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T Sekine

Publications and source records attributed to T Sekine.

At least 37 records · Page 2Linked to original sources
PubMed2001

In vivo evaluation of a new sealant material on a rat lung air leak model.

The ability of an albumin-based hydrogel sealant (ABHS) to prevent air leakage through the suture line after pulmonary surgery was evaluated by comparison with that of a fibrin glue (FG). As an air-leak model, a rat lung was used in which a standard incision was made and the burst pressure for ABHS and FG was measured. The average burst pressures at time 0 for the FG and ABHS groups were 30.8+/-15.2 and 77.5 +/-19.1 mmHg, respectively. At Day 3, the value of ABHS (76.3 +/- 15.8 mmHg) was still significantly higher (P<0.05) than that of FG (60.0 +/- 21.9 mmHg). At Day 7, no statistical difference was observed between the FG group(71.2 +/- 18.6 mmHg) and the ABHS group(88.8 +/- 11.7 mmHg). Histological examination of the incision at Day 14 revealed that neither sealant was not visible at the incision site, and there was no evidence of adverse tissue reaction. It was concluded that ABHS had good sealing properties and is an alternative to FG for air leakage treatment in pulmonary surgery.

Air↗
PubMed2001

Applicability of a mobile accelerator for intraoperative radiation therapy to colorectal cancer.

PURPOSE: Intraoperative radiation therapy is reportedly effective for local control and pain relief in colorectal cancer. However, this treatment requires a large number of medical personnel, which hinders expanded use of this method. A mobile electron linear accelerator for intraoperative radiation therapy has been developed and is now commercially available. This report analyzes the applicability of this accelerator to colorectal cancer. The applicability of the mobile accelerator is analyzed based on its specifications by simulating the intraoperative radiation therapy delivered to these patients with a conventional intraoperative radiation therapy unit. METHODS: From 1987 to 1999, 49 colorectal cancer patients underwent 54 surgical resections and received intraoperative radiation therapy to 75 sites. RESULTS: The mean intraoperative radiation therapy dose for colorectal cancer with the conventional unit was 22 (range, 10-30) Gy. The mean electron energy level was 10 (range, 3-30) MEV. Applicator size ranged from 4 to 10 cm in diameter. The mobile accelerator can achieve a dose rate of 10 Gy/min and an applicator unit size range of 3 to 10 cm in diameter, facilitating intraoperative radiation therapy for colorectal cancer. The electron energy limitation (12 MEV at maximum) suggests that the indications for this machine are limited. In our experience, 30 percent of patients received intraoperative radiation therapy with electron energy levels exceeding 12 MEV. Of these cases, 81 percent had macroscopic residual tumor and 69 percent had pain. CONCLUSION: An intraoperative radiation therapy mobile accelerator can cover 72 percent of the irradiation sites covered using our conventional unit. This accelerator is useful for intraoperative radiation therapy with curative intent for patients with no or slight residual tumor. Patients with gross residual tumor and pain may not be suitable.

Adult↗
PubMed2001

Real-time [11C]methionine translocation in barley in relation to mugineic acid phytosiderophore biosynthesis.

[11C]Methionine was supplied through barley roots and the 11C signal was followed for 90 min using a real-time imaging system (PETIS), with subsequent development of autoradiographic images of the whole plant. In all cases, [11C]methionine was first translocated to the 'discrimination center', the basal part of the shoot, and this part was most strongly labeled. Methionine absorbed by the roots of the plants was subsequently translocated to other parts of the plant. In Fe-deficient barley plants, a drastic reduction in [11C]methionine translocation from the roots to the shoot was observed, while a greater amount of 11C was found in the leaves of Fe-sufficient or methionine-pretreated Fe-deficient plants. Treatment of Fe-deficient plants with aminooxyacetic acid, an inhibitor of nicotianamine aminotransferase, increased the translocation of [11C]methionine to the shoot. The retention of exogenously supplied [11C]methionine in the roots of Fe-deficient barley indicates that the methionine is used in the biosynthesis of mugineic acid phytosiderophores in barley roots. This and the absence of methionine movement from shoots to the roots suggest that the mugineic acid precursor methionine originates in the roots of plants.

Aminooxyacetic Acid↗
PubMed2001

Mechanical properties of artificial tracheas composed of a mesh cylinder and a spiral stent.

Much work has been done on the materials used for mesh-type artificial tracheas, but a precise mechanical evaluation of these structures has not yet been performed. In the present study, we determined the mechanical properties of typical mesh-type artificial tracheas and compared them with those of native trachea. Four types of artificial trachea were made and used for the mechanical tests. The basic frame of all the specimens was composed of a mesh cylinder and a spiral stent. The specimen whose mesh was sealed with collagen sponge showed almost the same behavior in the force-strain curve under compression, suggesting that collagen sealing has little effect on mechanical properties. Agreement between measured and estimated mechanical properties was good, especially in the low strain region, suggesting that artificial tracheas can be designed in terms of mechanical properties by mainly considering the basic frame structure.

Animals↗
PubMed2001

Sugar conformation of a stereospecific 2'-R or 2'-S deuterium-labeled DNA decamer studied with proton-proton J coupling constants.

The sugar conformation of a DNA decamer was studied with proton-proton 3J coupling constants. Two samples, one comprising stereospecifically labeled 2'-R-2H for all residues and the other 2'-S-2H, were prepared by the method of Kawashima et al. [J. Org. Chem. (1995) 60, 6980-6986; Nucleosides Nucleotides (1995) 14, 333-336], the deuterium labeling being highly stereospecific (> or = 99% for all 2''-2H, > or = 98% for 2'-2H of A, C, and T, and > or = 93% for 2'-2H of G). The 3J values of all H1'-H2' and H1'-H2'' pairs, and several H2'-H3' and H2''-H3' pairs were determined by line fitting of 1D spectra with 0.1-0.2 Hz precision. The observed J coupling constants were explained by the rigid sugar conformation model, and the sugar conformations were found to be between C3'-exo and C2'-endo with phi(m) values of 26 degrees to 44 degrees, except for the second and 3' terminal residues C2 and C10. For the C2 and C10 residues, the lower fraction of S-type conformation was estimated from JH1'H2' and JH1'H2'' values. For C10, the N-S two-site jump model or Gaussian distribution of the torsion angle model could explain the observed J values, and 68% S-type conformation or C1'-exo conformation with 27 degrees distribution was obtained, respectively. The differences between these two motional models are discussed based on a simple simulation of J-coupling constants.

Carbohydrate Conformation↗
PubMed2001

Real time visualization of 13N-translocation in rice under different environmental conditions using positron emitting Ttacer imaging system.

The ammonium ion is an indispensable nitrogen source for crops, especially paddy rice (Oryza sativa L. cv Nipponbare). Until now, it has been impossible to measure ammonium uptake and nitrogen movement in plants in real time. Using the new technologies of PETIS (positron emitting tracer imaging system) and PMPS (positron multi-probe system), we were able to visualize the real time translocation of nitrogen and water in rice plants. We used positron-emitting 13N-labeled ammonium (13NH4+) and 15O-water to monitor the movement. In plants cultured under normal conditions, 13NH4+ supplied to roots was taken up, and a 13N signal was detected at the discrimination center, the basal part of the shoots, within 2 minutes. This rapid translocation of (13)N was almost completely inhibited by a glutamine synthetase inhibitor, methionine sulfoximine. In general, nitrogen deficiency enhanced 13N translocation to the discrimination center. In the dark, 13N translocation to the discrimination center was suppressed to 40% of control levels, whereas 15O-water flow from the root to the discrimination center stopped completely in the dark. In abscisic acid-treated rice, 13N translocation to the discrimination center was doubled, whereas translocation to leaves decreased to 40% of control levels. Pretreatment with NO3- for 36 hours increased 13N translocation from the roots to the discrimination center to 5 times of control levels. These results suggest that ammonium assimilation (from the roots to the discrimination center) depends passively on water flow, but actively on NH4+-transporter(s) or glutamine synthetase(s).

Biological Transport↗
PubMed2001

Identification and characterization of human organic anion transporter 3 expressing predominantly in the kidney.

A cDNA encoding a multispecific organic anion transporter 3 (hOAT3) was isolated from a human kidney cDNA library. The hOAT3 cDNA consisted of 2179 base pairs that encoded a 543-amino-acid residue protein with 12 putative transmembrane domains. The deduced amino acid sequence of hOAT3 showed 36 to 51% identity to those of other members of the OAT family. Northern blot analysis revealed that hOAT3 mRNA is expressed in the kidney, brain, and skeletal muscle. When expressed in Xenopus laevis oocytes, hOAT3 mediated the transport of estrone sulfate (K(m) = 3.1 microM), p-aminohippurate (K(m) = 87.2 microM), methotrexate (K(m) = 10.9 microM), and cimetidine (K(m) = 57.4 microM) in a sodium-independent manner. hOAT3 also mediated the transport of dehydroepiandrosterone sulfate, ochratoxin A, PGE(2), estradiol glucuronide, taurocholate, glutarate, cAMP and uric acid. Estrone sulfate did not show any trans-stimulatory effects on either influx or efflux of [(3)H]estrone sulfate via hOAT3. hOAT3 interacted with chemically heterogeneous anionic compounds, such as nonsteroidal anti-inflammatory drugs, diuretics, sulfobromophthalein, penicillin G, bile salts and tetraethyl ammonium bromide. The hOAT3 protein was shown to be localized in the basolateral membrane of renal proximal tubules and the hOAT3 gene was determined to be located on the human chromosome 11q12-q13.3 by fluorescent in situ hybridization analysis. These results suggest an important role of hOAT3 in the excretion/detoxification of endogenous and exogenous organic anions in the kidney.

Amino Acid Sequence↗
PubMed2001

Recognition of YKL-39, a human cartilage related protein, as a target antigen in patients with rheumatoid arthritis.

OBJECTIVE: To investigate whether autoimmunity to YKL-39, a recently cloned cartilage protein, occurs in patients with rheumatoid arthritis (RA). METHODS: Autoantibody to YKL-39 was assayed by enzyme linked immunosorbent assay (ELISA) and western blotting in serum samples from patients with RA, systemic lupus erythematosus (SLE), and healthy donors, using recombinant YKL-39 protein. This reactivity was compared with that against a YKL-39 homologue, YKL-40 (human cartilage gp-39/chondrex), which has been reported to be an autoantigen in RA. RESULTS: Autoantibody to YKL-39 was detected in seven of 87 patients with RA (8%), but not in serum samples from patients with SLE or healthy donors. YKL-40 reactivity was found in only one of 87 RA serum samples (1%), with no cross reactivity to YKL-39. CONCLUSION: The existence of anti-YKL-39 antibody in a subset of patients with RA is reported here for the first time. Further, it was shown that the immune response to YKL-39 was independent of that to YKL-40. Clarification of the antibody and T cell responses to autoantigens derived from chondrocyte, cartilage, or other joint components may lead to a better understanding of the pathophysiology of joint destruction in patients with RA.

Adipokines↗
PubMed2001

Mechanism of burn injury during magnetic resonance imaging (MRI)--simple loops can induce heat injury.

To determine the mechanism of burn injury associated with magnetic resonance imaging (MRI), the induced current in the loops of a conductive lead was measured. Seven types of loops with effective areas within the range from 100 to 12 000 cm2 were made and then each loop was placed in the bore of a whole-body MR system at 0.5 T and MRI was carried out. During radio frequency (RF) irradiation, an induced voltage was observed in loops that were placed with their axes parallel to the linearly polarized transmitting RF field. The voltage had a sincfunction characteristic and was within the range 55-235 V at the RF pulse sequence for usual MR imaging. When the axis was vertical, negligible current was observed. A resistor inserted into the circuit of a 30 x 40 cm loop sparked and burned out. Simple loops of conductive material may result in the induction of a large and potentially hazardous voltage in the imaging system. Self-resonance of such a loop may add greatly to hazards by increasing the effective coupling to the RF transmitter. Also, impedance matching of the inserted resistor with the impedance of the loop increases the dissipated power at the resistor.

Burns, Electric↗
PubMed2001

Ardisiphenols A-C, novel antioxidants from the fruits of Ardisia colorata.

Novel alk(en)ylphenols, named ardisiphenols A--C (1--3) were isolated from the fruits of Ardisia colorata, together with known alk(en)ylresorcinols (4--6). Their structures were determined by the NMR and MS/MS analyses. All compounds showed scavenging activities towards 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and cytotoxicities against murine breast cancer cell line, FM3A.

Antioxidants↗
PubMed2001

Characterization of T cell receptor beta chains of accumulating T cells in chronic ongoing myocarditis demonstrated by heterotopic cardiac transplantation in mice.

Autoimmne mechanisms have been implicated in the pathogenesis of chronic ongoing mycarditis. An earlier study of murine chronic ongoing myocarditis reported that infiltrating T cells and macrophages were prominent in the normal donor heart, in a heterotopic cardiac transplantation model. It was demonstrated that myocarditis was transferred to a normal heart transplanted into a mouse with chronic myocarditis. The present study investigated an autoimmune link to the pathogenesis of chronic ongoing myocarditis by analyzing the T cell clonalities in the model. To characterize the accumulating T cells in the donor heart, the T cell receptor beta genes (TCRBG) were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) from mRNA in the donor hearts and accumulating TCRBG clonotypes were contrasted with those from recipient hearts. Inbred 3-week-old A/J mice were inoculated intraperitoneally with Coxsackievirus B3 (Nancy strain), 2 x 10(4) PFU, and housed for more than 60 days. Normal A/J mouse hearts were transplanted into the same strain of mice without myocarditis, as well as into the mice with chronic ongoing myocarditis. Both recipient and donor hearts were evaluated histologically 2 weeks after the transplantation. TCRBG were amplified by RT-PCR from mRNA of recipient and donor hearts and spleens. The specific accumulating TCRBG clonotypes were identified by their single strand conformation polymorphism. Multiple clonotypic accumulations occurred in the donor heart after cardiac transplantation. Distinct oligoclonal accumulation of TCR Vbeta1, 10, and 13 T cells was found in both recipient and donor hearts in 3 of 4 mice. Moreover, these clonotypes were not observed in spleen cells of the recipient mice. T specific cells expanding clonotypes of TCRBG are responsible for transferring myocarditis to the donor heart. An autoimmune response may, therefore, play a key role in the progression of chronic ongoing myocarditis.

Animals↗
PubMed2001

[Molecular identification of the multispecific organic anion transporter family (the OAT family): the role in the pharmacokinetics and toxicokinetics].

The multispecific organic anion transporters have been indicated to be involved in the transmembrane transport of various anionic substances. The kidney and liver possess the distinct organic anion transport pathways for the elimination of potentially toxic anionic drugs and metabolites. In the kidney, proximal tubular cells actively excrete organic anions of both endogenous and exogenous origin. We have isolated the renal multispecific organic anion transporter, OAT1 (organic anion transporter 1), from the rat kidney. OAT1 is a 551-amino acid residue protein with 12 putative membrane spanning domains. OAT1 mediates sodium-independent, anion exchange for a variety of organic anions including p-aminohippurate, cyclic nucleotides, prostanoides, dicarboxylates, and anionic drugs including beta-lactams, non-steroidal antiinflammatory drugs, diuretics and antiviral drugs. So far, three other isoforms have been identified. OATs comprise a new family of multispecific organic anion transporter, i.e., the OAT family. OATs show weak structural similarity to organic cation transporters (OCTs) and OCTN/carnitine transporters. All of the members of the OAT family are commonly expressed in the kidney, suggesting its significance in the renal organic anion excretion. In addition, OAT members appear to be responsible for the distribution/elimination of water soluble anionic drugs into/from the liver, brain and fetus.

Amino Acid Sequence↗
PubMed2001

Rapid N transport to pods and seeds in N-deficient soybean plants.

Non-nodulated soybean (Glycine max (L.) Merr.) plants were cultivated hydroponically under N-sufficient (5 mM NaNO(3)) or N-deficient (0.5 mM NaNO(3)) conditions. (13)N- or (15)N- labelled nitrate was fed to the cut end of the stems, and the accumulation of nitrate-derived N in the pods, nodes and stems was compared. Real-time images of (13)N distribution in stems, petioles and pods were obtained using a Positron Emitting Tracer Imaging System for a period of 40 min. The results indicated that the radioactivity in the pods of N-deficient plants was about 10 times higher than that of N-sufficient plants, although radioactivity in the stems and nodes of N-deficient versus N-sufficient plants was not different. A similar result was obtained by supplying (15)NO(3) to cut soybean shoots for 1 h. The fact that the N translocation into the pods from NO(3) fed to the stem base was much faster in N-deficient plants may be due to the strong sink activity of the pods in N-deficient plants. Alternatively, the redistribution of N from the leaves to the pods via the phloem may be accelerated in N-deficient plants. The temporal accumulation of (13)NO(3) in nodes was suggested in both N-sufficient and N-deficient plants. In one (13)NO(3) pulse-chase experiment, radioactivity in the stem declined rapidly after transferring the shoot from the (13)NO(3) solution to non-labelled NO(3); in contrast, the radioactivity in the node declined minimally during the same time period.

Amino Acids↗
PubMed2001

Characterization of the efflux transport of 17beta-estradiol-D-17beta-glucuronide from the brain across the blood-brain barrier.

The contribution of organic anion transporters to the total efflux of 17beta-estradiol-D-17beta-glucuronide (E(2)17betaG) through the blood-brain barrier (BBB) was investigated using the Brain Efflux Index method by examining the inhibitory effects of probenecid, taurocholate (TCA), p-aminohippurate (PAH), and digoxin. E(2)17betaG was eliminated through the BBB with a rate constant of 0.037 min(-1) after the microinjection into the brain. Probenecid and TCA inhibited this elimination with an IC50 value of 34 and 1.8 nmol/0.5 microl of injectate, respectively, whereas PAH and digoxin reduced the total efflux to about 80 and 60% of the control value, respectively. The selectivity of these inhibitors was confirmed by examining their inhibitory effects on the transport via organic anion transporting polypeptide 1 (Oatp1), Oatp2, organic anion transporter 1 (Oat1), and Oat3 transfectants using LLC-PK1 cells as hosts. Digoxin specifically inhibited the transport via Oatp2 (K(i) = 0.037 microM). The K(i) values of TCA for Oatp1 and Oatp2 (11 and 39 microM, respectively) were about 20 times lower than those for Oat1 and Oat3 (2.8 and 0.8 mM, respectively). PAH did not affect the transport via the Oatp family, but had a similar affinity for Oat1 and Oat3 (85 and 300 microM, respectively). Probenecid had a similar affinity for these transporters (Oatp1, Oatp2, Oat1, and Oat3) examined in this study. Taking the selectivity of these inhibitors into consideration, the maximum contribution made by the Oatp2 and Oat family to the total efflux of E(2)17betaG from the brain appears to be about 40 and 20%, respectively.

Animals↗
PubMed2001

Diagnosis of pancreatic adenocarcinoma by detection of human telomerase reverse transcriptase messenger RNA in pancreatic juice with sample qualification.

PURPOSE: We evaluated the diagnostic efficacy of detection of human telomerase reverse transcriptase (hTERT) message, a catalytic domain of human telomerase, in endoscopic retrograde pancreatography (ERP)-derived pancreatic juice. EXPERIMENTAL DESIGN: Both hTERT and CD25 expression were detected by reverse transcription-PCR (RT-PCR) in 17 patients with pancreatic adenocarcinoma (PC), 12 patients with chronic pancreatitis (CP), and 7 patients with no ERP abnormality (N). In the same patients, beta-actin message was semiquantified by competitive RT-PCR. K-ras codon 12 mutations were concomitantly analyzed by enriched PCR-SSCP in 11 and 7 PC and CP cases, respectively. RESULTS: Expression of hTERT was detected in 88% of PC cases and 17% of CP cases but not in the normal control (N). Alterations in K-ras were detected in 73% of PC cases and 57% of CP cases, respectively. beta-Actin mRNA was expressed in >3.0 x 10(1) copies/microl in all but two PC cases in which hTERT mRNA was not detected. CD25-positive and -negative peripheral lymphocytes were isolated from a normal volunteer using a fluorescent activating cell sorter. The hTERT message was detected in CD25-positive peripheral lymphocytes and in 18, 25, and 0% of the pancreatic juice samples from PC, CP, and N cases, respectively. All CP cases expressing hTERT message were also CD25 positive. CONCLUSIONS: These results suggest that detection of hTERT mRNA in pancreatic juice is a powerful tool to discriminate PC from CP, particularly when the samples are qualified against beta-actin mRNA levels and contaminating CD25-positive lymphocytes.

Actins↗
PubMed2001

Functional characterization of rat organic anion transporter 2 in LLC-PK1 cells.

Rat organic anion transporter 2 (rOat2) is abundantly expressed in the liver and localized to the basolateral membrane. A previous study using the Xenopus laevis oocyte expression system has shown that rOat2 transports organic anions such as salicylate () and, in the present study, rOat2 was characterized using a mammalian expression system. In addition to the substrates previously shown to be transported by rOat2, three substrates, indomethacin [IDM, Michaelis-Menten constant (K(m)) of 0.37 microM] and nucleoside derivatives such as 3'-azido-3'-deoxythymidine (AZT, K(m) of 26 microM) and 2',3'-dideoxycytidine (ddC, K(m) of 3.08 mM), were also identified for the first time The rank order of rOat2-mediated transport of these substrates was IDM > salicylate > prostaglandin E(2) > AZT > ddC > p-aminohippurate (PAH). Ketoprofen, indocyanine green and glibenclamide are potent inhibitors of the uptake of [(14)C]salicylate via rOat2 (K(i) of approximately 12 microM), while diclofenac, benzoate, verapamil, ibuprofen, and tolbutamide are moderate inhibitors (K(i) of approximately 150 microM). The affinity of PAH, a common substrate for the OAT family, for rOat2 is low (K(i) > 1 mM) compared with the other members of the OAT family (rOat1 and rOat3). Salicylate and IDM are also substrates for rOat1, but their affinity for rOat2 was higher than that for rOat1. The present study shows that rOat2 is a multispecific transporter and suggests that it may be involved at least partly, in the hepatic uptake of IDM, salicylate and nucleoside derivatives.

Algorithms↗
PubMed2000

Hydrogen peroxide downregulates human organic anion transporters in the basolateral membrane of the proximal tubule.

Hydrogen peroxide (H2O2) is known to be involved in drug-induced and ischemic proximal tubular damage. The purpose of this study was to elucidate the effects of hydrogen peroxide on organic anion transport mediated by human organic anion transporters 1 and 3 (hOAT1 and hOAT3), which are localized at the basolateral side of the proximal tubule. For this purpose, we established and utilized the second segment of the proximal tubule cells from mice stably expressing hOAT1 or hOAT3 (S2 hOAT1 or S2hOAT3, respectively). H2O2 induced a dose- and a time-dependent decrease in organic anion transport mediated by hOAT1 and hOAT3. Kinetic analysis revealed that H2O2 decreased the Vmax, but not Km of organic anion transport both in S2hOAT1 and S2hOAT3. The effects of gentamicin, known to induce proximal tubular damage via the production of H2O2, on the organic anion transporters were also examined. Gentamicin induced a significant decrease in organic anion transport in S2hOAT1 but not S2hOAT3. H2O2-induced decrease in organic anion transport was significantly inhibited by pretreatment with pyruvate as well as catalase, whereas the gentamicin-induced decrease was significantly inhibited by pretreatment with pyruvate but not with catalase. In conclusion, these results suggest that H2O2, which is produced during tubular injuries, downregulates organic anion transport mediated by both hOAT1 and hOAT3, leading to further modulation of pathophysiology.

Animals↗