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Biomedical subjects

A Maruyama

Publications and source records attributed to A Maruyama.

At least 55 records · Page 3Linked to original sources
PubMed1999

Hepatocellular carcinoma complicated by gastrointestinal hemorrhage caused by direct tumor invasion of stomach.

A 65-year-old man with multiple hepatocellular carcinoma (HCC) underwent intra-hepato-arterial chemotherapy (IHAC) through an implantable port over a period of 10 months after transcatheter arterial embolization (TAE) had been performed three times. TAE was performed twice more, and radiotherapy (total dose, 30 Gy; given over a 3-week period) was given for progressive disease in the lateral segment of the liver. Three months after the radiotherapy had finished, the patient suddenly developed melena. Diagnostic imaging revealed gastrointestinal (GI) hemorrhage from HCC invading the stomach, and total gastrectomy and lateral segmentectomy of the liver were performed because the bleeding could not be controlled. The resected specimen disclosed a centrally necrotic tumor that had invaded the lesser gastric curvature and perforated into the lumen. Pathology examination revealed that the HCC had expansively invaded the gastric mucosa, resulting in exposure in the lumen. The possible mechanisms of direct GI invasion by HCC are briefly discussed, with a review of the literature. GI bleeding secondary to involvement by HCC is rare. The enteric radiation injury seems to have been largely responsible for the GI bleeding in this patient.

Aged↗
PubMed1999

Preparation of dendritic graft copolymer consisting of poly-(L-lysine) and arabinogalactan as a hepatocyte specific DNA carrier.

The dendriTIc graft copolymers (PAX) consisting of a poly(L-lysine) (PLL) main chain and grafts of arabinogalactan (AG) were prepared as a liver cell-specific DNA carrier. The copolymers were successfully prepared by reductive amination reaction between a reductive end of AG and epsilon-amino groups of PLL using NaBH3CN as a catalyst. The fractionation of a low molecular weight fraction (Mn = 25 kDa) from a crude AG (Mn = 33 kDa) was essential for the reaction to proceed. The resulting copolymers were isolated by ultrafiltration from unreacted AG and characterized by 1H NMR and gel permeation chromatography equipped with a multiangle laser light scattering detector (GPC-MALLS). The binding and internalization of DNA to hepatoma cells, HepG2, were considerably enhanced by complexing DNA with PAX copolymers. The interactions between PAX/DNA complexes and HepG2 cells were thoroughly inhibited in the presence of a competitor to asialoglycoprotein receptors (ASGP-R), indicating high specificity of the complex to ASGP-R. Furthermore, the PAX copolymers allowed the expression of the reporter gene. Our results reveal that the PAX copolymers may provide a new research tool for cell-specific gene delivery and eventually enhance gene-therapy technology.

Animals↗
PubMed1999

Promotion mechanism of triplex DNA formation by comb-type polycations: thermodynamic analyses of sequence specificity and ionic strength dependence.

We have previously reported that in the presence of poly (L-lysine)-graft-Dextran (PLL-g-Dex) copolymer, the binding constant of the pyrimidine-motif triplex formation at neutral pH is about 100-times higher than that observed without any triplex stabilizer. Here, to explore the mechanism of the promotion effect of the PLL-g-Dex copolymer at neutral pH, the sequence specificity and the ionic strength dependence of the pyrimidine-motif triplex formation was examined in the absence or presence of the copolymer. The sequence specificity of the pyrimidine-motif triplex formation at neutral pH in the presence of copolymer was almost similar to that at acidic pH without the copolymer. As the concentration of magnesium cation increased, the binding constant of the pyrimidine-motif triplex formation without the copolymer increased. On the other hand, the binding constant of the pyrimidine-motif triplex formation in the presence of the copolymer decreased upon the increase in the concentration of magnesium cation. Considering these results in light of counterion condensation (CC) theory, we conclude that the copolymer does not hinder the sequence specificity of the triplex formation, and isolates the triplex formation from the CC effect, which may lead to a net increase in entropy change upon the triplex formation, providing a favorable component to binding constant of the triplex formation.

Base Sequence↗
PubMed1999

Acceleration of DNA strand exchange by polycation comb-type copolymer.

Polycation comb-type copolymers which are composed of poly(L-lysine) backbone and dextran graft chain (PLL-graft-Dex) accelerated DNA duplex and triplex formation and stabilized under physiologically relevant condition remarkably. In this study, we have examined the ability of polycation copolymer in promoting strand exchange between duplex DNA and its complementary single-stranded DNA. It was demonstrated that the strand exchange rate was considerably accelerated by the polycation comb-type copolymer.

DNA↗
PubMed1999

Preparation and evaluation of ODN conjugates with polycation comb-type copolymer.

Oligodeoxynucleotide (ODN) conjugates with the polylysine comb-type copolymer having an ability to promote and stabilize duplex and triplex DNA formation were prepared. 5'-Aminated ODN was succinylated with succinic anhydride. The resulting ODNs having carboxyl terminus were coupled with epsilon-amino groups of the comb-type copolymer using water soluble carbodiimide. The conjugate free from unconjugated ODNs was obtained by gel permeation chromatography. The resulting conjugate maintains ability to form duplex and triplex DNA as estimated by melting curve analysis. Both specificity and stability of the triplex DNA formation were increased by employing the ODN-copolymer conjugates compared to those with their mixture.

Chromatography, Gel↗
PubMed1999

The effect of jogging on P300 event related potentials.

Physical exercise has beneficial effects not only on cardiovascular system and fat metabolism, may also directly effect the cognitive process. We studied the effect of physical exercise on cognitive processes by measuring the P300 event related-potential (ERP) after jogging. Seven well-trained joggers were enrolled in this study and the P300 potentials using auditory oddball paradigm. ERPs were measured before and after 30 minutes of jogging. The amplitude of the P300 significantly increased after jogging compared to values recorded before jogging. These findings suggest that jogging has the effect of facilitating cognitive processes involved in generation of the P300.

Adult↗
PubMed1999

Left ventricular volumes and ejection fraction calculated from quantitative electrocardiographic-gated 99mTc-tetrofosmin myocardial SPECT.

UNLABELLED: We compared the left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) as calculated by Cedars automated quantitative gated SPECT (QGS) to those determined by first-pass radionuclide angiography (FPRNA) and contrast left ventriculography (LVG) in a group of 21 patients (mean age 61.4 +/- 9.2 y). METHODS: A total of 740 MBq 99mTc-tetrofosmin was administered rapidly into the right cubital vein at rest, and FPRNA was performed using a multicrystal gamma camera. One hour after injection, QGS was performed with a temporal resolution of 10 frames per R-R interval. LVG was performed within 2 wk. RESULTS: The EDV, ESV and LVEF calculated by QGS were highly reproducible (intraobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; interobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; P < 0.01) and were more consistent than those determined by FPRNA (intraobserver, r = 0.97, r = 0.95 and r = 0.93, respectively; interobserver, r = 0.86, r = 0.96 and r = 0.91, respectively; P < 0.01). There was a good correlation between EDV, ESV and LVEF by FPRNA and those by LVG (r = 0.61, r = 0.72 and r = 0.91, respectively; P < 0.01), and there was an excellent correlation between QGS and LVG (r = 0.73, r = 0.83 and r = 0.87, respectively; P < 0.01). The mean EDV by QGS (100 +/- 11.3 mL) was significantly lower than by FPRNA (132 +/- 16.8 mL) or LVG (130 +/- 8.1 mL), and the mean ESV by QGS (53.8 +/- 9.3 mL) was lower than by FPRNA (73.0 +/- 13.3 mL). Ejection fraction values were highest by LVG (57.1% +/- 3.2%), then QGS (51.8% +/- 3.0%) and FPRNA (48.9% +/- 2.4%). CONCLUSION: QGS gave more reproducible results than FPRNA. LV volumes and LVEF calculated by QGS correlated well to those by LVG.

Adult↗
PubMed1999

Effects of repeated selective serotonin reuptake inhibitor paroxetine treatments on mouse forced swimming.

Studies were performed in the mouse forced swimming model, a well known experimental depression model, in order to detect the mechanism of the antidepressive effects induced by repeated serotonin reuptake inhibitor (SSRI) dosing. Five-day repeat dosing of a typical SSRI, paroxetine, increased climbing, a distinctive antidepressive behavior, 1 h after but not 1 h before treatment. The coinjection of paroxetine and serum in mice treated with four repeated doses of paroxetine distinctively increased the behavior, but the coinjection of paroxetine and serum in mice without paroxetine did not. These results indicate that repeated dosing of paroxetine produces a serum substance related to the antidepressive effects induced by serotonin neuron activities. Furthermore, the behavior induced by 5-day repeated dosing of paroxetine was decreased by 100 and 10 micrograms/kg of ketanserin (5-HT2 antagonist) and 100 micrograms/kg of LY-278584 (5-HT3 antagonist). The present findings strongly suggest that repeated dosing of paroxetine produces a serum substance stimulating the antidepressive neuronal pathway sensitively mediated by 5-HT2 and 5-HT3 receptor activity.

Animals↗
PubMed1998

Poly(L-lysine)-graft-dextran copolymer: amazing effects on triplex stabilization under physiological pH and ionic conditions (in vitro).

Triplex DNA formation involving unmodified triplex-forming oligonucleotides (TFOs) is very unstable under physiological conditions. Here, we report a novel strategy to stabilize both purine and pyrimidine motif triplex DNA within the rat alpha1 (I) collagen gene promoter under physiologically relevant conditions by a poly(L-lysine)- graft -dextran copolymer. Using an in vitro electrophoretic mobility shift assay, we show that the copolymer almost completely abrogates the inhibitory effects of physiological concentrations of monovalent cations, particularly potassium ion (K+), on purine motif triplex formation involving very low concentrations of an unmodified guanine-rich TFO. Of importance, pH dependency in pyrimidine motif triplex formation involving an unmodified cytosine-rich TFO is also significantly overcome by the copolymer. Finally, the triplex-stabilizing efficiency of the copolymer is remarkably higher than that of other oligocations, like spermine and spermidine. We suggest that the ability of the graft copolymer to stabilize triplex DNA under physiologically relevant pH and salt concentrations will be a cue for further progress in the antigene strategy.

Cations, Monovalent↗
PubMed1998

Novel diglycosyldiacylglycerol from the gram-negative bacterium Deleya marina.

A glycosyldiacylglycerol was isolated from the marine bacterium Deleya marina (ATCC 25374). The structure was determined, mainly by spectral data, to be 1, 2-diacyl-3-O-[alpha-2-amino-2-deoxy-glucopyranose-(1-->4)-O-alpha-idu ronopyranuronic acid]-glycerol. This is, to our knowledge, the first isolation of diglycosyldiacylglycerol containing both iduronopyranuronic acid and 2-amino-2-deoxy-glucopyranose from Gram-negative bacteria.

Glycolipids↗
PubMed1998

A new non-viral DNA delivery vector: the terplex system.

A new DNA delivery vector (the terplex system) based on a balanced hydrophobicity and net surface charge between stearyl-poly(L-lysine), low density lipoprotein (LDL), and genetic material (i.e. plasmid DNA or antisense oligonucleotide) was developed. The pSV-beta-gal plasmid in terplex system showed a 2-5-fold increase in beta-galactosidase expression on murine smooth muscle cells (A7R5) compared to Lipofectin. Delivery of unmodified c-myb antisense oligonucleotide to A7R5 cells was also facilitated significantly by the terplex system, requiring as little as 5.4 nM of antisense oligonucleotide to achieve a 50% antiproliferative effect. Similar antiproliferative effect was observed when the c-myb antisense/terplex formulation was tested on CCD-32 Lu human lung fibroblasts. Characterization of the physical properties of the terplex system was performed using various techniques. Plasmid DNA was condensed by addition of stearyl-PLL and LDL, resulting in the terplex system of about 100 nm in diameter as shown by atomic force microscopy. A strong hydrophobic interaction between stearyl-poly(L-lysine) and LDL was registered by 1H-NMR spectrometry, showing a significant decrease in the epsilon-methylene signal of poly(L-lysine) backbone when stearyl-poly(L-lysine) was mixed with LDL; however, this phenomenon was not observed with unmodified poly(L-lysine). Agarose gel electrophoresis revealed that electrophoretic mobility of the terplex system decreased with increasing amounts of stearyl-poly(L-lysine), indicating that the surface charge of the terplex system became more positive by addition of stearyl-poly(L-lysine). Zeta-potential measurement showed that the terplex system exerted a slightly positive charge (+2 mV) at a 1:1:1 weight ratio of plasmid DNA:LDL:stearyl-poly(L-lysine). The obtained results will be utilized in the design of more efficient and safer DNA delivery vectors for in vivo gene therapy.

Animals↗
PubMed1998

Adenocarcinoma arising in a tailgut cyst: report of a case.

We report herein the unusual case of a 66-year-old woman found to have adenocarcinoma arising in a tailgut cyst. The patient had been observed for 6 months following the discovery of a presacral cystic mass measuring 10 x 9 cm for which she had refused surgery. The serum tumor marker, carcinoembryonic antigen, became slightly elevated, and diagnostic imaging distinctly revealed a tumorous lesion with papillary projection into the cyst lumen. The cystic mass was then excised through the transsacral approach. The pathological findings were compatible with moderately differentiated adenocarcinoma arising in a tailgut cyst. This entity is extremely rare, and only six cases, including our own, have been reported in the English literature. Early complete excision is advised because it is almost impossible to determine for certain whether presacral cystic masses are benign or malignant prior to surgery.

Adenocarcinoma↗
PubMed1998

Comb-type copolymer: stabilization of triplex DNA and possible application in antigene strategy.

By employing a reductive amination reaction between the epsilon-amino groups of poly(L-lysine) (PLL) and the reductive ends of the hydrophilic dextran (Dex) side chain, we have prepared different comb-type copolymers which varied in the degree of grafting and the length of the hydrophilic Dex chains. The resulting copolymers, poly(L-lysine)-graft-dextran (PLL-g-Dex), were tested for their ability to stabilize triplex DNA in vitro under physiologically relevant conditions. Thermal denaturation (UV-Tm) and circular dichroism experiments revealed that the graft copolymer with the higher degree of grafting of long Dex chains significantly increased the thermal stability of triplex structure of poly(dA). 2poly(dT) by more than 50 degreesC without affecting the transition between triplex and single-stranded DNA or the native structure of DNA. Of importance is that when triplex formation involving a 30-mer target duplex from rat alpha1 (I) collagen promoter was analyzed by an in vitro electrophoretic mobility shift assay, the graft copolymer also remarkably diminished potassium inhibition of the purine motif triplex formation up to 200 mM as well as pH-dependence of the pyrimidine motif triplex formation. Moreover the triplex-stabilizing efficiency of the copolymer was significantly higher than that of other oligocations like spermine and spermidine. We suggest that a molecular design of comb-type copolymers consisting of various types of polycation backbones (e.g., PLL) grafted with different hydrophilic side chains (e.g., Dex) is a novel strategy to create efficient triplex stabilizers that will certainly shed light on possible in vivo application of the antigene strategy.

DNA↗
PubMed1998

Terplex DNA delivery system as a gene carrier.

PURPOSE: To characterize the physical and biochemical properties of the DNA terplex delivery system, which has previously been shown to deliver and express pSV-beta-gal plasmid efficiently in cultured smooth muscle cells (SMC) (1). METHODS: Atomic force microscopy (AFM), zeta-potential measurement (ZP), gel electrophoresis (GE), circular dichroism (CD), fluorescence quenching and 1H-NMR spectrometry were used. RESULTS: AFM showed that the plasmid DNA of about 600 nm long in its extended state was condensed to the size of about 100 nm by terplex formation. The DNA condensing effect of the terplex system was as good as unmodified PLL, as shown by an ethidium bromide displacement assay. Zeta-potential measurement showed that the terplex system exerts a slightly positive surface charge (+2 mV) at a 1:1:1 weight ratio of DNA:LDL:stearyl-PLL, which showed the best transfection efficiency on SMC. GE indicated that electrophoretic mobility of the terplex system decreased with increasing amounts of stearyl-PLL, indicating that the surface charge of the terplex system became more positive as more stearyl-PLL was added. Results from CD showed that there was no significant changes in tertiary structure of plasmid DNA from the terplex formation. Presence of strong hydrophobic interaction between stearyl-PLL and LDL was confirmed by 1H-NMR, where about a 30% decrease in epsilon-methylene peak of PLL backbone was observed when stearyl-PLL was mixed with LDL, but this phenomenon was not observed when unmodified PLL was used. CONCLUSIONS: Our results indicate that the plasmid DNA, when formulated with the stearyl-PLL and LDL, forms a stable and hydrophobicity/charge balanced terplex system of optimal size for efficient cellular uptake and the DNA is still intact after the terplex formation. This information is expected to be utilized for the development of much improved transfection vectors for in vivo gene therapy.

Animals↗
PubMed1998

Cytosolic beta-cyanoalanine synthase activity attributed to cysteine synthases in cocklebur seeds. Purification and characterization of cytosolic cysteine synthases.

The activity of beta-cyanoalanine synthase (CAS, EC 4.4.1.9) in cotyledons of cocklebur seeds (Xanthium pennsylvanicum Wallr.) was detected both in the soluble and particulate fractions. The CAS activity of the soluble fraction (cytosolic CAS activity) was 10 times higher than that of the particulate fraction. The CAS activity of the particulate fraction was confirmed to be localized in the mitochondria. Both enzymatic activities were clearly separated by non-denaturing PAGE. The enzyme with cytosolic CAS activity has been extensively purified and separated into three different forms designated as cyt-1, cyt-2, and cyt-3. According to the SDS-PAGE analysis, the three enzymes are estimated to be a homodimer composed of 35-kDa subunits. The purified enzymes showed CS activity. Partial amino acid sequences of cyt-1 were determined and had a high homology with cysteine synthases (CS, EC 4.2.99.8) from other plant sources. The catalytic action of the purified CSs in converting cyanide and cysteine into H2S and beta-cyanoalanine was confirmed by the detection of significant 14CN incorporation into beta-cyanoalanine. These results indicated that cytosolic CAS activity is due to cytosolic CS and suggested that the CAS activity of CS is likely to be involved in cyanide metabolism in plant tissues.

Alanine↗
PubMed1998

[New coronary artery lesions in patients with ischemic heart disease].

The appearance of a new coronary artery lesion is important in patients with acute myocardial infarction or late coronary artery bypass grafting surgery, which sometimes lead to cardiac death. We studied coronary angiograms of 1,098 patients with coronary artery disease (from 1985 to 1996) and found new lesions in 94 patients (male 74, female 20; mean age 61.6 years). Mean observation period of all 1,098 patients was 50.1 +/- 30.4 months, and that of patients with new lesions was 73.2 +/- 31.2 months. Clinical findings of the 94 patients were acute myocardial infarction (n = 28), recurrent angina (n = 56), and silent ischemia (n = 10). The appearance of a new coronary lesion was found in 2.4% (1992), 1.9% (1993), 2.3% (1994), 1.7% (1995) of all patients with ischemic heart disease per year. The new lesions were found more often in patients with non-significant stenotic lesions (n = 74) than in patients with lesions of > or = 50% stenosis (n = 20). Complex lesions were found in 56% of the recurrent angina group, and in 22% of the silent ischemia group. In our study, the rate of appearance of new coronary artery lesions was much lower than in Europe or the United States of America. These results require careful consideration for coronary revascularization procedures in Japanese patients.

Angina Pectoris↗
PubMed1997

Simple preparation of nanoparticles coated with carbohydrate-carrying polymers.

Nanoparticles bearing carbohydrate chains on the surface can be prepared by the simple diafiltration method. The nanoparticles prepared by the present method displayed high yield, no-aggregation formation, small size, narrow size distribution, and one-step procedure. Also, the high density carbohydrate chains on the particles can be recognized by liver cells.

Animals↗