Bibliografie tematiche / Heparin

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Letteratura scientifica selezionata sul tema "Heparin"

Autore: Grafiati
Pubblicato: 4 giugno 2021
Ultima modifica: 30 luglio 2024

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Articoli di riviste sul tema "Heparin"

1

Zvibel, I., E. Halay e L. M. Reid. "Heparin and hormonal regulation of mRNA synthesis and abundance of autocrine growth factors: relevance to clonal growth of tumors". Molecular and Cellular Biology 11, n. 1 (gennaio 1991): 108–16. http://dx.doi.org/10.1128/mcb.11.1.108-116.1991.

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Abstract (sommario):
Highly sulfated, heparinlike species of heparan sulfate proteoglycans, with heparinlike glycosaminoglycan chains, are extracellular matrix components that are plasma membrane bound in growth-arrested liver cells. Heparins were found to inhibit the growth and lower the clonal growth efficiency of HepG2, a minimally deviant, human hepatoma cell line. Heparan sulfates, closely related glycosaminoglycans present in the extracellular matrix around growing liver cells, had no effect on the growth rate or clonal growth efficiency of HepG2 cells. Neither heparins nor heparan sulfates had any effect on the growth rate or clonal growth efficiency of two poorly differentiated, highly metastatic hepatoma cell lines, SK-Hep-1 and PLC/PRF/5. Heparin's inhibition of growth of HepG2 cells correlated with changes in the mRNA synthesis and abundance of insulinlike growth factor II (IGF II) and transforming growth factor beta (TGF beta). HepG2 cells expressed high basal levels of mRNAs encoding IGF II and TGF beta that were inducible, through transcriptional and posttranscriptional mechanisms, to higher levels by specific heparin-hormone combinations. For both IGF II and TGF beta, the regulation was multifactorial. Transcriptionally, IGF II was regulated by the additive effects of insulin, glucagon, and growth hormone in combination with heparin; TGF beta was regulated primarily by the synergistic effects of insulin and growth hormone in combination with heparin. Posttranscriptionally, the mRNA abundance of the IGF II 4.5- and 3.7-kb transcripts was affected by insulin. Heparin induction of all IGF II transcripts was also dependent on triiodotyronine and prolactin, but it is unknown whether their induction by heparin was via transcriptional or posttranscriptional mechanisms. Heparin-insulin combinations regulated TGF beta posttranscriptionally. The poorly differentiated hepatoma cell lines PLC/PRF/5 and SK-Hep-1 either did not express or constitutively expressed low basal levels of IGF I, IGF II, and TGF beta, whose mRNA synthesis and abundance showed no response to any heparin-hormone combination. We discuss the data as evidence that matrix chemistry is a variable determining the expression of autocrine growth factor genes and the biological responses to them.
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2

Zvibel, I., E. Halay e L. M. Reid. "Heparin and hormonal regulation of mRNA synthesis and abundance of autocrine growth factors: relevance to clonal growth of tumors." Molecular and Cellular Biology 11, n. 1 (gennaio 1991): 108–16. http://dx.doi.org/10.1128/mcb.11.1.108.

Testo completo
Abstract (sommario):
Highly sulfated, heparinlike species of heparan sulfate proteoglycans, with heparinlike glycosaminoglycan chains, are extracellular matrix components that are plasma membrane bound in growth-arrested liver cells. Heparins were found to inhibit the growth and lower the clonal growth efficiency of HepG2, a minimally deviant, human hepatoma cell line. Heparan sulfates, closely related glycosaminoglycans present in the extracellular matrix around growing liver cells, had no effect on the growth rate or clonal growth efficiency of HepG2 cells. Neither heparins nor heparan sulfates had any effect on the growth rate or clonal growth efficiency of two poorly differentiated, highly metastatic hepatoma cell lines, SK-Hep-1 and PLC/PRF/5. Heparin's inhibition of growth of HepG2 cells correlated with changes in the mRNA synthesis and abundance of insulinlike growth factor II (IGF II) and transforming growth factor beta (TGF beta). HepG2 cells expressed high basal levels of mRNAs encoding IGF II and TGF beta that were inducible, through transcriptional and posttranscriptional mechanisms, to higher levels by specific heparin-hormone combinations. For both IGF II and TGF beta, the regulation was multifactorial. Transcriptionally, IGF II was regulated by the additive effects of insulin, glucagon, and growth hormone in combination with heparin; TGF beta was regulated primarily by the synergistic effects of insulin and growth hormone in combination with heparin. Posttranscriptionally, the mRNA abundance of the IGF II 4.5- and 3.7-kb transcripts was affected by insulin. Heparin induction of all IGF II transcripts was also dependent on triiodotyronine and prolactin, but it is unknown whether their induction by heparin was via transcriptional or posttranscriptional mechanisms. Heparin-insulin combinations regulated TGF beta posttranscriptionally. The poorly differentiated hepatoma cell lines PLC/PRF/5 and SK-Hep-1 either did not express or constitutively expressed low basal levels of IGF I, IGF II, and TGF beta, whose mRNA synthesis and abundance showed no response to any heparin-hormone combination. We discuss the data as evidence that matrix chemistry is a variable determining the expression of autocrine growth factor genes and the biological responses to them.
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3

Bar-Ner, M., A. Eldor, L. Wasserman, Y. Matzner, IR Cohen, Z. Fuks e I. Vlodavsky. "Inhibition of heparanase-mediated degradation of extracellular matrix heparan sulfate by non-anticoagulant heparin species". Blood 70, n. 2 (1 agosto 1987): 551–57. http://dx.doi.org/10.1182/blood.v70.2.551.551.

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Abstract (sommario):
Abstract Incubation of human platelets, human neutrophils, or highly metastatic mouse lymphoma cells with sulfate-labeled extracellular matrix (ECM) results in heparanase-mediated release of labeled heparan sulfate cleavage fragments (0.5 less than Kav less than 0.85 on Sepharose 6B). This degradation was inhibited by native heparin both when brought about by intact cells or their released heparanase activity. Degradation of heparan sulfate in ECM may facilitate invasion of normal and malignant cells through basement membranes. The present study tested the heparanase inhibitory effect of nonanticoagulant species of heparin that might be of potential use in preventing heparanase mediated extravasation of bloodborne cells. For this purpose, we prepared various species of low-sulfated or low-mol-wt heparins, all of which exhibited less than 7% of the anticoagulant activity of native heparin. N-sulfate groups of heparin are necessary for its heparanase inhibitory activity but can be substituted by an acetyl group provided that the O-sulfate groups are retained. O-sulfate groups could be removed provided that the N positions were resulfated. Total desulfation of heparin abolished its heparanase inhibitory activity. Heparan sulfate was a 25-fold less potent heparanase inhibitor than native heparin. Efficiency of low-mol-wt heparins to inhibit degradation of heparan sulfate in ECM decreased with their main molecular size, and a synthetic pentasaccharide, representing the binding site to antithrombin III, was devoid of inhibitory activity. Similar results were obtained with heparanase activities released from platelets, neutrophils, and lymphoma cells. We propose that heparanase inhibiting nonanticoagulant heparins may interfere with dissemination of bloodborne tumor cells and development of experimental autoimmune diseases.
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4

Bar-Ner, M., A. Eldor, L. Wasserman, Y. Matzner, IR Cohen, Z. Fuks e I. Vlodavsky. "Inhibition of heparanase-mediated degradation of extracellular matrix heparan sulfate by non-anticoagulant heparin species". Blood 70, n. 2 (1 agosto 1987): 551–57. http://dx.doi.org/10.1182/blood.v70.2.551.bloodjournal702551.

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Abstract (sommario):
Incubation of human platelets, human neutrophils, or highly metastatic mouse lymphoma cells with sulfate-labeled extracellular matrix (ECM) results in heparanase-mediated release of labeled heparan sulfate cleavage fragments (0.5 less than Kav less than 0.85 on Sepharose 6B). This degradation was inhibited by native heparin both when brought about by intact cells or their released heparanase activity. Degradation of heparan sulfate in ECM may facilitate invasion of normal and malignant cells through basement membranes. The present study tested the heparanase inhibitory effect of nonanticoagulant species of heparin that might be of potential use in preventing heparanase mediated extravasation of bloodborne cells. For this purpose, we prepared various species of low-sulfated or low-mol-wt heparins, all of which exhibited less than 7% of the anticoagulant activity of native heparin. N-sulfate groups of heparin are necessary for its heparanase inhibitory activity but can be substituted by an acetyl group provided that the O-sulfate groups are retained. O-sulfate groups could be removed provided that the N positions were resulfated. Total desulfation of heparin abolished its heparanase inhibitory activity. Heparan sulfate was a 25-fold less potent heparanase inhibitor than native heparin. Efficiency of low-mol-wt heparins to inhibit degradation of heparan sulfate in ECM decreased with their main molecular size, and a synthetic pentasaccharide, representing the binding site to antithrombin III, was devoid of inhibitory activity. Similar results were obtained with heparanase activities released from platelets, neutrophils, and lymphoma cells. We propose that heparanase inhibiting nonanticoagulant heparins may interfere with dissemination of bloodborne tumor cells and development of experimental autoimmune diseases.
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5

Fareed, Jawed, Adrian Sonevytsky, Omer Iqbal, Walter P. Jeske, Massimo Iacobelli e Debra Hoppensteadt. "Inhibition of Heparinase I by Defibrotide with Potential Clinical Implications." Blood 108, n. 11 (16 novembre 2006): 1626. http://dx.doi.org/10.1182/blood.v108.11.1626.1626.

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Abstract (sommario):
Abstract Defibrotide represents a poly-deoxyribonucleotide derived antischemic and antithrombotic agent. Currently this agent is used for the management of transplantation associated with vascular complications. Defibrotide is a polyanionic electrolyte capable of releasing endogenous antithrombotic mediators such as (tissue factor pathway inhibitor (TFPI) and heparans. Co-administration of defibrotide with heparin has been shown to produce an augmentation of the effect of heparin and an increase in the biologic half-life. This may be due to the drug interactions or inhibition of endogenous heparin digesting enzyme by defibrotide. To test the hypothesis that defibrotide may inhibit heparin digesting enzymes such as heparinases (I–III), the effects of defibrotide were investigated on the digestion of unfractionated heparin. Unfractionated heparin was subjected to bacterial heparinase I (flavobacterion heparinicum) in an isolated biochemical systems where unfractionated heparin was used as a substrate at a fixed concentration of 750 μg/ml. Graded amounts of defibrotide in the range of 6.25–250 μg/ml were supplemented to this mixture. The degree of heparinase digestion of unfractionated heparin was determined by using high performance liquid chromatographic methods and computation of oligosaccharide profiles. Heparinase I was found to digest heparin (MW=15.2kDa) converting it to low molecular mass heparins (MW=4.1kDa). At concentrations of >125 μg/ml defibrotide produced an almost complete inhibition of heparinase I digestion. This inhibition of heparinase digestion was dependent on defibrotide concentration and the IC50 was found to be 12.5 μg/ml. These results suggest that polyelectrolytes such as defibrotide are capable of inhibiting heparin/heparan digestion enzymes. The observed potentiation of anticoagulant effect of heparin in patients treated simultaneously with defibrotide may partially be due to the inhibition of endogenous heparin digesting enzymes. Subsequent studies in primates have revealed that the anticoagulant effects of both unfractionated heparin and low-molecular mass heparins are potentiated by defibrotide as determined by AUC measurements for the circulating level of these agents. Thus, these interactions should be taken into account to optimize anticoagulant management where these drugs are used in a combination regimen.
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6

Pinhal, Maria A. S., Isabel A. N. Santos, Irani F. Silva, Carl P. Dietrich e Helena B. Nader. "Minimum Fragments of the Heparin Molecule Able to Produce the Accumulation and Change of the Sulfation Pattern of an Antithrombotic Heparan Sulfate from Endothelial Cells". Thrombosis and Haemostasis 74, n. 04 (1995): 1169–74. http://dx.doi.org/10.1055/s-0038-1649898.

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Abstract (sommario):
SummaryHeparin and low molecular weight heparins stimulate two to three fold the accumulation of an antithrombotic heparan sulfate secreted by endothelial cells in culture. This led us to search for the minimum structural requirements of the heparin molecule able to elicit the enhancement of the heparan sulfate. Fragments were prepared from heparin by degradation with bacterial heparinase and heparitinases. A heparin pentasulfated tetrasaccharide was shown to be the minimum structural sequence able to enhance two to three fold the secretion of heparan sulfate by endothelial cells. The stimulation is specific for the endothelial cell, is concentration dependent and the effect is already noticed afterone hour of exposure of the cells to heparinand the tetrasaccharide. Degradation of the [35S]-heparan sulfate synthesized in the presence of heparin or the tetrasaccharide has shown a higher degree of sulfation of its iduronic acid residues.
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7

Hovingh, P., M. Piepkorn e A. Linker. "Biological implications of the structural, antithrombin affinity and anticoagulant activity relationships among vertebrate heparins and heparan sulphates". Biochemical Journal 237, n. 2 (15 luglio 1986): 573–81. http://dx.doi.org/10.1042/bj2370573.

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Abstract (sommario):
We analysed the distribution, structural characteristics, antithrombin-III-binding properties and anticoagulant activities of heparins and heparan sulphates isolated from the tissues of a wide range of vertebrates. Heparin has a curiously limited distribution, since it was absent from lower aquatic vertebrate species, present in only certain organs such as intestine in many higher vertebrates, and completely absent from the rabbit among mammals examined. The heparins were structurally diverse, and they exhibited a broad range of anticoagulant activities, from approx. 50% to 150% of average commercial heparins. Although there was a rough correlation between the anticoagulant potency of the starting isolate and the proportional content of material exhibiting high-affinity binding to the proteinase inhibitor antithrombin III, activities of high-affinity fractions from heparins low in activity overlapped those of low-affinity fractions from highly active heparins. Heparan sulphates, which in contrast were isolated from nearly all vertebrate organs, contained high-affinity subfractions constituting up to 5% of the starting material and possessing anticoagulant potencies of 2-30 units/mg. In consideration of the heparin data, we infer that its biological function is either species-specific or may be served by other molecular elements, and that there exists considerable diversity in the antithrombin-III-binding sequence of heparin. The more-generally distributed glycosaminoglycan heparan sulphate possesses within its variable structure a small high-affinity subfraction with low anticoagulant potency, whether isolated from aorta or other tissues. Although heparan sulphate appears to have an essential function at the cellular level, we suggest that this is probably not that of providing heparin-like antithrombotic effects on vascular surfaces.
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8

Sieme, Daniel, Christian Griesinger e Nasrollah Rezaei-Ghaleh. "Metal Binding to Sodium Heparin Monitored by Quadrupolar NMR". International Journal of Molecular Sciences 23, n. 21 (29 ottobre 2022): 13185. http://dx.doi.org/10.3390/ijms232113185.

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Abstract (sommario):
Heparins and heparan sulfate polysaccharides are negatively charged glycosaminoglycans and play important roles in cell-to-matrix and cell-to-cell signaling processes. Metal ion binding to heparins alters the conformation of heparins and influences their function. Various experimental techniques have been used to investigate metal ion-heparin interactions, frequently with inconsistent results. Exploiting the quadrupolar 23Na nucleus, we herein develop a 23Na NMR-based competition assay and monitor the binding of divalent Ca2+ and Mg2+ and trivalent Al3+ metal ions to sodium heparin and the consequent release of sodium ions from heparin. The 23Na spin relaxation rates and translational diffusion coefficients are utilized to quantify the metal ion-induced release of sodium ions from heparin. In the case of the Al3+ ion, the complementary approach of 27Al quadrupolar NMR is employed as a direct probe of ion binding to heparin. Our NMR results demonstrate at least two metal ion-binding sites with different affinities on heparin, potentially undergoing dynamic exchange. For the site with lower metal ion binding affinity, the order of Ca2+ > Mg2+ > Al3+ is obtained, in which even the weakly binding Al3+ ion is capable of displacing sodium ions from heparin. Overall, the multinuclear quadrupolar NMR approach employed here can monitor and quantify metal ion binding to heparin and capture different modes of metal ion-heparin binding.
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9

Diamond, M. S., R. Alon, C. A. Parkos, M. T. Quinn e T. A. Springer. "Heparin is an adhesive ligand for the leukocyte integrin Mac-1 (CD11b/CD1)." Journal of Cell Biology 130, n. 6 (15 settembre 1995): 1473–82. http://dx.doi.org/10.1083/jcb.130.6.1473.

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Abstract (sommario):
Previous studies have demonstrated that the leukocyte integrin Mac-1 adheres to several cell surface and soluble ligands including intercellular adhesion molecule-1, fibrinogen, iC3b, and factor X. However, experiments with Mac-1-expressing transfectants, purified Mac-1, and mAbs to Mac-1 indicate the existence of additional ligands. In this paper, we demonstrate a direct interaction between Mac-1 and heparan sulfate glycans. Heparin affinity resins immunoprecipitate Mac-1, and neutrophils and transfectant cells that express Mac-1 bind to heparin and heparan sulfate, but not to other sulfated glycosaminoglycans. Inhibition studies with mAbs and chemically modified forms of heparin suggest the I domain as a recognition site on Mac-1 for heparin, and suggest that either N- or O-sulfation is sufficient for heparin to bind efficiently to Mac-1. Under conditions of continuous flow in which heparins and E-selectin are cosubstrates, neutrophils tether to E-selectin and form firm adhesions through a Mac-1-heparin interaction.
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10

Basic-Micic, M., K. Krupinski, A. Thalhammer, C. Dechent, Ch Rauschenbach e H. K. Breddin. "Beeinflußt niedermolekulares Heparin die Thrombozytenfunktion?" Hämostaseologie 09, n. 05 (settembre 1989): 248–57. http://dx.doi.org/10.1055/s-0038-1655278.

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Abstract (sommario):
ZusammenfassungFolgende Thrombozytenfunktionen wurden unter dem Einfluß von unfraktioniertem Heparin und von drei niedermolekularen Heparinen untersucht:Die Thrombozytenzahl in Zitratblut und Zitratplasma, die spontane Aggregation (PAT III), die ADPund die adrenalininduzierte Aggregation, die Thrombozytenausbreitung und die Thrombozytenhaftung an silikonisiertem Glas und an boviner subendothelialer Matrix. Die Untersuchungen erfolgten an Zitratblut bzw. Zitratplasma, aber auch an Blutproben, die mit den verschiedenen Heparinen antikoaguliert waren.Im Zitrat-PRP findet sich eine Verminderung der Thrombozytenzahl unter dem Einfluß von UFH, die durch Bildung von kleinen Aggregaten bedingt ist. Niedermolekulare Heparine zeigen diese Wirkung nicht, sie haben auch in wesentlich höheren Konzentrationen als UFH einen steigernden Effekt auf die Spontanaggregation der Thrombozyten im Zitratblut. Niedermolekulare Heparine hemmen die Plättchenausbreitung gering und die Plättchenhaftung an silikonisiertem Glas sowie an endothelialer boviner Matrix deutlich.Die »aktivierenden« Effekte von unfraktioniertem Heparin waren in mit UFH antikoagulierten Blutproben nicht mehr vorhanden. Im PRP von mit niedermolekularen Heparinen gewonnenen Blutproben war die Plättchenhaftneigung an Glas und an subendothelialer Matrix stärker gehemmt als im PRP von mit UFH antikoagulierten Blutproben. Tauschversuche zeigten ein unterschiedliches Verhalten, je nachdem, ob ein niedermolekulares Heparin zu Zitrat oder umgekehrt Zitrat zu PRP zugegeben wurde, das aus den mit niedermolekularem Heparin antikoagulierten Blutproben gewonnen wurde. Zugabe von Zitrat zu dem mit niedermolekularem Heparin antikoagulierten Blut-PRP hob die Haftungshemmung auf, während die Hemmung der adrenalininduzierten Aggregation nicht aufgehoben werden konnte.Ein Teil der Effekte von Heparin und niedermolekularen Heparinen auf die Plättchenfunktion im Zitratblut ist wahrscheinlich auf die Abwesenheit von Kalziumionen zurückzuführen. Es wird postuliert, daß für die thrombosehemmende Wirkung von Heparin, besonders aber von niedermolekularen Heparinen, eine Hemmung der Plättchenhaftneigung an Endothelzelldefekten mitverantwortlich ist.
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Più fonti

Tesi sul tema "Heparin"

1

Raghuraman, Arjun. "Designing Non-saccharide Heparin/Heparan Sulfate Mimics". Online version available 8/19/2013, 2008. http://hdl.handle.net/10156/2269.

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2

Carelli, Guareide [UNESP]. "Associação de doses baixas de heparina não fracionada e de heparina de baixo peso molecular na prevenção de trombose venosa experimental". Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/88962.

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Abstract (sommario):
Made available in DSpace on 2014-06-11T19:23:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2003Bitstream added on 2014-06-13T19:09:44Z : No. of bitstreams: 1 carelli_g_me_botfm.pdf: 357124 bytes, checksum: 5673f0ccb2732bdb65892b407c35e19c (MD5)
A heparina é um glicosaminoglicano sulfatado, de cadeia longa, que vem sendo largamente utilizada, desde meados do século passado, no tratamento e profilaxia das tromboses arteriais e venosas e cuja utilização permitiu o desenvolvimento das cirurgias cardíaca e vascular. As heparinas de baixo peso molecular (HBPM) são frações ou fragmentos da heparina separados do complexo polissacarídico por extração com solvente ou por gel filtração, ou por clivagem química ou enzimática aplicada antes dessa separação física. No presente artigo são revistos os diversos aspectos da estrutura, mecanismo de ação, farmacocinética, monitorização laboratorial e aplicações clínicas de ambos os tipos de substâncias, sendo chamada a atenção para as diferenças entre elas. As HBPM tendem a substituir a heparina não fracionada, na maior parte de suas indicações, por serem de mais simples utilização e apresentarem maior eficácia e segurança em algumas indicações, embora sejam de custo mais alto.
Heparin is a long sulfated glucosaminoglicane chain has been used in the treatment and prophylaxis of arterial and venous thombosis since the 50’s of last century. Its use also aided the development of cardiac and vascular surgery. Low molecular weight heparins (LMWH) are fractions or fragments of heparin separated from the polysaccharide complex by solvent extraction or gel filtration, or by chemical or enzymatic cleavage, before the extraction. In this article the main aspects of structure, mechanism of action, pharmacokinetics, laboratorial control, and clinical indications of both kinds of substances are reviewed and their main differences emphasized. Despite their high cost, LMWH presently tend to substitute unfractionated heparin in the majority of indications because of its simpler use, high efficacy and security in some cases.
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3

Noti, Christian. "Synthesis of heparin oligosaccharides and the creation of heparin microarrays /". Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17150.

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4

Albig, Thomas. "Synthese und Untersuchung von Heparin-Prodrugs auf Glyceridbasis /". [S.l.] : [s.n.], 1986. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=7990.

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5

Jaime, Rodríguez Juan Carlos. "Unveiling Heparin and Heparan Sulfate Conformations : a Journey into Paramagnetic NMR Analysis". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASF016.

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Abstract (sommario):
L'héparine (HP) et les héparane sulfates (HS) sont des polysaccharides sulfatés linéaires qui jouent divers rôles biologiques, notamment dans la croissance cellulaire, l'adhésion, la reconnaissance virale et la métastase du cancer. Leur variété moléculaire et leur motif de sulfatation contribuent à leur polyvalence biologique. Par ailleurs, leur flexibilité conformationnelle a été étudiée par des méthodes telles que la cristallographie aux rayons X et la RMN. Malgré des avancées, interpréter ces caractéristiques reste difficile, surtout pour de longs saccharides. Cette thèse propose l'utilisation de la RMN paramagnétique, notamment des déplacements de pseudo-contacts (PCS), dans l’étude conformationnelle des molécules d’HS. Les résultats obtenus sur un octasaccharide d'HS, montrent une corrélation entre les PCS expérimentales et les simulations de dynamique moléculaire, suggérant des conformations spécifiques des motifs IdoA. Ces découvertes élargissent les applications de la RMN paramagnétique, ouvrant la voie à une analyse approfondie des interactions protéine-polysaccharide
Heparin (HP) and heparan sulfates (HS) are linear and sulfated polysaccharides that play various biological roles, including cell growth, adhesion, viral recognition, and cancer metastasis. Their molecular diversity and sulfation pattern contribute to their biological versatility. Furthermore, their conformational flexibility has been studied through methods such as X-ray crystallography and NMR. Despite advancements, interpreting these features remains challenging, especially for long saccharides. This thesis proposes the use of paramagnetic NMR, particularly pseudo-contact shifts (PCS) measurements, in studying the conformation of HS molecules. Results obtained on an HS octasaccharide show a correlation between experimental PCS and molecular dynamics simulations, suggesting specific conformations of IdoA motifs. These findings expand the applications of paramagnetic NMR, paving the way for a thorough analysis of protein-polysaccharide interactions
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6

Nazir, Ahmad Mohamad Farha. "The role of heparin and heparin-binding growth factors in pre-eclampsia". Thesis, Middlesex University, 2016. http://eprints.mdx.ac.uk/21321/.

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The aims of this study tested the hypothesis that expression of heparin-binding growth factors (HBGFs) in normal placental development was altered in a specific pregnancy disorder preeclampsia. HBGFs bind to heparin, a glycosaminoglycan (GAG) affecting activity. I investigated the role of heparin and HBGFs in pathophysiology of pre-eclampsia. Placental tissue from a cohort study of 87 women was performed following uncomplicated pregnancy at term, but not in labour (TNL, n=26), preterm labour (PTL, n=17), following labour onset (TL, n=21), first trimester (FNL, n=4) and pre-eclampsia (PE, n=19). The HBGFs studied were vascular endothelial growth factor (VEGF), placental growth factor (PLGF), fibroblast growth factor 2 (FGF2), hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF), heparin-binding epidermal growth factor (HB-EGF), midkine (MK), pleiotrophin (PTN), and cluster differentiation (CD105). The localisation of HBGFs and receptors VEGFR-1, /(sflt-1), PLGFR-1, VEGFR-2 and FGF2R-1 in placenta were detected. The expression of VEGF, PLGF, FGF2, HGF, PDGF, CD105 was confined to villous trophoblast, endothelial cells except for MK, HB-EGF and PTN was specifically to villous trophoblast. The total RNA production in human placentae samples (n=7) from PE and controls were analysed using qRTPCR. Placental expression of mRNA was extracted for primer assays of PLGF, FGF2, MK, PTN, and endogenous housekeeping gene as Succinate dehydrogenase complex subunit A (SDHA). FGF2 and SDHA mRNA expression was significantly different using Mann-Whitney U test. An in vitro villous trophoblast invasion model was performed with human fibrosarcoma HT1080 invasive cells (positive control), mouse embryonic fibroblast NIH/3T3 non-invasive cells (negative control) and immortalised human primary villous trophoblastic cell lines TCL-1.The greatest stimulation was by FGF2, PDGF-BB, HGF, MK and co-incubation with heparin enhanced these responses, except for PTN using the Mann-Whitney U test. Heparin’s role is indicated in mediating the effects of HBGFs. It’s suggests heparin therapeutic use in the treatment of pre-eclampsia.
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7

KRISHNASAMY, CHANDRAVEL. "MOLECULAR MODELING STUDIES OF HEPARIN AND HEPARIN MIMETICS BINDING TO COAGULATION PROTEINS". VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/18.

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Heparin, a glycosaminoglycan (GAG), is a complex biopolymer of varying chain length and consisting of uronic acid and glucosamine residues, which are sulfated at various positions. The interaction of heparin with antithrombin is the basis for anticoagulation therapy. Heparin accelerates the antithrombin mediated inhibition of factor Xa and thrombin by a conformational activation mechansism and bridging mechanism, respectively. The sequence specific pentasaccharide DEFGH in full length heparin is the most important fragment for high affinity and activation of antithrombin, without which the heparin is incapable of binding to antithrombin. Although heparin is a commonly used anticoagulant, it suffers from serious side effects including bleeding complications, heparin-induced thrombocytopenia, and intra- and inter-patient dose response variability. Desai and co-workers have shown that it is possible to replace the GAG skeleton by small, non-saccharide sulfated molecules as antithrombin activators. However, the designed molecules were found to be weak activators of antithrombin due to their binding to the extended heparin-binding site (EHBS), instead of the pentasaccharide-binding site (PBS), of antithrombin. To design better non-saccharide antithrombin activators, a virtual screening-based approach was employed. Combinatorial virtual screening of 24576 molecules based on tetrahydroisoquinoline core scaffold resulted in 92 hits that were predicted to bind preferentially in the PBS of activated antithrombin with good affinity. The work resulted in a predicted pharmacophore consisting of a 5,6-disulfated bicyclic tetrahydroisoquinoline and a 2′,5′-disulfated unicyclic phenyl ring connected by a 4- to 5-carbon linker. The work has led to several hypotheses, which are being tested in the laboratory through synthesis and biochemical evaluation. To understand the mechanism of heparin binding to thrombin in greater detail, structural biology and molecular modeling approaches were used. More specifically, the nature of the heparin binding to thrombin was studied with a special focus on understanding the specificity of recognition. Comparative analysis was performed with heparin–antithrombin interaction to assess similarities and differences between the two heparin binding systems. In antithrombin, three important amino acids are involved in heparin pentasaccharide binding, while in thrombin, at least seven basic amino acids are predicted to be involved. For biological systems, one would expect greater specificity with more interacting points. However, the heparin–thrombin system interestingly displays a lack of specificity. The molecular basis for this lack of specificity is not clear. A study of antithrombin and thrombin crystal structures with regard to surface exposure, flexibility, and geometry of basic amino acids present in the respective heparin binding site provides the basis for the specificity of recognition (or lack thereof) in the two systems. Interestingly, analysis of thrombin exosite-II showed that Arg101, Arg165 and Arg233 are spatially conserved and form a local asymmetric center. Using in-silico docking techniques, selected tetrasaccharide sequences were found to specifically recognize this triad of amino acids indicating the possibility of specific recognition of thrombin. This hypothesis led to the design of a putative lead sequence that is 50% smaller in size and contains 62.5% fewer charges in comparison to the literature reported known exosite II sequence. The design of novel putative ‘specific’ exosite II sequence challenges the idea that the thrombin–heparin interaction is completely non-specific and gives rise to novel opportunities of designing specific thrombin exosite-II ligands.
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8

Sachchidanand. "Heparin binding to fibronectin". Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393457.

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Evans, Dyfed Ll. "The heparin activateable serpins". Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385390.

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Freitas, Cristiane Fonseca. "Efeitos do Bay 41-2272 na hipertensão pulmonar experimental em cães anestesiados". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/308951.

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Orientador: Edson Antunes
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
Made available in DSpace on 2018-08-09T08:05:23Z (GMT). No. of bitstreams: 1 Freitas_CristianeFonseca_D.pdf: 2119434 bytes, checksum: 58a318beb1d3946d852e010325a6187c (MD5) Previous issue date: 2007
Resumo: Neste estudo, investigamos os efeitos protetores do BAY 41-2272 sobre a hipertensao pulmonar induzida pelo complexo heparina-protamina e hipoxia em cães anestesiados. Os animais foram anestesiados com pentobarbital sodico (Hypnol, 30mg/kg, iv) combinado com citrato de fentanila (0,01 mg/kg/h, i.v.) e diazepam (0,25mg/kg/h, iv). A hipertensao pulmonar pelo complexo heparina-protamina foi induzida com a administracao de 500 UI/kg de heparina, seguida da administracao de protamina (10 mg/kg). A interacao heparina-protamina causou aumento de aproximadamente 350% da pressao media da arteria pulmonar (PMAP), acompanhado de aumento significativo do indice de resistencia vascular pulmonar (IRVP) e da pressao capilar pulmonar (PcP). Este aumento foi significativo 2 min apos a injecao de protamina, mantendo-se significativamente elevado ate aproximadamente 5 minutos apos administracao da mesma. Ao mesmo tempo em que se detectou a hipertensao pulmonar, observamos reducao significativa da pressao arterial media (PAM). Observamos ainda um aumento significativo da frequencia cardiaca (FC) aos 2 minutos apos administracao da protamina com discreta diminuicao do indice cardiaco (IC). O indice de resistencia vascular sistemica (IRVS) nao sofreu alteracoes significativas. A saturacao do oxigenio (SpO2) foi significativamente diminuida apos a formacao do complexo heparina-protamina. Nos animais tratados com BAY 41-2272 (10 /kg/min, i.v.), observamos reducao marcante do aumento da PMAP, do IRVP e da PcP. Por outro lado, este tratamento potencializou a reducao da PAM. Alem disso, o BAY 41-2272 reduziu significantemente o IRVS e aumentou a FC. A diminuicao da SpO2 foi atenuada significativamente pelo BAY 41- 2272. Os niveis plasmaticos de GMPc foram dosados aos 2 min apos a formacao do complexo heparina-protamina, tendo-se mostrado elevados no grupo tratado com o BAY41-2272. O tempo de tromboplastina parcial ativado (TTPA) nao apresentou alteração significativa no tratamento com o BAY 41-2272. O veiculo do BAY 41-2272 (DMSO 30%) nao alterou significativamente os parametros estudados. A hipertensao pulmonar por hipoxia foi induzida com a instalacao de uma baixa tensao de oxigenio (FiO2=12%). Nesta circunstancia, a PMAP elevou-se em aproximadamente 280% aos 5 minutos, mantendo-se significativamente elevada ate 15 minutos apos instalacao da hipoxia. A elevacao da PMAP foi acompanhada de aumentos significativos no IRVP e PcP. A PAM, IRVS, FC e IC nao apresentaram alterações significativas. A SpO2 diminuiu na presenca da hipoxia. O tratamento com BAY 41-2272 (10 /kg/min, i.v.), reduziu significativamente a PMAP, PcP e IRVP. O IRVS foi significativamente potencializado pelo BAY 41-2272. A PAM, FC e IC nao alteraram significativamente. A diminuicao da SpO2 foi atenuada significativamente pelo BAY 41- 2272. Os niveis plasmaticos de GMPc elevaram-se significativamente no grupo tratado com o BAY 41-2272. Em conclusao, o BAY 41-2272 atenuou a acao vasoconstritora pulmonar induzida pelo complexo heparina-protamina e hipoxia levando a uma prevencao da hipertensao pulmonar.
Doutorado
Farmacologia
Doutor em Farmacologia
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Libri sul tema "Heparin"

1

1960-, Warkentin Theodore E., e Greinacher Andreas, a cura di. Heparin-induced thrombocytopenia. 4a ed. New York: Informa Healthcare USA, 2007.

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1960-, Warkentin Theodore E., e Greinacher Andreas, a cura di. Heparin-induced thrombocytopenia. 3a ed. New York: Marcel Dekker, 2004.

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Warkentin, Theodore E., e Andreas Greinacher. Heparin-induced thrombocytopenia. 4a ed. New York: Informa Healthcare, 2007.

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1960-, Warkentin Theodore E., e Greinacher Andreas, a cura di. Heparin-induced thrombocytopenia. New York: Dekker, 2000.

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5

1960-, Warkentin Theodore E., e Greinacher Andreas, a cura di. Heparin-induced thrombocytopenia. 2a ed. New York: Dekker, 2001.

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6

Lane, David A., Ingemar Björk e Ulf Lindahl, a cura di. Heparin and Related Polysaccharides. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4899-2444-5.

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1949-, Lane D. A., Björk Ingemar e Lindahl Ulf 1939-, a cura di. Heparin and related polysaccharides. New York: Plenum Press, 1992.

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8

Barrowcliffe, Trevor W. Low molecular weight heparin. Chichester, West Sussex, England: Wiley, 1992.

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9

Chang, Shau-Feng. Studies on structure, heparin-binding, and gene expression of hepatic lipase. München: Dissertationsverlag NG Kopierladen, 1993.

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10

institutet, Karolinska, a cura di. Lipoprotein lipase, hepatic lipase and plasma lipolytic activity: Effects of heparin and a low molecular weight heparin fragment (Fragmin®). Stockholm: Acta medica Scandinavica, 1988.

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Capitoli di libri sul tema "Heparin"

1

Harr, Jeffrey N., Philip F. Stahel, Phillip D. Levy, Antoine Vieillard-Baron, Yang Xue, Muhammad N. Iqbal, Jeffrey Chan et al. "Heparin". In Encyclopedia of Intensive Care Medicine, 1071–75. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-00418-6_715.

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2

Roth, Elliot J. "Heparin". In Encyclopedia of Clinical Neuropsychology, 1686–87. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-57111-9_2219.

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3

Petroianu, Georg, e Peter Michael Osswald. "Heparin". In Anästhesie in Frage und Antwort, 79–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/978-3-662-05715-5_28.

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Petroianu, Georg, e Peter Michael Osswald. "Heparin". In Anästhesie in Frage und Antwort, 99–101. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-662-05717-9_43.

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Roth, Elliot J. "Heparin". In Encyclopedia of Clinical Neuropsychology, 1–2. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-56782-2_2219-2.

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6

Wilson, John Fawcett. "Heparin". In The Immunoassay Kit Directory, 1555. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0679-5_26.

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Watkins, Evan, e Daniel Thomas Ginat. "Heparin". In Neuroimaging Pharmacopoeia, 257–60. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-12715-6_33.

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Watkins, Evan, Daniel Thomas Ginat e Juan E. Small. "Heparin". In Neuroimaging Pharmacopoeia, 313–16. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-08774-5_44.

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Bährle-Rapp, Marina. "Heparin". In Springer Lexikon Kosmetik und Körperpflege, 254. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_4679.

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10

Roth, Elliot J. "Heparin". In Encyclopedia of Clinical Neuropsychology, 1236–37. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-0-387-79948-3_2219.

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Atti di convegni sul tema "Heparin"

1

Eldor, A., M. Bar-Ner, L. Wasserman, Y. matzner, Z. Fuks e I. Viodavsky. "HEPARIN AND NON-ANTICOAGULANT HEPARINS INHIBIT HEPARANASE ACTIVITY IN NORMAL AND MALIGNANT CELLS:POSSIBLE THERAPEUTIC USE IN PREVENTION OF EXTRAVASATION AND DISSEMINATION OF BLOOD BORNE CELLS". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643664.

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Degradation of vascular subendothelium occurs in_vivo during the process of inflammation and tumor invasion. Various observations suggest that the capacity of some blood-borne cells to extravasate may depend in part on their ability to express hepara-nase activity. Incubation of human platelets, human nc-utrophils, or highly metastatic mouse lymphoma cells with sulfate-labeled extracellular matrix (ECM) results in heparanase mediated release of labeled heparan sulfate cleavage fragments (0.5<Kav<0.85 on Sepharose 5B) (J. Clin.Invest. 74: 1842 and 76: 1306; Cancer Res. 43: 2704). The present study was undertaken to test the heparanase inhibitory effect of heparin and non-anticoagulant species of heparin that might havea potential therapeutic use in preventing heparanase mediated extravasation ofblood-borne cells. We prepared totallyor N-desulfated heparins which were either left with their N-position exposed or were subsequently N-acetylated or N-resulfated. These heparins exhibited less than 5% of the anticoagulant activityof native heparin. It was found that total desulfation of heparin abolished its heparanase inhibitory activity whether desulfation was followed by N-acetylation or not. Inhibitory effect was restored by resulfation of the N-position. When only the N-sulfate group was desulfated, inhibitory activity was lost but could be restored by acetylation of the N-position. These results indicate that N-sulfate groups of heparin are necessary for its heparanase inhibitory activity but can be substituted by an acetyl group provided that the 0-sulfate groups are retained. Low Mr heparins (main Mr species of 2500 and 4500 daltons) and heparin fragments as small as the tetrasaccharide inhibited degradation of heparan sulfate in the ECM, albeit to a lower extent than native heparin. Similar effects of the different heparins were observed with heparanase activities from platelets, neutrophils and lymphoma cells. Preliminary in vivo experiments suggest that non-anticoagulant heparins interfere with tumor metastasis and experimental autoimmune diseases (some heparins were kindly provided by Inst. Choay, Paris and Kabi Vitrum, Stockholm).
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2

Borowska, A., D. Lauri, A. Maggi, E. Dejana, G. de Gaetano e J. Pangrazzi. "IMPAIREMENT OF PRIMARY HAEMOSTASIS BY LMW-HEPARINS". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643172.

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Low molecular weight (LMW) heparlns have been developed with the aim of reducing anticoagulant activity thereby minimizing the bleeding complications of conventional heparin. Unexpectedly, bleeding events were reported during treatment with some LMW-heparins, in clinical and experimental studies. We studied the effect of four different LMW-heparlns on primary haemostasis In male rats (CD COBS, Charles River) after l.v. administration of 0.75 mg/kg b.w. of the drugs. LMW heparin A was devoid of any activity on an experimental model of “template” bleeding time in rats (110.6±5.9 sec versus 108.7±4.1 control values) whereas LMW-heparins B, C and D prolonged the bleeding time to a different extent (228.7±19.9, 161.5±6.4 and 161.7±8.6 respectively). Pretreatment of animals with aspirin (100 mg/kg b.w. per o.s). resulted In a significant potentiation of the “template” bleeding time. In vitro platelet aggregation Induced by collagen (20 μg/ml) or by collagen in combination with ADP (5-10 μM) was strongly inhibited by LMW-heparln B, while LMW-heparln A showed no effect. LMW-heparins C and D exerted an Intermediate level of Inhibition of platelet aggregation. The same pattern of aggregating response was found when LMW-heparins A and B were given i.v. to rats (0.75 mg/kg b.w.) and platelet aggregation was studied “ex vivo” 15 min after drug administration.These data may help explain the impairment of primary haemostasis associated with some LMW-heparin preparations.
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3

Maggi, A., T. W. Barrowcliffe, E. Gray, M. B. Donati, R. E. Merton e I. Pangrazzi. "RELATIONSHIP BETWEEN HAEMORRHAGIC AND LIPASE-RET EASING PROPERTIES OF HEPARIN AND LMV HEPARIN". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642929.

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In a preliminary study, a good correlation (r = 0.97) was noted between the relative abilities of an unfractionated heparin, a LMW heparin, pentosan poly sulphate and dermatan sulphate to prolong the template bleeding time in rabbits and their lipase-releasing potencies. In the present study, we have measured the prolongation of both the template and transection bleeding times in groups of 5 rats given i.v. injections of 0.75 mg/kg of two different unfractionated heparins (UEH), A and B, three different LMW heparins, X, Y and Z, and a heparan sulphate, HS. Lipase release was measured in plasma samples from different groups of 5 rats, using a tritiated triolein method.UFH A had the most haemorrhagic effect, with an approximate doubling of both template and transection bleeding times and was also the most potent lipase-releaser, giving an average lipase level of 1126 mu/ml. UFH B had no significant effect on the template bleeding time, but did prolong the transection time; its lipase releasing potency was 70% of UFH A. IMW heparin X had no effect on template or transection bleeding time and released only 40% lipase compared with UEH A. LMW heparins Y and Z did not affect the template bleeding time but did prolong the transection time; they released more lipase (60%) than LMW heparin X. Correlation coefficients with lipase release were 0.97 for the template bleeding time and 0.69 for the transection bleeding time. HS released only 7% lipase but gave significant prolongations of both bleeding times.These results confirm a strong positive correlation between the haemorrhagic and lipase releasing properties of heparin and LMW heparin, suggesting very similar structural requirements for the two biological activities. This correlation exists also for dermatan sulphate and pentosan polysulphate, but not for the heparan sulphate sample tested.
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4

Dawes, J., e D. S. Pepper. "A COMPARISON OF THE BINDING OF ANTITHROMBIN III AND HEPARIN COFACTOR II TO HEPARINS, NATURALLY OCCURRING GLYCOSAMINOGLYCANS AND OTHER SULPHATED POLYMERS". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642827.

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Antithrombin III (ATIII) and heparin cofactor II (HCII) are currently thought to be the most important protein mediators of the anticoagulant and antithrombotic activities of glycosamino-glycans. A simple, quantitative method for assessing the affinity of a protein for a sulphated polymer in the liquid phase, based on competition with immobilised heparin, has been developed. Using this technique, the binding of ATIII and HCII to a wide range of glycosaminoglycans and other sulphated polymers have been compared, and the contributions to binding of size, degree of sulphation and backbone structure of the polymers analysed.In the presence of the high protein concentrations found in plasma, unfractionated heparin inhibited the binding of ATIII to immobilised heparin with a Ki of 1 x 10-6. Binding was destroyed by N-desulphation. 1 Results with a range of low molecular weight (LMW) heparins and heparan sulphates are consistent with the view that they all contain the ATIII-binding sequence, but at a lower molar ratio than heparin. Highly sulphated synthetic polymers such as dextran sulphate bound ATIII by a different mechanism, which was molecular weight-dependent.The affinity of HCII for heparins increased markedly with heparin chain length. Binding was largely, but not entirely, mediated by sulphate residues. HCII bound to heparan and dermatan sulphates with lower affinities than to heparin, and to synthetic sulphated polymers with similar or higher affinities. Pentosan polysulphate (SP54) bound HCII as effectively as did heparin. Binding of HCII to dextran sulphate was highly dependent on molecular weight. The affinity of HCII for a sulphated polymer appears to depend both on its chain length and density of sulphation.Thus the profiles of binding of ATIII and HCII to glycosaminoglycans and other sulphated polymers are quite different. This technique is useful both for investigating the interactions of existing therapeutic anticoagulants and assessing new products.
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Messmore, H., B. Griffin, J. Seghatchian e E. Coyne. "HIGH CONCENTRATIONS OF HEPARIN ARE MORE INHIBITORY TO PLATE- AGGREGATION IN-VITRO THAN ARE LOW MOLECULAR WEIGHT HEPARINS AND HEPARINOIDS AT THE SAME CONCENTRATION". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644186.

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Other investigators have shown that heparin in the usual therapeutic range (0.1-0.5 units/ml) has an enhancing effect on ADP aggregation and an inhibitory effect on collagen and thrombin induced aggregation. The effects of low molecular weight heparin (LMWH)and heparinoids (dermatan sulfate, heparan sulfate) on platelet aggregation have not been as extensivelystudied. We have utilized citrated platelet rich plasma (3.2%citrate-whole blood 1:9) drawn in plastic and adjusted to a final platelet count of 250,000/ul. A Bio-Data 4 channgl aggregometer was utilized with constantstirring at 37 C. The reaction was allowed to run for 20 minutes. Platelet rich plasma was supplemented 1:9 with saline or heparin and various agonists were then added ifno aggregation occurred. ADP, collagen, thrombin, ristocetin and serum from patients with heparin inudced thrombocytopenia (HIT) were utilized as agonists. Heparin was substituted at concentrations of 0.1 to 500 units per ml and various LMWH and heparinoids were substituted in equivalent anti-Xa or gravimetric concentrations. At low concentrations no inhibitory effect on any ofthe agonists was observed with any of the heparins or heparinoids. At concentrations of heparin of 100 u/ml or greater, all agonists were inhibited. At equivalent concentrations of five different LMWH (Cy 216, Cy 222, Pk 10169, Kabi 2165 and pentasaccharide) inhibition did notoccur at all or at very high concentions only. Dermatan sulfate and heparan sulfate inhibited only at high concentrations. HIT serum could not aggregate platelets with dermatan sulfate or pentasaccharide atany concentrations, but it was a good agonist with the other heparins and heparinoids.
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Ordu, Y., J. Augustin, E. V. Hodenberg, V. Bode e J. Harenberg. "COMPARATIVE CLINICAL PHARMACOLOGY OF LOW MOLECULAR WEIGHT HEPARINS IN MAN". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643228.

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Low molecular weight (LMW) heparins are obtained by diffent chemical procedures from conventional pig intestinal mucosa heparin. The LMW heparins differ in their molecular weight distribution and physicochemical properties. Therefore, we report of comparative studies on the anticoagulant and lipolytic effects of low molecular weight heparins in man.The following LMW heparins were used: BM 21-23 (Braun, Melsungen, FRG), CY 216 (Choay Laboratories, Paris, France), Heparin NM (Sandoz, Niimberg, FRG), Kabi 2165 (Kabi Vitrum AB, Stockholm, Sweden), RD Heparin (Hepar Industries, Franklin, US A), normal heparin (Braun). All heparins were administered intravenously and subcutaneously to six volunteers each.The data show considerable differences in the anticoagulant and lipolytic effects between the different low molecular weight heparins. From the area under the activity time curves (AUC) of the clotting assays for factor Xa (heptest), aPTT and thrombin clotting time the aXa/aPTT ratio ex vivo and aXa/alla ratio ex vivo were determined (table, average values)It can be seen that there are clear differences in the ex vivo ratios of the LMW heparins. There is a good correlation between the average molecular weight of the LMW heparins and the aXa/aPTT ratio after s.c. administration and of the aXa/alla ratio ex vivo after s.c. administration. Therefore, LMW heparins differ significantly in their clinical pharmacological properties.
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Jackson, Craig M. "A DEFINITION OF HEPARIN ANTICOAGULANT POTENCY APPLICABLE TO ALL HEPARINS AND HEPARIN-LIKE SUBSTANCES AND ITS PRACTICAL APPLICATION IN ASSAYING HEPARIN". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642928.

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Heparins increase the rate of inactivation of proteinases by antithrombin without being consumed in the inactivation reaction. The anticoagulant activity of any heparin or heparin preparation is thus determined by the increase in the inactivaton rate which it produces. This rate increase is dependent on the concentration of the heparin in the sample and on some now well known structural properties of the individual heparin molecules that produce high affinity for antithrombin . All proteinases are not inactivated by antithrombin equally rapidly in the absence of heparin, nor are heparins and heparin derivatives of different molecular weight equally effective in the inactivation of the same proteinase. Under appropriate conditions, the observed rate constant (kObs) for the heparin catalyzed proteinase inactivation reaction is simply related to the intrinsic potencies and concentrations of the individual high affinity heparin molecules in the sample. The intrinsic potency of a high affinity heparin molecule is the efficiency with which it catalyzes the inactivation of the particular proteinase, e.g. Factor Xa or thrombin, i.e., it is a second order rate constant, (designated k*) . After k* has been determined from kobs for a known heparin or heparin preparation and a particular proteinase, the concentration of heparin in an unknown sample can be calculated from the equation[H] = [HAT] = kobs/k* In general terms, the appropriate conditions, i.e.,the antithrombin and proteinase concentrations, the pH, and ionic strength, required for this equation to be used are those conditions for which all of the high affinity heparin is bound to the antithrombin and pseudo first order kinetic behavior occurs. At very low heparin concentrations, a correction for the inactivation of the proteinase by antithrombin alone is necessary, but is easily made.Supported by Organon Teknika Corporation and an Established Investigator Award from the American National Red Cross
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Zimmerman, R. A., C. T. Rieger, K. Hübner, C. W. Harenber e W. Kübler. "EXPERIMENTAL THROMBUS FORMATION AND HAEMOSTASIS OF DIFFERENT LOW MOLECULAR WEIGHT HEPARINS AND DOSAGES". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644162.

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Low molecular weight heparin induces a higher anti factor Xa (a-Xa) and a lower antithrombin activity in plasma in comparison to conventional heparin. From this constellation a more pronounced antithrombotic effect and a minor incidence of bleeding Complications has been suggested.Therefore the antithrombotic activity of heparins was studied in a standardized experimental thrombosis model in rabbits. Three low molecular weight heparins with a mean molecular weight of 4.200 (heparin I),4.000 (heparin II),4.600 Dalton (heparin III) and standard heparin were tested at different dosages in 120 experiments. In the first series the dose of 60 anti Xa units (a-Xa U) given initially and 60 a-Xa U/kg/h induced a reduction of the thrombus size by 40 % (heparin I),37 % (heparin II) and 53 % (heparin III) and a prolongation of the aPTT to 45 (heparin I),66 (heparin II) and 79 sec (heparin III). The a-Xa activity was minor than 0.1 U/ml. In the second series heparins were given to aim at an a-Xa activity of 0.2-0.3 U/ml. Thereby the thrombus formation could be reduced by 84 % (heparin I), 62 % (heparin II) and 39 % (heparin III). aPTT and a-Xa activity were measured at 65.5 sec and 0.22 a-Xa U/ml (heparin I),67.3 sec and 0.3 a-Xa U/ml (heparin II) and 67.5 and 0.31 a-Xa U/ml (heparin III),respectively. In the third series the increase of the a-Xa activity to more than 0.3 U/ml showed no further reduction of the thrombus formation by heparin I, while heparins II and III already at this level reachedthe antithrombotic activity of heparin I.Our data on three different low molecular weight heparins demonstrate that already a heparin level ranging at a minimal a-Xa activity induces a clear and statistically significant antithrombotic effect. A higher heparin dosage with higher a-Xa activity increases the antithrombitic effect. At a level of 0.2-0.3 a-Xa U/ml an obvious and maximum effect could be reached, but the further elevation of the a-Xa activity produced no further antithrombotic action.
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Rathjen, A., e Carolyn L. Geczy. "PRODUCTION AND CHARACTERISATION OF MONOCLONAL ANTIBODIES AGAINST HEPARIN Deborah". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644188.

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To complement the studies using MAbs to AT III and because of the reported ability of heparin to modulate several aspects of the cell-mediated immune response, we have prepared two mouse monoclonal antibodies (MAbs) to porcine mucosal heparin.MAb 25/15 is an IgGl and MAb 26/7 is an IgM. Both MAbs have iso-electric points between pH5.85 and 6.55. The MAbs recognise porcine and bovine mucosal heparin and rat mast cell heparin. Heparins with both high and low affinitiesfor antithrombin III (ATIII) bound both MAbs but neither MAb altered the binding of heparin to AT III. These antibodies did not recognise other proteoglycans (chondroitin sulphate types A, B and C, keratan sulphate and hyaluronic acid) with the exception of heparan sulphate, (the cellular equivalent of heparin) and Arte- paron (Luitpold-Werk, Munchen; a synthetically poly- sulphated chondriotin sulphate), in competition and solid-phasebinding assays. Dextransulphate(Pharmacia) was also recognised by these MAbs. Cross-reactivity with Arteparon and dextran sulphate indicate that charged sulphate goups on the mucopolysaccharides may be importantBfor MAb binding. The Mabs described may beuseful probes for endogenous heparin at the cellular and tissue level and may allow further investigation of the many biological activitiesof heparin
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10

Fenichel, R. L., W. Carmint, B. Small e J. Willis. "COMPARISON OF THE ANTITHROMBOTIC, ANTICLOTTING AND ANTIPLATELET AGGREGATORY ACTIVITIES OFLOW MOLECULAR WEIGHT RD HEPARIN WITH HEPARIN". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644854.

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An initial comparison of in vitro plasma anti-factor Xa (anti Xa) and activated partial thromboplastin time (APTT) values of RD heparin with heparin based upon USP units shows increased anti Xa and decreased APTT activity of RD heparin. An ex vivo experiment in rabbits in which 100 USP units/kg of RD heparinand 200 USP units/kg of heparin, when given by the subcutaneous route, reflects the significantly increased anti Xa activity generated by RD heparin as wellas its longer duration of action. No significant difference in APTT activity was observed for the two heparins, but an increased anti Xa/APTT ratio (greaterthan two) was observed for the RD heparin. Heparin (10 yg/ml), but not RD heparin, potentiated adenosinediphosphate (ADP) induced platelet aggregation in human platelet rich plasma. Subcutaneous administration of RD heparin or heparin to rabbits over the dosage range of 0.75 to 1.75 mg/kg gives similar mean dose response lines for these heparins in the thrombosis-stasis model as measured by the extent of jugular vein clotting. Administration of these heparins to rabbits on a USP unitage basis shows a significantly greater antithrombotic effect for RD heparin at 120 and 160 USP units/kg. Moreover, this experiment indicates that if the optimum dosage of 120 USP units/kgfor RD heparin is exceeded then we begin to see an indication of loss of antithrombotic activity.
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Rapporti di organizzazioni sul tema "Heparin"

1

Carlin, Stephanie, Andrew M. Morris, Zainab B. Abdurrahman, Jacob J. Bailey, Martin E. Betts, William Ciccotelli, Bradley J. Langford et al. Heparin Anticoagulation for Hospitalized Patients with COVID-19. Ontario COVID-19 Science Advisory Table, settembre 2021. http://dx.doi.org/10.47326/ocsat.2021.02.41.1.0.

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2

Upchurch, G. R., Valeri Jr., Khuri C. R., Rohrer S. F., Welch M. J. e G. N. The Effect of Heparin on Fibrinolytic Activity and Platelet Function. Fort Belvoir, VA: Defense Technical Information Center, settembre 1995. http://dx.doi.org/10.21236/ada360274.

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3

Salomon, David. The Role of Heparin-Binding EGF-Like Growth Factor in Breast Cancer. Fort Belvoir, VA: Defense Technical Information Center, ottobre 1995. http://dx.doi.org/10.21236/ada300394.

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4

Khuri, S. F., C. R. Valeri, J. Loscalzo, M. Weinstein e V. Birjiniuk. Heparin Causes Platelet Dysfunction and Induces Fibrinolysis Before the Institution of Cardiopulmonary Bypass. Fort Belvoir, VA: Defense Technical Information Center, settembre 1995. http://dx.doi.org/10.21236/ada360259.

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5

Chen, Chen, Peng Chen, Xia Liu e Hua Li. Combined 5-Fluorouracil and Low Molecular Weight Heparin for the Prevention of Postoperative Proliferative Vitreoretinopathy in Patients with Retinal Detachment. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, agosto 2021. http://dx.doi.org/10.37766/inplasy2021.8.0117.

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Review question / Objective: The aim of this meta-analysis is to evaluate the efficacy and safety of intraoperative infusion of combined 5-fluorouracil and low molecular weight heparin (LMWH) for the prevention of postoperative proliferative vitreoretinopathy in patients with retinal detachment. Condition being studied: Postoperative proliferative vitreoretinopathy (PVR) is the primary cause of failure of retinal reattachment surgery. 5-fluorouracil (5-FU) inhibits the proliferation of fibroblasts, and suppresses collagen contraction. On the other hand, heparin reduces fibrin exudation, and inhibits the adhesion and migration of retinal pigment epithelial cells. We conduct this comprehensive literature search and meta-analysis to address whether intraoperative infusion of combined 5-FU and LWMH improves the primary success rate of pars plana vitrectomy, as well as reduces postoperative PVR. Our study aims to provide clinical evidence for retinal surgeons concerning their choice of intraoperative medication.
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6

Li, Rui, Xiang Gao, Tao Zhou, Yunjie Li, Jianhui Wang e Peirong Zhang. Regional citrate versus heparin anticoagulation for CRRT in critically ill patients: a meta-analysis of RCTS. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, dicembre 2021. http://dx.doi.org/10.37766/inplasy2021.12.0093.

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7

Chan, Shan-Ho, Cheng-Kai Huang, Po-Nien Hou e Jay Wu. Meta-Analysis of the Effectiveness of Heparin in Suppressing Physiological Myocardial FDG Uptake in PET/CT. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, marzo 2023. http://dx.doi.org/10.37766/inplasy2023.3.0015.

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8

Wei, Qingqing, Weiying Wang, Guobin Miao, Li Li, Ge Wang, Chang Meng e Peng Liu. Aspirin Versus Low-Molecular-Weight Heparin for Venous Thromboembolism Prophylaxis in Patients after Postoperative Joint Surgery: A Meta-Analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, febbraio 2023. http://dx.doi.org/10.37766/inplasy2023.2.0117.

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9

Lin, Yun-Kuan, Yu-Ning Huang e Jen-Hung Wang. Effects of heparin on venom-induced consumption coagulopathy: protocol for a systematic review, meta-analysis, and trial sequential analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, febbraio 2024. http://dx.doi.org/10.37766/inplasy2024.2.0070.

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10

huang, kun, yan sun e hai jiang. Effect of low molecular weight heparin combined with aspirin on pregnancy outcomes of unexplained recurrent abortion: a systematic review and meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, ottobre 2023. http://dx.doi.org/10.37766/inplasy2023.10.0005.

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