[A case of postoperative cutaneointestinal fistula responding to somatostatin analog, with a special reference to serum level of gastrointestinal hormones].
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Aged↗
Biomedical subjects
S Ohki
Publications and source records attributed to S Ohki.
Mg2+ inhibits formation of 4Ca(2+)-calmodulin-enzyme complex at lower Ca2+ concentration. 1H and 113Cd NMR studies.
Our previous 1H NMR studies indicated that when mastoparan (MP) is added to Ca(2+)-half-saturated calmodulin (2Ca(2+)-CaM) in the absence of Mg2+ ions, Ca2+ ions transfer from the C-terminal-half domain of CaM not interacting with MP to the N-terminal-half domain of CaM interacting with MP at lower MP concentrations (Ohki, S., Yazawa, M., Yagi, K., and Hikichi, K. (1991b) J. Biochem. (Tokyo) 110, 737-742). As a consequence, the active form of 4Ca(2+)-CaM.MP complex is formed. In the present study, we studied the effect of Mg2+ ions on Ca2+ transfer. In the presence of Mg2+ ions, such Ca2+ transfer does not occur. The effects of Mg2+ ions are also studied by observing 113Cd NMR in the presence of M13, the 26-residue peptide of the CaM-binding region of myosin light chain kinase. The 113Cd NMR results show that Mg2+ ions prevent to form the active complex. Mg2+ plays an important role as an inactivating factor to CaM.
Amino Acid Sequence↗
Effect of glycosaminoglycans and PEG on fusion of Sendai virus with phosphatidylserine vesicles.
The fusion of Sendai virus with phosphatidylserine vesicles was monitored by a pyrene-phosphatidylcholine fluorescence assay. A strong influence of pH and ionic strength on the extent of fusion was observed. The negatively-charged polymers (dextran sulfate, heparin and chondroitin sulfate) inhibited the ability of the viruses to fuse with the liposomes. The extent of inhibition, for a given amount (w/v) of the polymers, was the greatest for dextran sulfate followed by heparin and chondroitin sulfate. The extent of inhibition depended on the pH and ionic strength of the solution; the lower the pH of the solution, the more effective the fusion inhibition by the polymers. The molecular weight of dextran sulfate (DS) influenced the inhibition effect, i.e., DS with higher molecular weight exhibited a stronger inhibition effect. The presence of sodium sulfate, even in excess concentration, had no inhibitory effect on fusion. On the other hand, PEG had an opposite effect on fusion compared to the negatively-charged polymers, and it decreased their inhibition effect when both were present in the same media. It is concluded that the inhibition of the fusion activity of Sendai virus results from the adherence of negatively-charged polymers to the virus surface preventing close contacts between the virus and liposome surface.
Dextran Sulfate↗
Ion-induced fusion of phosphatidic acid vesicles and correlation between surface hydrophobicity and membrane fusion.
Divalent cation (Ca2+ and Mg2+) and hydrogen ion-induced fusions of small unilamellar phosphatidic acid vesicles were studied by the use of fluorescence fusion assay. These fusogenic ions also increased interfacial tension and reduced the surface dielectric constant of phosphatidic acid membranes as the ion concentration increased. A good correlation was found between the threshold of vesicle fusion and the degree of changes in such membrane properties induced by these fusogenic ions. At the fusion threshold point, the increase in interfacial tension and the decreased surface dielectric constant of the membrane were approximately 6 and 14 dyn/cm, respectively, regardless of Ca2+, Mg2+ or H+. Such changes correspond to the increases in surface hydrophobicity of the membrane. As these fusogenic ionic concentrations increased, the electrophoretic mobility of the phosphatidic acid vesicle decreased, because of the binding of ions to negatively charged sites of the membranes. However, the quantities of the reduced negative surface charges were not necessarily in good correlation with the threshold of vesicle fusion. It is suggested that the complexes of the phosphate group with these fusogenic ions are responsible for increases in the surface hydrophobicity of the membrane, which is an important factor for membrane fusion.
Calcium↗
Fusion of spherical membranes.
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Cations, Divalent↗
Surface chemical techniques in membrane fusion.
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Cations, Divalent↗
Effect of cholesterol, diacylglycerol and phosphatidylethanolamine on PEG 6000 induced lipid mixing and surface dielectric constant of phosphatidylcholine vesicle.
Using the NBD/Rh fluorescence assay the PEG 6000 induced phospholipid mixing of phosphatidylcholine liposomes containing cholesterol, diacylglycerol or phosphatidylethanolamine was measured. All 3 components shifted the PEG 6000 concentration necessary to induce 50% of maximal phospholipid mixing to lower concentrations. After the addition of PEG cholesterol containing PC liposomes exhibit different values of the surface dielectric constant as measured by the stokes shift of the fluorophore dansyl-PE compared to pure PC, whereas in DAG- and PE-containing PC liposomes no differences were observed. It is concluded that the incorporation of cholesterol leads to a different surface dielectric constant after PEG addition. The changed surface dielectric properties are a prerequest for the onset of fusion, as shown by Ohki and Arnold (1990). The incorporation of DAG and PE into PC membranes leads to structural instabilities as proposed by Siegel et al. (1989). This additional structurally unstable region created by molecules like PE or DAG may shift the onset of fusion to lower PEG concentration.
Cholesterol↗
Association of lysozyme to phospholipid surfaces and vesicle fusion.
Lysozyme-induced fusion of phosphatidylserine (PS) vesicles was studied as a function of pH. Fusion, monitored by lipid-mixing, was measured by following the dilution of pyrene-labelled phosphatidylcholine, incorporated in PS vesicles, into unlabelled bilayers. It is demonstrated that lysozyme-induced fusion is pH-dependent and significant fusion is triggered at pH 5 or below. The interaction of lysozyme with the vesicle bilayer was characterized by measuring resonance energy transfer from tryptophane, present in the protein, to pyrene. It is shown that concomitant with fusion, a strong resonance energy transfer signal appears at pH 5 or below. Furthermore, in monolayer experiments it was found that addition of lysozyme to the subphase caused an increase in surface pressure, when the pH was kept below 5.5. Very low concentrations of lysozyme sufficed to bring about the observed effects. The results are taken to indicate that lysozyme-induced fusion results from penetration of protein into the hydrophobic core of the bilayer, occurring at acidic pH.
Energy Transfer↗
Dextran sulfate-dependent fusion of liposomes containing cationic stearylamine.
The incorporation of the positively charged stearylamine into phosphatidylcholine liposomes was studied by measuring electrophoretic mobilities. Up to a molar ratio SA/PC = 0.5 an increase of the positive zeta potential can be observed. Addition of the negatively charged macromolecule dextran sulfate leads to a change of the sign of the surface potential of the PC/SA liposomes indicating binding of the macromolecule to the surface. This process is accompanied by an increase in turbidity, which is dependent on the molecular weight of the dextran sulfate and the SA concentration (measured by turbidimetry). Using the NBD/Rh and Pyr-PC fluorescence assays the fusion of SA containing liposomes was investigated. A strong influence of the SA content and molecular weight of dextran sulfate on the fusion extent was observed. The fusion extent is proportional to the SA content in the PC membrane and the molecular weight of dextran sulfate. PC/SA/PE liposomes exhibit a higher fusion extent after addition of dextran sulfate compared to PC/SA liposomes indicating that PE additionally destabilizes the bilayer. Freeze-fracture electron microscopy reveals that the reaction products are large complexes composed of multilamellar stacks of tightly packed, straight membranes and aggregated vesicles. The tight packing of the membranes in the stacks (and the narrow contact of the aggregated vesicles) indicates a strong adherence of opposite membrane surfaces induced by dextran sulfate.
Amines↗
Effect of anionic polymers on fusion of Sendai virus with human erythrocyte ghosts.
The effect of anionic polymers (dextran sulfate, heparin and chondroitin sulfate) on fusion of Sendai virus with erythrocyte ghosts was studied. The effect of pH on the activity of these anionic polymers was also investigated. In order to examine the interaction of such polymers with the Sendai virion and erythrocyte ghost surfaces, the binding of virions to erythrocyte ghosts and the aggregation of virions and/or erythrocyte ghosts were also measured with respect to the same parameters. It was found that the anionic polymers suppressed the fusion of Sendai virus with erythrocyte ghosts. The order of effectiveness of the polymers in suppression was dextran sulfate greater than heparin greater than chondroitin sulfate, for the application of a same quantity (weight/ml) of the polymers. The lower the pH of the suspending medium, the more effective were the polymers in suppressing virion-erythrocyte ghost aggregation and fusion. The suppression of fusion was dependent on the concentration of the polymers applied: the higher the concentration of the polymer applied, the more the suppression was observed. Evidence from binding studies, turbidity measurements and electrophoretic mobility measurements indicates that the anionic polymers interact preferentially with the virion surface.
Adsorption↗
A typology of difficult patients with long-term stays on a secure ward in Japan.
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Adult↗
[Expression of c-erbB-2 protein and vessel invasion in colorectal cancer].
Using sections of formalin-fixed, paraffin-embedded tissues from 64 colorectal cancer patients, the expression of c-erbB-2 oncoprotein was studied immunohistochemically. Twenty-seven percent of the cases with liver metastasis showed positive staining. On the other hand, only 3% of cases without liver metastasis were positive. Expression rates of c-erbB-2 protein in liver metastasis cases showed no significant difference between primary operation (26%) and recurrence (27%). Of all c-erbB-2 positive patients, 90% (9/10) had liver metastasis. Secondly, vessel invasions of 45 rectal cancer patients were studied using Victoria Blue (VB) elastic staining and endothelial staining by factor VIII-related antigen and Ulex europaeus agglutinin I (UEA-I) lectin. VB-HE double stain was efficacious to detect vascular invasion, but endothelial staining was not. There were statistically more vascular invasions in 30 patients with liver or lymph node metastases than in those without metastasis. And in cases with metastasis, many vascular invasions into the extra-muscular layer were seen. Both vascular invasions and c-erbB-2 protein were valuable indicators of possible liver metastasis.
Biomarkers, Tumor↗
Effect of dextran sulfate on fusion of Sendai virus with human erythrocyte ghosts.
The effect of dextran sulfate on the fusion of Sendai virus and erythrocyte ghosts was studied as a function of dextran sulfate concentration and pH of cell suspension solutions. In order to examine the interaction of dextran sulfate with Sendai virion and erythrocyte ghost surfaces, the turbidity of cell suspensions was also measured with respect to the same parameters as above. It was found that dextran sulfate inhibited the fusion of Sendai virus with erythrocyte ghosts. The lower the pH of the suspension solution was, the more effective was dextran sulfate in suppressing virion erythrocyte ghost fusion. Dextran sulfate of a higher molecular weight was slightly more effective in suppressing fusion than that of a lower molecular weight. From turbidity measurements of Sendai virus and erythrocyte ghost suspensions, it is likely that dextran sulfate interacts preferentially with Sendai virion surfaces and inhibits interaction between Sendai virions and erythrocyte ghosts.
Depression, Chemical↗
1H NMR study on amide proton exchange of calmodulin-mastoparan complex.
Amide proton exchange rates of Ca2(+)-saturated calmodulin and Ca2(+)-saturated calmodulin-mastoparan complex were studied by 1H NMR spectroscopy. Exchange rates of Gly25, Gly61, Gly98, Gly134, Ile27, Ile100, and Asn137 were determined for Ca2(+)-saturated calmodulin and for Ca2(+)-saturated calmodulin-mastoparan complex, and were found to be less than 10(-4)s-1. All these residues of which the amide proton resonances appear at lower fields were considered to form hydrogen bonds, based on the results of X-ray analysis. Exchange rates of Ile27 and Asn137 became an order of magnitude smaller when mastoparan bound to Ca2(+)-saturated calmodulin, while those of the four glycines and Ile100 did not change appreciably. The reduction in accessibility of Asn137 to water cased by mastoparan binding suggests that a part of the mastoparan binding site is probably located in or near the hydrophobic cluster of the C-terminal-half domain. The reduction in accessibility of Ile27 also suggests that another part of the mastoparan binding site is located in or near the hydrophobic cleft of the N-terminal-half domain.
Amino Acids↗
[Effects and complications of continuous hepatic arterial infusion chemotherapy using implantable reservoir for liver metastases from colorectal cancer].
Continuous arterial infusion chemotherapy using implantable reservoir was performed for unresectable liver metastases from colorectal cancer and the therapeutic effects, side effects and complications were evaluated. Eleven patients were treated with four kinds of arterial infusion courses that mainly consisted of 5-FU. The arterial infusion courses were discontinued in 2 patients because of nausea and vomiting, and in one patient because of diarrhea. The catheters were dislocated in 2 patients and another 2 developed fistulous between the hepatic artery and bile duct. Three patients developed duodenal ulcer. Serum CEA was reduced in 4 patients (36%). After all, response rate was 9% (1/11). The one-year survival rates of all cases and cases treated with more than 4 courses were 36.3% and 80.0%, respectively.
Antineoplastic Combined Chemotherapy Protocols↗
Surface dielectric constant, surface hydrophobicity and membrane fusion.
Membrane fusion induced by ions and its associated membrane property, surface dielectric constant, were studied with the use of acidic and neutral phospholipid vesicles. The fusion of vesicles was monitored by utilizing two fluorescence fusion assays: fluorescence content mixing method and fluorescence labelled membrane component dilution method. For the surface dielectric constant measurements, a fluorescence method was used which detected the environmental effect on the membrane surface upon the addition of various fusogenic cations. Also, the effects of poly-(ethylene glycol) on both fusion and surface dielectric properties were examined. It was found that the extent of fusion correlated well with the degree of lowering in the dielectric constant of the surface membrane, which corresponds to the increase in hydrophobicity of the membrane surface. This agrees with the previously obtained experimental results that the increase in interfacial tension of the membrane, which also corresponds to the increase in surface hydrophobicity, correlates with the extent of membrane fusion.
Calcium↗
Interaction of dextran sulfate with phospholipid surfaces and liposome aggregation and fusion.
The binding of dextran sulfate to phospholipid liposomes was investigated by microelectrophoresis experiments. The polyanion binds to neutral phospholipid liposomes (DMPC and PE) only in the presence of Ca2+. If positively charged stearylamine is incorporated in the vesicles dextran sulfate is bound without Ca2+. Negatively charged phospholipids as PS do not bind dextran sulfate, even in the presence of millimolar concentrations of Ca2+. The adsorption of dextran sulfate results in an aggregation of vesicles due to a bridging mechanism. In all cases the aggregation is followed by a disaggregation toward higher dextran sulfate concentrations. The disaggregation process starts at polymer concentrations smaller than the concentration of the onset of saturation of the adsorption. By use of the probe dilution method a fusion of small DMPC and DMPC/PE vesicles in the presence of Ca2+ and dextran sulfate was found.
Calcium↗
[Continuous hepatic arterial infusion chemotherapy using implantable reservoir in liver metastases from colorectal cancer].
Continuous hepatic arterial infusion chemotherapy using implantable reservoir was performed for liver metastases from colorectal cancer, and the therapeutic effects, side effects, and complications were evaluated. 9 patients with unresectable liver metastases were as follows, 1. Group A; 3 patients, MMC 2 mg.one shot + 5-FU 250 mg/day.continuous infusion x 14 days, and then 5-FU tablets 150 mg/day.p.o. x 14 days, 2. Group B; 4 patients, MMC 2 mg.one shot + 5-FU 500 mg/day.continuous infusion x 7 days, and then 5-FU tablets 150 mg/day.p.o. x 14 days, 3. Group C; 2 patients, 5-FU 500 mg/day.continuous infusion x 14 days, and then free from agents for 14 days. In 2 of 3 group A patients, the catheters became dislocated and one died of perforation of duodenum. In group A and group B, no severe side effects were noted. But both of group C patients showed nausea, vomiting and diarrhea. In 8 of 9 patients (89%), serum CEA level fell below the preoperative level. In 4 of 7 patients who underwent CT scan, the size of the tumor regressed. Total infused dose of 5-FU was 8.17 +/- 7.56 g in group A, 16.9 +/- 2.88 g in group B, and 21.0 +/- 9.90 g in group C on average. In 2 patients of group B, therapy was repeated seven times.
Antineoplastic Combined Chemotherapy Protocols↗