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E Kimoto

Publications and source records attributed to E Kimoto.

At least 37 records · Page 2Linked to original sources
PubMed1994

Effects of cross-linking of membrane proteins on vesiculation induced by dimyristoylphosphatidylcholine in human erythrocytes.

To study the effect of cross-linking of membrane proteins on vesiculation of human erythrocytes by dimyristoylphosphatidylcholine (DMPC), red cells were treated with diamide at atmospheric pressure or 100 MPa and then incubated with DMPC in buffers of pH 6.5-8.5. Irrespective of buffer pH, the amount of released vesicles increased upon cross-linking of membrane proteins but approached the control level upon reduction of the cross-linking by dithiothreitol. Similar enhancement of vesicle release was also observed in N-ethylmaleimide-treated red cells. Hemolysis during vesiculation was observed only in red cells treated with diamide at 100 MPa. Furthermore, the composition of membrane proteins in released vesicles was analyzed by SDS-PAGE. Membrane vesicles released from intact red cells or the cells treated with diamide at atmospheric pressure contained band 3 as a major membrane protein. On the other hand, membrane vesicles from red cells treated with diamide at 100 MPa contained protein 4.1 in addition to band 3 and the orientation of these proteins was similar to that in intact cells. These results indicate that the amount and membrane protein composition of DMPC-induced vesicles are much affected by chemical modification of SH-groups in red cell membrane proteins.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1994

Hemolytic properties of Ca(2+)-treated human erythrocytes under hydrostatic pressure.

The effect of intracellular Ca2+ on high pressure-induced hemolysis of human erythrocytes was examined. Red cells were incubated with Ca2+ (0.01-1 mM) in the presence of ionophore A23187. The Ca(2+)-loaded cells were subjected to a pressure of 200 mPa. Treatment with 0.1 mM Ca2+ had the greatest suppressive effect on the hemolysis. On removal of intracellular Ca2+, red cells showed a morphological change from echinocytes to normal discocytes but the hemolysis remained unaltered. Measurement of intracellular K+ and viscosity demonstrated that the suppressive effect of Ca2+ on the hemolysis is irreversible and is largely associated with the increase of intracellular viscosity induced by K+ efflux.

Blood Viscosity↗
PubMed1994

Property and amino acid sequence of a subtilisin inhibitor from seeds of beach canavalia (Canavalia lineata).

A subtilisin inhibitor was purified from the seeds of Canavalia lineata by ammonium sulfate precipitation, ultrafiltration on a YM-30 membrane, column chromatography on DEAE-Toyopearl and SP-Toyopearl, followed by reverse-phase HPLC. The inhibitor (CLSI-I) is a low molecular weight protein (M(r) about 6500) containing no half-cystine residue, and quite stable as to extreme heat and pH treatment. CLSI-I inhibited subtilisin-type serine proteases including S. griseus alkaline protease. The amino acids of CLSI-I were sequenced by manual Edman degradation after enzymatic digestion with Achromobacter lyticus lysyl endopeptidase and Staphylococcus aureus V8 protease. CLSI-I contains 65 amino acid residues and showed a high homology to potato inhibitor I family proteins.

Amino Acid Sequence↗
PubMed1994

Purification and characterization of three proteinase inhibitors from Canavalia lineata seeds.

Three proteinase inhibitors (CLTI-I, -II and -III) were purified from the seeds of Canavalia lineata by DEAE-Toyopearl, hydroxyapatite, and anhydrotrypsin-Sepharose column chromatographies. All the inhibitors bound to trypsin at a 1:1 molar ratio and inhibited the enzyme with dissociation constants of 3-7 x 10(-9) M. They also showed the inhibitory activities on chymotrypsin. CTLI-I and -II had an identical M(r) of 8000 and very close isoelectric points (4.57 and 4.50), and existed mainly as trimers under physiological conditions. The high content of half-cystine residues and the high stability to pH and heat have suggested that these are Bowman-Birk type inhibitors. On the other hand, CLTI-III, with an M(r) of 20,500 was classified as a Kunitz (soybean) family inhibitor on the basis of the amino acid composition as well as the homology of its N-terminal 17 residues to other Kunitz inhibitors.

Amino Acid Sequence↗
PubMed1994

Amino acid sequences of double-headed proteinase inhibitors from the seeds of Canavalia lineata.

The amino acids of two Bowman-Birk type proteinase inhibitors (CLTI-I and -II) from the seeds of Canavalia lineata were sequenced by a manual Edman degradation using the DABITC/PITC double coupling method after enzymatic digestions with Achromobacter lyticus lysyl endopeptidase, Staphylococcus aureus V8 protease, and chymotrypsin. CLTI-I contains 75 amino acid residues. CLTI-II has an identical sequence to CLTI-I except an extra Asp residue attached at the C-terminus. The inhibitors showed a homology (40-70%) to other Bowman-Birk inhibitors. The reactive-site peptide bonds were estimated to be Lys21-Ser22 and Leu48-Ser49 against trypsin and chymotrypsin, respectively. An inhibitory active fragment containing only the chymotrypsin-reactive site was also described.

Amino Acid Sequence↗
PubMed1993

Release of protein 4.1-rich vesicles from diamide-treated erythrocytes under hydrostatic pressure.

The effect of cross-linking of membrane proteins on vesiculation under high pressure (2.0 kbar) of human erythrocytes was examined. To get the large molecular weight aggregates characterized by cross-linking of cytoskeletal proteins with integral ones, the erythrocytes were pretreated with diamide under pressure (1.0 kbar) where no vesiculation occurs. Vesicles released at 2.0 kbar from such erythrocytes contained protein 4.1 as major membrane protein. Upon reduction of cross-linking by dithiothreitol prior to vesiculation, the released vesicles contained membrane proteins similar to intact cells. On the other hand, in the erythrocyte pretreated with diamide at atmospheric pressure, no such large molecular weight aggregate was observed and the membrane protein composition of the vesicles released from the cells at 2.0 kbar was also similar to that of intact cells. These results suggest that the membrane protein composition of released vesicles is much affected by the properties of cross-linking of membrane proteins in erythrocytes.

Cytoskeletal Proteins↗
PubMed1993

Analysis of the transformation products of dehydro-L-ascorbic acid by ion-pairing high-performance liquid chromatography.

Dehydro-L-ascorbic acid, the oxidation form of L-ascorbic acid, converts nonenzymatically to a variety of transformation products depending upon the incubating conditions. These products, called the ascorbate cascade, possess different absorption spectra and reducing activities. Ion-pairing high-performance liquid chromatography with multiwavelength uv absorption and amperometric electrochemical detection has proven to be a useful technique for the analysis of these products. Separation and characterization in the present investigations reveal three kinds of transformation products: the polymerized intermediates of browning reaction, the reductant possessing an absorption maximum at 345 nm as the six-carbon compound, and erythro-L-ascorbic acid, 2-furoic acid, 3-hydroxy-2-pyrone, 5-methyl-3,4-dihydroxytetrone, reductic acid, and furfural as the five-carbon compound. These products possess an absorption maximum above 240 nm, and most of them are electrochemically active reducing compounds which are derived from nonreducing dehydro-L-ascorbic acid through the processes of delactonization, decarboxylation, and intramolecular rearrangement.

Chromatography, High Pressure Liquid↗
PubMed1993

Primary structures of concanavalin A-like lectins from seeds of two species of Canavalia.

The amino acid sequences of two lectins from the seeds of Canavalia lineata and C. virosa have been determined by the manual Edman degradation method. Both proteins were found to be highly homologous to concanavalin A, a lectin from C. ensiformis. All the residues suggested to participate in binding to carbohydrates and metal ions are completely conserved in the proteins.

Amino Acid Sequence↗
PubMed1993

Effects of drugs, salts, and phospholipid vesicles on hemoglobin release from hydrostatic pressure-treated human erythrocytes.

When human erythrocytes subjected to a pressure of 2.0 kbar were incubated at 0 degree C and atmospheric pressure, hemoglobin was released from the membrane. Effects of drugs, salts, and phospholipid vesicles on hemoglobin release were examined. The hemoglobin release was suppressed by the addition of amphiphathic drugs such as chlorpromazine, trifluoperazine, tetracaine, indomethacin, and phenylbutazone or by a hypertonic condition. The suppressive effect induced by these drugs or hypertonic buffer was enhanced by the addition of aminophospholipid vesicles containing phosphatidylserine (PS) and/or phosphatidylethanolamine (PE) but decreased by vesicles composed of phosphatidylcholine (PC) and sphingomyelin. In the isotonic buffer without these drugs, such effects of vesicles were small. The suppressive effects of PS and PE were decreased by chemical modification of carboxylic groups and amino groups with 1-ethyl-3-(3-dimethylaminopropyl)carbodimide and 2,4,6-trinitrobenzenesulfonate, respectively. The size of vesicles as well as phospholipid composition was also an important factor in the suppression of hemoglobin release. The ESR spectrum of pressure-treated membrane spin-labeled with a maleimide was changed by PC vesicles but not by PS vesicles. These results indicate that the resealing of pressure-induced membrane holes by amphipathic drugs or hypertonic medium is synergistic with aminophospholipid vesicles and the hole size is affected by the vesicle-membrane protein interaction.

Chlorpromazine↗
PubMed1993

Hemolytic properties under hydrostatic pressure of neuraminidase- or protease-treated human erythrocytes.

We investigated the hemolytic properties under high pressure (200 MPa) of human erythrocytes in which sialic acids and glycopeptides had been removed from membrane surface by using neuraminidase and proteolytic enzymes such as trypsin and chymotrypsin, respectively. The degree of hemolysis increased in proportion to the amounts of sialic acids or glycopeptides released from intact erythrocytes. Studies of the time course of hemolysis showed that upon enzymatic digestion erythrocyte membranes became more fragile against high pressure. Such fragility decreased in the presence of chlorpromazine and trifluoperazine but was unaffected by chlorpromazine methiodide or indomethacin. Furthermore, the effect of cross-linking of membrane proteins by diamide on the fragility was examined. The degree of hemolysis at 200 MPa increased upon removal of sialic acids from red cells in which spectrin is mainly cross-linked, but did not upon enzymatic digestion of red cells in which glycophorins, in addition to cross-linking of themselves, are included in the large-molecular-weight aggregates formed by cross-linking of the membrane skeleton with transmembrane proteins. In the latter case, however, upon reduction of the cross-linking by dithiothreitol the effect of enzymatic digestion appeared again. On the other hand, such an enzymatic digestion effect on osmotic hemolysis was not observed either in intact erythrocytes or in diamide-treated red cells. These results suggest that the interaction of the cytoplasmic domains of glycophorins with cytoskeletal proteins may be weakened by enzymatic digestion of the exofacial domains of glycophorins.

Chlorpromazine↗
PubMed1992

Inhibition of phosphate transport across the human erythrocyte membrane by chemical modification of sulfhydryl groups.

Effects of sulfhydryl-reactive reagents on phosphate transport across human erythrocyte membranes were examined using 31P NMR. Phosphate transport was significantly inhibited in erythrocytes treated with sulfhydryl modifiers such as N-ethylmaleimide, diamide, and Cu2+/o-phenanthroline. Quantitation of sulfhydryl groups in band 3 showed that the inhibition is closely associated with the decrease of sulfhydryl groups. Data from erythrocytes treated with diamide or Cu2+/o-phenanthroline demonstrated that intermolecular cross-linking of band 3 by oxidation of a sulfhydryl group, perhaps Cys-201 or Cys-317, decreases the phosphate influx by about 10%. The inhibition was reversed by reduction using dithiothreitol. These results suggest that sulfhydryl groups in the cytoplasmic domain of band 3 may play an important role in the regulation of anion exchange across the membrane.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1991

Value of endoscopic ultrasonography in the detection of anomalous connections of the pancreatobiliary duct.

Endoscopic ultrasonography (EUS) was evaluated in the detection of anomalous connection of the pancreatobiliary duct (ACPBD), which is known to cause cholangitis and has been found to be associated with cholangiocarcinoma. Fourteen patients with ACPBD were examined preoperatively by EUS in addition to ERCP and/or PTC. In all cases, the anomalous connections between the biliary and pancreatic duct were demonstrated to be located outside the proper muscle of the duodenal wall and within the pancreatic parenchyma. EUS classification of ACPBD corresponded well with the findings obtained by retrograde ductal opacification on ERCP and PTC. Biliary malignancy complicating ACPBD was detected correctly by EUS in two patients. In contrast, no connections between biliary and pancreatic ducts were found by EUS in 13 normal controls. It is concluded that EUS is highly sensitive in detecting ductal anomaly in ACPBD. Further studies will show if EUS can replace ERCP in the diagnosis of ACPBD.

Adult↗
PubMed1991

Vesiculation induced by hydrostatic pressure in human erythrocytes.

When human erythrocytes were subjected to hydrostatic pressure (1.1-2.0 kbar), it was found that membrane vesicles were released from the red cells above 1.4 kbar. As with hemolysis under high pressure, the amount of released vesicles was increased with increasing pressure but decreased by the cross-linking of membrane proteins with diamide. Vesicles obtained at 2.0 kbar were heterogeneous in size but similar to intact erythrocytes in phospholipid composition. Although it has been reported that spectrin-free vesicles are released by echinocytogenic agents, pressure-induced vesicles did contain considerable and similar amounts of spectrin irrespective of the difference in size. These results suggest that vesiculation by high pressure is associated with the disruption of the membrane skeleton, as previously seen in pressure-induced hemolysis [Yamaguchi et al. (1989) J. Biochem. 106, 1080-1085].

Adult↗
PubMed1990

Hemolysis of human erythrocytes under hydrostatic pressure is suppressed by cross-linking of membrane proteins.

The effects of cross-linking of membrane proteins on hemolysis of human erythrocytes under high pressure (2.0 kbar) were examined. The membrane proteins were cross-linked by oxidation of their SH-groups with diamide (0.05-0.5 mM) under different pressures (1-1,000 bar) at which no hemolysis occurs. As the pressure during diamide treatment was raised, the degree of hemolysis under 2.0 kbar and the quantity of cytoskeletal proteins extracted in a low ionic strength medium were gradually decreased. However, both values were increased by reduction with dithiothreitol. From the determination of membrane SH-groups, it was found that cross-linking of membrane proteins by diamide was accelerated under pressure. Only in erythrocytes treated with diamide under pressure were parts of spectrin and ankyrin, in addition to band 3 and band 4.2 proteins, extracted by using Triton X-100. One- and two-dimensional SDS-PAGE of membrane proteins showed that cross-linking of the membrane with cytoskeletal meshwork through linking proteins, in addition to that of membrane proteins themselves, was formed only in the diamide treatment under pressure. These results indicate that pressure-induced hemolysis is greatly suppressed by the supramolecular-weight polymers formed among membrane proteins, and that the high pressure technique is useful for cross-linking membrane proteins with diamide.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1990

Endoscopic ultrasonography in the diagnosis of depth invasion and lymph node metastasis of carcinoma of the papilla of Vater.

To evaluate diagnostic accuracy of endoscopic ultrasonography (EUS) on the extent of carcinoma of the papilla of Vater, 28 patients were preoperatively evaluated using our EUS grading system. EUS was accurate in diagnosing carcinoma infiltration into the duodenal proper muscle layer (100%) and into the pancreas (75%). When compared with postoperative histologic findings, the overall accuracy of EUS in assessing local infiltration was 89.3%. Misdiagnoses occurred in three cases due to microinfiltration of the carcinoma. Lymph node metastasis around the pancreatic head was accurately diagnosed in nine cases; however, mesenteric lymph node metastasis could not be detected in four cases because the tumor was far from the scanning site.

Adult↗
PubMed1989

Clinicopathologic analysis of endoscopic ultrasonograms in pancreatic mass lesions.

Endoscopic ultrasonography (EUS) was performed in 40 patients with pancreatic masses who subsequently underwent surgical resection, and we compared the ultrasonograms with the histopathologic findings. Ductal adenocarcinoma: The cephalad margin between the tumor and pancreatic tissue was distinct, while the caudal margin was blurred because the severe fibrosis accompanying secondary pancreatitis, and the contour of the tumor was irregular. The internal echo pattern was hypoechoic, with an uneven central echogenic portion corresponding to irregularly arranged carcinomatous canaliculi or coagulation necrosis. Benign islet cell tumor: Both the cephalad and caudal margins were distinct, the contour was smooth and the internal echo pattern was hypoechoic, with a homogeneous central echogenic portion corresponding to regularly arranged alveoli. Pseudotumorous pancreatitis: The caudal margin was indistinct, the contour was smooth, and the internal echo pattern was homogeneously hypoechoic, with deep attenuation caused by dense fibrosis. On the basis of these results, it is believed that EUS with its high resolution is useful in the differential diagnosis of pancreatic mass lesions.

Adenoma, Islet Cell↗
PubMed1989

Percutaneous cholecystoscopy.

Since 1981, we have been conducting research on percutaneous transhepatic cholecystoscopy through the sinus tract of percutaneous cholecystostomy and this method has been employed in 72 patients with gallbladder diseases. We have already reported on percutaneous transhepatic cholecystoscopy and its usefulness for the diagnosis of early gallbladder carcinoma. Histological diagnosis was possible on the basis of cholecystoscopic biopsies in all 21 patients with gallbladder carcinoma, including eight patients with early carcinoma. Percutaneous cholecystoscopy is a reliable method for making the differential diagnosis between carcinoma and polypoid lesions of the gallbladder, and the diagnosis of cancer extension on the mucosa to the cystic duct. This method is recommended as a further and final step for the early diagnosis of gallbladder carcinoma. We performed endoscopic lithotripsy with the Nd:YAG laser or electrohydraulic lithotripter, and treated 21 patients with cholecystolithiasis. We report here on the results and features of this method as a nonsurgical treatment for cholecystolithiasis.

Adenoma↗