Objective To investigate the protective effects of ischemic postconditioning (IPo) on ischemiareperfusion (I/R) myocardium and the relationship with mitochondrial adenosine triphosphate (ATP) sensitive K+ channels (mitoKATP) and provide evidences to the development of druginduced postconditioning. Methods Langendorff models were established in 40 Wistar rats which were divided into 5 groups by random number table with 8 rats in each group. Normal control group(NC group): the rat hearts were continuously reperfused by KrebsHenseleit bicarbonate buffer (K-HB) for 100 min without any other treatment; I/R group: the rat hearts underwent a 40-min global ischemia followed by a 60-min reperfusion; IPo group: after a 40-min global ischemia, the process of 10-second reperfusion followed by a 10-second ischemia was repeated 6 times, then there was a continuous 58min reperfusion; 5-hydroxydecanoic acid(5-HD) group: after a 40min global ischemia, hearts with 5HD(100 μmol/L) K-HB were reperfused for 15min and then perfused without 5HD for 45min；IPo+5-HD group: after a 40-min global ischemia, the process that the isolated hearts with 5-HD(100 μmol/L) KHB were reperfused for 10second followed by a 10second ischemia was repeated 6 times, then the hearts with 5-HD(100 μmol/L) KHB were continuously [CM(159mm]perfused for 13-min followed by reperfusion without 5-HD(100 μmol/L) K-HB for 45-min. The cardiac function,coronary flow(CF), cardiac troponin I(cTnI) content in coronary effluent, the area of acute myocardial infarction (AMI) and myocardial ultrastructure were observed. Results Left ventricular developed pressure(74.3±3.3 mm Hg vs. 57.1±3.3 mm Hg,t=1300, P=0.000),+dp/dtmax(1 706.6±135.6 mm Hg/s vs. 1 313.3±96.2 mm Hg/s,t=6.28,P=0.000),－dp/dtmax(1 132.8±112.1 mm Hg/s vs. 575.7±67.7 mm Hg/s,t=13.48, P=0.000) and CF(6.49±0.30 ml/min vs. 3.70±0.24 ml/min,t=28.6,P=0.000) in IPo group were higher than those in I/R group. Left ventricular enddiastolic pressure(10.9±1.7mm Hg vs. 26.2±1.5 mm Hg,t=－19.21, P=0000)and cTnI content in coronary effluent (0.62±0.01 ng/ml vs. 0.71±0.01 ng/ml, t=-12.00,P=0.000) were lower than those in I/R group; the area of AMI decreased 20.8％ compared with that in I/R group (Plt;0.05). The myocardial protective effect in IPo+5HD group was similar with that in IPo group, but lower than that in IPo group. The electron microscope showed that IPo and IPo+5HD could reduce myocardial fiber damage and mitochondrial damage caused by I/R. Conclusion IPo can protect I/R myocardium, which is achieved mainly by activating mitoK-ATP channels.
Objective To analyze the research hotspots and trends in the field of hyperkalemia in hemodialysis patients at home and abroad, and to provide reference for the research and prevention and control of hyperkalemia in hemodialysis patients. Methods China National Knowledge Infrastructure (CNKI) and Web of Science databases were searched by computer for literature about the hyperkalemia in hemodialysis patients published between January 1995 and January 2023. The included literature was analyzed using visualization analysis tools for visualization, including high-frequency keywords, keyword co-occurrence map, keyword emergence intensity and keyword time series prediction. Results A total of 10 275 articles were included. Among them, there were 10 036 articles from web of science and 239 articles from CNKI. The number of articles in this research field showed a trend of steady increase year by year. The United States was in a leading position in the research and development in this field, followed by China. At the same time, the research in this field presents the characteristics of multidisciplinary integration. The development trends of research hotspots in the next 5 years were risk and health education research. Conclusions The number of research articles related to hyperkalemia in hemodialysis patients is gradually increasing. Multidisciplinary approach and integration is a research hotspot and frontier in the development of hyperkalemia in hemodialysis patients both domestically and internationally.
Objective To evaluate the safety and efficacy of potassium and magnesium supplement with potassium aspartate and magnesium aspartate injection in gastrointestinal surgery patients during absolute fasting．Methods A multicenter randomized controlled clinical trial was conducted in 111 patients after gastrointestinal surgery. For trial group，56 patients were given potassium aspartate and magnesium aspartate injection （Panangin®） in half of the total potassium replenished dose and the rest half of the potassium replenished dose was given in 10% potassium chloride injection．For control group，55 patients were given 10% potassium chloride injection for the total dose of potassium replenished．Such treatments maintained five consecutive days after surgical operation．Clinical observations were performed until patients were discharged from the hospitals．Results Before the intervention，there were no significant differences for the baseline between two groups （P＞0.05）．There was no significant difference for the serum potassium level between two groups （P＞0.05） after intervention．The amount of urinary potassium （mmol/24 h） for patients in the trial group was significantly lower than that in the control group during treatment after operation．The serum magnesium level of control group was much lower than that of control group （P＜0.05）. In the clinical observation process，no drug-related adverse event was observed．Conclusions The supplementary effect of potassium and magnesium for potassium aspartate and magnesium aspartate injection in patients with gastrointestinal surgery during absolute fasting is significant，and superior to potassium chloride injection for potassium supplement．Potassium aspartate and magnesium aspartate injection is a safe and appropriate choice for patients with potassium depletion．
Objective To investigate the role of mitochondrial adenosine triphosphatesensitive potassium channel(mitoKATP) in immature myocardial ischemic preconditioning, and to provide evidence for immature myocardial protection. Methods Langendorff isolated heart infused model was used in the experiment. Twentyfour rabbits (aged from 14 to 21 days) were randomly divided into 4 groups：ischemiareperfusion group（I/R group）, myocardial ischemic preconditioning group(E1 group), 5hydroxydecanoate(5-HD) group (E2 group) and Diazoxide (Diaz) group(E3 group). Hemodynamics recovery rate, myocardial water content(MWC), the leakage rates of serum creatine kinase and lactate dehydrogenase, adenosine triphosphate content, superoxide dismutase activity, malondialdehyde content, myocardial cell Ca2+ content and myocardial mitochondrial Ca2+ content, myocardial mitochondrial Ca2+-ATPase activity, the adenosine triphosphate(ATP) synthesizing ability of myocardial mitochondria were tested, and myocardial ultrastructure was observed via electron microscopy. Results The hemodynamics recovery rate, myocardial water content(P＜0.05), adenosine triphosphate content, superoxide dismutase activity, myocardial mitochondrial Ca2+-adenosine triphosphyatase(ATPase) activity and the ATP synthesizing ability of myocardial mitochondria of the rabbits in E1 and E3 group were significantly better than that in I/R group and E2 group(P＜0.05). Malondialdehyde content, the leakage rates of serum creatine kinase and lactate dehydrogenase, myocardial cell Ca2+ content and myocardial mitochondrial Ca2+ content of the rabbits in E1 group and E3 group were significantly lower than that in I/R group and E2 group (P＜0.05). The myocardial ultrastructure injury in E1 and E3 group were significantly reduced compared with that in I/R and E2 group. Conclusion Myocardial ischemic preconditioning has significant protective effects on immature myocardium. Its mechanism may be related to the activation of mitoKATP.
Weightlessness in the space environment affects astronauts’ learning memory and cognitive function. Repetitive transcranial magnetic stimulation has been shown to be effective in improving cognitive dysfunction. In this study, we investigated the effects of repetitive transcranial magnetic stimulation on neural excitability and ion channels in simulated weightlessness mice from a neurophysiological perspective. Young C57 mice were divided into control, hindlimb unloading and magnetic stimulation groups. The mice in the hindlimb unloading and magnetic stimulation groups were treated with hindlimb unloading for 14 days to establish a simulated weightlessness model, while the mice in the magnetic stimulation group were subjected to 14 days of repetitive transcranial magnetic stimulation. Using isolated brain slice patch clamp experiments, the relevant indexes of action potential and the kinetic property changes of voltage-gated sodium and potassium channels were detected to analyze the excitability of neurons and their ion channel mechanisms. The results showed that the behavioral cognitive ability and neuronal excitability of the mice decreased significantly with hindlimb unloading. Repetitive transcranial magnetic stimulation could significantly improve the cognitive impairment and neuroelectrophysiological indexes of the hindlimb unloading mice. Repetitive transcranial magnetic stimulation may change the activation, inactivation and reactivation process of sodium and potassium ion channels by promoting sodium ion outflow and inhibiting potassium ion, and affect the dynamic characteristics of ion channels, so as to enhance the excitability of single neurons and improve the cognitive damage and spatial memory ability of hindlimb unloading mice.
The effects on rat’s liver preservation using HX solation with high potassium and low sodium or HXm solution with high sodium and low potassium were studied with isolated perfusion of rat livers (IPRL). Sixty inbred Wistar rats were randomly divided into group HX (preserved with HX solution, n=30) and group HXm (preserved with HXm solution,n=30). The preservation effects of the storage solutions were assessed by measuring the sinunoidal lining cell mortality (SLCM), the Krebs-hense-leit perfusate ketone bidy ratio (PKBR), the hepatic sugar release (SL), and the hepatic tissue water content (HTWC). The results showed that there no significant differences between the two storage solutions after 6 hours preservation. If the preserved time was prolonged to 12 hours or more, the effect of rat’s liver preservation using HX solution were much superior to those using HXmsolutin.