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Bo Mattiasson - One of the best experts on this subject based on the ideXlab platform.
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chemically modified poly 2 hydroxyethyl methacrylate cryogel for the adsorption of heparin
Journal of Biomedical Materials Research Part B, 2014Co-Authors: R La Spina, Carla Tripisciano, Tommaso Mecca, Francesca Cunsolo, Viktoria Weber, Bo MattiassonAbstract:Various clinical procedures, such as cardiovascular surgery or extracorporeal blood purification, involve systemic anticoagulation using heparin. High concentrations of circulating heparin require neutralization due to possible serious bleeding complications. The intravenous administration of the heparin antagonist protamine sulfate is routinely clinically performed, but is frequently associated with adverse reactions. Therefore, there is a need for a valid and safe alternative to achieve extracorporeal heparin removal from blood or plasma, such as a filter, a matrix, or an adsorbent. Here, we describe the development of a macroporous poly(2-hydroxyethyl methacrylate)-based monolithic cryogel functionalized with l-lysine (pHEMA-lys) and the characterization of its selective heparin adsorption. The Maximum Binding Capacity was quantified in vitro using aqueous and serum solutions under static and dynamic conditions, and fresh human plasma under static conditions. The pHEMA-lys bound 40,500 IU and 32,500 IU heparin/g cryogel at the equilibrium in aqueous solution and 50% serum, respectively. In human plasma spiked with 100 IU/mL of heparin, the Binding was still highly efficient (4330 IU/g cryogel after 30 min, i.e., 87% of the initial concentration). The cryogels showed good blood compatibility, as indicated by negligible adsorption of albumin, antithrombin III, and total protein, and may thus be suitable for extracorporeal heparin removal. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014. (Less)
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chemically modified poly 2 hydroxyethyl methacrylate cryogel for the adsorption of heparin
Journal of Biomedical Materials Research Part B, 2014Co-Authors: R La Spina, Carla Tripisciano, Tommaso Mecca, Francesca Cunsolo, Viktoria Weber, Bo MattiassonAbstract:Various clinical procedures, such as cardiovascular surgery or extracorporeal blood purification, involve systemic anticoagulation using heparin. High concentrations of circulating heparin require neutralization due to possible serious bleeding complications. The intravenous administration of the heparin antagonist protamine sulfate is routinely clinically performed, but is frequently associated with adverse reactions. Therefore, there is a need for a valid and safe alternative to achieve extracorporeal heparin removal from blood or plasma, such as a filter, a matrix, or an adsorbent. Here, we describe the development of a macroporous poly(2-hydroxyethyl methacrylate)-based monolithic cryogel functionalized with l-lysine (pHEMA-lys) and the characterization of its selective heparin adsorption. The Maximum Binding Capacity was quantified in vitro using aqueous and serum solutions under static and dynamic conditions, and fresh human plasma under static conditions. The pHEMA-lys bound 40,500 IU and 32,500 IU heparin/g cryogel at the equilibrium in aqueous solution and 50% serum, respectively. In human plasma spiked with 100 IU/mL of heparin, the Binding was still highly efficient (4330 IU/g cryogel after 30 min, i.e., 87% of the initial concentration). The cryogels showed good blood compatibility, as indicated by negligible adsorption of albumin, antithrombin III, and total protein, and may thus be suitable for extracorporeal heparin removal.
G N Woodruff - One of the best experts on this subject based on the ideXlab platform.
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characterisation of 3h gabapentin Binding to a novel site in rat brain homogenate Binding studies
European Journal of Pharmacology, 1993Co-Authors: N Sumanchauhan, Louise Webdale, David R. Hill, G N WoodruffAbstract:Abstract The Binding characteristics of [3H]gabapentin, the radiolabelled analogue of the novel anticonvulsant gabapentin (1-(aminomethyl)cyclohexaneacetic acid) were studied using purified synaptic plasma membranes prepared from rat cerebral cortex. In 10 mM HEPES buffer [3H]gabapentin bound to a single population of sites with high affinity (KD = 38 ± 2.8 mM) with a Maximum Binding Capacity of 4.6 ± 0.4 pmol/mg protein, reaching equilibrium after 30 min at 20°C. This novel site was unique to the central nervous system with little or no specific [3H]gabapentin Binding being measurable in a range of peripheral tissues. Binding was potently inhibited by a range of gabapentin analogues and 3-alkyl substituted γ-aminobutyric acid (GABA) derivatives although GABA itself and the selective GABAB receptor ligand baclofen, were only weakly active. Gabapentin itself (IC50 = 80 nM) and 3-isobutyl GABA (IC50 = 80 nM) which also has anticonvulsant properties, showed the highest affinity for the Binding site. Of a wide range of other pharmacologically active compounds only the polyamines spermine and spermidine influenced [3H]gabapentin Binding, with both compounds producing a Maximum of 50% inhibition of specific Binding. Magnesium ions produced a similar pattern of inhibition but the effect of the polyamines and magnesium ions were not additive. The data provide evidence for the existence in brain of a novel Binding site that may mediate the anticonvulsant effects of gabapentin and other potential anticonvulsant compounds.
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characterisation of 3h gabapentin Binding to a novel site in rat brain homogenate Binding studies
European Journal of Pharmacology, 1993Co-Authors: N Sumanchauhan, Louise Webdale, David R. Hill, G N WoodruffAbstract:The Binding characteristics of [3H]gabapentin, the radiolabelled analogue of the novel anticonvulsant gabapentin (1-(aminomethyl)cyclohexaneacetic acid) were studied using purified synaptic plasma membranes prepared from rat cerebral cortex. In 10 mM HEPES buffer [3H]gabapentin bound to a single population of sites with high affinity (KD = 38 +/- 2.8 nM) with a Maximum Binding Capacity of 4.6 +/- 0.4 pmol/mg protein, reaching equilibrium after 30 min at 20 degrees C. This novel site was unique to the central nervous system with little or no specific [3H]gabapentin being measurable in a range of peripheral tissues. Binding was potently inhibited by a range of gabapentin analogues and 3-alkyl substituted gamma-aminobutyric acid (GABA) derivates although GABA itself and the selective GABAB receptor ligand baclofen, were only weakly active. Gabapentin itself (IC50 = 80 nM) and 3-isobutyl GABA (IC50 = 80 nM) which also has anticonvulsant properties, showed the highest affinity for the Binding site. Of a wide range of other pharmacologically active compounds only the polyamines spermine and spermidine influenced [3H]gabapentin Binding, with both compounds producing a Maximum of 50% inhibition of specific Binding. Magnesium ions produced a similar pattern of inhibition but the effect of the polyamines and magnesium ions were not additive. The data provide evidence for the existence in brain of a novel Binding site that may mediate the anticonvulsant effects of gabapentin and other potential anticonvulsant compounds.
R La Spina - One of the best experts on this subject based on the ideXlab platform.
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chemically modified poly 2 hydroxyethyl methacrylate cryogel for the adsorption of heparin
Journal of Biomedical Materials Research Part B, 2014Co-Authors: R La Spina, Carla Tripisciano, Tommaso Mecca, Francesca Cunsolo, Viktoria Weber, Bo MattiassonAbstract:Various clinical procedures, such as cardiovascular surgery or extracorporeal blood purification, involve systemic anticoagulation using heparin. High concentrations of circulating heparin require neutralization due to possible serious bleeding complications. The intravenous administration of the heparin antagonist protamine sulfate is routinely clinically performed, but is frequently associated with adverse reactions. Therefore, there is a need for a valid and safe alternative to achieve extracorporeal heparin removal from blood or plasma, such as a filter, a matrix, or an adsorbent. Here, we describe the development of a macroporous poly(2-hydroxyethyl methacrylate)-based monolithic cryogel functionalized with l-lysine (pHEMA-lys) and the characterization of its selective heparin adsorption. The Maximum Binding Capacity was quantified in vitro using aqueous and serum solutions under static and dynamic conditions, and fresh human plasma under static conditions. The pHEMA-lys bound 40,500 IU and 32,500 IU heparin/g cryogel at the equilibrium in aqueous solution and 50% serum, respectively. In human plasma spiked with 100 IU/mL of heparin, the Binding was still highly efficient (4330 IU/g cryogel after 30 min, i.e., 87% of the initial concentration). The cryogels showed good blood compatibility, as indicated by negligible adsorption of albumin, antithrombin III, and total protein, and may thus be suitable for extracorporeal heparin removal. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014. (Less)
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chemically modified poly 2 hydroxyethyl methacrylate cryogel for the adsorption of heparin
Journal of Biomedical Materials Research Part B, 2014Co-Authors: R La Spina, Carla Tripisciano, Tommaso Mecca, Francesca Cunsolo, Viktoria Weber, Bo MattiassonAbstract:Various clinical procedures, such as cardiovascular surgery or extracorporeal blood purification, involve systemic anticoagulation using heparin. High concentrations of circulating heparin require neutralization due to possible serious bleeding complications. The intravenous administration of the heparin antagonist protamine sulfate is routinely clinically performed, but is frequently associated with adverse reactions. Therefore, there is a need for a valid and safe alternative to achieve extracorporeal heparin removal from blood or plasma, such as a filter, a matrix, or an adsorbent. Here, we describe the development of a macroporous poly(2-hydroxyethyl methacrylate)-based monolithic cryogel functionalized with l-lysine (pHEMA-lys) and the characterization of its selective heparin adsorption. The Maximum Binding Capacity was quantified in vitro using aqueous and serum solutions under static and dynamic conditions, and fresh human plasma under static conditions. The pHEMA-lys bound 40,500 IU and 32,500 IU heparin/g cryogel at the equilibrium in aqueous solution and 50% serum, respectively. In human plasma spiked with 100 IU/mL of heparin, the Binding was still highly efficient (4330 IU/g cryogel after 30 min, i.e., 87% of the initial concentration). The cryogels showed good blood compatibility, as indicated by negligible adsorption of albumin, antithrombin III, and total protein, and may thus be suitable for extracorporeal heparin removal.
Jeanfrancois Charles - One of the best experts on this subject based on the ideXlab platform.
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resistance in a laboratory population of culex quinquefasciatus diptera culicidae to bacillus sphaericus binary toxin is due to a change in the receptor on midgut brush border membranes
FEBS Journal, 1995Co-Authors: Christina Nielsenleroux, Jeanfrancois Charles, Isabelle Thiery, George P GeorghiouAbstract:Direct Binding experiments with isolated brush border membrane fractions (BBMF) from larvae of a susceptible laboratory strain of Culex quinquefasciatus Say, indicated the presence of a single class of Bacillus sphaericus binary toxin receptors. The dissociation constant (Kd) was approximately 11 nM and the Maximum Binding Capacity (Bmax) approximately 8 pmol/mg BBMF protein. Similar Binding experiments with a field population of C. quinquefasciatus that had been selected in the laboratory to more than 100000-fold resistance to B. sphaericus binary toxin failed to reveal the presence of any specific Binding. Thus this resistant strain had lost the functional receptor for B. sphaericus toxin. The Binding characteristics of BBMF from the F, larval progeny (susceptible females×resistant males) were very close to those of the parental susceptible strain, consistent with the resistance being recessive.
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Binding of bacillus sphaericus binary toxin to a specific receptor on midgut brush border membranes from mosquito larvae
FEBS Journal, 1992Co-Authors: Christina Nielsenleroux, Jeanfrancois CharlesAbstract:The presence of specific receptors for Bacillus sphaericus binary toxin on brush-border membrane fractions (BBMF) from Culex pipiens larvae midgut cells was demonstrated by an in vitro Binding assay. Both activated and radiolabelled polypeptides from the 51-kDa and 42-kDa binary toxin of B. sphaericus 1593 specifically bound to BBMF. Direct Binding and homologous competition experiments indicated a single class of B. sphaericus toxin receptors, with a dissociation constant (Kd) of approximately 20 nM and a Maximum Binding Capacity (Bmax) of approximately 7 pmol/mg BBMF protein. The sugars GalNAc, GlcNAc and N-acetyl neuraminic acid had no detectable inhibitory effect on toxin Binding to C. pipiens BBMF. Binding experiments with the non-susceptible mosquito species Aedes aegypti failed to detect significant Binding of B. sphaericus binary toxin to A. aegypti BBMF.
Christina Nielsenleroux - One of the best experts on this subject based on the ideXlab platform.
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resistance in a laboratory population of culex quinquefasciatus diptera culicidae to bacillus sphaericus binary toxin is due to a change in the receptor on midgut brush border membranes
FEBS Journal, 1995Co-Authors: Christina Nielsenleroux, Jeanfrancois Charles, Isabelle Thiery, George P GeorghiouAbstract:Direct Binding experiments with isolated brush border membrane fractions (BBMF) from larvae of a susceptible laboratory strain of Culex quinquefasciatus Say, indicated the presence of a single class of Bacillus sphaericus binary toxin receptors. The dissociation constant (Kd) was approximately 11 nM and the Maximum Binding Capacity (Bmax) approximately 8 pmol/mg BBMF protein. Similar Binding experiments with a field population of C. quinquefasciatus that had been selected in the laboratory to more than 100000-fold resistance to B. sphaericus binary toxin failed to reveal the presence of any specific Binding. Thus this resistant strain had lost the functional receptor for B. sphaericus toxin. The Binding characteristics of BBMF from the F, larval progeny (susceptible females×resistant males) were very close to those of the parental susceptible strain, consistent with the resistance being recessive.
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Binding of bacillus sphaericus binary toxin to a specific receptor on midgut brush border membranes from mosquito larvae
FEBS Journal, 1992Co-Authors: Christina Nielsenleroux, Jeanfrancois CharlesAbstract:The presence of specific receptors for Bacillus sphaericus binary toxin on brush-border membrane fractions (BBMF) from Culex pipiens larvae midgut cells was demonstrated by an in vitro Binding assay. Both activated and radiolabelled polypeptides from the 51-kDa and 42-kDa binary toxin of B. sphaericus 1593 specifically bound to BBMF. Direct Binding and homologous competition experiments indicated a single class of B. sphaericus toxin receptors, with a dissociation constant (Kd) of approximately 20 nM and a Maximum Binding Capacity (Bmax) of approximately 7 pmol/mg BBMF protein. The sugars GalNAc, GlcNAc and N-acetyl neuraminic acid had no detectable inhibitory effect on toxin Binding to C. pipiens BBMF. Binding experiments with the non-susceptible mosquito species Aedes aegypti failed to detect significant Binding of B. sphaericus binary toxin to A. aegypti BBMF.