Neutralization of hemostatic disorders induced by Lachesis muta venom using Brazilian antivenoms

The Animal Models for Hemorrhage and Thrombosis in the Neonate

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651075 ◽

1987 ◽

Vol 57 (01) ◽

pp. 118-122 ◽

Cited By ~ 3

Author(s):

C Thomas Kisker

Keyword(s):

Animal Models ◽

Normal Development ◽

Relevant Information ◽

Relevant Model ◽

Current Information ◽

Single Animal ◽

Hemostatic Disorders ◽

Thrombotic Diseases

SummaryAnimal models have added significantly to our understanding of adult hemorrhagic and thrombotic diseases. Few models, however, have been developed for studies of the hemostatic disorders in the fetus and newborn. This report reviews the current information on animal models of fetal and neonatal hemostasis. The requirements of a relevant model are addressed and previous studies using fetal and neonatal animal models are reviewed. A recommendation of a single animal for all studies of fetal and neonatal hemostasis is not possible. However, the lamb has been the most frequently studied and appears to provide relevant information regarding normal development and the factors which may adversely influence hemostasis in the fetus and newborn.

Download Full-text

Impairment of Platelet Aggregation by Echis colorata Venom Mediated by L-Amino Acid Oxidase or H2O2

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657280 ◽

1982 ◽

Vol 48 (03) ◽

pp. 277-282 ◽

Cited By ~ 22

Author(s):

I Nathan ◽

A Dvilansky ◽

T Yirmiyahu ◽

M Aharon ◽

A Livne

Keyword(s):

Hydrogen Peroxide ◽

Amino Acid ◽

Platelet Aggregation ◽

Snake Venom ◽

Oxidase Activity ◽

Enzyme Preparation ◽

Acid Oxidase ◽

Crude Venom ◽

Amino Acid Oxidase ◽

Hemostatic Disorders

SummaryEchis colorata bites cause impairment of platelet aggregation and hemostatic disorders. The mechanism by which the snake venom inhibits platelet aggregation was studied. Upon fractionation, aggregation impairment activity and L-amino acid oxidase activity were similarly separated from the crude venom, unlike other venom enzymes. Preparations of L-amino acid oxidase from E.colorata and from Crotalus adamanteus replaced effectively the crude E.colorata venom in impairment of platelet aggregation. Furthermore, different treatments known to inhibit L-amino acid oxidase reduced in parallel the oxidase activity and the impairment potency of both the venom and the enzyme preparation. H2O2 mimicked characteristically the impairment effects of L-amino acid oxidase and the venom. Catalase completely abolished the impairment effects of the enzyme and the venom. It is concluded that hydrogen peroxide formed by the venom L-amino acid oxidase plays a role in affecting platelet aggregation and thus could contribute to the extended bleeding typical to persons bitten by E.colorata.

Download Full-text

Mechanism of Inhibitory Action on Platelet Activation of a Phospholipase A2 Isolated from Lachesis muta (Bushmaster) Snake Venom

Thrombosis and Haemostasis ◽

10.1055/s-0038-1665414 ◽

1997 ◽

Vol 78 (05) ◽

pp. 1372-1380 ◽

Cited By ~ 56

Author(s):

André L Fuly ◽

Olga L T Machado ◽

Elias W Alves ◽

Célia R Carlinis

Keyword(s):

Platelet Aggregation ◽

Enzymatic Activity ◽

Phospholipase A2 ◽

Inhibitory Activity ◽

Thermal Inactivation ◽

Anticoagulant Activity ◽

Gel Filtration ◽

Apparent Molecular Weight ◽

Crude Venom ◽

Lachesis Muta

SummaryCrude venom from Lachesis muta exhibited procoagulant, proteolytic and phospholipase A2 activities. A phospholipase A2, denoted LM-PLA2 was purified from L. muta venom to homogeneity, through a combination of chromatographic steps involving gel-filtration on Sephacryl S-200 HR and reverse phase chromatography on a C2/C18 column. LM-PLA2 presented a single polypeptide chain with an isoelectric point at pH 4.7 and apparent molecular weight of 17 kDa. Partial aminoacid sequence indicated a high degree of homology for LM-PLA2 with other PLA2 from different sources.LM-PLA2 displayed a potent enzymatic activity as measured by indirect hemolysis of red blood cells but it was neither lethal when injected i.p. into mice nor did it present anticoagulant activity. Furthermore, LM-PLA2 displayed a moderate inhibitory activity on the aggregation of rabbit platelets induced by low levels of ADP, thrombin and arachidonate. In contrast, platelet aggregation induced by high doses of collagen was strongly inhibited by LM-PLA2 as well as ATP-release. Treatment of the protein with p-bromophenacyl bromide or 2-mercapto-ethanol, as well as thermal inactivation studies, suggested that the platelet inhibitory effect of LM-PLA2 is dependent on its enzymatic activity. Thus, the platelet inhibitory activity of LM-PLA2 was shown to be dependent on the hydrolysis of plasma phospholipids and/or lipoproteins, most probably those rich in phosphatidylcholine. Surprisingly, lyso-phosphatidylcholine released by LM-PLA2 from plasma was shown to preferentially inhibited collagen-induced platelet aggregation, in contrast to other PLA2s, whose plasma hydrolytic products indistinctly affect platelet’s response to several agonists.

Download Full-text

Personalized Approaches to the Treatment of Hemostatic Disorders

Seminars in Thrombosis and Hemostasis ◽

10.1055/s-0041-1723800 ◽

2021 ◽

Vol 47 (02) ◽

pp. 117-119

Author(s):

Roger J.S. Preston ◽

Jamie M. O'Sullivan

Keyword(s):

Hemostatic Disorders

Download Full-text

Protective action of N-acetyl-L-cysteine associated with a polyvalent antivenom on the envenomation induced by Lachesis muta muta (South American bushmaster) in rats

Toxicon ◽

10.1016/j.toxicon.2021.04.018 ◽

2021 ◽

Vol 198 ◽

pp. 36-47

Author(s):

Aline G. Leão-Torres ◽

Carina V. Pires ◽

Amanda C. Ribelato ◽

Maria C. Zerbinatti ◽

Cecília L. Santarém ◽

...

Keyword(s):

Protective Action ◽

South American ◽

Lachesis Muta

Download Full-text

Small Angle X-ray Scattering, Molecular Modeling, and Chemometric Studies from a Thrombin-Like (Lmr-47) Enzyme of Lachesis m. rhombeata Venom

Molecules ◽

10.3390/molecules26133930 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3930

Author(s):

Salvatore Giovanni De-Simone ◽

Guilherme Curty Lechuga ◽

Paloma Napoleão-Pêgo ◽

Larissa Rodrigues Gomes ◽

David William Provance ◽

...

Keyword(s):

Molecular Modeling ◽

3D Structure ◽

Ph Variation ◽

Critical Elements ◽

X Ray Scattering ◽

Plot Analysis ◽

Competitive Inhibitors ◽

Resolution Model ◽

Lachesis Muta ◽

Lachesis Muta Rhombeata

Introduction: Snakebite envenomation is considered a neglected tropical disease, and SVTLEs critical elements are involved in serious coagulopathies that occur on envenoming. Although some enzymes of this group have been structurally investigated, it is essential to characterize other proteins to better understand their unique properties such as the Lachesis muta rhombeata 47 kDa (Lmr-47) venom serine protease. Methods: The structure of Lmr-47 was studied in solution, using SAXS, DLS, CD, and in silico by homology modeling. Molecular docking experiments simulated 21 competitive inhibitors. Results: At pH 8.0, Lmr-47 has an Rg of 34.5 ± 0.6 Å, Dmax of 130 Å, and SR of 50 Å, according to DLS data. Kratky plot analysis indicates a rigid shape at pH 8.0. Conversely, the pH variation does not change the center of mass’s intrinsic fluorescence, possibly indicating the absence of fluorescent amino acids in the regions affected by pH variation. CD experiments show a substantially random coiled secondary structure not affected by pH. The low-resolution model of Lmr-47 presented a prolate elongated shape at pH 8.0. Using the 3D structure obtained by molecular modeling, docking experiments identified five good and three suitable competitive inhibitors. Conclusion: Together, our work provided insights into the structure of the Lmr-47 and identified inhibitors that may enhance our understanding of thrombin-like family proteins.

Download Full-text

A novel coagulation inhibitor fromSchistosoma japonicum

Parasitology ◽

10.1017/s0031182015001328 ◽

2015 ◽

Vol 142 (14) ◽

pp. 1663-1672 ◽

Cited By ~ 12

Author(s):

SHIWANTHI L. RANASINGHE ◽

KATJA FISCHER ◽

GEOFFREY N. GOBERT ◽

DONALD P. MCMANUS

Keyword(s):

Human Blood ◽

Neutrophil Elastase ◽

Molecular Mechanisms ◽

Genomic Sequence ◽

Proteolytic Enzymes ◽

Venous Blood ◽

Coagulation Factors ◽

Intestinal Wall ◽

Hemostatic Disorders

SUMMARYLittle is known about the molecular mechanisms whereby the human blood flukeSchistosoma japonicumis able to survive in the host venous blood system. Protease inhibitors are likely released by the parasite enabling it to avoid attack by host proteolytic enzymes and coagulation factors. Interrogation of theS. japonicumgenomic sequence identified a gene,SjKI-1, homologous to that encoding a single domain Kunitz protein (Sjp_0020270) which we expressed in recombinant form inEscherichia coliand purified.SjKI-1is highly transcribed in adult worms and eggs but its expression was very low in cercariae and schistosomula.In situimmunolocalization with anti-SjKI-1 rabbit antibodies showed the protein was present in eggs trapped in the infected mouse intestinal wall. In functional assays, SjKI-1 inhibited trypsin in the picomolar range and chymotrypsin, neutrophil elastase, FXa and plasma kallikrein in the nanomolar range. Furthermore, SjKI-1, at a concentration of 7·5µm, prolonged 2-fold activated partial thromboplastin time of human blood coagulation. We also demonstrate that SjKI-1 has the ability to bind Ca++. We present, therefore, characterization of the first Kunitz protein fromS. japonicumwhich we show has an anti-coagulant properties. In addition, its inhibition of neutrophil elastase indicates SjKI-1 have an anti-inflammatory role. Having anti-thrombotic properties, SjKI-1 may point the way towards novel treatment for hemostatic disorders.

Download Full-text

Hemostatic Disorders and Platelet Nucleotide Release in Myeloproliferative Disease

10.1055/s-0039-1684370 ◽

1979 ◽

Author(s):

A.B. Hagedorn ◽

E.J.W. Bowie ◽

C.A. Owen

Keyword(s):

Platelet Aggregation ◽

Postoperative Bleeding ◽

Myeloproliferative Disorders ◽

Myeloproliferative Disease ◽

Myeloid Metaplasia ◽

Normal Platelet ◽

Agnogenic Myeloid Metaplasia ◽

Nucleotide Release ◽

The One ◽

Hemostatic Disorders

Since patients with myeloproliferative disorders may have bleeding tendencies, the surgeon, in particular, is anxious for an hemostatic evaluation if splenectomy is contemplated. It is known that platelet aggregation, particularly with epinephrine, tends to be reduced in these patients. The nucleotide content of their platelets may be deficient. Furthermore, megakaryocytic fine structure is often abnormal. We have studied, In detail, 9 patients with hemostatic disorders. Diagnoses included polycythemia vera, agnogenic myeloid metaplasia, evolving myeloproliferative disease and erythroleukemia. Ages ranged from 36 to 75 years. Bleeding tendencies, including bruising, operative or postoperative bleeding, melena, hematuria, and hemarthrosis, characterized 8 of the 9 patients; the one exception had normal platelet ADP and elevated ATP. All had abnormal platelet aggregation, but the extent of the abnormality could not be related to the ADP and ATP contents of the platelet.ADP (normal 26.7 ± 6.5 nmol/109 platelets) was reduced in 7. ATP (normal 38.6 ± 7.6 nmol/109 platelets) was reduced in 1, elevated in 2 and normal in the other 6. In no patient were both values normal. Nucleotide release induced by collagen activation was measured in 6 of the patients. In all 6 it was deficient whether platelet ADP were normal (1 case) or depressed (5) and whether platelet ADP were elevated (1) or decreased (3).

Download Full-text