Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Batroxobin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed2001

Time to reconstitution: purified Fab antivenom vs. unpurified IgG antivenom.

We conducted prospective, randomized analytical and observational trials to assess reconstitution times of two lyophilized crotaline snake antivenoms, Antivenin (Crotalidae) Polyvalent [Wyeth-Ayerst] (ACP) and affinity-purified, mixed monospecific crotalid antivenom ovine Fab (CroTAb) (Fab antivenom). The analytical experiment indicated Fab antivenom and ACP reached their maximum protein concentration at 25 and 45min, respectively. In the observational experiment, Fab antivenom (median 40min) had a shorter reconstitution time than ACP (>90min, p<0.008).

Antivenins↗
PubMed1997

Mechanism of thrombin inhibition by antithrombin and heparin cofactor II in the presence of heparin.

The kinetics of thrombin inhibition by antithrombin (AT) and heparin cofactor II (HC II) were analysed as a function of the heparin concentration, from 10(-9) to 10(-4) M. The initial concentrations of inhibitor (l) and thrombin (E) were set at equimolar levels (CI = CE = 10(-8) M). The experimental data indicate that the reaction of thrombin inhibition was second-order both in the absence and in the presence of heparin, and that the apparent rate constant increased at heparin concentrations ranging from 10(-9) to 10(-6) M and decreased at higher concentrations. The data fit with the kinetic model established by Jordan et al. [J. Biol. Chem. 1979, 254, 2902-2913] for the catalysis of the thrombin-AT reaction by a low-molecular-weight heparin fraction. In this model, heparin (H) binds quickly to the inhibitor (I) and forms a heparin-inhibitor complex (HI), which is more reactive than the free inhibitor towards thrombin, leading to the formation of an inactive inhibitor-thrombin complex (I*E) and the release of free heparin, in a second step which is rate limiting. KH,I, the dissociation constant of HI, and k, the second-order rate constant of free thrombin inhibition by HI, were found to be 3.7 x 10(-7) M and 1.3 x 10(9) M-1 min-1, respectively, for AT, compared to a KH,I of 2.0 x 10(-6) M and k of 6.4 x 10(9) M-1 min-1 for HC II. These data indicate that heparin-HC II complex reactivity is greater than that of the heparin-AT complex towards thrombin, whereas heparin affinity is stronger for AT. At heparin concentrations higher than 10(-6) M, the decrease in the reaction rate was in keeping with the formation of a heparin-thrombin complex (HE), whose inactivation by the heparin-inhibitor complex (HI) is slower than that of the free protease.

Antithrombins↗
PubMed1984

Glycosylated A alpha chains in chicken fibrinogen.

Fibrinogen immunoprecipitated from cultured chick embryo hepatocytes was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and compared with fibrinogen from chicken plasma. The character and relatedness of the constituent polypeptide bands were established on the basis of enzymatic treatment, peptide analysis, metabolic labeling with [14C]glucosamine, and inhibition of glycosylation with tunicamycin. Hepatocyte-derived fibrinogen resolved into five polypeptides that, in order of decreasing apparent molecular weight, were identified as glycosylated A alpha, non-glycosylated A alpha, B beta, gamma', and gamma. Fibrinogen immunoprecipitated directly from chicken plasma yielded an identical profile except for an additional smaller A alpha chain. This small A alpha chain appears to be the product of partial proteolysis in the circulation and was the only A alpha band found in purified plasma fibrinogen (fraction I-2). The observation of glycosylated A alpha chains is novel. The gamma/gamma' chain heterogeneity appears to be due to an amino acid extension similar to that observed in mammalian fibrinogens. Fibrinogen from cells exposed to fetal bovine serum, a potent stimulator of fibrinogen production, was enriched in glycosylated A alpha chains, which constituted approximately one-third of the A alpha chain population. Serum did not affect the gamma/gamma' chain distribution.

Animals↗
PubMed1999

Soluble fibrin augments platelet/tumor cell adherence in vitro and in vivo, and enhances experimental metastasis.

There is considerable evidence for a relationship between hemostasis and malignancy. Since platelet adhesion to tumor cells has been implicated in the metastatic process and plasma levels of fibrinogen (Fg) and soluble fibrin (sFn) monomer are increased in cancer, we hypothesized that these molecules might enhance tumor-platelet interaction. We therefore studied binding of sFn monomer to tumor cells in a static microplate adhesion assay and determined the effect of pre-treating tumor cells with sFn on tumor cell-induced thrombocytopenia and experimental metastasis. Soluble fibrin (produced by adding thrombin to FXIII- and plasminogen-free Fg in the presence of Gly-Pro-Arg-Pro-amide (GPRP-NH2) significantly increased platelet adherence to tumor cells. This effect was primarily mediated by the integrins alphaIIb beta3 on the platelet and CD 54 (ICAM-1) on the tumor cells. Platelets adhered to untreated A375 cells (28 +/- 8 platelets/tumor cell) and this was not significantly affected by pre-treatment of the tumor cells with fibrinogen or GPRP-NH2. Although thrombin treatment increased adherence, pre-incubation of the tumor cells with sFn resulted in a further increase in platelet binding to tumor cells. In contrast to untreated tumor cells, intravenous injection of sFn-treated A 375 cells reduced the platelet count in anticoagulated mice, supporting the in vitro finding that sFn enhanced tumor cell-platelet adherence. In a more aggressive model of experimental metastasis, treating tumor cells with sFn enhanced lung seeding by 65% compared to untreated cells. Extrapolation of our data to the clinical situation suggests that coagulation activation, and subsequent increase in circulating Fn monomer, may enhance platelet adhesion to circulating tumor cells and thereby facilitate metastatic spread.

Animals↗
PubMed1986

Influence of Ca2+ on the structure of reptilase-derived and thrombin-derived fibrin gels.

The effects of Ca2+ ion on the structure of thrombin-derived and reptilase-derived fibrin gels formed at various ionic strengths were studied turbidimetrically. For both enzymes clotting times were shorter, final gel turbidities were higher and fibre mass/length ratios were increased as the ionic strength was lowered. The addition of 5 mM-Ca2+ augmented each of these effects for any given ionic strength. In the thrombin system, Ca2+ increased the final gel turbidity from 0.04 to 0.26 A632.8 at ionic strength 0.15. Under identical conditions in the reptilase system, the final gel turbidity increased from 0.03 A632.8 in the absence of Ca2+ to 0.345 A632.8 in the presence of 5 mM-Ca2+. In the thrombin system, fibre mass/length ratios increased from 0.4 X 10(12) to 6.9 X 10(12) Da/cm in the absence of Ca2+, and from 4.4 X 10(12) to 7.9 X 10(12) Da/cm in the presence of Ca2+, as the ionic strengths were decreased from 0.15 to 0.08 and to 0.11 respectively. In the reptilase system, the mass/length ratios increased from 0.9 X 10(12) to 5.8 X 10(12) Da/cm in the absence of Ca2+, and from 4.8 X 10(12) to 8.7 X 10(12) Da/cm in the presence of Ca2+, as the ionic strengths were decreased from 0.15 to 0.08 and to 0.10 respectively. At ionic strengths below 0.10, the presence of 5 mM-Ca2+ caused precipitation and macroscopic aggregation of fibrinogen upon the addition of either enzyme. In the presence of 5 mM-Ca2+, the fibres composing thrombin-induced and reptilase-induced gels were virtually identical.

Batroxobin↗
PubMed1987

Fibrin assembly after fibrinopeptide A release in model systems and human plasma studied with magnetic birefringence.

Magnetically induced birefringence was used to monitor fibrin polymerization after the release of the small negatively charged A fibrinopeptides from human fibrinogen by the action of the snake-venom-derived enzymes reptilase and ancrod. A range of conditions was investigated. Fibrin polymerization in solutions of purified fibrinogen shows a distinct break near the gelation point. On addition of Ca2+ or albumin the lag period is shortened, fibre thickness is increased and the break in assembly almost vanishes, probably because both of these additives promote lateral aggregation. There are minor differences in the kinetics, depending on the venom enzyme used. The kinetics of fibrin assembly in model systems containing either Ca2+ or albumin and in human plasma with a largely dormant coagulation cascade are very similar. Therefore in the latter condition there is no significant alteration in the assembly process due to interaction between fibrin or the venom enzymes and any of the plasma proteins. When the cascade is activated, the polymerization progress curves have a character that resembles a combination of the reactions observed when the venom enzymes and endogenously generated thrombin separately induce coagulation, except for a region near gelation where, paradoxically, polymerization appears to be slower on activation. The low-angle neutron-diffraction patterns from oriented gels made with thrombin or reptilase are identical. Therefore at low resolution the packing of the monomers within fibres is the same when fibrinopeptide A only or both fibrinopeptides A and B are removed.

Ancrod↗
PubMed2003

Changes in functional activities of plasma fibrinogen after treatment with methylene blue and red light.

BACKGROUND: Methylene blue (MB) plus light treatment used for virus inactivation of human plasma units may lead to changes in the functional activities of fibrinogen. STUDY DESIGN AND METHODS: Single-donor units of fresh plasma were treated with 1.0 microM MB and a red light dose of 48 J per cm2. The effects of MB plus red light treatment on fibrinogen clottability, fibrin polymerization and gelation, clot stabilization, and fibrinolysis were studied. RESULTS: The concentration of clottable fibrinogen was unchanged during MB plus red light treatment, but a light-dose-dependent decrease of the concentration of functional fibrinogen was found. The initial release rate of fibrinopeptide A was slightly increased after MB plus red light treatment. Turbidity measurements of fibrin gel showed prolonged clotting time, lower fibrin fiber mass-to-length ratio, and slightly smaller fiber diameter. At a given clotting time, a gel with lower fibrin fiber mass-to-length ratio was produced. Clot stability and fibrinolysis remained normal. l-Histidine added to plasma before MB plus red light treatment normalized the thrombin-induced coagulation time in a dose-dependent way. CONCLUSION: MB plus red light treatment affected the polymerization and gelation phase of fibrin. A tighter fibrin gel structure was formed. No effect on stabilization of fibrin clot or fibrinolysis was found.

Batroxobin↗
PubMed2003

Fibrinogens Kosai and Ogasa: Bbeta15Gly-->Cys (GGT-->TGT) substitution associated with impairment of fibrinopeptide B release and lateral aggregation.

We found two heterozygous dysfibrinogenemias, designated fibrinogen Kosai and fibrinogen Ogasa. Kosai was associated with arteriosclerosis obliterans but Ogasa showed no bleeding or thrombotic tendencies. The plasma fibrinogen concentrations from the two propositi (Ogasa and Kosai) were much lower when determined by the thrombin-time method (0.94 and 1.06 g L(-1), respectively) than when determined by the immunological method (2.87 and 2.72 g L(-1), respectively). We performed DNA sequencing and functional analyses to clarify the relationship between the structural and functional abnormalities. Genetic analysis of PCR-amplified DNA from the propositi identified the heterozygous substitution Bbeta15Gly-->Cys (GGT-->TGT). Western blotting analysis of purified fibrinogen revealed the existence of albumin-fibrinogen complexes. Functional analyses indicated that compared with the normal control, the propositi's fibrinogen released only half the normal amount of fibrinopeptide B and showed markedly impaired polymerization. In addition, the observation of thinner fibers in fibrin clots (by scanning electron microscopy) indicated markedly defective lateral aggregation in the variant fibrinogens. The impaired functions may be due to the substitution of Cys for Bbetao15Gly plus the existence of some additional disulfide-bonded forms.

Adult↗
PubMed1976

Impaired anticoagulant effect of heparin in the artificial kidney. An experimental study.

Dialysis of blood and plasma was performed in vitro, in a 'mini-Kill' dialyser as well as in dialysis bags. A marked shortening of the thrombin-clotting time was observed, indicating fall in heparin anticoagulant effect. The concentration of heparin, however, as measured by polybrene titration, was substantially less reduced. Fibrin formation, as evidenced by the ethanol gelation test, occurred more often in the dialysed than in the control plasma. In conclusion, the discrepancy between concentration and anticoagulant effect of heparin could be partly explained by influx from the dialysate of calcium, magnesium, and acetate ions. The fibrin-polymerizing effect of these ions was confirmed by a shortening of the clotting time with Reptilase, a proteolytic enzyme not influenced by thrombin inhibitors such as heparin. In addition, liberation of platelet factor 4 may be responsible for some reduction in antithrombin activity of heparin. No evidence of heparin being dialysed or adhering to the dialysis membrane was found.

Acetates↗
PubMed2003

Defibrinogenation therapy for idiopathic sudden sensorineural hearing loss in comparison with high-dose steroid therapy.

OBJECTIVE: The efficacy of defibrinogenation therapy for idiopathic sudden sensorineural hearing loss was studied in comparison with high-dose steroid therapy. MATERIAL AND METHODS: Eighty-eight consecutive patients with hearing levels > 40 dB and who had suffered hearing loss for < or = 30 days were enrolled: 40 patients for high-dose steroid therapy (PSL group) and 48 for defibrinogenation therapy (BX group). Hearing recovery was evaluated by grade assessment and by the improvement in hearing compared to the unaffected contralateral ear. RESULTS: The overall hearing outcomes of the two groups were roughly equivalent. However, with regard to patients with initial hearing levels < 80 dB, the hearing improvement rate of the BX group was significantly worse than that of the PSL group (61.2% +/- 7.3% vs 88.7% +/- 8.9%; p < 0.05), whereas in patients with initial hearing levels > or = 80 dB, the hearing outcomes did not differ between the 2 groups. Three patients in the PSL group manifested hyperglycemia while no serious side-effects were observed in the BX group. CONCLUSION: These results indicate that high-dose steroid therapy should be employed in preference to defibrinogenation therapy for patients with moderate hearing loss, whereas defibrinogenation therapy has an advantage for those with severe hearing loss, in view of its lower frequency of side-effects.

Administration, Oral↗
PubMed2002

Acute renal failure after thrombotic agent therapy due to excessive bleeding after cosmetic liposuction.

Suction lipoplasty is practiced popularly for obesity control and cosmetic purposes and severe complications are rare. We report the first documented case of acute renal failure, with anuric period, that developed after excessive bleeding following cosmetic liposuction. The use of homocoagulase and the presence of rhabdomyolysis might have contributed to the acute renal failure and disseminated intravascular coagulation observed in this case.

Acute Kidney Injury↗
PubMed1979

Detection of fibrin monomer. Comparison of the immune precipitate method with the serial-dilution protamine sulfate test and the ethanol gel test.

In a previous publication, a method for measuring fibrin monomer in plasma with the use of an immune precipitate of fibrinogen was described. The method was found to be more sensitive to unstabilized fibrin monomer than the serial-dilution protamine sulfate test, or the ethanol gel test, and detected fibrin in a mixture of the plasmin digestion products of fibrin. In the present study the sensitivity of the immune precipitate method for detecting specific plasmin digestion products of fibrin X, Y, D, and E, its sensitivity for stabilized fibrin monomer complexes, and its sensitivity for fibrin retaining B-peptide were measured and compared with the corresponding sensitivities of the serial-dilution protamine sulfate test and the ethanol gel test for detecting these same products. The immune precipitate method was found to be highly sensitive to stabilized fibrin monomer complexes and to fibrin retaining B-peptide; to be significantly less sensitive to the plasmin digestion fragments X, Y, and E; and to be insensitive to fragment D. The serial-dilution protamine sulfate test and the ethanol gel test were found to be insensitive to all of the plasmin digestion products of fibrin and less sensitive to the other fibrin complexes.

Batroxobin↗
PubMed1986

Prevalence and clinical implications of heparin-associated false positive tests for serum fibrin(ogen) degradation products.

An electrophoretic method has been applied to characterize specific fibrinogen and fibrin degradation products (FDP) in 135 serum samples from 59 consecutive patients having a positive latex agglutination test for serum FDP in the evaluation of consumption coagulopathy. In 20 of 135 positive samples, the principal fibrinogen derivatives present were not degradation products of fibrinogen or fibrin but were instead residual fibrinogen or fibrin monomer and polymers (FFMP) due to incomplete clotting. Heparin exposure was common in patients with positive FDP tests occurring in 29 of 59 patients (49%) with 81 of 135 samples (60%). Heparin exposure by parenteral administration or catheter was significantly correlated with a false positive serum FDP test because of residual FFMP occurring in 19 of 81 (23%) samples from heparin-exposed patients but in only 1 of 54 (2%) samples from patients without exposure (P less than 0.005). Treatment of the false positive samples with reptilase, an enzyme unaffected by heparin, resulted in complete removal of the residual FFMP, and in vitro experiments demonstrated that heparin-containing plasma samples could be completely clotted with either reptilase or protamine sulfate plus thrombin. Survey of 20 regional laboratories showed that only 10% used reptilase or protamine sulfate to prepare serum if heparin exposure had occurred and that this was done in only 22 of 5,049 (0.4%) of samples in the last calendar year. Greater attention should be given to proper preparation of serum from heparin-exposed patients, and physicians should be aware of the possibility of falsely positive or falsely elevated serum FDP tests in evaluation of consumption coagulopathy in heparin-exposed patients.

Batroxobin↗
PubMed1984

Prolongation of thrombin and reptilase times in patients with amyloidosis and acquired factor X deficiency.

A patient with acquired factor X deficiency due to amyloidosis had a prolonged thrombin time. Investigation of this abnormality suggested that an inhibitor of thrombin was present. A review of the literature demonstrated that prolonged thrombin time or reptilase time was present in many of the patients with acquired factor X deficiency due to amyloidosis. We were unable to relate prolongation of the thrombin time or reptilase time to the severity of bleeding. We believe that determination of thrombin and reptilase times should be part of the coagulation profile in all patients with acquired factor X deficiency.

Aged↗