The effect of lanthanide and transition metal ions on the fluorescence spectra of the anticoagulation factor(ACF)of snake venom has been studied.It is postulated that the quenching of tryptophan residue fluorescence b...The effect of lanthanide and transition metal ions on the fluorescence spectra of the anticoagulation factor(ACF)of snake venom has been studied.It is postulated that the quenching of tryptophan residue fluorescence by lanthanide and transition metal ions is caused by the metal ion-induced conformation change of ACF.展开更多
The effects of Pr3+, Gd3+ ions on the H-1 NMR spectrum of anticoagulation factor (ACF) from snake venom were investigated. It was observed that the quartet peaks at delta 4.16 and the triplet peaks at delta 1.37 are g...The effects of Pr3+, Gd3+ ions on the H-1 NMR spectrum of anticoagulation factor (ACF) from snake venom were investigated. It was observed that the quartet peaks at delta 4.16 and the triplet peaks at delta 1.37 are gradually broadened with the increase of Pr3+ ion content, but the broadening effects of Pr3+ ion on the two single peaks at delta 1.99 and delta 2.29 were not observed obviously, and the obvious chemical shifts of all peaks induced by Pr3+ were not found. Two peaks contributed to alphaH and PH of the Ala side chain in ACF are broadened by Gd3+ ion, while two single peaks at delta 2.29 and delta 2.29 are not affected basically by Gd3+ ion. This result proves that the distance between the Ca2+-binding site in ACF and aH or PH of the Ala side chain in ACF is shorter than that between the Ca2+-binding site in ACF and proton in Met residue.展开更多
It was observed that rare earth ions (Nd 3+, Sm 3+, Eu 3+, Gd 3+, Tb 3+) have significant quenching effects on the fluorescence of anticoagulation factor I (ACF I). The results of the fluorescence titra...It was observed that rare earth ions (Nd 3+, Sm 3+, Eu 3+, Gd 3+, Tb 3+) have significant quenching effects on the fluorescence of anticoagulation factor I (ACF I). The results of the fluorescence titration of ACF I with rare earth ions demonstrate that ACF I has two RE 3+-binding sites, and the rare earth ions and Ca 2+ bind to ACF I competitively in the two similar sites. The association constants K 1 and K 2 of ACF I with each rare earth ions (Nd 3+, Sm 3+, Eu 3+, Gd 3+, Tb 3+) are close to each other, which indicates the structural similarity of the two binding sites in ACF I. Although the ionic radii of Nd 3+, Sm 3+, Eu 3+, Gd 3+ and Tb 3+ are different, both their K 1 and K 2 are similar, respectively. This reveals the conformational flexibility of the two binding sites in ACF I, which offers a possibility for Ca 2+ to take play in the inducing conformational changes of ACF I and the promoting the binding of ACF I with activated coagulation factor X.展开更多
Objective:To analyze the risk factors for death during hospitalization in patients with acute myocardial infarction(AMI)complicated by gastrointestinal bleeding(GIB).Methods:260 patients with AMI complicated by GIB wh...Objective:To analyze the risk factors for death during hospitalization in patients with acute myocardial infarction(AMI)complicated by gastrointestinal bleeding(GIB).Methods:260 patients with AMI complicated by GIB who were admitted to the cardiology department of a hospital from January 2022 to December 2023 were retrospectively analyzed.27 patients who died during hospitalization were designated as the control group and the 233 patients who survived as the observation group.Baseline data and clinical indexes of patients in the two groups were compared,and multifactorial logistic regression was applied to analyze the risk factors for death during hospitalization in patients with AMI complicated by GIB.Results:Univariate analysis showed that the control group had higher proportions of patients with Killip classification III to IV on admission,new arrhythmias,and mechanical complications,as well as higher heart rates,white blood cell counts,urea nitrogen,and creatinine levels.The proportion of patients who received transfusion therapy during hospitalization was also higher in the control group.Conversely,the control group had lower systolic and left ventricular ejection fraction rates compared to the observation group,with statistically significant differences(P<0.05).Multifactorial logistic regression analysis revealed that new-onset arrhythmia(OR=2.724,95%CI 1.289-5.759),heart rate>100 beats/min(OR=3.824,95%CI 1.472-9.927),left ventricular ejection fraction<50%(OR=1.884,95%CI 0.893-3.968),BUN level(OR=1.029,95%CI 1.007-1.052),and blood transfusion(OR=3.774,95%CI 1.124-6.345)were independently associated with an increased risk of death during hospitalization in patients with AMI complicated by GIB.Conclusions:New arrhythmia,heart rate>100 beats/min,left ventricular ejection fraction<50%,elevated BUN levels,and blood transfusion are risk factors for death during hospitalization in patients with AMI complicated by GIB.展开更多
基金Project supported by the National Natural Science Foundation of China
文摘The effect of lanthanide and transition metal ions on the fluorescence spectra of the anticoagulation factor(ACF)of snake venom has been studied.It is postulated that the quenching of tryptophan residue fluorescence by lanthanide and transition metal ions is caused by the metal ion-induced conformation change of ACF.
文摘The effects of Pr3+, Gd3+ ions on the H-1 NMR spectrum of anticoagulation factor (ACF) from snake venom were investigated. It was observed that the quartet peaks at delta 4.16 and the triplet peaks at delta 1.37 are gradually broadened with the increase of Pr3+ ion content, but the broadening effects of Pr3+ ion on the two single peaks at delta 1.99 and delta 2.29 were not observed obviously, and the obvious chemical shifts of all peaks induced by Pr3+ were not found. Two peaks contributed to alphaH and PH of the Ala side chain in ACF are broadened by Gd3+ ion, while two single peaks at delta 2.29 and delta 2.29 are not affected basically by Gd3+ ion. This result proves that the distance between the Ca2+-binding site in ACF and aH or PH of the Ala side chain in ACF is shorter than that between the Ca2+-binding site in ACF and proton in Met residue.
文摘It was observed that rare earth ions (Nd 3+, Sm 3+, Eu 3+, Gd 3+, Tb 3+) have significant quenching effects on the fluorescence of anticoagulation factor I (ACF I). The results of the fluorescence titration of ACF I with rare earth ions demonstrate that ACF I has two RE 3+-binding sites, and the rare earth ions and Ca 2+ bind to ACF I competitively in the two similar sites. The association constants K 1 and K 2 of ACF I with each rare earth ions (Nd 3+, Sm 3+, Eu 3+, Gd 3+, Tb 3+) are close to each other, which indicates the structural similarity of the two binding sites in ACF I. Although the ionic radii of Nd 3+, Sm 3+, Eu 3+, Gd 3+ and Tb 3+ are different, both their K 1 and K 2 are similar, respectively. This reveals the conformational flexibility of the two binding sites in ACF I, which offers a possibility for Ca 2+ to take play in the inducing conformational changes of ACF I and the promoting the binding of ACF I with activated coagulation factor X.
文摘Objective:To analyze the risk factors for death during hospitalization in patients with acute myocardial infarction(AMI)complicated by gastrointestinal bleeding(GIB).Methods:260 patients with AMI complicated by GIB who were admitted to the cardiology department of a hospital from January 2022 to December 2023 were retrospectively analyzed.27 patients who died during hospitalization were designated as the control group and the 233 patients who survived as the observation group.Baseline data and clinical indexes of patients in the two groups were compared,and multifactorial logistic regression was applied to analyze the risk factors for death during hospitalization in patients with AMI complicated by GIB.Results:Univariate analysis showed that the control group had higher proportions of patients with Killip classification III to IV on admission,new arrhythmias,and mechanical complications,as well as higher heart rates,white blood cell counts,urea nitrogen,and creatinine levels.The proportion of patients who received transfusion therapy during hospitalization was also higher in the control group.Conversely,the control group had lower systolic and left ventricular ejection fraction rates compared to the observation group,with statistically significant differences(P<0.05).Multifactorial logistic regression analysis revealed that new-onset arrhythmia(OR=2.724,95%CI 1.289-5.759),heart rate>100 beats/min(OR=3.824,95%CI 1.472-9.927),left ventricular ejection fraction<50%(OR=1.884,95%CI 0.893-3.968),BUN level(OR=1.029,95%CI 1.007-1.052),and blood transfusion(OR=3.774,95%CI 1.124-6.345)were independently associated with an increased risk of death during hospitalization in patients with AMI complicated by GIB.Conclusions:New arrhythmia,heart rate>100 beats/min,left ventricular ejection fraction<50%,elevated BUN levels,and blood transfusion are risk factors for death during hospitalization in patients with AMI complicated by GIB.
