Molecular dynamics symulation of hydrogen diffusion in palladium

In the present work, the diffusion of hydrogen atoms in the crystal lattice of palladium was investigated using the molecular dynamics. The diffusion coefficients, activation energies and preexponential factors were determined for structures with different hydrogen concentration. It is determined that the diffusion coefficients decrease and the activation energy of diffusion grows with increasing concentrations of hydrogen

Comparison of F(ab') versus Fab antivenom for pit viper envenomation: A prospective, blinded, multicenter, randomized clinical trial

BACKGROUND: Crotalidae Polyvalent Immune Fab (Ovine) has been the only antivenom commercially available in the US since 2007 for treatment of Crotalinae envenomation. Late coagulopathy can occur or recur after clearance of Fab antivenom, often after hospital discharge, lasting in some cases more than 2 weeks. There have been serious, even fatal, bleeding complications associated with recurrence phenomena. Frequent follow-up is required, and additional intervention or hospitalization is often necessary. F(ab')2 immunoglobulin derivatives have longer plasma half life than do Fab. We hypothesized that F(ab')2 antivenom would be superior to Fab in the prevention of late coagulopathy following treatment of patients with Crotalinae envenomation. METHODS: We conducted a prospective, double-blind, randomized clinical trial, comparing late coagulopathy in snakebitten patients treated with F(ab')2 with maintenance doses [F(ab')2/F(ab')2], or F(ab')2 with placebo maintenance doses [F(ab')2/placebo], versus Fab with maintenance doses [Fab/Fab]. The primary efficacy endpoint was coagulopathy (platelet count < 150 K/mm(3), fibrinogen level < 150 mg/dL) between end of maintenance dosing and day 8. RESULTS: 121 patients were randomized at 18 clinical sites and received at least one dose of study drug. 114 completed the study. Of these, 11/37 (29.7%) in the Fab/Fab cohort experienced late coagulopathy versus 4/39 (10.3%, p < 0.05) in the F(ab')2/F(ab')2 cohort and 2/38 (5.3%, p < 0.05) in the F(ab')2/placebo cohort. The lowest heterologous protein exposure was with F(ab')2/placebo. No serious adverse events were related to study drug. In each study arm, one patient experienced an acute serum reaction and one experienced serum sickness. CONCLUSIONS: In this study, management of coagulopathic Crotalinae envenomation with longer-half-life F(ab')2 antivenom, with or without maintenance dosing, reduced the risk of subacute coagulopathy and bleeding following treatment of envenomation

Der kanalikuläre Gallensäurentransporter der Leber als Kandidatengen für den Gallensteinlocus Lith 1

The formation of cholesterol gallstones is a polygenic disease. This implies, that the interaction of multiple genetic factors with the environment determines the quantitative expression of the phenotype. Gallstone genes co-localize with Quantitative Trait Loci (QTLs), chromosomal regions associated with cholesterol cholelithiasis. In this thesis a candidate gene for the cholesterol gallstone locus Lith 1, the gene encoding the canalicular bile salt export pump of the liver Abcb11, was characterized in detail and overexpressed in vivo by generating a BAC (bacterial artificial chromosome) transgenic mouse. In a molecular biological analysis, sequence information in unknown regions of the Abcb11 gene was generated and the genomic structure of the gene was determined by using DNA fragments cloned in plasmids or BACs as well as by adapter ligated PCR (genome walking). The sequences of the gallstone sensitive mouse strain C57L/J and the resistant strain AKR/J were compared by single strand conformation polymorphism (SSCP) analysis and by direct sequencing of PCR fragments. The cDNA of both strains is identical. In the 5' region of the gene a C/T polymorphism was detected at -3.757, and in intron 1 19 single nucleotide exchanges as well as a 5 bp insertion and a 3 bp deletion were identified. The functional relevance of these polymorphisms was investigated in dual luciferase assays by cotransfection with nuclear receptors and in electrophoretic mobility shift assays (EMSAs). The experimental procedures were complemented by in silico sequence analyses. Even though a regulatory potential was shown for the analyzed regions, their function for the differential transcriptional regulation between the inbred mouse strain could not be proven. In order to investigate the physiological effect of an increased Abcb11 expression on cholesterol homeostasis, a genomic BAC library was screened for Abcb11 positive clones by using a radioactively labelled probe. Subsequently, the BAC DNA was isolated and purified. After microinjection into pronuclei of selected gallstone resistant mouse strains, two Abcb11 BAC transgenic founder lines on the 129S1/SvImJ background were generated. Employing Southern and Northern hybridizations it could be demonstrated, that both lines have 1 - 2 extra gene copies apart from their endogenous Abcb11 copies, which are integrated into their genomes and expressed correctly. The transgenic mice show a normal development and no visible phenotype. By feeding a cholesterol rich lithogenic diet, cholesterol crystallization and gallstone formation were induced. Transgenic mice display a higher gallstone susceptibility in comparison to wildtype controls. The generation of the BAC transgenic mouse opens new perspectives for in vivo investigations. It will deliver an important contribution to the question of the identity of the cholesterol gallstone locus Lith 1 and the canalicular bile salt export pump Abcb11 as well as to the investigation of the complex protein interactions in biliary cholesterol homeostasis

Der kanalikuläre Gallensäurentransporter der Leber als Kandidatengen für den Gallensteinlocus Lith 1

The formation of cholesterol gallstones is a polygenic disease. This implies, that the interaction of multiple genetic factors with the environment determines the quantitative expression of the phenotype. Gallstone genes co-localize with Quantitative Trait Loci (QTLs), chromosomal regions associated with cholesterol cholelithiasis. In this thesis a candidate gene for the cholesterol gallstone locus Lith 1, the gene encoding the canalicular bile salt export pump of the liver Abcb11, was characterized in detail and overexpressed in vivo by generating a BAC (bacterial artificial chromosome) transgenic mouse. In a molecular biological analysis, sequence information in unknown regions of the Abcb11 gene was generated and the genomic structure of the gene was determined by using DNA fragments cloned in plasmids or BACs as well as by adapter ligated PCR (genome walking). The sequences of the gallstone sensitive mouse strain C57L/J and the resistant strain AKR/J were compared by single strand conformation polymorphism (SSCP) analysis and by direct sequencing of PCR fragments. The cDNA of both strains is identical. In the 5' region of the gene a C/T polymorphism was detected at -3.757, and in intron 1 19 single nucleotide exchanges as well as a 5 bp insertion and a 3 bp deletion were identified. The functional relevance of these polymorphisms was investigated in dual luciferase assays by cotransfection with nuclear receptors and in electrophoretic mobility shift assays (EMSAs). The experimental procedures were complemented by in silico sequence analyses. Even though a regulatory potential was shown for the analyzed regions, their function for the differential transcriptional regulation between the inbred mouse strain could not be proven. In order to investigate the physiological effect of an increased Abcb11 expression on cholesterol homeostasis, a genomic BAC library was screened for Abcb11 positive clones by using a radioactively labelled probe. Subsequently, the BAC DNA was isolated and purified. After microinjection into pronuclei of selected gallstone resistant mouse strains, two Abcb11 BAC transgenic founder lines on the 129S1/SvImJ background were generated. Employing Southern and Northern hybridizations it could be demonstrated, that both lines have 1 - 2 extra gene copies apart from their endogenous Abcb11 copies, which are integrated into their genomes and expressed correctly. The transgenic mice show a normal development and no visible phenotype. By feeding a cholesterol rich lithogenic diet, cholesterol crystallization and gallstone formation were induced. Transgenic mice display a higher gallstone susceptibility in comparison to wildtype controls. The generation of the BAC transgenic mouse opens new perspectives for in vivo investigations. It will deliver an important contribution to the question of the identity of the cholesterol gallstone locus Lith 1 and the canalicular bile salt export pump Abcb11 as well as to the investigation of the complex protein interactions in biliary cholesterol homeostasis

Comparison of F(ab') versus Fab antivenom for pit viper envenomation: A prospective, blinded, multicenter, randomized clinical trial

BACKGROUND: Crotalidae Polyvalent Immune Fab (Ovine) has been the only antivenom commercially available in the US since 2007 for treatment of Crotalinae envenomation. Late coagulopathy can occur or recur after clearance of Fab antivenom, often after hospital discharge, lasting in some cases more than 2 weeks. There have been serious, even fatal, bleeding complications associated with recurrence phenomena. Frequent follow-up is required, and additional intervention or hospitalization is often necessary. F(ab')2 immunoglobulin derivatives have longer plasma half life than do Fab. We hypothesized that F(ab')2 antivenom would be superior to Fab in the prevention of late coagulopathy following treatment of patients with Crotalinae envenomation. METHODS: We conducted a prospective, double-blind, randomized clinical trial, comparing late coagulopathy in snakebitten patients treated with F(ab')2 with maintenance doses [F(ab')2/F(ab')2], or F(ab')2 with placebo maintenance doses [F(ab')2/placebo], versus Fab with maintenance doses [Fab/Fab]. The primary efficacy endpoint was coagulopathy (platelet count &lt; 150 K/mm(3), fibrinogen level &lt; 150 mg/dL) between end of maintenance dosing and day 8. RESULTS: 121 patients were randomized at 18 clinical sites and received at least one dose of study drug. 114 completed the study. Of these, 11/37 (29.7%) in the Fab/Fab cohort experienced late coagulopathy versus 4/39 (10.3%, p &lt; 0.05) in the F(ab')2/F(ab')2 cohort and 2/38 (5.3%, p &lt; 0.05) in the F(ab')2/placebo cohort. The lowest heterologous protein exposure was with F(ab')2/placebo. No serious adverse events were related to study drug. In each study arm, one patient experienced an acute serum reaction and one experienced serum sickness. CONCLUSIONS: In this study, management of coagulopathic Crotalinae envenomation with longer-half-life F(ab')2 antivenom, with or without maintenance dosing, reduced the risk of subacute coagulopathy and bleeding following treatment of envenomation