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Biomedical subjects

Y Komori

Publications and source records attributed to Y Komori.

At least 73 records · Page 4Linked to original sources
PubMed1993

Isolation and characterization of procoagulant from the venom of Vipera aspis aspis.

1. A procoagulant protein was isolated from Vipera aspis aspis (Aspic viper) venom by Sephadex G-75, DEAE-Sephacel, Q-Sepharose and Sephadex G-150 column chromatography. 2. The purified protein has a molecular weight of 125,000 and an isoelectric point of 4.3. 3. This procoagulant decreased the clotting time of plasma from humans, however, direct fibrongen clotting activity was not detected. 4. Diisopropyl fluorophosphate, a serine-protease inhibitor affected coagulant activity of purified protein significantly, while a factor Xa inhibitor (3-ABPE) possessed a slight inhibitory effect. 5. Bovine prothrombin incubated with isolated protein, phospholipid emulsion, bovine factor V and calcium ions drastically decreased the clotting time of fibrinogen and expressed hydrolytic activity against synthetic arginine esterase substrates. However, no hydrolytic activity these substrates was detected with the procoagulant alone indicating that this protein might participate in activation of prothrombin.

Amino Acid Sequence↗
PubMed1993

Effect of bilineobin, a thrombin-like proteinase from the venom of common cantil (Agkistrodon bilineatus).

A thrombin-like proteinase, named bilineobin, was isolated from Agkistrodon bilineatus venom by Sephadex G-75, DEAE-Sephacel and Heparin-Sepharose CL-6B column chromatography. The purified enzyme has a mol. wt of 57,000 and catalysed the hydrolysis of arginine esters and thrombin substrates Boc-Val-Pro-Arg-MCA and Boc-Asp(OBz)-Pro-Arg-MCA. Although bilineobin converted fibrinogen into fibrin resulting in the production of fibrinopeptides, the activity was relatively low (0.65 NIH units/mg). Fibrinopeptides released upon hydrolysis by this proteinase were identified as fibrinopeptide A (FpA) and fibrinopeptide B (FpB) by measuring fast atom bombardment (FAB) mass spectra and amino acid sequence. This indicates that bilineobin hydrolyses the Arg(19)-Gly(20) bond in the A alpha chain and the Arg(21)-Gly(22) bond in the B beta chain of the bovine fibrinogen molecule. Kinetic study of FpA and FpB release reveals that bilineobin has a preference for cleaving the B beta chain. In addition, bilineobin is resistant to thrombin inhibitors such as hirudin. These suggest that the mechanism of action of bilineobin is similar but not identical to that of thrombin. It was demonstrated that the NH2-terminal region of bilineobin has significant similarities in sequence with thrombin-like proteinases from other snake venoms; however, only three residues were common with thrombin up to residue number 24.

Amino Acid Sequence↗
PubMed1993

Determination of estrogen 3-sulfates in biological fluids of mammary tumor-bearing rats by radioimmunoassay.

Determination of estradiol 3-sulfate (E2 3-S) and estriol 3-sulfate (E3 3-S) in plasma, urine or tumor tissues of mammary tumor-bearing rats were performed using the superior radioimmunoassay (RIA) system. The plasma level of E2 3-S after tumorigenesis was found to be about one-third of the normal level. As to E3 3-S, the levels in urine were significantly high both before and after tumorigenesis. Before that, the average level was about 1.5 times, and after that, about 2.5 times as high as the normal level. In tumor tissues, an extremely high level of E3 3-S (399.6 +/- 113.9 pg/g tissue) was determined.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1993

[Relationship between lymphocyte subsets of the peripheral blood and noise induced hearing loss].

Biochemical examination and two-color flow cytometric analysis of lymphocyte subsets of the peripheral blood were carried out in 107 healthy males working in high noise environments. The level of hearing disorder was compared with these results. By audiometry at six frequency levels, 51 of the 107 healthy males showed hearing loss. Their mean value of hearing ability was 30 dB and/or above. Among the peripheral lymphocyte subsets, helper T cells of CD4+CD45R- were significantly increased and the CD4/CD8 ratio tended to be elevated. CD20 that indicate B cells were reduced. These results suggested a relationship between susceptibility to acoustic trauma and cell-mediated immunity.

Adult↗
PubMed1992

Isolation and characterization of arginine ester hydrolase from Heloderma horridum (beaded lizard) venom.

1. An arginine ester hydrolase was isolated from Heloderma horridum (beaded lizard) venom by Sephadex G-75, DEAE-Sephacel and Q-Sepharose column chromatography, resulting in 5.4 mg of purified enzyme from 320.0 mg of crude venom. 2. The enzyme was shown to be homogeneous by both SDS and non-SDS disc electrophoresis on polyacrylamide gel at pH 8.3. 3. The enzyme possesses arginine ester hydrolase and transglutaminase-like activities, but did not exhibit clotting activity. 4. Molecular weight was determined to be ca 29 kDa, with an isoelectric point of 4.4. 5. The enzyme was stable to heat treatment (95 degrees C, 10 min) and to pH changes over the range 2-11. 6. The arginine ester hydrolase was inactivated by diisopropylfluorophosphate (DFP), beta-mercaptoethanol and N-bromosuccinimide, suggesting that serine, disulfide bonds and tryptophan are involved in enzymatic activity. 7. Amino terminal sequences were determined and appear to be similar to porcine pancreatic kallikrein.

Amino Acid Sequence↗
PubMed1992

Identification of effective component from a traditional herbal medicine and the inhibitory effects on experimental glomerular lesion in mice.

Effective constituents for renal disease were partially purified from a herbal prescription. The efficacy on renal diseases was examined using an experimental model system of glomerular lesion in mice induced by Agkistrodon acutus venom (Ac1-P). The extract of boiling water of the herbal prescription (P-3) was first fractionated by ether into an acidic fraction and a mixture of basic and neutral fractions. The acidic fraction was proved to be more effective and then further examined by thin layer chromatography and spectrophotometry. One of the main components was confirmed to be caffeic acid which had inhibitory effect on renal failure in mice by Ac1-P. This effect was considered to be caused by caffeic acid inhibiting the proteolytic enzyme activity of Ac1-P. Caffeic acid should thus have prophylactic or inhibitory effect on glomerular disease in which proteolytic enzymes may have pathogenic roles.

Animals↗
PubMed1991

Isolation and characterization of hemorrhagic toxin from the venom of Trimeresurus elegans.

1. Hemorrhagic toxin from the venom of Trimeresurus elegans was purified in a homogeneous form using gel filtration and ion exchange chromatographies. 2. Hemorrhagic toxin possessed hemorrhagic and TAME (tosyl-L-arginine methyl ester) hydrolytic activities. These activities were inhibited when hemorrhagic toxin was incubated with benzamidine or N-bromosuccinimide. 3. Its mol. wt was 28,500 and the isoelectric point was 7.4. 4. This toxin contains ca 1.5 mol Ca per mol of protein.

Amino Acid Sequence↗
PubMed1991

Characterization of Ac1-Proteinase from the venom of Agkistrodon acutus (Hundred-pace snake) from Taiwan.

1. Ac1-Proteinase from the venom of Agkistrodon acutus was isolated in a homogeneous form by a previously published method. 2. Ac1-Proteinase possessed lethal, hemorrhagic, caseinolytic, azocaseinolytic, azoalbumin hydrolytic and hide powder azure hydrolytic activities. 3. The toxin also hydrolyzed the oxidized B chain of insulin and fibrinogen. The cleavage sites in the oxidized B chain of insulin were identified as Ala(14)-Leu(15) and Tyr(16)-Leu(17). The A alpha chain of fibrinogen was digested. 4. Biological properties of Ac1-Proteinase were investigated further and are reported in this paper.

Amino Acid Sequence↗
PubMed1991

A pathologic study on the inhibitory effects of a herbal medicine against the glomerular lesion induced by Agkistrodon venom in mice.

The inhibitory effects of a prescription of herbal medicine, tentatively named P-3, were studied pathologically in an experimental model of the glomerular lesion induced by purified snake Agkistrodon acutus venom proteinase (Ac1-P) in mice. Ac1-P was intravenously inoculated at a single LD50 dose. In the treated group, mice were intraperitoneally injected with an extract of P-3 at a designated time once every two days from 2 days before to 1 week after Ac1-P inoculation. The control group mice were injected with saline instead of P-3. In the control group, the main pathologic changes within 48 hrs after inoculation were pulmonary and gastrointestinal tract hemorrhage and renal petechiae with hematuria. The kidney microscopically showed cystic transformation of the glomerular capillary tufts. followed by occlusive thrombosis. One week after inoculation, the glomerular lesions were mostly replaced by proliferative or proliferative-sclerosing changes with occasional crescent formation. Early signs of tubular atrophy accompanying the glomerular changes were observed. In the P-3 treated mice surviving 48 hrs and 1 week, the changes observed in the controls were markedly inhibited, although P-3 treated mice dying earlier than 30 hrs exhibited hemorrhagic changes similar to controls. This indicated that the herbal medicine had efficacy against the tissue injuries induced by Ac1-P as a proteolytic enzyme.

Angiography↗
PubMed1990

Characterization of a new inhibitor for angiotensin converting enzyme from the venom of Vipera aspis aspis.

1. Angiotensin converting enzyme inhibitor has been isolated from the venom of Vipera aspis aspis by gel filtration and reverse phase HPLC. 2. The purified inhibitor is a decapeptide, whose amino-terminal is blocked, with mol. wt 1044 determined by fast atom bombardment mass spectrometry. 3. The peptide inhibited the conversion of angiotensin I to angiotensin II, and Ki values were determined to be 7.54 x 10(-4) and 1.36 x 10(-4) M, respectively, using Hip-His-Leu and Hip-Gly-Gly as substrates 4. The peptide also inhibited the degradation of bradykinin, induced hypotension in spontaneously hypertensive rats and caused an increase in capillary permeability in rabbits, however, it possessed no lethality.

Amino Acid Sequence↗
PubMed1990

Isolation and characterization of factor X activator from the venom of Vipera aspis aspis.

1. A factor X activator was isolated from the venom of Vipera aspis aspis (Aspic viper) by gel filtration and ion-exchange chromatography. 2. The purified activator has a mol. wt of 75,000 and an isoelectric point of 4.6. Upon reduction, this activator migrated as two bands with mol. wts of 16,000 and 14,000 in sodium dodecyl sulfate polyacrylamide gel electrophoresis. 3. The activator from V. a. aspis venom shortened activated partial thromboplastin time (APTT) of normal plasma and factor IX-deficient plasma from humans. 4. Factor X incubated with isolated activator and calcium ions drastically shortened APTT of factor X-deficient plasma and expressed hydrolytic activity against synthetic substrates for factor Xa, however no hydrolytic activity was detected with the activator alone, indicating that the activator converted factor X to the active form.

Amino Acid Sequence↗
PubMed1990

Purification and physiological study of a hypotensive factor from the venom of Vipera aspis aspis (aspic viper).

A hypotensive factor was isolated from the venom of Vipera aspis aspis by Sephadex G-75, S-Sepharose column chromatography, and reverse phase HPLC using a Develosil 300 ODS-7 column. The purified factor was a basic protein with a mol. wt of 25,000 and an isoelectric point of 7.95. Intravenous injection of hypotensive factor induced an immediate fall in blood pressure of rats, whose duration depended on the dose employed. The hypotensive response was not affected by dithiothreitol, beta-mercaptoethanol, EDTA, p-tosyl-L-phenylalanine chloromethylketone, p-chloromercuribenzoic acid, or diisopropyl fluorophosphate, and was resistant to heat-treatment at 100 degrees C for 30 min, however, it disappeared after incubation with antivenom prepared against the hypotensive factor. The factor is devoid of proteinase, esterase, phospholipase A2 and kallikrein-like activities, and lethal, hemorrhagic and capillary permeability increasing activities are also absent. Compared to the hypotension induced by the hypotensive factor in normotensive rats, a more potent response was observed when it was administered to 11-week-old spontaneously hypertensive rats.

Amino Acids↗
PubMed1990

Comparative study of three phospholipase A2s from the venom of Vipera aspis.

1. Three phospholipase A2s, PLA2-I, PLA2-II and PLA2-III, were isolated from Vipera aspis venom by gel filtration and ion exchange chromatography. 2. Purified PLA2-I, -II and -III have mol. wts of 30,200, 16,000 and 13,500, and isoelectric points of 9.45, 7.65 and less than 4.1, respectively. 3. PLA2-I consists of an acidic subunit (mol. wt 13,700, pI: less than 3.5) and a basic subunit (mol. wt 16,500, pI: 10.6), which can be separated under highly acidic conditions. 4. PLA2-I possessed lethal activity and LD50 for this preparation was estimated to be 0.288 (0.209-0.397) micrograms/g, while lethality was not observed when PLA2-II, -III or each subunit of PLA2-I were administered. 5. Capillary permeability-increasing activity was found in the samples which possessed basic isoelectric points. Additionally, PLA2-I and its basic subunit drastically prolonged activated partial thromboplastin time of platelet rich plasma. 6. Intramuscular injections of PLA2-I, -II and -III increased serum creatine phosphokinase activity in mice, indicating that damage in muscle was caused by these enzymes. 7. NH2-terminal sequences of the three PLA2s were compared with other phospholipase A2s from snake venoms. Furthermore, antigenicities were tested using antiserum prepared against each sample.

Amino Acid Sequence↗
PubMed1990

Mammary tumor immunoscintigraphy in rats: the use of 131I-anti-estriol 3-sulfate antibody.

The scintigraphic imaging of mammary tumors with anti-estriol 3-sulfate (E3 3-S) antibody was studied in rats. A chemical carcinogen, 7,12-dimethylbenz(a)anthracine (DMBA), induced mammary tumors in Sprague-Dawley female rats. Highly specific anti-E3 3-S antibody was prepared and radioiodinated by [131I]NaI using the chloramine-T method. At 24 h after administration of 131I-anti-E3 3-S antibody, goat anti-guinea pig immunogloblin G (IgG) was injected as the second antibody (SA) and nuclear scintigraphy was performed. Mammary tumors were clearly visualized following SA injection.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

4, 6-0-benzylidene-D-glucopyranose (BG) in the treatment of solid malignant tumours, an extended phase I study.

4, 6-0-Benzylidene-D-glucopyranose (BG), a derivative of benzaldehyde (BA), whose anti-tumour action has often been reported, showed responses in 10 out of 24 patients (41.7%). These patients consisted of 11 cases of primary lung cancer, 4 of metastatic lung cancer, 5 of gastric cancer, and one each of cancer of the sigmoid colon, liver, pancreas and prostate. There were two complete responses (one each of ipsilateral lung metastasis from breast cancer and metastatic liver lesions due to gastric cancer). The mean total dose of BG was 392.6 g, given by intravenous infusion of 1.2 g BG in 100 ml saline twice daily. The treatment was discontinued when no response was observed after two months. Careful monitoring showed no toxic action of BG at these large doses. Complete necrotic liquefaction of tumour, without any damage to surrounding tissue, was seen in 2 of 3 cases in which histological examination was feasible. It is apparent that BG, like BA, is not a cytotoxic agent in the ordinary sense, but its mechanism of action is still unknown.

Adult↗
PubMed1988

Biochemical and physiological studies on a kallikrein-like enzyme from the venom of Crotalus viridis viridis (prairie rattlesnake).

A kallikrein-like enzyme was isolated from Crotalus viridis viridis (Prairie rattlesnake) venom by Sephadex G-50, DEAE-Sephacel and heparin-Sepharose CL-6B column chromatography. The purified enzyme has a molecular mass of 32 kDa and an isoelectric point of 5.4. The enzyme catalyzed the hydrolysis of arginine esters, kallikrein substrates Pro-Phe-Arg-MCA and Z-Phe-Arg-MCA. The specificity of the enzyme's substrate requirement is demonstrated by the fact that no proteolytic activity was detected against either dimethyl casein or fibrinogen. The enzyme also cleaves kininogen analogs to release bradykinin. Although the enzyme induced contraction of the isolated rat uterus directly at high concentrations, more forceful contractions resulted when the reaction mixture of the enzyme and bovine plasma was applied to the uterus. The reaction mixture of 5.10(-11) M of the enzyme and plasma caused contractions equal to that of 10(-9) M of bradykinin. Additionally the enzyme demonstrated capillary permeability-increasing activity and hypotensive activity on the anesthetized rat, suggesting that the enzyme releases the dilator of the wall of capillaries from plasma. Uterine contraction, capillary permeability-increasing activity and arginine esterolytic activity were inhibited by diisopropyl fluorophosphate, indicating that the serine hydroxyl group is essential for enzymatic and biological activities. It was demonstrated that the NH2-terminal region of the enzyme has significant similarities in sequence with kallikrein-like enzymes from other snake venoms and porcine pancreatic kallikrein.

Amino Acid Sequence↗