| beta-bungarotoxin, a pre-synaptic toxin with enzymatic activity. | beta-bungarotoxin, a pre-synaptic neurotoxin isolated from the venom of the snake bungarus multicinctus, has been shown to modify release of neurotransmitter at the neuromuscular junction. in this communication, we demonstrate that beta-bungarotoxin is a potent phospholipase a2 (phosphatide 2-acyl hydrolase, ec 3.1.1.4), comparable in activity with purified phospholipase enzymes from naja naja and vipera russellii. the phospholipase activity of beta-bungarotoxin requires calcium and is stimulate ... | 1976 | 1749 |
| studies on the action mechanism of the antihemostatic effect of lodopeptides. | a synthetic iodopeptide having a glutamic acid-diiodotyrosine molar ratio of 1:1 has been shown to be an effective anticoagulant both in vivo and in vitro. contrasted with heparin the following general conclusions may be made regarding its action. the iodopeptide does not act through the inactivation of thrombin in plasma. iodopeptide does interact with fibrinogen to form a complex which, in vitro, is not soluble in buffered saline at physiological ph. at ph 8, iodopeptide interacts with fibrino ... | 1976 | 9704 |
| purification and characterization of a coagulant protein from the venom of russell's viper. | the coagulant protein from the venom of russell's viper was purified by means of successive chromatography on sephadex g-50, deae-cellulose and sephadex g-200. the purified coagulant protein was homogeneous by polyacrylamide gel electrophoresis and ultracentrifugation. the molecular weight was estimated to be about 100 000 by ultracentrifuge analysis and 130 000 by gel filtration. the coagulant protein contains 11.1% carbohydrate which includes 5.1% hexose (galactose: mannose = 1:1), 5% hexosami ... | 1976 | 11825 |
| humoral factor that specifically regulates factor x levels in rabbits (coagulopoietin-x). | a heat-stable humoral substance (coagulopoietin-x) is present in rabbits partially depleted of factor x, which is capable of raising factor x levels when injected into recipient rabbits. rabbits were partially depleted of factor x by slow infusion of a globulin fraction of goat anti-rabbit factor x antibody. this resulted in the reduction of factor x to 40--50% of normal at 1 h and 60--70% of normal at 6 h. no effect was noted on levels of factors ii, v, or vii. plasma from these animals, when i ... | 1979 | 41003 |
| coagulation abnormalities induced by russell's viper venom in the rhesus monkey. | coagulation studies were carried out in a group of non-human primates (rhesus monkeys) following envenomation with lethal and sublethal doses of russell's viper venom. the envenomated animals showed significant fibrinogenopenia in association with or without disseminated intravascular coagulation. the findings offer a rational explanation for the bleeding manifestations seen in clinical cases of russell's viper bite. | 1979 | 111572 |
| gonadotropin receptors in plasma membranes of bovine corpus luteum. i. effect of phospholipases on the binding of 125i-choriogonadotropin by membrane-associated and solubilized receptors. | the ability of bovine corpus luteum plasma membranes to bind 125i-choriogonadotropin has been examined after prior treatment of the membranes with phospholipases a, c, and d. treatment of the purified membranes with low concentrations of phospholipases a and c resulted in the inhibition of the binding of 125i-choriogonadotropin to its receptors, whereas phospholipase d had no effect. receptor activity was decreased by low concentrations of phospholipase a from either bee venom, vipera russelli o ... | 1976 | 187585 |
| effects of deoxycholate and phospholipase a2 on choline and ethanolamine phosphotransferases of chicken brain microsomes. | ethanolamine phosphotransferase (ec 2.7.8.1) and choline phosphotransferase (ec 2.7.8.2) activities were assayed in fresh microsomes from adult chicken brains with either diacylglycerols or alkylacylglycerols. pretreatment of microsomes with 1.25 mm sodium deoxycholate, a concentration less than the critical micelle concentration, produced a slight inhibition of choline phosphotransferase activity. a deoxycholate concentration (5.0 mm) greater than the critical micelle concentration (3.0 mm) dec ... | 1977 | 201287 |
| effect of hydrolytic enzymes and protein-modifying reagents on gonadotropin receptors in bovine corpus luteum cell membranes. | preincubation of membranes with various concentrations of pronase, trypsin, lipase, phospholipase a from vipera russelli and from crotalus durissus terrificus, phospholipase c from bacillus cereus and from clostridium welchii, acetic anhydride, 2,4-dinitrofluorobenzene and tetranitromethane resulted in a dose-dependent inhibition of 125i-labeled human choriogonadotropin binding. at the submaximal concentrations of enzymes and at both submaximal and maximal concentrations of protein-modifying rea ... | 1978 | 202334 |
| venom of russell's viper uncouples the dopamine receptor from striatal adenylyl cyclase. | | 1978 | 205317 |
| comparative thermometric coagulation studies of plasmas from normal outbred swiss webster mice and persons. | the functional capabilities of a thermometric clot-timer have been demonstrated in a comparative study of human and mouse plasma coagulation. the influence of some variables on coagulation times of mouse and human plasmas were examined in activated partial thromboplastin time, one-stage prothrombin time, and russell's viper venom time assays. mouse plasma coagulation times were generally shorter and more reproducible than those of human plasma. optimal assay conditions are also described. | 1979 | 224738 |
| the activation of human factor ix. | the activation of factor ix purified from human plasma has been studied. factor xia and kallikrein separately activated factor ix to factor ixa. in both cases factor ixa had an apparent molecular wight of about 42-45000 in sodium dodecyl sulphate-polyacrylamide disc gel electrophoresis compared with a molecular weight of about 70000 for the native factor ix. the activation by xia required ca2+-ions, wherease ca2+-in and factor vii or russell's-viper venom alone did not activate factor ix. trypsi ... | 1975 | 239460 |
| comparison of amino acid sequence of bovine coagulation factor ix (christmas factor) with that of other vitamin k-dependent plasma proteins. | the amino acid sequence of bovine blood coagulation factor ix (christmas factor) is presented and compared with the sequences of other vitamin k-dependent plasma proteins and pancreatic trypsinogen. the 416-residue sequence of factor ix was determined largely by automated edman degradation of two large segments, containing 181 and 235 residues, isolated after activating factor ix with a protease from russell's viper venom. subfragments of the two segments were produced by enzymatic digestion and ... | 1979 | 291916 |
| complement depletion following envenomation by russell's viper and echis carinatus (saw-scaled viper) in the rhesus monkey. | significant depletion of c3 was observed following administration of lethal and sublethal doses of russell's viper and echis carinatus venom to rhesus monkeys. a sequential study carried out over a period of 3 weeks following sublethal envenomation showed a steady rise in the c3 level from 48 hours onwards. by the 20th day the c3 values had attained the pre-envenomation levels. the extent of depletion of c3 was similar in both russell's viper and e. carinatus envenomation. because of the close i ... | 1977 | 410316 |
| activation of decarboxyfactor x by a protein from russell's viper venom. purification and partial characterization of activated decarboxyfactor x. | 1. incubation of decarboxyfactor x with the factor x-activating enzyme from russell's viper venom revealed the generation of amidase activity towards bz-ile-glu-gly-arg-pna, but not of activity in blood coagulation. 2. the rate of activation of both factor x and decarboxyfactor x depends on the ability of the zymogens to bind ca2+. the relationship between ca2+ concentration and velocity of the activation reaction is sigmoid in the case of factor x, but hyperbolic with decarboxyfactor x. 3. acti ... | 1978 | 417734 |
| neuronal degeneration induced by stereotaxic injection of beta-bungarotoxin into rat brain. | the presynaptic protein neurotoxin beta-bungarotoxin (beta-bgt) caused degeneration of neurons, following stereotaxic administration into rat brain. focal lesions were induced with as little as 0.1 ng (5 fmol) of beta-bgt; indicating that the toxin is over 10(6) times more potent than kainic acid. more extensive studies in the septo-hippocampal system showed beta-bgt lesions affected both cell bodies and nerve terminals and were not neurotransmitter-specific. the endogenous phospholipase a2 acti ... | 1979 | 460683 |
| severe conditioned taste aversion elicited by venom of russell's viper. | conditioned taste aversion (cta) established in rats by associating saccharin drinking with subsequent poisoning by russell's viper venom. retention test revealed 76 and 56% reduction of saccharin intake in venom and antivenom-venom groups. no cta was observed in antivenom and control groups. | 1979 | 488281 |
| molecular properties of the factor v-activating enzyme from russell's viper venom. | the protease from russell's viper venom that activates factor v was purified by gel filtration on sephadex g-150 and ion exchange column chromatography on sulfopropyl (sp)-sephadex c-50. the purified enzyme is a glycoprotein containing 6% carbohydrate. it migrated as a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular weight of 29,000. a minimum molecular weight of 27,200 was determined by sedimentation equilibrium in the presence of 6 m guanidin ... | 1979 | 500708 |
| effect of five thai snake venoms on coagulation, fibrinolysis and platelet aggregation. | the effects of five thai snake venoms--malayan pit viper--mpv (ancistrodon rhodostoma); russell's viper--rvv (vipera russelli); cobra--cv (naja naja); king cobra--kcv (naja hannah) and banded krait--bkv (bungarus fasciatus)--on blood coagulation fibrinolysis and platelet aggregation were studied. mpv has strong thrombin-like coagulant action. rvv has activating effect most probably on factor x. other three venoms--cv, kcv and bkv have been shown to be anti coagulant, on both intrinsic and extrin ... | 1979 | 524153 |
| enzymatic reactions on thin-layer chromatographic plates. ii. phospholipase a2 hydrolysis of phosphatidylcholine and separation of the products on a single plate. | a procedure for the phospholipase a2 hydrolysis of phosphatidylcholine on a thin-layer chromatographic plate and subsequent separation of the products on the same plate is described. a 0.2-0.8-mg amount of russell's viper venom (phospholipase a2) in 0.2 ml of 0.005 m calcium chloride solution was applied on a 0.5-mm silica gel g plate as a band over which 2-5 mg of egg phosphatidylcholine in 0.2 ml of diethyl ether containing 5% of methanol was evenly applied. after the reaction had proceeded fo ... | 1979 | 546882 |
| activation of factor x by russell's viper venom. | | 1977 | 615114 |
| activation of bovine factor ix (christmas factor) by factor xia (activated plasma thromboplastin antecedent) and a protease from russell's viper venom. | | 1978 | 632245 |
| kinetic studies on the activation of human factor x. the role of metal ions on the reaction catalyzed by the venom coagulant protein of viper russelli. | the effect of ca2+, mg2+, and mn2+ on the initial rate of activation of human factor x by the venom coagulant protein of vipera russelli has been investigated. neither mg2+ nor mn2+ alone support the reaction. ca2+ is an essential activator and exhibits cooperative kinetics. both mg2+ and mn2+ enhance the reaction cooperatively when ca2+ is present at suboptimal concentrations. similarly, ca2+ quenches the intrinsic fluorescence of human factor x in a cooperative manner. while neither mg2+ nor m ... | 1978 | 659436 |
| activation of human factor ix (christmas factor). | human factor ix (christmas factor) is a single-chain plasma glycoprotein (mol wt 57,000) that participates in the middle phase of the intrinsic pathway of blood coagulation. it is present in plasma as a zymogen and is converted to a serine protease, factor ixabeta, by factor xia (activated plasma thromboplastin antecedent) in the presence of calcium ions. in the activation reaction, two internal peptide bonds are hydrolyzed in factor ix. these cleavages occur at a specific arginyl-alanine peptid ... | 1978 | 659613 |
| the influence of metal ions in the activation of bovine factor ix by the coagulant protein of russell's viper venom. | | 1978 | 718171 |
| the binding of calcium ions to bovine factor x by rate dialysis. | the binding of ca+2 to bovine factor x (molecular weight of 74,000) (yue und gertler 1977) was studied by the technique of rate dialysis and with the use of 45ca+2. the binding data are consistent with a model of sequential mechanism. one mole of ca+2 binds to the glycoprotein with a dissociation constant of 5.2 x 10(-5) m and additional 39 +/- 4 moles of ca+2 bind to this zymogen with a dissociation constant of 3.7 x 10(-3) m. the binding of the high affinity ca+2 causes a functionally signific ... | 1978 | 734634 |
| nerve growth factor receptor binding. influence of enzymes, ions, and protein reagents. | nerve growth factor (ngf) receptor binding in membrane fractions of rabbit superior cervical ganglia has been measured after treatment with a variety of enzymes, protein-modifying reagents, and ions. receptor binding is degraded by low concentrations of trypsin but is much less sensitive to alpha-chymotrypsin. low concentrations of phospholipase a from vipera russelli decrease ngf receptor binding by lowering the number of binding sites, while phospholipase a preparations from crotalus terrificu ... | 1975 | 803504 |
| isolation of the high molecular form of bovine factor x and some of its physical properties. | a high molecular form of bovine factor x has been isolated from freshly collected bovine blood by baso4 absorption, exhaustive washing with 0.001 m bacl2 and chromatographed on deae-cellulose column employing a linear salt gradient. this isolated factor x showed a single protein band on analytical polyacrylamide gel disc electrophoresis. only one single protein peak was observed in the chromatogram of deae-sephadex a-50 chromatography conducted at 3 degrees c. sedimentation equilibrium analysis ... | 1977 | 836878 |
| demonstration and mode of action of an inhibitor for activated hageman factor (factor xiia) of the intrinsic blood coagulation pathway from schistosoma mansoni. | an anticoagulant activity from adult schistosoma mansoni whole worm homogenate is described. the inhibitor appears to be specific for the contact activation step of the intrinsic pathway. experiments with both human and mouse plasmas have defined the specificity of the inhibitor as follows: (1) it lengthens the partial thromboplastin time of normal plasma. (2) it has no effect on the prothombin time and russell's viper venom time of normal plasma. (3) preactivation of normal plasma by a contact ... | 1977 | 843620 |
| preparation of toxoids from the venoms of pakistan species of snakes. (naja naja, vipera russellii and echis carinatus). | | 1977 | 875234 |
| effects of russell's viper venom on blood coagulation, platelets and the fibrinolytic enzyme system. | the effects of russell's viper venom (rvv) on blood coagulation, platelts and fibrinolysis were studied in vivo and in vitro in rabbits and dogs as experimental subjects. rvv was shown to be a strong coagulant, and at the time of manifestation of bleeding due to consumption coagulopathy, the most striking hemostatic abnormalities were fall of fibrinogen level, reduction in platelet count, delayed adp aggregation of platelets, increased fibrinolytic activity and presence of fibrin degradation pro ... | 1977 | 916351 |
| activation of human factor x (stuart factor) by a protease from russell's viper venom. | | 1977 | 921929 |
| snake venom proteinase inhibitors. iii. isolation of five polypeptide inhibitors from the venoms of hemachatus haemachatus (ringhal's corbra) and naja nivea (cape cobra) and the complete amino acid sequences of two of them. | five proteinase inhibitors which all inhibit the activity of bovine trypsin [ec 3.4.21.4] were isolated from african elapid venoms of hemachatus haemachatus (hhv, ringhal's cobra) and naja nivea (nnv, cape cobra). all the inhibitors were essentially homogeneous by polyacrylamide gel electrophoresis in the presence or absence of sodium dodecylsulfate. amino acid analysis and terminal analysis also supported their chemical homogeneities, except for one of the two inhibitors from hemachatus haemach ... | 1976 | 950337 |
| spectral changes in bovine factor x associated with activation by the venom coagulant protein of vipera russelli. | bovine factor x is a zymogen involved in blood coagulation that is converted to activated factor x in the presence of ca(ii) by the coagulant protein of russell's viper venom. to monitor structural transitions in factor x during conversion to activated factor x, the ultraviolet absorption, fluorescence emission, and circular dichroism spectra of activated factor x and factor x were compared. the ultraviolet absorption difference spectrum in the aromatic region comparing activated factor x and fa ... | 1976 | 977597 |
| the clotting of a snake (crotalus viridis helleri) plasma and its interaction with various snake venoms. | the clotting of c. v. helleri plasma is not accelerated by the factor x activator or thrombin-like enzymes from its own venom. clotting of the plasma is accelerated by the factor xactivator from russell's viper venom, but not by the thrombin-like enzyme from agkistrodon rhodostoma venom ("arvin"). the prothrombin activator from the taipan venom clots c.v. helleri plasma equally well as human plasma, but the thrombin which is produced has a marked specificity for its own fibrinogen, and clots bov ... | 1976 | 989631 |
| proteolytic activation of protein c from bovine plasma. | protein c is a vitamin k dependent protein present in bovine plasma (stenflo, j. (1976), j. biol. chem. 251, 355). it is a glycoprotein (mol wt approximately 62 000) composed of a heavy chain (mol wt 41 000) and a light chain (mol wt 21 000). the heavy chain has an amino-terminal sequence of asp-thr-asn-gln and contains nearly three-fourths of the carbohydrate. the light chain has an amino-terminal sequence of ala-asn-ser-phe. incubation of protein c with either factor x activator from russell's ... | 1976 | 990250 |
| role of gamma-carboxyglutamic acid. cation specificity of prothrombin and factor x-phospholipid binding. | divalent cations are required for two roles in prothrombin-phospholipid interaction. the first role, catalysis of a prothrombin protein transition has a reaction half-life of 100 min at 0 degrees and is a prerequisite to phospholipid binding. the binding sites required for the transition have a very low cation specificity. all di- and trivalent cations tested were effective in this role with the exception of beryllium. barium catalyzed the transition but only at high concentrations (6.6 mm was r ... | 1976 | 993198 |
| bovine factor x1 (stuart factor): amino-acid sequence of heavey chain. | the amino-acid sequence of the heavy chain of bovine blood coagulation factor x1 (stuart factor) isolated before and after activation has been determined. sequence analysis was performed on fragments obtained by cleavage with cyanogen bromide and by tryptic digestion. comparison of the complete sequence with those of other hepatic and pancreatic serine proteases demonstrates homology of the heavy chain of activated factor x1 (factor x1a) with the b chain of bovine thrombin as well as with bovine ... | 1975 | 1059093 |
| platelet function in calves: a study of adhesion, aggregation, release, clotting factor activity and life span. | normal calf platelets were found to significantly differ human platelets in a number of important respects. the average calf platelet count is more than twice the average human value. calf platelets demonstrated no adhesion to glass, in a test in which over 50% of human platelets adhered. responsiveness to several aggregating, agents, including adp, thrombin and collagen, was markedly diminished in the calf platelet, requiring much higher concentrations of the stimulating agent to produce compar ... | 1975 | 1146035 |
| effects of nerve growth factors from mouse salivary glands and snake venom on the sympathetic ganglia of neonatal and developing mice. | 1. quantitative histological analysis has been made of the effects of nerve growth factor (ngf) from mouse submaxillary gland and from the venom of vipera russelli on superior cervical ganglia of neonatal mice. 2. the hypertrophic and hyperplastic effects reported by other workers have been confirmed. 3. the hypertrophic effect arises from an increase in the rate at which the sympathetic neurones attain their mature size. the size at maturity is never exceeded. 4. the hyperplastic effect arises ... | 1975 | 1151776 |
| interaction of lanthanide ions with bovine factor x and their use in the affinity chromatography of the venom coagulant protein of vipera russelli. | the substitution of trivalent lanthanide ions for ca(ii) in the ca(ii)-dependent activation of bovine factor x by the coagulant protein of russell's viper venom was studied at ph 6.8. factor x contains two high affinity metal binding sites which bind gd(iii), sm(iii), and yb(iii) with a kd of about 4 x 10-7 m and four to six lower affinity metal binding sites which bind gd(iii), sm(iii) with a kd of about 1.5 x 10-5m. in comparison, 1 mol of factor x binds 2 mol of ca(ii) with a kd of 3 x 10-4m ... | 1975 | 1167543 |
| characterization of the fawn-hooded rat as a model for hemostatic studies. | a large colony of fawn-hooded (fh) rats, comprising five original families and six generations of their progeny, was developed for genetic and comparative studies of their bleeding tendency. the characteristics of the bleeding diathesis in these rats are similar to those originally reported in related rats by tschopp and zucker. fh rats have normal clot retraction, adp-induced platelet aggregation and platelet adp; variable aggregation with collagen; minimal aggregation with adrenaline and cobra ... | 1975 | 1169825 |
| properties of nerve growth factor from the venom of bothrops atrox. | a glycoprotein fraction islated in poor yield (approx. 0.04%) from the venom of bothrops atrox contained nerve growth factor. the material had biological activity, stability, the property of anomalous adsorption onto surfaces, apparent molecular weight and sub-unit structure that were similar to those for nerve growth factor that had been previously purified from the venom of vipera russelli. antiserum raised against nerve growth factor from vipera russelli showed definite cross-reactivity with ... | 1975 | 1174566 |
| prothrombin and factor x activating properties of bothrops erythromelas venom. | the enzymatic properties of factor ii (fii) and factor x (fx) activators from bothrops erythromelas venom were investigated. both activators were inhibited by ethylenediaminetetraacetate (edta) and 1,10-phenanthroline, and are thought to be metalloproteinases with molecular weights of 90 kda and 70-90 kda, respectively. the activity of the fii activator in the crude venom was about 30 times greater than that in oxyuranus scutellatus venom and the level of fx activator activity, which was ca2+ io ... | 1992 | 1288438 |
| toxicities, ld50 prediction and in vivo neutralisation of some elapid and viperid venoms. | toxicity levels of elapid (naja naja and naja oxiana) viperid (vipera lebetina and vipera russelli) venoms for mice and rat for intraperitoneal intravenous and intramuscular routes have been determined. the data have been analysed using a mathematical expression to calculate lethal venom concentrations in human snake bite cases. further, in vivo neutralisation of snake venom potency (after experimental injection) using high voltage-low current electric shock treatment has been attempted. this tr ... | 1992 | 1294479 |
| characterization and molecular cloning of neurotoxic phospholipases a2 from taiwan viper (vipera russelli formosensis). | two phospholipases a2 (pla2s), designated as rv-4 and rv-7 were purified from venom of the taiwan russell's viper (vipera russelli formosensis) by gel-filtration and reverse-phase hplc. their primary structures were solved by both protein sequencing and cdna cloning and sequencing. the cdna synthesized was amplified by the polymerase-chain reaction using a pair of synthetic oligonucleotide primers corresponding to the n- and the c-terminal flanking regions of the enzymes. the deduced amino acid ... | 1992 | 1425670 |
| neutralization potency of russell's viper venom toxoid antivenom, as compared with standard antivenom. | rabbits were immunized with gamma (gamma) irradiated russell's viper venom toxoid, adsorbed to aluminium phosphate adjuvant. antibody (raised against toxoid inoculation) titer was compared to a commercial antivenom on the basis of its ability to neutralize hemorrhagic, necrotic and lethal effects of viper venom. toxoid immunization (on day 0, 15 and 30) produced antivenom which showed approximately one-third antilethal, half antihemorrhagic and antinecrotic titers as compared to those of the com ... | 1992 | 1428059 |
| neutralization of factor x activity by factor x-specific monoclonal antibodies. | factor x, a vitamin k-dependent protein, is the plasma zymogen for the active serine protease factor xa. factor xa is the proteolytic enzyme for prothrombinase, the multi-protein membrane complex that catalyses the cleavage of prothrombin to thrombin. a panel of 10 monoclonal antibodies (identified by their corresponding clone numbers: 1, 2, 3, 5, 7, 26, 27, 54, 73, and 79) to factor x were produced by immunizing mice with purified factor x. all of the antibodies bound both human factor x and fa ... | 1992 | 1450323 |
| haematopoietic malignancies in zoo animals. | myelogenous leukaemia was found in a russell's viper, a honduran milk snake, a marine toad, a byrne's marsupial mouse and an african hedgehog. lymphocytic leukaemia was present in a broad banded copperhead and an indian lion. visceral lymphomatosis was observed in a snowy owl. | 1992 | 1556254 |
| intrinsic pathway activation of factor x and its activation peptide-deficient derivative, factor xdes-143-191. | the role of the activation peptide in determining the substrate specificity of intrinsic pathway factor x (fx) activation was studied by using a novel derivative of fx in which 49 residues were removed enzymatically from the nh2 terminus of the 52-residue activation peptide by an enzyme from the venom of the snake agkistrodon rhodostoma. the modified protein, designated fxdes-143-191, is inactive but is activated to alpha-fxa by either the intrinsic fx activation complex (intrinsic fxase) compos ... | 1992 | 1560014 |
| a national hospital-based survey of snakes responsible for bites in thailand. | snakes which had been killed and brought to hospital with the patients they had bitten were collected in 80 district and provincial hospitals throughout 67 provinces in thailand in order to establish the geographical distribution and relative medical importance of the venomous species. of the 1631 snakes collected, 1145 were venomous: malayan pit vipers (calloselasma rhodostoma), green pit vipers (trimeresurus albolabris) and russell's vipers (daboia russelii) were the most numerous, while t. al ... | 1992 | 1566285 |
| detection, using antibodies, of pharmacologically active sites, apart from the catalytic site, on venom phospholipase a2. | polyclonal antibodies to a purified neurotoxic phospholipase a2 vrv pl-v from vipera russelli venom were raised in rabbits. the gamma globulin fraction from the serum of the rabbits injected with vrv pl-v-toxoid (anti vrv pl-v antibodies) is termed anti pl-v ig. anti pl-v ig neutralized the neurotoxic symptoms and lethal effects of neurotoxic pla2s (vrv pl-v, vrv pl-vi and vrv pl-viiia) and neurotoxic symptoms of whole v. russelli venom, without affecting their phospholipase a2 activities. their ... | 1990 | 1691868 |
| a model for the extracellular release of paf: the influence of plasma membrane phospholipid asymmetry. | recent studies suggesting that cellular activation leads to enhanced transbilayer movement of phospholipids and loss of plasma membrane phospholipid asymmetry lead us to hypothesize that such events may govern the release of paf, a potent, but variably release, lipid mediator synthesized by numerous inflammatory cells. to model these membrane events, we studied the transbilayer movement of paf across the human erythrocyte and erythrocyte ghost plasma membrane, membranes with documented phospholi ... | 1991 | 1705442 |
| intracellular mechanisms involved in the stimulation of growth hormone release from rat anterior pituitary cells by russell's viper venom. | we have previously shown that a heat-stable component of russell's viper venom (rvv) releases gh in a dose-dependent manner from cultured rat anterior pituitary cells. we have now investigated the intracellular mechanisms involved in rvv-stimulated gh release by concomitant administration of rvv with known intracellular mediators in rat pituitary cells. 3-isobutyl-1-methylxanthine (ibmx; 0.5 mmol/l), added to cultured rat anterior pituitary cells simultaneously with rvv, at concentrations up to ... | 1990 | 1715895 |
| deletion analysis of recombinant human factor v. evidence for a phosphatidylserine binding site in the second c-type domain. | human coagulation factor v is an integral component of the prothrombinase complex. rapid activation of prothrombin is dependent on the interactions of this nonenzymatic cofactor with factor xa and prothrombin in the presence of calcium ions and a phospholipid or platelet surface. factor v is similar structurally and functionally to the homologous cofactor, factor viii, which interacts with factor ixa to accelerate factor x activation in the presence of calcium and phospholipids. both of these co ... | 1992 | 1740460 |
| the site of activation of factor x by cancer procoagulant. | cancer procoagulant (cp) is a cysteine proteinase found in a variety of malignant cells and tissues and in human amnion-chorion tissue. it initiates coagulation by activating factor x. however, the amino acid sequence of the substrate protein that determines the cleavage site of cysteine proteinases is different from that of the serine proteinases that normally activate factor x, such as factor ixa, viia and russell's viper venom (rvv). therefore, it was of interest to determine the site of clea ... | 1991 | 1799660 |
| neuropharmacological studies on the venom of vipera russelli. | neuropharmacological studies have been conducted on the venom of v. russelli on experimental animals. the venom was found to produce alteration in general behaviour pattern, reduction in spontaneous motility, hypothermia, potentiation of pentobarbitone hypnosis, analgesia, reduction in exploratory behaviour pattern, muscle relaxant action, and suppression of aggressive behaviour. the venom caused a significant increase in brain gaba content in mice. the observations are suggestive of a potent cn ... | 1991 | 1814834 |
| development of renal function abnormalities following bites by russell's vipers (daboia russelii siamensis) in myanmar. | renal function was monitored in 24 patients with systemic envenoming following proven russell's viper bite. in all patients, blood clotted within 20 min on admission. in 15 cases severe defibrination (systemic envenoming) developed during the next 3-5 d. none of the patients received antivenom before admission but enzyme-refined monospecific antivenom was given to those who developed signs of systemic envenoming. specific antigen was detected by enzyme immuno-assay in all 21 subjects tested. nin ... | 1991 | 1835190 |
| inhibition of the activation of hageman factor (factor xii) and of platelet aggregation by extracts of brugia malayi microfilariae. | in human filariasis, large numbers of blood-borne microfilariae circulate unimpeded through the blood stream. how intravascular filarial parasites avoid precipitating thrombosis has not been studied in detail. we hypothesized that extracts of brugia malayi microfilariae would contain factors that inhibit activation of hemostatic mechanisms. initial studies demonstrated an inhibitor specific for the intrinsic coagulation cascade. the addition of microfilarial extracts to human plasma prolonged th ... | 1991 | 1902251 |
| lethal and haemorrhagic activity of russell's viper venom--neutralization by polyvalent, monovalent and toxoid antiserum. | lethal and haemorrhagic activity of russell's viper venom was compared against polyvalent bivalent commercial antiserum and monovalent antiserum raised in rabbit. formaldehyde-detoxified venom offered 7-fold protection against lethal activity and 12.5-fold against haemorrhagic activity of the venom. whole venom and formaldehyde-detoxified venom along with freund's complete adjuvant, injected in rabbits produced high titre antiserum. amongst all the six antiserum tested, the monovalent antiserum ... | 1991 | 1916944 |
| active immunization of rabbit with gamma irradiated russell's viper venom toxoid. | russell's viper venom detoxified by gamma (gamma)-radiation (100 kr or 200 kr) was used as a toxoid for active immunization of rabbits following a short or long schedule of immunization without any adjuvant. effective neutralization of venom toxin by immune sera of rabbits was observed with both schedules. sera of rabbits immunized with 100 kr irradiated venom toxoid (100 kr toxoid antisera) were more potent than 200 kr toxoid antisera. the presence of antibody in the immune sera was detected by ... | 1990 | 1964253 |
| structure-function relationships among neurotoxic phospholipases: nn-xiii-pla2 from indian cobra (naja naja naja) and vrv pl-v from russell's viper (vipera russelli) venoms. | though venom phospholipases induce various pharmacological effects their mechanism of action is in some cases unclear. there may be separate pharmacological sites on the venom phospholipase molecule. in order to understand the structure-function relationships among venom phospholipases, studies on interaction of venom phospholipases with its antibodies and various alkaloids were carried out. the alkaloids aristolochic acid, ajmaline and reserpine were incapable of inhibiting the phospholipase a2 ... | 1991 | 2028476 |
| the use of acetylated factor x to prevent feedback activation of factor viii during factor x activation: a tool for kinetic studies. | the modification of human factor x by 2-sulfo-n-succinimidyl acetate was investigated and shown to produce a factor x species which, when activated, has no activity toward factor viii. acylation of factor x (0.9 microm) was carried out in the presence of 1 mm calcium at different reagent concentrations and ph values at 22 degrees c for time courses up to 1 h. optimal modification was achieved using 0.3 mm reagent at ph 8.0 for 30 min. the modified zymogen, acetylated factor x, is activated at fu ... | 1990 | 2109550 |
| antibodies to a phospholipase a2 from vipera russelli selectively neutralize venom neurotoxicity. | polyclonal antibodies to a purified neurotoxic phospholipase a2 (pla2), vrv pl-viiia, from vipera russelli venom were raised in rabbits. anti-pl-viiia-ig (gamma-globulin fraction of rabbit antiserum injected with vrv pl-viiia) selectively neutralized the neurotoxicity of vrv pl-viiia, vrv pl-v, vrv pl-vi (neurotoxic pla2 of v. russelli venom) and whole v. russelli venom without affecting their pla2 activity, which clearly demonstrates that the catalytic site and the neurotoxic site (the site thr ... | 1990 | 2115497 |
| active site-specific immunoassays. | this study describes a process by which serine proteases that contain an s-1 arginine subsite and active site histidine may be inactivated and subsequently quantitated using a combination of peptidyl chloromethylketone chemistry and immune recognition technology. active site labeling and inactivation of proteases is attained by modification of the active site histidine with a peptidyl chloromethylketone. in the specific illustrations demonstrated, we used the compound biotinyl-epsilon-aminocapro ... | 1990 | 2116928 |
| analysis of the generation and inhibition of factor xa. area under generation curves is independent of enzyme generation rate. | the activation of factor x in the presence of antithrombin has been studied in order to determine the parameters that control the area under the resulting factor xa generation curve. generation curves were analyzed using a model containing three parameters: the total generation of factor xa, emax; the rate of factor xa generation, expressed as a first-order rate constant, kappa 1; and the rate of inhibition, expressed as another first-order rate constant, kappa 2. using factor ixa-viiia to activ ... | 1990 | 2211647 |
| the nephrotoxic action of russell's viper (vipera russelli) venom. | sixteen rabbits were injected s.c. with 2 ld50 doses of russell's viper venom. kidneys from 10 rabbits that died after envenomation were examined by microdissection and light microscopy. nephrons from five animals showed destruction of the proximal tubules with normal distal tubules. nephrons from three animals were normal throughout, while those from two animals were destroyed. in the in vitro experiment, kidney slices from normal rabbits were incubated with varying dilutions of russell's viper ... | 1990 | 2389249 |
| expression and characterization of recombinant human factor v and a mutant lacking a major portion of the connecting region. | human coagulation factor v is a protein cofactor that is an essential component of the prothrombinase complex. a full-length factor v cdna has been subcloned into the mammalian expression vector pdx and used to transfect cos cells. approximately 95 +/- 4% of the recombinant human factor v (rhfv) synthesized in cos cells is secreted into the culture medium. forty-eight hours after transfection rhfv antigen levels in the conditioned medium were 70 +/- 15 ng/ml. factor v activity determined by fibr ... | 1990 | 2397212 |
| molecular recognition in the activation of human blood coagulation factor x. | factor x can be activated by the extrinsic activation complex (factor viia:tissue factor), the intrinsic activation complex (factor ixa:factor viiia) and by an enzyme from russell's viper venom (rvv-x). to identify the regions on the surface of factor x that mediate its association with these three activators, we have prepared 21 synthetic peptides representing 65% of the primary structure of factor x. only 3 of the 21 peptides inhibited the rate of factor x activation, indicating the regions re ... | 1989 | 2500433 |
| lupus anticoagulant, anticardiolipin antibodies, and human immunodeficiency virus in haemophilia. | the prevalence of lupus anticoagulant, using the dilute russell's viper venom time (drvt), was determined in 22 patients with mild to severe haemophilia a to see if there was any association with the presence of viral disease. twelve haemophiliacs (58%) were lupus anticoagulant positive, with a mean patient:control ratio of 1.24 (range 1.15-1.52, normal range 0.84-1.06 which partially corrected with lysed, washed platelets). nine of these patients were igg or igm, or both, anticardiolipin antibo ... | 1989 | 2500459 |
| snake venoms in science and clinical medicine. 1. russell's viper: biology, venom and treatment of bites. | russell's viper, vipera russelli (shaw), is distributed erratically in 10 south asian countries and is a leading cause of fatal snake bite in pakistan, india, bangladesh, sri lanka, burma and thailand. in burma it has been the 5th most important cause of death. its venom is of great interest to laboratory scientists and clinicians. the precoagulant activity of the venom was used by macfarlane and others to elucidate the human clotting cascade. up to 70% of the protein content is phospholipase a2 ... | 1989 | 2533418 |
| burmese russell's viper venom causes hormone release from rat pituitary cells in vitro. | acute and chronic hypopituitarism is associated with severe envenoming by the burmese russell's viper. we have demonstrated that in vitro, burmese russell's viper venom (0.1-10 micrograms/ml) causes a dose-dependent release of gh, tsh and acth from dispersed rat anterior pituitary cells in culture. at 10 micrograms/ml, venom causes a significant increase in the release of gh (344%, p less than 0.001), tsh (168%, p less than 0.005) and acth (greater than 700%, p less than 0.001). we have also sho ... | 1989 | 2549160 |
| acute effect of russell's viper (vipera russelli siamensis) venom on renal hemodynamics and autoregulation of blood flow in dogs. | renal hemodynamics and autoregulation of blood flow were investigated following intravenous injection of russell's viper venom (0.1 mg/kg) in dogs anesthetized with sodium pentobarbital. after venom injection, the glomerular filtration rate fell significantly throughout the experimental period of three hr. urine flow rate and renal blood flow also decreased and the filtered load of electrolytes declined significantly. the fractional excretion of sodium, potassium and phosphorus increased followi ... | 1989 | 2617538 |
| effects of venom proteases on peptide chromogenic substrates and bovine prothrombin. | eighteen proteases were isolated from six hemorrhagic venoms of snakes belonging to the families of crotalidae and viperidae. according to their actions, they are classified as thrombin-like enzymes, alpha-fibrinogenases, beta-fibrinogenases, factor x activator, prothrombin activator, hemorrhagins and esterases. thrombin-like enzymes, beta-fibrinogenases, hemorrhagins and esterase hydrolyzed phe-pip-arg-pna (s-2238, substrate for thrombin) more strongly than cbz-ile-glu-gly-arg-pna (s-2222, subs ... | 1989 | 2655180 |
| dissociation of catalytic activity and neurotoxicity of a basic phospholipase a2 from russell's viper (vipera russelli) venom. | a neurotoxic phospholipase a2, vrv pl-v was purified from vipera russelli venom in a single step by cm-sephadex c-25 column chromatography. vrv pl-v is a basic pla2 with a mol. wt of approximately 10,000. the lethal potency of vrv pl-v was greater than that of the crude v. russelli venom. vrv pl-v showed anticoagulant activity and induced edema in the foot pad of the mouse. vrv pl-v undergoes aggregation at ph 4.8. the size of the aggregate increased as the temperature at which the enzyme was in ... | 1989 | 2781586 |
| the inhibition of clotting complexes of the extrinsic coagulation cascade by the phospholipase a2 isoenzymes from naja nigricollis venom. | phospholipase a2 (pla2) isoenzymes from naja nigricollis venom exhibit anticoagulant activity with varying potencies. to determine which complexes in the extrinsic coagulation cascade are inhibited by these pla2 enzymes, we examined their effects on the coagulation of bovine plasma initiated by the addition of thromboplastin, russell's viper venom (rvv) or thrombin. the weakly anticoagulant pla2 enzymes, cm-i and cm-ii, prolonged clotting initiated by thromboplastin, but not that initiated by rv ... | 1989 | 2814939 |
| phospholipase a2 modulation of cyclic gmp metabolism: characteristics of guanylate cyclase activation. | characteristics of phospholipase a2 (pla2) modulation of guanylate cyclase were evaluated. addition of phospholipase a2 from vipera russelli venom led to a significant increase in the activity of guanylate cyclase in various rat organs. the activation of the enzyme was selective and was only observed in the particulate fractions of tissue homogenate. the soluble guanylate cyclase from all the tissue tested exhibited lack of stimulation. the treatment of membranes with pla2 resulted in solubiliza ... | 1985 | 2866436 |
| hereditary blood coagulation factor-vii deficiency: a comparison of the defect in beagles from several sources. | 1. hereditary blood coagulation factor-vii deficiency has previously been identified in beagles from a number of sources in britain and north america. 2. a study is now reported in which the nature of the defect is compared in plasma samples from these sources. 3. when prothrombin times and russell's viper venom clotting times were determined on mixtures of samples, no cross-correction of the defective coagulation activity was detected. 4. antibody neutralization assays of factor-vii related ant ... | 1988 | 2896576 |
| direct nephrotoxicity of russell's viper venom demonstrated in the isolated perfused rat kidney. | envenoming by russell's viper (vipera russelli) is an important cause of acute renal failure. the mechanism of renal damage is unresolved. it is difficult to obtain evidence of a direct nephrotoxic action because of the coincidental disturbance to the systemic circulation. we studied the action of russell's viper venom on the function of the isolated perfused rat kidney. direct nephrotoxic action was indicated by a dose dependent decrease in inulin clearance and an increase in fractional excreti ... | 1989 | 2929855 |
| inhibition of red cell ca2+-dependent k+ channels by snake venoms. | we have investigated the effects of several snake venoms on the ca2+-dependent k+ channels of human red cells. a heat-resistant component of the venom of the snake notechis scutatus irreversibly inhibited ca2+-dependent k+ transport with a ki value of 0.1-0.2 micrograms/ml. metabolic changes of the cells modified the maximal effect of the venom. binding of the venom required extracellular ca2+ and was quick, but development of full inhibition required additional time. the effects of the venoms f ... | 1989 | 2930782 |
| inhibition of [3h]nitrendipine binding by phospholipase a2. | phospholipase a2 from several sources inhibited [3h]nitrendipine binding to membranes from brain, heart and ileal longitudinal muscle. the enzymes from bee venom and russell's viper venom were most potent, having ic50 values of approximately 5 and 14 ng/ml, respectively, in all three membrane preparations. inhibition of binding by bee venom phospholipase a2 was time- and dose-dependent. mastoparan, a known facilitator of phospholipase a2 enzymatic activity, shifted the bee venom phospholipase a2 ... | 1985 | 2995742 |
| mechanism of action of the platelet function inhibitor from vipera russelli siamensis snake venom. | human platelet aggregation induced by adp, adrenaline, collagen or thrombin was inhibited by the venom inhibitor. heating reduced both its phospholipase a2 enzymatic and anti-aggregatory activities, although not in parallel. the inhibitor caused significant dose-related inhibitory effects on the clot retraction of rabbit platelet-rich plasma caused by thrombin, while platelet malondialdehyde formation stimulated by thrombin was not affected. furthermore, the venom inhibitor increased basal cycli ... | 1986 | 3027921 |
| the factor v-activating enzyme (rvv-v) from russell's viper venom. identification of isoproteins rvv-v alpha, -v beta, and -v gamma and their complete amino acid sequences. | the complete amino acid sequences of two isoproteins of the factor v-activating enzyme (rvv-v) isolated from vipera russelli (russell's viper) venom were determined by sequencing s-pyridylethylated derivatives of the proteins and their peptide fragments generated by either chemical (cyanogen bromide and 2-(2-nitrophenylsulfenyl)-3-methyl-3-bromoindolenine) or enzymatic (trypsin, alpha-chymotrypsin, and lysyl endopeptidase) cleavages. both enzymes, designated rvv-v alpha and rvv-v gamma, consist ... | 1988 | 3053712 |
| bovine coagulation factor v visualized with electron microscopy. ultrastructure of the isolated activated forms and of the activation fragments. | single chain bovine factor v (mr = 330,000) was isolated and visualized by means of high resolution transmission electron microscopy of negatively stained samples. both factor va, activated by thrombin or by the factor v activator from russell's viper venom, and the isolated fragments, d (mr = 105,000), c1 (mr = 150,000), and f1f2 (mr = 72,000), were studied. single chain factor v appeared as a multidomain structure with three globular domains of similar size (diameter approximately 80 a), and o ... | 1986 | 3087994 |
| purification and partial biochemical characterization of an edema inducing phospholipase a2 from vipera russelli (russell's viper) snake venom. | a phospholipase a2 (vrv pl-vi) from vipera russelli venom was purified to homogeneity in a single step on cm-sephadex c-25 column. vrv pl-vi is a basic protein with a mol. wt of about 12,000 and showed a basic ph optimum and a high temperature maximum. it hydrolysed purified phospholipids in the order of phosphatidylethanolamine greater than phosphatidylcholine much greater than phosphatidylserine greater than phosphatidylinositol = 0. it is toxic with an ld50 value (i.p.) of 3.5 micrograms/g bo ... | 1988 | 3188061 |
| antigenic relationships and relative immunogenicities of venom proteins from six poisonous snakes of thailand. | venoms from naja naja siamensis, ophiophagus hannah, bungarus fasciatus, vipera russelli, calloselasma rhodostoma and trimeresurus albolabris have been studied by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting. the immunoblots were stained with rabbit homologous and heterologous antibodies. in general, the higher the mol. wt the protein the higher the immunogenicity although two proteins with mol. wts of 23,000 and 25,000 from o. hannah venom are extraordin ... | 1988 | 3201490 |
| factors contributing to fatal snake bite in the rural tropics: analysis of 46 cases in thailand. | records of 46 cases of fatal bites by identified snakes from 15 provincial hospitals throughout thailand contained sufficient information for detailed analysis. bungarus candidus and calloselasma rhodostoma were each responsible for 13 deaths, naja kaouthia for 12, vipera russelli for 7 and b. fasciatus for one. major causes of death among elapid victims were respiratory failure (26) and complications of prolonged mechanical ventilation (10), and among viper victims shock (12), intracranial haem ... | 1988 | 3257001 |
| plasmodium falciparum: effect of infected erythrocytes on clotting time of plasma. | procoagulant activity of erythrocytes infected with plasmodium falciparum was determined by measuring the effect of infected erythrocytes on the clotting time of platelet-poor human plasma in the presence of russell's viper venom. we found that erythrocytes infected with p. falciparum enhanced clotting. in the presence of the infected erythrocytes, clotting times were significantly shortened compared to clotting times in the presence of uninfected erythrocytes. procoagulant activity of infected ... | 1987 | 3310682 |
| a competitive radioimmunoassay using a monoclonal antibody to detect the factor x activator of russell's viper venom. | a radioimmunoassay (ria) has been developed for the detection of russell's viper venom in body fluids. this is a competitive binding technique using a monoclonal antibody directed against the factor x activator of russell's viper venom. the sensitivity of the test in urine was 4 ng/ml, in 0.1% bovine serum albumin-phosphate buffered saline it was 20 ng/ml and in serum it was 5 micrograms/ml. this was adequate to detect venom in the serum of four patients bitten by russell's viper. urine from an ... | 1987 | 3313812 |
| degradation of coagulation proteins by an enzyme from malayan pit viper (akistrodon rhodostoma) venom. | three hydrolases from the crude venom of the malayan pit viper (akistrodon rhodostoma) can be differentiated. the first, which we designate arh alpha, is the well-known fibrinogenolytic enzyme ancrod. the second, arh beta, which has not been described previously, is identified by its electrophoretic mobility after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page), by its ability to hydrolyze h-d-phenylalanyl-l-piperyl-l-arginyl-rho-nitroanilide, and by inhibition of its activi ... | 1987 | 3322404 |
| effects of serum versus plasma on agglutination of antibody-coated indicator cells by human rheumatoid factors. | plasma and serum contain an inhibitor (i) of the agglutination of rabbit igg-coated sheep erythrocytes by human rheumatoid factor (rf). plasma but not serum contains an inhibitor of the inhibitor (i/i) which allows rf to interact with its target. in normal blood, there is more i than i/i, and i can be removed by solid-phase chromatography through concanavalin a (con a). plasma i/i is heat labile being eliminated by heating at 56 degrees c for 30 min. addition of exogenous calcium clots edta plas ... | 1988 | 3338191 |
| preparation and properties of derivatives of bovine factor x and factor xa from which the gamma-carboxyglutamic acid containing domain has been removed. | limited proteolysis of bovine blood coagulation factor x by chymotrypsin produces a derivative in which the light chain is cleaved between tyr 44 and lys 45. two peptide products, residues 1-44 of the factor x light chain and a modified zymogen, factor x(-gd) have been isolated and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, elution behavior on anion-exchange chromatography, amino acid composition, and by partial amino acid sequence determination. factor x(-gd) no ... | 1986 | 3512564 |
| the action of various venoms on escherichia coli. | the antibacterial activity of honeybee venom (apis mellifera), three snake venoms (naja naja sputatrix, vipera russellii and crotalus adamanteus) and the polypeptide melittin was investigated against escherichia coli. minimum inhibitory concentration values, cell lysis and alterations in cell permeability were determined and action against e. coli was in the order: a. mellifera venom greater than melittin greater than n. naja sputatrix venom much greater than v. russellii venom greater than c. a ... | 1986 | 3542922 |
| blood coagulation induced by the venom of bothrops atrox. 2. identification, purification, and properties of two factor x activators. | we have characterized and purified the two components of the venom of bothrops atrox that activate the coagulation factor x. activator 1 and activator 2 were separated by ion-exchange chromatography but otherwise presented similar characteristics. they consist of a heavy polypeptide of mr 59,000 and either one or two light chains forming a doublet of mr 14,000-15,000. they are inactive on synthetic substrates and on prothrombin or fibrinogen and thus appear to act specifically on factor x. they ... | 1987 | 3552032 |
| antithrombotic activity of a synthetic heparin pentasaccharide in a rabbit stasis thrombosis model using different thrombogenic challenges. | a synthetic pentasaccharide, representing the critical sequence required in heparin for binding to antithrombin iii (at iii), produces strong anti-factor xa activity in vitro in the presence of at iii and is devoid of any activity directed towards thrombin. this pentasaccharide provides a unique tool to study the question of whether an agent capable of inhibiting factor xa but devoid of anti-factor iia activity in vitro, has the capacity to produce an antithrombotic effect in vivo. we have previ ... | 1987 | 3603420 |
| in vitro studies of russell's viper venom on blood coagulation and fibrinolysis. | the effect of russell's viper venom (rvv) on clot formation and lysis and the effect thereon of specific antivenom for russell's viper venom, were studied in vitro. rvv had fibrinogenolytic activity, but only at a concentration greatly in excess of that likely to be achieved in vivo after russell's viper bite. similarly, rvv did not directly activate the fibrinolytic system in vitro, even at very high concentrations (10,000 micrograms/ml). furthermore, 40 ml of antivenom (asv) was found to be su ... | 1987 | 3603429 |
| effect of russell's viper (vipera russelli siamensis) venom on renal hemodynamics in dogs. | the effect on renal hemodynamics of russell's viper (vipera russelli siamensis) venom was studied in 8 mongrel dogs. the venom (0.10 mg/kg) was injected i.v. measurements of general circulation and renal function were carried out over 48 hr. during the initial post-injection period, mean arterial blood pressure, pulse pressure and heart rate decreased. total peripheral vascular resistance and renal vascular resistance showed a tendency to increase. there was no change in cardiac output. thereaft ... | 1986 | 3715903 |
| presence of phosphatidylserine in the outer membrane bilayer of newborn human erythrocytes. | the phospholipid distribution across red cell membrane bilayer is asymmetrical. sphingomyelin and phosphatidylcholine are predominantly present in the outer membrane bilayer, whereas only small amounts of phosphatidylethanolamine and no phosphatidylserine are present in the outer membrane bilayer. the present study, using specific phospholipase, chemical probe, and russell's viper venom clotting time has found that in neonatal red cells a portion of ps is also present in the outer membrane bilay ... | 1986 | 3718503 |
| analysis of the generation and inhibition of activated coagulation factor x in pure systems and in human plasma. | the overall generation and inhibition of human factor xa have been studied in pure systems and plasma to determine the kinetic characteristics of inhibition during factor xa generation. generation curves were measured amidolytically in a pure system containing factor x and antithrombin, which was activated with the factor x-activating enzyme of russell's viper venom (rvv-x). the measured change in factor xa level with time was fitted to a 3-parameter 2-exponential model to determine apparent fir ... | 1986 | 3722168 |
| fibrin assembly in human plasma and fibrinogen/albumin mixtures. | magnetic birefringence is used to monitor the kinetics of thrombin-catalyzed fibrin polymerization in model systems of increasing complexity (i.e., fibrinogen solutions, fibrinogen/albumin mixtures, and plasma anticoagulated with citrate) and in plasma containing free calcium which is the physiological condition. the introduction of albumin into fibrinogen solutions shortens the lag period and enhances fiber thickness. the polymerization progress curves are sigmoidal at zero or low albumin conce ... | 1986 | 3768349 |
| trial of russell's viper venoid. i. immunization of monkeys with venoid. burma, dmr working group on russell's viper venoid. | refined russell's viper venoid was prepared by the mild and step-wise formalinization of pooled first four fractions obtained by sephadex g-50 fractionation of russell's viper venom. this preparation was found to be potent and immunogenic with minimum undesirable side effects. satisfactory rise of circulating antitoxin levels was seen in monkeys immunized with the venoid and this rise persisted for 24 weeks. the immunized monkeys withstood intramuscular challenge with 2 mg/kg of the crude venom ... | 1986 | 3798536 |