Biochemical markers in the diagnosis of myocardial infarction

Prognostic Value of High-Sensitivity Troponin T After On-Pump Coronary Artery Bypass Graft Surgery

INTRODUCTION

High-sensitivity troponin T (hs-TnT), as a single or serial measurement to predict postoperative mortality and morbidity, appears to be attractive due to its direct relationship in assessing myocardial damage and the widespread availability of hs-TnT testing. Therefore, this study aimed to identify any prognostic value of hs-TnT in predicting in-hospital outcomes after coronary artery bypass graft (CABG) surgery.

METHOD

We identified all consecutive patients who underwent on-pump CABG between July 2011 and December 2018. To evaluate the prognostic value of hs-TnT after CABG, we assessed the probability and odds ratio (OR) of adverse events concerning the maximum value of postoperative hs-TnT (measured within 24 hrs). TnT was routinely collected at 0, 6, 12 and 72 hours postoperatively. Values were categorised into intervals of 200 for analysis. A fully Bayesian logistic regression of the adverse event with the troponin T interval (0-200) as the reference level was used. A subgroup analysis was performed in patients with normal and elevated preoperative hs-TnT (< or ≥30 ng/L). The pre-specified primary outcome was a major adverse cardiac or cerebrovascular event (MACCE), defined as a composite of death within 30 days of operation for any cause, myocardial infection (MI), or stroke.

RESULTS

1,318 people underwent on-pump CABG during this period. One hundred and twenty-three (123) (9.3%) experienced MACCE, 14 (1.1%) experienced death within 30 days, 105 (8.0%) experienced MI and 14 (1.1%) experienced stroke. Compared to the reference category (hs-TnT ≤200 ng/L) we found there was an increase in OR with increasing level of hs-TnT for MACCE (p<0.001), 30-day mortality (p=0.003), MI (p<0.001) and ICU stay >48 hours (p<0.001). However, there was no statistically significant association present between hs-TnT and stroke, readmission to the intensive care unit (ICU), return to theatre for bleeding, or new-onset renal dysfunction.

CONCLUSION

Peak hs-TnT level, greater than 400 ng/L, measured within 24 hours after CABG surgery is associated with MACCE, 30-day mortality, MI and ICU stay >48 hours. Prospectively designed trials, with clear prognostic and outcome variables, may provide further insight into the prognostic value of hs-TnT post-CABG.

Protective Effect of Paeoniflorin on Acute Cerebral Infarction in Rats

OBJECTIVE

The purpose of this paper was to study the protective effect of paeoniflorin on acute cerebral ischemia. The animal model of cerebral infarction induced by Middle Cerebral Artery Occlusion (MCAO) was blocked by the suture method. Sixty SD rats were randomly divided into the shame group, MCAO group, paeoniflorin (60, 120, 240 mg/kg, respectively) and Nimodipine (NMDP) group (n = 10 per group).

METHODS

The rats were intragastrically administered immediately after the operation. After 7 days of gavage, the brains were decapitated at 24 h. Hematoxylin and Eosin (HE) staining was used to observe the degree of cell damage in the cerebral cortex of rats. Immunohistochemistry was used to detect silver plating and to observe changes in nerve cells. Rats in the model group showed obvious symptoms of neurological deficits, such as the ischemic morphological changed, the Malondialdehyde (MDA), Lactate Dehydrogenase (LD) content and lactate dehydrogenase (LDH) activity were significantly increased in the ischemic brain tissue, while the Superoxide Dismutase (SOD) activity was decreased.

RESULTS

The decrease in Na+-K+-ATPase activity was significantly lower than that in the sham group. The neurological symptoms and signs of MCAO in the different doses of paeoniflorin group were improved, and the neuronal edema in the cortical area was alleviated. The activities of SOD, LDH and Na+-K+-ATPase were significantly increased, and the contents of MDA and LD were decreased.

CONCLUSION

Therefore, paeoniflorin could alleviate the degree of tissue damage in rats with acute cerebral infarction, inhabit the formation of free radicals in the brain tissue after ischemia, and reduce the degree of lipid peroxidation. Thus, the degree of cell damage was reduced greatly and a protective effect was showed on cerebral ischemia.

Nanostructured aptamer-based sensing platform for highly sensitive recognition of myoglobin

A composite was prepared from PtSn nanoparticles and carbon nanotubes (PtSnNP/CNTs) and applied to the electrochemical determination of myoglobin (Mb). An Mb-aptamer was immobilized on a glassy carbon electrode (GCE), and hexcyanoferrate was used as an electrochemical probe. The PtSnNP/CNTs were synthesized by a microwave-aided ethylene glycol reduction method. Detection is based on electron transfer inhibition that is caused by the folding and conformational change of the Mb-aptamer in the presence of Mb. The amperometric signal for hexacyanoferrate, best measured at 0.2 V vs. Ag/AgCl depends on the concentration of Mb that interacts with the aptamer on the GCE. This approach is selective and sensitive for Mb due to (a) the highly specific recognition ability of the aptamer for Mb, (b) the powerful electronic properties of carbon nanotubes, (c) the arranged decoration of CNTs with PtSnNPs, and (d), the superior electron transfer to hexacyanoferrate. The assay is highly selective, with linear relationships from 0.01-1 nM and 10 nM-200 nM, and a limit of detection as low as 2.2 ± 0.1 pM. The modified GCE was applied to the quantitation of Mb in spiked human serum samples. Graphical abstract Schematic illustration of the method for Mb detection.