Effect of iron overload on electrophysiology of slow reaction autorhythmic cells of left ventricular outflow tract in guinea pigs

Objective: To investigate the electrophysiology effects and mechanism of iron overload on the slow response autorhythmic cells in the left ventricular outflow tract of guinea pigs.Methods: Standard microelectrode cell recording techniques were adopted to observe the electrophysiological effects of different concentrations of Fe^(2+)(100 μmol/L, 200 μmol/L) on the left ventricular outflow tract autorhythmic cells.Heart tissues were perfused with FeSO_4(200 μmol/L) combing with CaCl_2(4.2 mmol/L), Verapamil,(1 μmol/L), and nickel chloride(200μmol/L) respectively to observe the influences of these contents on electrophysiology of FeSO_4(200μmol/L) on the left ventricular outflow tract autorhythmic cells.Results: Fe^(2+)at both 100 μmol/L and 200 μmol/L could change the electrophysiological parameters of the slow response autorhythmic cells of the left ventricular outflow tract in a concentrationdependent manner resulting into decrease in Vmax, APA and MDP, slower RPF and VDD, and prolonged APD_(50) and APD_(90)(P all <0.05).Besides, perfusion of increased Ca^(2+) concentration could partially offset the electrophysiological effects of Fe^(2+)(200 μmol/L).The L-type calcium channel(LTCC) blocker Verapamil(1 μmol/L) could block the electrophysiological effects of Fe^(2+)(200 μmol/L).But the T-type calcium channel(TTCC) blocker nickel chloride(NiCl_2, 200 μmol/L) could not block the electrophysiological effects of Fe^(2+)(200 μmol/L).Conclusions: Fe^(2+) can directly change the electrophysiological characteristics of the slow response autorhythmic cells of the left ventricular outflow tract probably through the L-type calcium channel.

Industrial Application of an Iron-Tolerant FCC Catalyst CMT-1HN

CMT-1HN(catalyst with metal trap),the new iron-tolerant catalyst for fluidized catalytic cracking(FCC),has been successfully applied in the resid catalytic cracking unit of Sinopec Hainan Refinery and Chemical Co.,Ltd(HNRC).Two test runs were carried out to compare its performance with that of the catalyst used in the Base run.The properties of the feedstocks and operating conditions were almost similar.During the first test run,the added iron on the catalyst reached 7628μg/g,and the total iron,nickel,vanadium,and calcium contents were equivalent to those in the base run.The yield of“LPG+gasoline”increased by 0.65 percentage points,and that of dry gas decreased by 45%;the volume ratio of hydrogen to methane decreased by 9.33%.During the second test run using the upgraded CMT-1HN catalyst,the added iron on the catalyst reached 6579μg/g,and the total iron,nickel,vanadium,and calcium contents reached 23210μg/g.The yield of“LPG+gasoline”increased by 1.15 percentage points,and that of dry gas decreased by 20%;the volume ratio of hydrogen to methane decreased by 20.67%.Industrial application of the CMT-1HN catalyst proved its strong tolerance to metal contamination,especially iron poisoning,as well as its strong bottom cracking ability,leading to improved product distribution.Using CMT-1HN,the tank-bottom crude at HNRC lying in storage since several years,which is the main source of iron contamination in the equilibrium FCC catalyst(FCC E-cat),can be continuously processed to ensure smooth and cost-effective execution of the process scheme in the refinery.