and heart could be the reason for this difference. Poor repair in all five organs could be an important component for the multiple ailments and shortened life span in SAMP1 mice.

Aging↗

PubMed1999

Regulation of inner ear fluid in the rat by vasopressin.

The anti-diuretic hormone vasopressin has been shown to be important in regulating inner ear fluid. The diuretic hormone, CNP, and its receptor, ANP-B receptor, may also function in the regulation of inner ear fluid. To determine whether vasopressin directly affects the fluid level, we infused this hormone to rat and assay of V2-AVP receptor mRNA by semiquantitative RT-PCR demonstrated a significantly lower level of this transcript in vasopressin-infused animals than in saline-infused animals. The levels of CNP and ANP-B receptors mRNA, however, were the same in both groups of rats. Results suggest that high plasma levels of vasopressin may be a principal causal factor of endolymphatic hydrops in Meniere's disease, perhaps by down-regulating the number of vasopressin receptors.

Animals↗

PubMed1999

Synthetic studies on glycosphingolipids from the parasite Echinococcus multilocularis.

Novel neutral glycosphingolipids isolated from the metacestodes of Echinococcus multilocularis by Persat, may be expected to be involved in host-parasite interactions. We have synthesized these glycosphingolipid analogues containing 2-branched fatty alkyl residues in place of ceramide. The glycosylation of galactosyl donors 4 and 5 with each of the acceptors 2 and 11 in the presence of N-iodosuccinimide (NIS)/TfOH, and the glycosylation of fucosyl donor 13 with acceptors 12 and 20 in the presence of dimethyl(methylthio)sulfonium triflate (DMTST) gave the desired oligosaccharide derivatives at good yield. The fully per-O-acylated 2-(trimethylsilyl)ethyl glycosides 6, 15, 21, and 26 were converted to glycosylimidates 7, 16, 22, and 27, which were condensed with 2-(tetradecyl)hexadecanol and subsequently deacylated give four target glycosphingolipid analogues.

Animals↗

PubMed1999

Tyrosine phosphorylation of STAT3 by leptin through leptin receptor in mouse metaphase 2 stage oocyte.

Leptin is the product of the obese gene (ob), and is secreted in plasma from mature adipocytes. It has been recently reported that leptin is synthesized in granulosa and cumulus cells within the follicle of the ovary, and is present in mature human oocytes, suggesting possible roles of leptin in several aspects of pre- and post-ovulatory follicular development. On the other hand, STAT (Signal Transducer and Activator of Transcription) transcription factors are involved in leptin-associated signal transduction. In this report, we studied the expression of leptin receptor and STAT3 activation by leptin in metaphase 2 stage (M2) oocytes. Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunoblotting showed that mRNA and protein of leptin receptor were expressed in M2 stage oocyte. Leptin at 15 ng/ml, the concentration observed in follicular fluid, caused tyrosine phosphorylation of STAT3 in mouse M2 stage oocytes. These results suggest possible roles of leptin in several aspects during oocyte maturation by activating the STAT signal transduction pathway.

Adipocytes↗