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Abstract The goal of this work is to identify new fatty acid-mimetic 99mTc-complexes to be used as myocardial imaging agents that allow studying heart abnormalities in high-risk patients. In this sense, we designed a fatty acid-mimetic substructure including an amide moiety that, among other properties, could improve myocardial residence time. A diamide with a chain length of 15 atoms and porting a 6-hydrazinonicotinyl (HYNIC) chelator, and an analog with a short carbon-chain, were prepared with convergent organic synthetic procedures and radiolabeled with 99mTc using tricine as the sole coligand. The in vivo proofs of concept were performed using healthy mice. The new 99mTc-complexes were obtained with adequate radiochemical purity. The lipophilicities were in agreement with the length of the chains. While both 99mTc-complexes showed uptake in the myocardial muscle, the designed radiopharmaceutical with the longest chain length had preferential target-uptake and target-retention compared to other complexes described in the bibliography. Further studies, involving imaging assays, synthetic modifications, and assay of new coligands for 99mTc-HYNIC complexes, are currently ongoing.
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Objective To study the ambient radiation of patients undergoing 18F-FDG PET/CT myocardial metabolism imaging, and to provide data for protection of surrounding people against radiation. Methods A total of 33 patients were selected for 18F-FDG PET/CT myocardial metabolism imaging. Dose equivalent rate was measured at the height of patient chest, in different directions, at different time points and at different distances, to investigate the distribution of ambient radiation of the patient. Results At the same time point and distance, the dose equivalent rates at the left and right sides of the patient were lower than the front and back sides. The dose equivalent rate at 1 m in front of the patient was 13-21 μSv/h after 18F-FDG injection, and decreased to 5-14 μSv/h after PET/CT imaging, with a mean decrease of 46%. The ambient dose equivalent rate decreased exponentially with distance (10~300 cm), and the mean power was −1.2. Conclusion The ambient radiation of patients undergoing 18F-FDG PET/CT myocardial metabolism imaging was high after 18F-FDG injection, and the ambient dose equivalent rate decreased rapidly with time and distance. Our results suggest that patients undergoing myocardial metabolism imaging should avoid prolonged and close contact with other people on the day of examination.
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Objective 5-Hydroxytrytamine (5-HT) system was reported to be associated with myocardial infarction (MI) and depression. The aim of the present study was to study the effect of trimetazidine on 5-HT in MI and/or depression rats.Methods Ninety rats were divided into three groups:trimetazidine, sertraline and saline groups (n=30 in each group), and pretreated with trimetazidine, sertarline, or saline, respectively, by gavage once a day for 4 weeks. Thereafter, each group was further divided into three subgroups: MI subgroup, depression subgroup, and MI + depression subgroup. Serum 5-HT,platelet 5-HT,5-HT2A receptor(5-HT2AR),and serotonin transporter(SERT)were detected by enzyme linked immunosorbent assay. Results Similar to sertarline, comparing to saline, trimetazidine treatment increased serum 5-HT [(221±23) pg/ml vs. (176±11) pg/ml; (395±31) pg/ml vs. (195±5) pg/ml; (348±28) pg/ml vs.(183±10)pg/ml],platelet 5-HT[(305±22)pg/ml vs.(130±27)pg/ml;(252±18)pg/ml vs.(175±5) pg/ml;(241±26)pg/ml vs.(181±11)pg/ml],and platelet 5-HT2AR levels[(247±13)pg/ml vs.(197±12)pg/ml;(320±13)pg/ml vs.(193±18)pg/ml;(334±17)pg/ml vs.(206±15)pg/ml]),and lowered platelet SERT levels [(248±11)pg/ml vs.(323±36)pg/ml;(188±7)pg/ml vs.(278±20)pg/ml;(170±23)pg/ml vs.(282±22)pg/ml] in MI,depression and MI+depression subgroups,respectively(all P<0.05).When compared the effect of trimetazidine and sertarline treatment, serum 5-HT and platelet 5-HT2AR in MI group were significantly lower in trimetazidine than in sertraline group (P<0.05), while serum 5-HT and platelet 5-HT, 5-HT2AR in depression group rats were significantly higher in trimetazidine than in sertraline group (P<0.05).Interestingly,platelet 5-HT2AR in MI+depression rats was much higher in trimetazidine than in sertraline group(P<0.05).Conclusions Trimetazidine,a kind of myocardial metabolism agent,could play a role on the regulation of 5-HT,5-HT2AR,and SERT levels in rats with MI and/or depression.
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Objective: To assess the effect of coronary collateral circulation (CCC) on myocardial viabilityin patients with chronic total occlusion of left anterior descending (LAD) artery. Methods: A total of 101 consecutive patients with confirmed diagnosis of total LAD occlusion in our hospital were enrolled. Rest 99mTc-MIBISPECT myocardial perfusion and 18F-FDG PET were performed, in addition all patients received coronary angiography (CAG) at 3 months front and back. Both images were reconstructed in the same machine and QPS software was used to obtain the summed rest score (SRS), abnormal resting total perfusion defect (TPD), viable and non-viable myocardium, LVEDV, LVESV and LVEF in relevant patients. Based on CAG result, the patients were divided into 2 groups: CCC group, n=39 and No CCC group, n=62; according to existing old myocardial infarctionand location of LAD occlusion, the patients were further divided into 4 subgroups. The above parameters were compared among different groups. Results: There were 86 male and 15 female patients with the mean age at (59.92±11.43) years. Relevant parameters in CCC group and No CCC groupwere as in SRS: (21.23±9.68) vs (28.56±8.76), TPD: (30.03±13.69) %vs (40.37±12.50) %, viable myocardium: (21.77±13.12) % vs (13.66±9.23) %, non-viable myocardium (8.28±8.58) %vs (27.40±12.97) %, all P<0.05; in LVEDV: (109.82±30.01) ml vs (173.71±57.69) ml, LVESV: (62.82±22.39) ml vs (122.53±51.66) ml, LVEF: (43.85±8.46) % vs (31.03±8.30) %, all P<0.05. Conclusion: Our preliminary study found that CCC could maintain left ventricular rest perfusion, myocardial viability and protect cardiac function in patients with chronic total LAD occlusion.
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Objective To characterize myocardial metabolism using positron emission tomography (PET) in porcine models of ventricular fibrillation cardiac arrest (VFCA) and asphyxiation cardiac arrest (ACA) after resuscitation.Methods Thirty-two healthy miniature pigs were randomized into two groups.The pigs of VFCA group (n =16) were subject to programmed electric stimulation to create a ventricular fibrillation cardiac arrest,and the pigs of ACA group (n =16) were subjected to endotracheal tube clamping to establish a cardiac arrest (CA).Once modeling was established,pigs with CA were left untreated for a period of 8 min.Two minutes following initiation of cardiopulmonary resuscitation (CPR),defibrillation was attempted until the restoration of spontaneous circulation (ROSC) was achieved or animals died.To assess myocardial metabolism,PET was performed before modeling,4 hrs and 24hrs after ROSC.To analyze 18F-FDG myocardial uptake in PET,the maximum standardized uptake value (SUVmax)) was measured.Results ROSC was obtained in 100％ of pigs in VFCA group and only 50％ in ACA group.The average survival time in VFCA pigs was significantly longer than that in ACA pigs (22.63 ± 0.95) hvs.(8.75 ± 2.54) h,P ＜0.01.VFCA pigs had better mean arterial pressure and cardiac output after ROSC than ACA pigs.Myocardial metabolism imaging using PET demonstrated that myocardial metabolism injuries after ACA were more severe and widespread than those after VFCA at 4 hrs and 24hrs after ROSC and SUVmax) was much higher in VFCA group than that in ACA group [4 h after ROSC:(1.9 ± 0.3) vs.(1.0 ± 0.4),P ＜ 0.01;24 hafterROSC:(2.4±0.6) vs.(1.2±0.5),P＜0.01].Conclusions Compared with VFCA,ACA causes more severe cardiac metabolism dysfunction associated with less successful resuscitation and shorter survival time;therefore they should be treated as different pathological entities.
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Objective To study the effects of sodium bicarbonate (SB) on resuscitation in swine model of asphyxiation cardiac arrest (CA).Methods Thirty-two healthy miniature pigs were randomized (ramdom number) into two groups,the SB group (n =16) and the control group (n =16).Animals in both groups underwent endotracheal tube clamping to induce CA.Once induced,CA left untreated for a period of 8 minutes.At the beginning of initiation of cardiopulmonary resuscitation (CPR),SB (1.0 mEq/kg,diluted to 40 mL) was injected in central venous in SB group and isopyknic normal saline solution was injected in control group.Two minutes following initiation of CPR,defibrillation was attempted until return of spontaneous circulation (ROSC) was achieved or animals died.To assess the SB effects on myocardial metabolism,positron emission tomography (PET) was performed at baseline and 6 after ROSC.To analyze 18F-FDG myocardial uptake identified in PET,the maximum standardized uptake value (SUV) was measured.Results ROSC was 10/16 successful in SB group and only 8/16 successful in control group.The average survival time of SB group was (3.63 ± 0.76) h and that of control group was (2.45 0.70) h.Myocardial metabolism imaging using PET demonstrated that myocardial metabolism injuries in control group were more severe than in SB group at 6 h after ROSC and SUVmax was more higher in SB group than in control group (6 hrs after ROSC:1.32 ± 0.20 vs.1.10 ± 0.14,P =0.035).Conclusions In swine model of asphyxiation CA,SB improve the myocardial metabolism and might raise the possibility of ROSC and have no hypernatronemia.
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Myocardial metabolism activating drugs can increase the energy supply and decrease the energy consumption of the myocardial cells,playing a role in the nourishment and protection of cardiac muscles and the optimization of the energy metabolism.It is the adjuvant drug in treatment of myocarditis,myocardiosis,severe arrhythmia,acute or chronic heart failure and cardiosurgery,with an irreplaceable role in the salvage therapy of severe angiocardiopathy.Due to its safety and little side effects,it has been widely used in pediatrics.
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Objective To observe the protective effects of Diemailing Injection(DMLI) on experimental myocardial infarction in rats and its mechanism.Methods The experimental myocardial infarction model was induced by left anterior descending coronary occulusion for 24 h in rats.The rats were randomly divided into sham group,myyocardial infaction model group,DMLI groups with different doses(2.5,5.0,10.0 mL?kg~(-1))(n=20).The changes of myocardial infarction size(MIS),aspartate aminotransferase(AST),actate dehydrogenase(LDH),creatine phosphokinase(CK),superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) activities and malondialdehyde(MDA) content in serum,endothelin(ET) and angiotensinⅡ(AngⅡ) levels in plasma,and low shearing specific viscosity,middle shearing specific viscosity and high shearing specific viscosity of blood and specific viscosity of plasma were determined.At the same time,myocardial free fatty acid(FFA) contents of infarction and noninfarction area were determined.Results In rats treated by DMLI(in doses of 2.5,5.0 and 10.0 mL?kg~(-1) i.v after coronary occulusion),the MIS was significantly reduced(P
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0.05) after SVT episode. Compared to the SVT group and basic status, the extraction ration of glucose and oxygen of CAD patients obviously increased( P
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AIM To study the protective effects of total flavones metasequosia(TFM) on experimental acute myocardial infarction (AMI) in anaesthetized dogs. METHODS The parameters of coronary circulation and myocardial oxygen consumption, the degree and range of myocardial ischemia, myocardial infarct size, the activity of serum CK,LDH and the content of FFA were determined by using the AMI model of ligature of LAD in the anaesthetized open-chest dogs. RESULTS In dogs treated with TFM(in a dosage of 25, 100 mg?kg -1 , id), the myocardial oxygen consumption, degree and range of myocardial ischemia, myocardial infarct size, the activity of serum CK,LDH and the content of FFA were decreased. At the same time, myocardial blood flow was increased and coronary vascular resistance decreased significantly. CONCLUSION TFM possesses a protective effect on myocardial ischemia by modifying dysfunction of FFA, decreasing myocardial oxygen consumption and increasing myocardial blood supply.-