The Hemostatic Effect of Bovine Peptide-B from Fibrinogen

1974 ◽  
Vol 32 (01) ◽  
pp. 149-156
Author(s):  
A. J OSBAHR
Keyword(s):  
Smooth Muscle ◽  
Bleeding Time ◽  
Hemostatic Agent ◽  
Coagulation Time ◽  
Prolonged Incubation ◽  
Hemostatic Effect ◽  
Muscle Receptor ◽  
Rat Tail

SummaryBovine peptide-B from fibrinogen was active in the hemostasis of rat tail arterioles. The time of bleeding exhibits an inverse log proportionality to the concentration of bovine peptide-B. The peptide produced a 10-fold decrease in the time of bleeding at the highest concentration tested. Prolonged incubation of the peptide with the system was unnecessary and it appeared to participate immediately as a hemostatic agent.These findings suggest that hemostasis was due to vasoconstriction since coagulation time remained constant as the bleeding time decreased with increasing concentration of peptide-B. Bovine peptide-B is interpreted as a physiological substance which probably acts on some smooth muscle receptor.

Improved hemostasis with superactive analogs of factor VIIa in a mouse model of hemophilia A

Blood ◽  
2003 ◽  
Vol 102 (10) ◽  
pp. 3615-3620 ◽  
Author(s):  
Mikael Tranholm ◽  
Kim Kristensen ◽  
Annemarie T. Kristensen ◽  
Charles Pyke ◽  
Rasmus Røjkjær ◽  
...  
Keyword(s):  
Blood Loss ◽  
Bleeding Time ◽  
Hemophilia A ◽  
Recombinant Factor Viia ◽  
Factor Viia ◽  
Intrinsic Activity ◽  
Hemostatic Effect ◽  
Therapeutic Doses ◽  
Hemostatic Effects

AbstractIt is currently debated whether the mechanism of action of therapeutic doses of recombinant factor VIIa (rFVIIa, Novo-Seven) relies on the tissue factor (TF)-independent activity of the enzyme. The present study was conducted to investigate the in vivo hemostatic effects of rFVIIa and 3 analogs thereof with superior intrinsic activity (FVIIaIIa, K337A-FVIIaIia, and M298Q-FVIIa) in mice with antibody-induced hemophilia A. A highly significant dose response was observed for the bleeding time and blood loss for each of the rFVIIa variants. The bleeding time and blood loss were normalized after administration of 10 mg/kg rFVIIa, 3 mg/kg K337A-FVIIaIia, and 3 mg/kg M298Q-FVIIa, indicating a potency of these FVIIa analogs 3-4 times above that of rFVIIa in FVIII-depleted mice. The different in vivo potencies of the various forms of FVIIa could not be explained by the pharmacokinetics. Histopathological evaluation of kidneys revealed no signs of treatment-related pathological changes even after treatment with the superactive variants. The fact that FVIIa analogs with enhanced intrinsic activity are more efficacious in the murine hemophilia A model strongly suggests that the TF-independent procoagulant activity of FVIIa contributes to its clinical hemostatic effect. (Blood. 2003; 102:3615-3620)

scholarly journals HAEMOSTATIC EFFECT OF ETHANOLIC EXTRACT OF Ageratum conyzoides L TO STRAINS OF MICE MALE SWISS WEBSTER INDUCED WITH COMBINATION OF ASPIRIN, CLOPIDOGREL AND ENOXAPARIN

2017 ◽  
Vol 10 (7) ◽  
pp. 276
Author(s):  
Yedy Purwandi Sukmawan ◽  
Hendy Suhendy
Keyword(s):  
Bleeding Time ◽  
Ethanolic Extract ◽  
Bleeding Complications ◽  
Negative Group ◽  
Clotting Time ◽  
Ageratum Conyzoides ◽  
Coronary Syndrome ◽  
Hemostatic Effect ◽  
Significant Difference ◽  
Life Threatening

Objective: Bleeding complications are a common concern with the use of combination of antiagregations and anticoagulant agents especially on acute coronary syndrome treatment. In selected situations such as life-threatening, reversing may be desired, but no specific antidotum for the newer agents such as enoxaparin, fondaparinux, levirudin, bivalirudin, and argatroban. Ageratum conyzoides L is a medicinal plants that have a hemostatic effect. The objective of the study is to know the hemostatic effect of A. conyzoides L to induction of acetosal, clopidogrel, and enoxaparin.Methods: A total of 20 mice are divided into five groups that are normal, negative, positive, Test I and II. There were no treatment for normal, induction of drugs combination for negative, induction of drugs combination and tranexamic acid for positive, induction of drugs combination and ethanolic extract of A. conyzoides L (100 mg/Kg BW) for Test I, induction of drugs combination and ethanolic extract of A. conyzoides L (250 mg/Kg BW) for Test II.Results: The Test Groups I and II showed reversing of clotting time to normal baseline and shown a significant difference (p<0.05) compared with the negative group. In addition, the Test Groups I and II showed significant difference (p<0.05) of bleeding time compared with the negative group and the Test II (250 mg/Kg BW) shown reversing of bleeding time to normal baseline.Conclusion: The hemostatic effect showed by ethanolic extract of A. conyzoides L to induction of combination acetosal, clopidogrel and enoxaparin are very valuable for reversing agent novel.

Two types of calcium channels in isolated smooth muscle cells from rat tail artery

1989 ◽  
Vol 256 (5) ◽  
pp. H1361-H1368 ◽  
Author(s):  
R. Wang ◽  
E. Karpinski ◽  
P. K. Pang
Keyword(s):  
Smooth Muscle ◽  
Steady State ◽  
Calcium Channels ◽  
Rat Tail Artery ◽  
Inward Current ◽  
Tail Artery ◽  
Channel Current ◽  
Steady State Inactivation ◽  
Channel Currents ◽  
Rat Tail

Whole cell patch-clamp recordings were carried out on smooth muscle cells from rat tail artery in short-term culture to verify the existence of and to characterize the calcium channels that are present. Two types of voltage-dependent calcium channels were identified in 55 of 63 cells studied. The T-type calcium channel was activated at -50 mV, and the peak inward current occurred at -10 mV, whereas the L-type channel was activated at -20 mV, and the peak inward current occurred at +10 or +20 mV. The T-type channel current inactivated quickly in contrast to the much slower inactivation of the L-channel current. The voltage dependence of steady-state inactivation of the two channels was similar to that reported for other vascular smooth muscle preparations. An internal solution containing Cs2-aspartate maintained the calcium-channel currents for at least 20 min with only a 5-10% decline. BAY K 8644 had no effect on T-channel currents, but the L-channel current was increased by at least a factor of two. In addition, BAY K 8644 shifted the activation threshold, the peak inward current, and the steady-state inactivation-activation curves of L-type channel currents in the direction of hyperpolarization.

o-Raffinose cross-linked hemoglobin improves the hemostatic defect associated with anemia and thrombocytopenia in rabbits

Blood ◽  
2000 ◽  
Vol 96 (10) ◽  
pp. 3630-3636 ◽  
Author(s):  
David H. Lee ◽  
Leslie Bardossy ◽  
Nichole Peterson ◽  
Morris A. Blajchman
Keyword(s):  
Blood Loss ◽  
Bleeding Time ◽  
Platelet Reactivity ◽  
Inhibitory Effect ◽  
Clinical Settings ◽  
No Donor ◽  
Hemostatic Effect ◽  
Circulating Levels

Abstract Several different preparations of cross-linked hemoglobin (CLHb) are being evaluated for their efficacy and safety as red cell substitutes in a variety of preclinical and clinical settings. Because CLHb is known to sequester nitric oxide (NO) and inhibit NO-mediated processes, we hypothesized that CLHb would have a hemostatic effect by enhancing platelet reactivity, inducing vasoconstriction, or both. Infusion of o-raffinose CLHb shortened the prolonged microvascular bleeding time and decreased blood loss from ear incisions in rabbits rendered anemic and thrombocytopenic. Moreover, this hemostatic effect persisted for at least 24 hours after infusion. Phenylephrine induced a degree of vasoconstriction similar to that induced by CLHb but did not shorten the bleeding time or decrease blood loss, suggesting that vasoconstriction alone cannot account for the hemostatic effect of CLHb. There was no evidence of CLHb-induced activation of coagulation in vivo, since infusion of CLHb did not increase circulating levels of thrombin-antithrombin complex. In vitro, CLHb abolished the inhibitory effect of the NO donor 3-morpholinosydnonimine on platelet aggregation and enhanced the aggregation of stimulated but not resting platelets. This potentiating effect was not attenuated by the addition of superoxide dismutase or catalase. To evaluate the potential arterial thrombogenicity of CLHb, a model of carotid artery thrombosis was developed in rabbits without thrombocytopenia or anemia. Compared with albumin infusion, CLHb infusion shortened the time to complete carotid occlusion. These data suggest that CLHb may shift the thromboregulatory balance toward clot formation, resulting in decreased bleeding in anemic and thrombocytopenic rabbits and possibly increasing arterial thrombogenicity in normal rabbits.

Regulation of prostacyclin production by [Ca2+]i and protein kinase C in aortic smooth muscle cells

1992 ◽  
Vol 263 (4) ◽  
pp. E800-E806
Author(s):  
A. C. Erbrich ◽  
D. J. Church ◽  
M. B. Vallotton ◽  
U. Lang
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Prolonged Incubation ◽  
Aortic Smooth Muscle Cells ◽  
Aortic Smooth Muscle ◽  
Kinase C ◽  
Prostacyclin Production

The respective roles of protein kinase C (PKC) and of cytosolic free Ca2+ concentration ([Ca2+]i) in prostacyclin synthesis were investigated in aortic smooth muscle cells by using A23187 and phorbol 12-myristate 13-acetate (PMA) to bypass the hormonal receptor. Exposure of the cells to A23187 markedly increased prostacyclin production, which was not affected by the PKC inhibitor staurosporine or by PKC depletion after prolonged incubation (48 h) of cells with PMA. The increase in [Ca2+]i induced by A23187 did not affect membranous or cytosolic PKC activity in control and PMA-stimulated cells. Activation of PKC by PMA, a weak stimulant of prostacyclin production by itself, strongly potentiated A23187-induced prostacyclin production, as well as that induced by the calcium-mobilizing hormone arginine vasopressin (AVP). The potentiating effect persisted for 30 min after the removal of PMA. However, this "memory" effect was not due to sustained levels of membranous PKC activity but probably to the prolonged influence of PKC-induced phosphorylation(s). Taken together, our results suggest that, although an increase in [Ca2+]i is sufficient for inducing prostacyclin production in rat aortic smooth muscle cells, activation of PKC is necessary for AVP-induced prostacyclin production in this same tissue.

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