Serum markers in the emergency department diagnosis of acute myocardial infarction

piRNAs as emerging biomarkers and physiological regulatory molecules in cardiovascular disease

Cardiovascular diseases (CVD) represent one of the most considerable global health threats, owing to their high incidence and mortality rates. Despite the ongoing advancements in detection, prevention, treatment, and prognosis of CVD, which have resulted in a decline in both incidence and mortality rates, CVD remains a major public health concern. Therefore, novel diagnostic biomarkers and therapeutic interventions are imperative to minimise the risk of CVD. Non-coding RNAs (ncRNAs) have recently gained increasing attention, with PIWI-interacting RNAs (piRNAs) emerging as a class of small ncRNAs traditionally recognised for their role in silencing transposons within cells. Although the functional roles of PIWI proteins and piRNAs in human cells remain unclear, growing evidence suggests that these molecules are gradually becoming valuable biomarkers for the diagnosis and treatment of CVD. This review provides a comprehensive summary of the latest studies on piRNAs in CVD. This review discusses the roles of piRNAs in various cardiovascular subtypes, including myocardial hypertrophy, heart failure, myocardial infarction, and cardiac regeneration. The perceived insights may contribute novel perspectives for the diagnosis and treatment of CVD.

Expression and diagnostic value of PIWI-interacting RNA by serum in acute myocardial infarction

OBJECTIVE

To detect the expression level of PIWI-interacting RNA in the serum of patients with acute myocardial infarction, and to explore the role of PIWI-interacting RNA in acute myocardial infarction.

METHODS

RNA was extracted from the serum of acute myocardial infarction patients and healthy subjects, and high-throughput sequencing of PIWI-interacting RNAs was performed to screen differentially expressed PIWI-interacting RNAs. Quantitative polymerase chain reaction was used to detect the expression of four differentially expressed PIWI-interacting RNAs in 52 patients with acute myocardial infarction and 30 healthy people. Receiver operating characteristic (ROC) curve was further used to analyze the correlation between differentially expressed PIWI-interacting RNAs and the occurrence of acute myocardial infarction. Kyoto Encyclopedia of Genes and Genomes analysis was used to analyze the role of PIWI-interacting RNA in the occurrence of acute myocardial infarction.

RESULTS

RNA sequencing and bioinformatics analysis revealed that most piRNAs were upregulated in AMI patients, with 195 upregulated and 13 downregulated. Among them, piR-hsa-9010, piR-hsa-28646, and piR-hsa-23619 were significantly up-regulated in the serum of patients with acute myocardial infarction, but their expression in the acute heart failure group and coronary heart disease group was not significantly different from that in the healthy group. ROC curve analysis showed that piR-hsa-9010, piR-hsa-28646, and piR-hsa-23619 had high diagnostic values in acute myocardial infarction. In vitro, there was no significant difference in the expression of piR-hsa-9010 among THP-1, HUVEC, and AC16, while the expression of piR-hsa-28646 and piR-hsa-23619 in HUVEC was significantly higher than that in THP-1 and AC16. Pathway analysis showed that piR-hsa-23619 was mainly involved in TNF signaling pathway, and piR-hsa-28646 was mainly involved in Wnt signaling pathway.

CONCLUSION

piR-hsa-9010, piR-hsa-28646, and piR-hsa-23619 were significantly up-regulated in the serum of patients with acute myocardial infarction. It can be used as a new biomarker for the diagnosis of acute myocardial infarction, which may be a therapeutic target for acute myocardial infarction.

Diagnostic Performance of Serum MicroRNAs for ST-Segment Elevation Myocardial Infarction in the Emergency Department

Prompt diagnosis of ST-segment elevation myocardial infarction (STEMI) is essential for initiating timely treatment. MicroRNAs have recently emerged as biomarkers in cardiovascular diseases. This study aimed to evaluate the discriminatory capacity of serum microRNAs in identifying an ischemic origin in patients presenting with chest discomfort to the Emergency Department. The study included 98 participants (78 with STEMI and 20 with nonischemic chest discomfort). Significant differences in the expression levels of miR-133b, miR-126, and miR-155 (but not miR-1, miR-208, and miR-208b) were observed between groups. miR-133b and miR-155 exhibited 97% and 93% sensitivity in identifying STEMI patients, respectively. miR-126 demonstrated a specificity of 90% in identifying STEMI patients. No significant associations were found between microRNAs and occurrence of major adverse cardiovascular events (MACE). However, patients with MACE had higher levels of interleukin (IL)-15, IL-21, IFN-γ-induced protein-10, and N-terminal pro B-type natriuretic peptide compared to non-MACE patients. Overall, there were significant associations among the expression levels of microRNAs. However, microRNAs did not demonstrate associations with either inflammatory markers or cardiovascular risk scores. This study highlights the potential of microRNAs, particularly miR-133b and miR-126, as diagnostic biomarkers for distinguishing patients with STEMI from those presenting with nonischemic chest discomfort to the Emergency Department.

Antioxidant Flavonoid Diosmetin Is Cardioprotective in a Rat Model of Myocardial Infarction Induced by Beta 1-Adrenergic Receptors Activation

Myocardial infarction (MI) is a common and life-threatening manifestation of ischemic heart diseases (IHD). The most important risk factor for MI is hypertension. Natural products from medicinal plants have gained considerable attention globally due to their preventive and therapeutic effects. Flavonoids have been found to be efficacious in ischemic heart diseases (IHD) by alleviating oxidative stress and beta-1 adrenergic activation, but the mechanistic link is not clear. We hypothesized that antioxidant flavonoid diosmetin is cardioprotective in a rat model of MI induced by beta 1-adrenergic receptor activation. To test this hypothesis, we evaluated the cardioprotective potential of diosmetin on isoproterenol-induced MI in rats by performing lead II electrocardiography (ECG), cardiac biomarkers including troponin I (cTnI) and creatinine phosphokinase (CPK), CK-myocardial band, (CK-MB), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and aspartate aminotranferase (AST) by using biolyzer 100, as well as histopathological analysis. We found that diosmetin (1 and 3 mg/kg) attenuated isoproterenol-induced elevation in the T-wave and deep Q-wave on the ECG, as well as heart-to-body weight ratio and infarction size. In addition, pretreatment with diosmetin attenuated the isoproterenol-induced increase in serum troponin I. These results demonstrate that flavonoid diosmetin may provide therapeutic benefit in myocardial infarction.

Juglone from Walnut Produces Cardioprotective Effects against Isoproterenol-Induced Myocardial Injury in SD Rats

Therapeutic and/or preventive interventions using phytochemical constituents for ischemic heart disease have gained considerable attention worldwide, mainly due to their antioxidant activity. This study investigated the cardioprotective effect and possible mechanism of juglone, a major constituent of the walnut tree, using an isoproterenol (ISO)-induced myocardial infarction (MI) model in rats. Rats were pretreated for five (5) days with juglone (1, 3 mg/kg, i.p) and atenolol (1 mg/kg, i.p) in separate experiments before inducing myocardial injury by administration of ISO (80 mg/kg, s.c) at an interval of 24 h for 2 consecutive days (4th and 5th day). The cardioprotective effect of juglone was confirmed through a lead II electrocardiograph (ECG), cardiac biomarkers (cTnI, CPK, CK-MB, LDH, ALT and AST) and histopathological study. The results of our present study suggest that prior administration of juglone (1 and 3 mg/kg) proved to be effective as a cardioprotective therapeutic agent in reducing the extent of myocardial damage (induced by ISO) by fortifying the myocardial cell membrane, preventing elevated T-waves, deep Q-waves in the ECG, heart to body weight ratio, infarction and also by normalizing cardiac marker enzymes (cTnI, CPK, CK-MB, LDH, ALT and AST) and histopathological changes, such as inflammation, edema and necrosis. In conclusion, this study has identified phytochemical constituents, in particular juglone, as a potential cardioprotective agent.

Synthesis of Fluorescent Titanium Nanoclusters at ambient temperature for highly sensitive and selective detection of Creatine Kinase MM in myocardial infarction

Fluorescent-based biosensing in Photoluminescence nanomaterials has emerged as a new sensing platform commonly used for disease diagnosis. However, the synthesis of Titanium nanoclusters is highly challenging since Titanium is easily oxidized into TiO₂ at ambient temperature. To overcome this problem, we used an acidic medium and simple and robust protocol to synthesize the Titanium nanoclusters of 3-4 nm diameter, which could report the first fluorescent Titanium nanoclusters. New approaches for the novel synthesis of TiNCs can be used for rapid sensing of myocardial infarction (cardiac arrest). In converting creatine to phosphocreatine, CK-MM activates the reaction to convert ATP to ADP, thereby releasing the phosphate groups. Titanium nanoclusters bind strongly to the phosphate group and then quench the Fluorescence. Thus, this phenomenon can be further applied for quantification approaches. The quenching of fluorescence intensity with CK-MM concentration is linear with R² = 0.9829. The current approach can be applied for CK-MM sensing for a wide concentration range (0.625 U/L - 10 U/L). The detection limit was 0.2513 ng/ml in aqueous medium and 0.3465 ng/ml in human serum with high sensitivity when compared with the previous reported methods. Also, this is the first fluorescent-based sensing method to detect CK- MM. The fluorescent TiNCs is a novel platform to be widely applied for the phosphopeptide and phosphoprotein analysis due to the strong and covalent bondings between Ti with P atoms in the near future in medicine, biomedicine, and biological fields.

Up-Regulation of Cell-Free MicroRNA-1 and MicroRNA-221-3p Levels in Patients with Myocardial Infarction Undergoing Coronary Angiography

Purpose: Myocardial infarction (MI), known as a multifactorial disease, remains the predominant cause of mortality and sudden deaths annually. The current study aimed to measure the expression of microRNA-1 and microRNA-221-3p in MI patients.

Methods: In the current study, 100 healthy controls (with no history of heart disease) and 200 patients with MI were selected. Patients were divided into two groups based on angiography results: normal (no significant artery stenosis) and primary percutaneous coronary intervention (primary PCI, significant artery stenosis). The levels of microRNA-1 and microRNA-221-3p were quantified using real-time quantitative polymerase chain reaction. The correlation between levels of microRNAs and the common cardiac markers were analyzed statistically.

Results: In comparison to fold change, microRNA-1 elevations were 8.5-fold in normal patients and 60-fold in patients with primary PCI; while microRNA-221-3p levels were 210- fold higher in primary PCI and 31.31-fold higher in normal cases compared with the healthy controls. Receiver operating characteristic analysis showed that the area under the curve (AUC) for circulating microRNA-1 and microRNA-221 were 0.903 and 0.958 in normal patients and 0.927 and 0.985 in primary PCI patients (p < 0.0001), respectively. Pearson correlation (ρ) analysis showed that circulation of microRNA-1 correlated with serum levels of cardiac troponin I (CTnI) (ρ =0.24), creatinine (ρ =0.34), creatinine kinase-myocardial band (CK-MB) (ρ =0.31), and microRNA-221-3p was significantly correlated with serum levels of CTnI (ρ =0.6), creatinine (ρ =0.41), and CK-MB (ρ =0.37), (P < 0.0001).

Conclusion: The study underscored the potential of microRNA-1 and microRNA-221-3p as informative biomarkers and positively correlated with artery stenosis in MI.

Role of Creatine Kinase in the Troponin Era: A Systematic Review

Introduction

The diagnosis of non-ST-elevated myocardial infarction (NSTEMI) depends on a combination of history, electrocardiogram, and cardiac biomarkers. The most sensitive and specific biomarkers for cardiac injury are the troponin assays. Many hospitals continue to automatically order less sensitive and less specific biomarkers such as creatine kinase (CK) alongside cardiac troponin (cTn) for workup of patients with chest pain. The objective of this systematic review was to identify whether CK testing is useful in the workup of patients with NSTEMI symptoms.

Methods

We undertook a systematic review to ascertain whether CK ordered as part of the workup for NSTEMI was useful in screening patients with cardiac chest pain. The MEDLINE, Embase, and Cochrane databases were searched from January 1995–September 2020. Additional papers were added after consultation with experts. We screened a total of 2,865 papers, of which eight were included in the final analysis. These papers all compared CK and cTn for NSTEMI diagnosis.

Results

In each of the eight papers included in the analysis, cTn showed a greater sensitivity and specificity than CK in the diagnosis of NSTEMI. Furthermore, none of the articles published reliable evidence that CK is useful in NSTEMI diagnosis when troponin was negative.

Conclusion

There is no evidence to continue to use CK as part of the workup of NSTEMI acute coronary syndrome in undifferentiated chest pain patients. We conclude that CK should not be used to screen patients presenting to the emergency department with chest pain.

Gold Nano/Micro-Islands Overcome the Molecularly Imprinted Polymer Limitations to Achieve Ultrasensitive Protein Detection

Here, we report on an electrochemical biosensor based on core-shell structure of gold nano/micro-islands (NMIs) and electropolymerized imprinted ortho-phenylenediamine (o-PD) for detection of heart-fatty acid binding protein (H-FABP). The shape and distribution of NMIs (the core) were tuned by controlled electrodeposition of gold on a thin layer of electrochemically reduced graphene oxide (ERGO). NMIs feature a large active surface area to achieve a low detection limit (2.29 fg mL^-1, a sensitivity of 1.34 × 10¹³ μA mM^-1) and a wide linear range of detection (1 fg mL^-1 to 100 ng mL^-1) in PBS. Facile template H-FABP removal from the layer (the shell) in less than 1 min, high specificity against interference from myoglobin and troponin T, great stability at ambient temperature, and rapidity in detection of H-FABP (approximately 30 s) are other advantages of this biomimetic biosensor. The electrochemical measurements in human serum, human plasma, and bovine serum showed acceptable recovery (between 91.1 ± 1.7 and 112.9 ± 2.1%) in comparison with the ELISA method. Moreover, the performance of the biosensor in clinical serum showed lower detection time and limit of detection against lateral flow assay (LFA) rapid test kits, as a reference method. Ultimately, the proposed biosensor based on the core-shell structure of gold NMIs and MIP opens interesting avenues in the detection of proteins with low cost, high sensitivity and significantstability for clinical applications.

Interventional cardiac catheterization predictors at Al-Arabi heart Center in Palestine in 2017

Background

Cardiac catheterization is performed for both therapeutic and diagnostic reasons, in which the outcome may vary from only medical treatment to the need of percutaneous coronary intervention and ending with coronary artery bypass graft. The primary goal of this study was to determine predictors of revascularization.

Methods

A retrospective cohort study was conducted on data collected from records of patients who underwent cardiac catheterization at Al-Arabi Heart Center in Palestine in 2017. Multivariate logistic regression analysis was carried out to assess the association of sociodemographic and pre-catheterization clinical predictors with revascularization.

Results

A total of 1550 patients were included in the study. The participants mean age was 58 with a SD of 11.7 years, 73.6% were males. 50.2% of patients who underwent an interventional cardiac catheterization tested negative for troponin on presentation. Multivariate logistic regression showed Troponin (RR = 4.5), Age (RR = 1.0), Female gender (RR = 0.4) previous catheterization (RR = 2.0), and existence of diabetes as significant predictors for revascularization. The correlation between ECG on presentation and the subsequent need for an interventional cardiac catheterization was significant only in case of ST-Elevation (RR = 1.5), and T wave inversion (RR = 1.6). CK-MB, Hypertension and ECG with ST-depression were not significant predictors.

Conclusion

This study assessed revascularization predictors in addition to characteristics and outcomes of patients who have undergone cardiac catheterization. The results showed the especially high predictive value of troponin in determining the need for revascularization which outweighed the importance of ECG findings on presentation in making clinical decision regarding catheterization.

Selective Recognition of Myoglobin in Biological Samples Using Molecularly Imprinted Polymer-Based Affinity Traps

The current work demonstrates the design, characterization, and preparation of molecularly imprinted microspheres for the selective detection of myoglobin in serum samples. The suspension polymerization approach was applied for the preparation of myoglobin imprinted microspheres. For this purpose, N-methacryloylamino folic acid-Nd3+ (MAFol- Nd3+) was chosen as the complex functional monomer. The optimization studies were performed changing the medium pH, temperature, and myoglobin concentration. pH 7.0 was determined as the optimum value where the prepared imprinted microspheres displayed maximum binding for myoglobin. The maximum binding capacity was achieved as 623 mgg-1. In addition, the selectivity studies were conducted. The results confirmed that the imprinted microspheres showed great selectivity towards myoglobin in the existence of hemoglobin, cytochrome c, and lysozyme which were chosen as potentially competing proteins.

Is the Yellow Knight Mushroom Edible or Not? A Systematic Review and Critical Viewpoints on the Toxicity of Tricholoma equestre

There is no scientific consensus regarding the safety of the Yellow Knight mushroom Tricholoma equestre (L.) P.Kumm. Following reports of cases of intoxication involving effects such as rhabdomyolysis, and supportive observations from in vivo experimental models, T. equestre is considered as a poisonous mushroom in some countries while in others it is still widely collected from the wild and consumed every year. In this paper, we review all the available information on T. equestre including its morphological and molecular characterization, nutritional value, levels of contaminants observed in fruiting bodies, the possibility of mistake with species that are morphologically similar, and the in vivo data on safety and cases of human intoxication. Based on available data, it is suggested that T. equestre cannot be considered as a toxic species and does not appear to exhibit any greater health threat than other mushroom species currently considered as edible. More care should be taken when reporting cases of human poisoning to fully identify T. equestre as the causative agent and to exclude a number of interfering factors. Specific guidelines for reporting future cases of poisoning with T. equestre are outlined in this paper. Any future research involving T. equestre should present the results of molecular phylogenetic analyses.

Aggregation of cysteamine-capped gold nanoparticles in presence of ATP as an analytical tool for rapid detection of creatine kinase (CK-MM)

Creatine kinase, a key biomarker associated with many debilitating physiological conditions has seldom been detected in biological fluids using functionalized gold nanoparticles (GNPs). We have developed a method based on the aggregation of cysteamine (Cys) functionalized GNPs in presence of ATP for effective detection of creatine kinase (CK-MM). Positively charged Cys-GNPs (brick red color) aggregate in presence of negatively charged ATP (blue color) but the process is prevented when CK-MM is added to the solution. The analytical response to the concentration of CK-MM is linear (R² = 0.9850). The proposed method is selective in sensing the CK-MM for a range of 5.617 × 10³ ng/ml, 0.5617 ng/ml. The limit of detection was found to be 0.569 ng/ml in solution and 0.553 ng/ml in human serum with high selectivity.

Higher prevalence of detectable troponin I among cocaine-users without known cardiovascular disease

BACKGROUND

While cocaine use is an established risk factor for acute cardiovascular complications, associations between cocaine use and markers of cardiac injury outside of acute hospital presentation remain poorly characterized. We leveraged advances in cardiac troponin (cTnI) testing to assess low but clinically meaningful levels of cardiac injury among cocaine users and non-users.

METHODS

We conducted a case control study comparing cTnI levels by the presence of cocaine among patients presenting for non-cardiac care in an urban safety net hospital. Samples were chosen sequentially among those for which urine drug screens were ordered by providers hospital-wide.

RESULTS

During 2015, 14% of all hospital drug screens ordered were cocaine-positive. Among unique persons providing cocaine-positive (N=100) and cocaine-negative (N=100) samples, 37% were female, 45% were African-American and the median age was 51. Detectable cTnI (> 0.02ng/mL) was observed in 21 samples (11%). It was more common in subjects using cocaine (Adjusted OR=2.81; 95% CI=1.03-7.65), but not other drugs. Moreover, there was a significant correlation between concentrations of cTnI and the cocaine metabolite, benzoylecgonine (Spearman Correlation=0.34, p<0.01).

CONCLUSIONS

Among urban safety net hospital patients, 11% had detectable cTnI, and cTnI concentration was significantly correlated with benzoylecgonine concentration. While these preliminary results require additional confirmation, they suggest the potential utility of considering cocaine use as more than just an episodic exposure leading to acute cardiac events. The consideration of cocaine use as an ongoing chronic exposure leading to subclinical cardiac injury may improve risk-stratification and patient outcomes in populations where cocaine use is high.

Post-MI free wall rupture syndrome. Case report, literature review, and new terminology

Common clinical features of subacute rupture left ventricular free wall after acute ST segment elevation myocardial infarction are: (1) recurrent or persistent chest pain; (2) recurrent or persistent ST segment elevation; (3) hypotension. Integrating these signs into a syndrome can increase the clinician's awareness to the fatal complication.

Treg/Th17 ratio acts as a novel indicator for acute coronary syndrome

The imbalance of CD4(+)CD25(+) regulatory T (Treg) cells and Th17 cells has shown to be involved in pathogenesis of atherosclerosis and acute coronary syndrome [ACS, including unstable angina (UA) and acute myocardial infarction (AMI)]. The purpose of this study is to explore the significance of Treg/Th17 ratio in early diagnosis for ACS. We detected expression of Treg and Th17 in patients with AMI, UA, stable angina, and subjects with normal coronary arteries at the time of admission. Our results showed that ACS patients have a significant increase of Th17 number, but a marked decline of Treg/Th17 ratio, Treg number, and Treg function. Significant positive correlations in Th17 frequency and negative correlation in Treg frequency, Treg/Th17 ratio were found to levels of oxidized low-density lipoprotein (Ox-LDL), high sensitive C-reactive protein (hsCRP), Lipoprotein (a) [Lp(a)], and Creatine kinase-MB(mass) (CK-MBmass) in serum. Receiver-operating characteristic curves shown that the predictive specificity and sensitivity of Treg/Th17 ratio for ACS and AMI was the highest among all the five markers: Ox-LDL, hsCRP, Lp(a), CK-MBmass, and Treg/Th17 ratio. In conclusion, Treg/Th17 ratio appeared to be a novel indicator for early diagnosis of ACS.

Endobiogeny: a global approach to systems biology (part 2 of 2)

ENDOBIOGENY AND THE BIOLOGY OF FUNCTIONS ARE BASED ON FOUR SCIENTIFIC CONCEPTS THAT ARE KNOWN AND GENERALLY ACCEPTED: (1) human physiology is complex and multifactorial and exhibits the properties of a system; (2) the endocrine system manages metabolism, which is the basis of the continuity of life; (3) the metabolic activity managed by the endocrine system results in the output of biomarkers that reflect the functional achievement of specific aspects of metabolism; and (4) when biomarkers are related to each other in ratios, it contextualizes one type of function relative to another to which is it linked anatomically, sequentially, chronologically, biochemically, etc.

Perspectives on the value of biomarkers in acute cardiac care and implications for strategic management

Biomarkers in acute cardiac care are gaining increasing interest given their clinical benefits. This study is a review of the major conditions in acute cardiac care, with a focus on biomarkers for diagnostic and prognostic assessment. Through a PubMed search, 110 relevant articles were selected. The most commonly used cardiac biomarkers (cardiac troponin, natriuretic peptides, and C-reactive protein) are presented first, followed by a description of variable acute cardiac conditions with their relevant biomarkers. In addition to the conventional use of natriuretic peptides, cardiac troponin, and C-reactive protein, other biomarkers are outlined in variable critical conditions that may be related to acute cardiac illness. These include ST2 and chromogranin A in acute dyspnea and acute heart failure, matrix metalloproteinase in acute chest pain, heart-type fatty acid binding protein in acute coronary syndrome, CD40 ligand and interleukin-6 in acute myocardial infarction, blood ammonia and lactate in cardiac arrest, as well as tumor necrosis factor-alpha in atrial fibrillation. Endothelial dysfunction, oxidative stress and inflammation are involved in the physiopathology of most cardiac diseases, whether acute or chronic. In summary, natriuretic peptides, cardiac troponin, C-reactive protein are currently the most relevant biomarkers in acute cardiac care. Point-of-care testing and multi-markers use are essential for prompt diagnostic approach and tailored strategic management.

Whole blood viscosity assessment issues II: Prevalence in endothelial dysfunction and hypercoagulation

Background:

Virchow's triad in cardiovascular disease comprises blood viscosity, plasma D-dimer and homocysteine as indices of three associated but separate vascular phenomena.

Aims:

This work investigates prevalence of hyperviscosity in hyperhomocysteinaemia and positive D-dimer; and differences or similarities in stasis status among sub-populations of hyperhomocysteinaemia vs. normohomocysteinaemia and negative vs. positive D-dimer.

Patients and Methods:

10-years de-identified archived clinical pathology data for the period of January 1999 to December 2008 were audited. All cases tested for D-dimer (n=6845) and homocysteine (n=1665), which were concomitantly tested for haematocrit and total proteins, were extracted.

Results:

The results show a very low prevalence of hyperviscosity associated with a positive D-dimer sub-population (1.48%), which is not statistically different in comparison with the negative D-dimer sub-population. The prevalence of hyperviscosity associated with hyperhomocysteinaemia (5.04%) was statistically significantly higher in comparison to the normohomocysteinaemia sub-population (p = 0.05). The prevalence of low viscosity is significantly higher in the positive D-dimer sub-population relative to the negative D-dimer sub-population (p < 0.00001), but not different between hyperhomocysteinaemia vs. normohomocysteinaemia. Normoviscosity is statistically significantly commoner in normoviscosity relative to hyper-homocysteinaemia as well as in negative compared with positive D-dimer (p < 0.00001).

Conclusion:

The findings reported here suggest putting into perspective the specificity of whole blood viscosity relative to stasis, not necessarily sensitivity to disease conditions where it is implicated.

Salivary biomarkers associated with myocardial necrosis: results from an alcohol septal ablation model

OBJECTIVE

To determine if salivary biomarkers demonstrate utility for identifying aspects of myocardial necrosis.

METHODS

Twenty-one patients undergoing alcohol septal ablation (ASA) for treatment of hypertrophic cardiomyopathy provided serum and unstimulated whole saliva at baseline and incremental time points post-ASA. Samples were analyzed for seven biomarkers related to myocardial damage, inflammation, and tissue remodeling using immunosorbent assays. Levels were compared with baseline and levels observed in 97 healthy controls.

RESULTS

Biomarkers of myocardial damage and inflammation (ie, troponin I, creatine kinase-MB, myoglobin, C-reactive protein) rose in serum 2- to 812-fold after ASA (P < .01). Significant elevations of 2.0- to 3.5-fold were observed with C-reactive protein and troponin I in saliva (P < .02). Significant correlations between levels in serum and saliva were observed for C-reactive protein, matrix metalloproteinase-9, and myeloperoxidase (P < .001).

CONCLUSIONS

Select salivary biomarkers reflect changes that occur during, and subsequent to, myocardial necrosis caused by ASA.

Detection of perioperative myocardial infarction with ischemia-modified albumin

We assessed the perioperative pattern of serum ischemia-modified albumin and its role as a myocardial ischemia indicator for early detection of perioperative myocardial infarction in patients undergoing off-pump coronary artery bypass grafting. Venous blood samples were collected from 63 consecutive patients before the operation, immediately after the operation, and at 3, 6, 12, and 24 h postoperatively. Serum ischemia-modified albumin levels were analyzed using an albumin cobalt binding test. The patients were divided into 2 groups retrospectively, according to the occurrence of perioperative myocardial infarction. The serum ischemia-modified albumin levels were compared between groups. The levels peaked immediately after the operation, followed by a gradual regression, but remained elevated during the first 24 h in all patients. The occurrence of perioperative myocardial infarction was identified in 10 patients who had significantly higher ischemia-modified albumin levels at 3 h postoperatively and slower regression rates. Perioperative serum ischemia-modified albumin levels might be helpful in predicting perioperative myocardial infarction.

CK/CK-MB ratio as an indirect predictor for survival in polytraumatized patients

BACKGROUND

Accurate assessment of injury severity is critical for decision making related to the prevention, triage, and treatment of several injured patients. Early estimation of mortality risk of critically injured patients is mandatory for adequate therapeutic strategies. Current risk stratification relies on clinical diagnosis and scoring systems. In our study, we hypothesized whether a simple laboratory test, the CK/CK-MB ratio, could help improving risk prediction in severely traumatized patients.

METHODS

In a 9-year period, 328 nonselected trauma patients were included in our retrospective study at a Level I Trauma Center up to September 2002. Data for this study were obtained from our computerized trauma database, established in September 1992.

RESULTS

In our study population, we could show a negative correlation between Injury Severity Score (ISS) and leukocytes. A positive correlation was detected for liver enzymes and CK-MB. The correlation between ISS and Na(+) was significant. No correlation between ISS, K(+), and Hb/Ht could be observed. Exitus was associated with ISS, alteration in thrombocytes, CK, CK-MB, CRP, Crea, and Na(+).

CONCLUSION

In our study population, CK-MB levels showed a significant correlation with overall surveillance in polytraumatized patients. In our opinion, this might suggest that CK-MB levels could be taken as an indirect predictor for survival. Our findings need to be proven in further prospective clinical trials.

Evaluation of the diagnostic indices and clinical utility of qualitative cardiodetect® test kit in diagnosis of ami within 12 hours of onset of chest pain in the emergency department

Introduction

Cardiac biomarkers may be invaluable in establishing the diagnosis of acute myocardial infarction (AMI) in the ED setting.

Objective

To assess the diagnostic indices of the Cardio Detect assay and the quantitative cardiac troponin T test, in diagnosing AMI in the ED, according to the time of onset of chest pain.

Methodology

A total of 80 eligible patients presenting with ischemic type chest pain with duration of symptoms within the last 36 h were enrolled. All patients were tested for H-FABP and troponin T at presentation to the ED. A repeated Cardio Detect test was performed 1 h after the initial negative result, and a repeated troponin T test was also performed 8-12 h after an initial negative result. The diagnostic indices [sensitivity, specificity, positive predictive value, negative predictive value, receiver operating curve (ROC)] were analyzed for Cardio Detect and Troponin T (individually and in combination) and also for the repeat Cardio Detect test. Data entry and analysis were performed using SPSS version 12.0 and Analyze-it software.

Results

The Cardio Detect test was more sensitive and had a higher NPV than the troponin T (TnT) test during the first 12 h of onset of chest pain. The repeat Cardio Detect had better sensitivity and NPV than the initial Cardio Detect. The sensitivity and NPV of the combination test (Cardio Detect and troponin T) were also superior to each test performed individually.

Conclusion

The Cardio Detect test is more sensitive and has a better NPV than the troponin T test during the first 12 h of AMI. It may be used to rule out myocardial infarction during the early phase of ischemic chest pain.

Elevated Soluble fms-Like Tyrosine Kinase-1 Levels in Acute Coronary Occlusion

Objective—

Early recognition of an acute coronary occlusion (ACO) improves clinical outcomes. Soluble fms-like tyrosine kinase-1 (sFLT1) is an endothelium-derived protein induced by hypoxia. We tested whether sFLT1 levels are elevated in ACO.

Methods and Results—

Serum sFLT1 levels were measured by enzyme-linked immunosorbent assay in patients with ST-segment elevations and angiographically confirmed ACO, unstable angina/non ST-segment elevation myocardial infarction, and 2 control groups. To further explore sFLT1 release, a mouse model of ACO and in vitro human coronary artery endothelial cell injury were used. sFLT1 levels were increased in ACO compared with unstable angina/non-ST-elevation myocardial infarction, catheterized controls, or healthy volunteers (200.7±15.5 versus 70.7±44.0 versus 10.2±4.0 versus 11.7±1.7 pg/mL respectively, P <0.001 versus ACO). At presentation, all ACO patients had elevated sFLT1 levels (>15 pg/mL, 99th percentile in controls), whereas 57% had levels of the MB isoform of creatine kinase levels >10 ng/mL ( P <0.01) and 85% had ultrasensitive troponin I levels >0.05 ng/mL ( P <0.05). Within 60 minutes after symptom onset, sFLT1 was more sensitive than the MB isoform of creatine kinase or ultrasensitive troponin I for ACO (100% versus 20% versus 20% respectively; P ≤0.01 for each). Within 60 minutes of ACO in mice, sFLT1 levels were elevated. Hypoxia and thrombin increased sFLT1 levels within 15 minutes in human coronary artery endothelial cells.

Conclusion—

sFLT1 levels may be an early indicator of endothelial hypoxia in ACO.

Directed immobilization of reduced antibody fragments onto a novel SAM on gold for myoglobin impedance immunosensing

The successful construction of an immunosensor depends on having an effective procedure for immobilising the bio-recognition element to the transducer surface. In the present study, an amino-terminated 4-aminothiophenol (ATP) self-assembled monolayer (SAM) was modified with heterobifunctional crosslinker sulfosuccinimidyl 4-[N-maleimidomethyl] cyclohexane-1-carboxylate to couple reduced anti-myoglobin half-antibody fragments. The disulphide groups present in the hinge region of IgG molecules were selectively cleaved by 2-mercaptoethylamine to produce reduced half-antibody fragments with free sulphydryl groups. The maleimide terminated 4-ATP SAM modified surface was coupled to these reduced antibody fragments to produce highly oriented immobilization of the half-antibody via its Fc domain and to allow free access to the Fv bindings sites. This represents an improvement by comparison with biotin/avidin mediated IgG attachment which is essentially randomly oriented. Functional immunosensors were able to detect myoglobin in both phosphate buffered saline and whole serum over the range of concentrations from 10(-13)M to 10(-6)M, and order of magnitude better than avidin/biotin linked immunosensors. In addition, atomic force microscopy (AFM) was carried out to elucidate the nanotopology of the immunosensor surface at different stages of fabrication; the images demonstrate that half antibodies bind as described and show structural changes on subsequent antigen binding.

Computed tomographic coronary artery calcium assessment for evaluating chest pain in the emergency department: long-term outcome of a prospective blind study

OBJECTIVE

To determine the long-term outcome of computed tomographic (CT) quantification of coronary artery calcium (CAC) used as a triage tool for patients presenting with chest pain to an emergency department (ED).

PATIENTS AND METHODS

Patients (men aged 30-62 years and women aged 30-65 years) with chest pain and low-to-moderate probability of coronary artery disease underwent both conventional ED chest pain evaluation and CT CAC assessment prospectively. Patients' physicians were blinded to the CAC results. The results of the conventional evaluation were compared with CAC findings on CT, and the long-term outcome in patients undergoing CT CAC assessment was established. Primary end points (acute coronary syndrome, death, fatal or nonfatal non-ST-segment elevation myocardial infarction, fatal or nonfatal ST-segment elevation myocardial infarction) and secondary outcomes (coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, coronary stenting, or a combination thereof) were obtained when the patient was dismissed from the ED or hospital and then at 30 days, 1 year, and 5 years.

RESULTS

Of the 263 study patients, 133 (51%) had a CAC score of zero. This absence of CAC correlated strongly with the likelihood of noncardiac chest pain. Among 133 patients with a CAC score of zero, only 1 (<1%) had cardiac chest pain. Conversely, of the 31 patients shown to have cardiac chest pain, 30 (97%) had evidence of CAC on CT. When a CAC cutoff score of 36 was used, as suggested by receiver operating characteristic analysis, sensitivity was 90%; specificity, 85%; positive predictive value, 44%; and negative predictive value, 99%. During long-term follow-up, patients without CAC experienced no cardiac events at 30 days, 1 year, and 5 years.

CONCLUSION

Findings suggest that CT CAC assessment is a powerful adjunct in chest pain evaluation for the population at low-to-intermediate risk. Absent or minimal CAC in this population makes cardiac chest pain extremely unlikely. The absence of CAC suggests an excellent long-term (5-year) prognosis, with no primary or secondary cardiac outcomes occurring in study patients at 5-year follow-up.

cDNA identification, comparison and phylogenetic aspects of lombricine kinase from two oligochaete species

Creatine kinase and arginine kinase are the typical representatives of an eight-member phosphagen kinase family, which play important roles in the cellular energy metabolism of animals. The phylum Annelida underwent a series of evolutionary processes that resulted in rapid divergence and radiation of these enzymes, producing the greatest diversity of the phosphagen kinases within this phylum. Lombricine kinase (EC 2.7.3.5) is one of such enzymes and sequence information is rather limited compared to other phosphagen kinases. This study presents data on the cDNA sequences of lombricine kinase from two oligochaete species, the California blackworm (Lumbriculus variegatus) and the sludge worm (Tubifex tubifex). The deduced amino acid sequences are analyzed and compared with other selected phosphagen kinases, including two additional lombricine kinase sequences extracted from DNA databases and provide further insights in the evolution and position of these enzymes within the phosphagen kinase family. The data confirms the presence of a deleted region within the flexible loop (the GS region) of all six examined lombricine kinases. A phylogenetic analysis of these six lombricine kinases clearly positions the enzymes together in a small subcluster within the larger creatine kinase (EC 2.7.3.2) clade.

Laboratory approach to the management of clinical emergencies: a diagnostic series

This article emphasizes on the laboratory investigations that may play a significant role in the prompt management of the patient. Hence, other conditions where laboratory investigations will not play a major role are not included in this article. An attempt has been made to highlight certain issues wherein we can prevent inadvertent ordering of tests to minimize the burden on the overworked emergency laboratory, without compromising patient care. The conditions that will be dealt here include: acute chest pain, acute abdominal pain, road traffic injuries, acute respiratory distress, high grade fever, vomiting, loss of consciousness, poisoning and laboratory accidents, and lastly occupational exposure to potential biological hazards.

Usefulness of 201TlCl/ 123I-BMIPP dual-myocardial SPECT for patients with non-ST segment elevation myocardial infarction

OBJECTIVE

Earlier studies suggested that elevated cardiac troponin T (cTnT) might be useful for detecting less severe types of myocardial injury (i.e., non-ST segment elevation myocardial infarction). The objective of this study is to elucidate the usefulness of (201)thallous chloride ((201)TlCl) and (123)I-betamethyl-p-iodophenyl-pentadecanoic acid ((123)I-BMIPP) dual-single-photon emission computed tomography (SPECT) imaging for patients with myocardial infarction (MI) without ST segment elevation.

METHODS

Consecutive 86 patients (56 men and 30 women; mean age 66 +/- 12 years) clinically diagnosed with acute myocardial infarction (AMI) were divided into two groups according to serum creatine kinase MB (CK-MB) and cTnT levels. Group A consisted of 53 patients with increased serum CK-MB and cTnT levels, and Group B, 33 patients with increased serum cTnT without increased serum CK-MB. All patients underwent (201)TlCl and (123)I-BMIPP dual-SPECT about 8 days following the onset. The left ventricular myocardium was divided into 20 segments on each SPECT image, and tracer accumulation in those segments was scored on a five-point scoring system. The total defect scores (TDS) were calculated by summing the scores for all 20 segments, and compared between groups A and B. Group B patients were subdivided into two groups according to the TDS on (123)I-BMIPP images as groups B(S) (severe; TDS > or = 8) and B(M) (mild; TDS < or = 7), and we compared the prognosis over a period of 2 years from the onset between the three groups.

RESULTS

The TDS of group A derived from (201)TlCl and (123)I-BMIPP images was significantly higher than those of group B (14.5 +/- 10.8 vs. 1.5 +/- 2.4 and 20.8 +/- 13.3 vs. 9.1 +/- 6.2, respectively; P < 0.0001). The sensitivities of (201)TlCl and (123)I-BMIPP images were 94.3% (50/53) and 96.2% (51/53) to detect the culprit coronary lesions in group A (no significant difference). In contrast, the sensitivity of (123)I-BMIPP images (72.7%, 24/33) was higher than that of (201)TlCl images (27.3%, 9/33) in group B (P < 0.05). At 2 years of follow-up, the incidence of hard cardiac events in groups A, B(S), and B(M) was 24.5%, 27.8%, and 6.7%, respectively. The rate of group BS, as well as that of group A, was significantly higher than that of group B(M) (P < 0.05).

CONCLUSIONS

Of those with a clinical diagnosis of AMI accompanied by increased cTnT, the CK-MB negative patients accounted for 38% (33/86) of all patients as having non-ST segment elevation myocardial infarction such as NTMI. For such patients, (123)I-BMIPP imaging is useful not only for the detection of the culprit lesions but also for the prediction of the prognosis.

Renal and hepatic injury with elevated cardiac enzymes in Amanita phalloides poisoning: a case report

Amatoxins are one of the most potent toxins that cause hepatic and renal failure. However, this is the first report demonstrating an elevation of cardiac enzymes in a patient with Amanita phalloides poisoning. A 56-year-old male was admitted to the emergency department (ED) 42 h after an unknown type of mushroom ingestion. Hepatic, renal function tests, amylase and cardiac enzymes (troponin I, creatine kinase (CK), CK-MB isoenzyme and myoglobin) were found elevated in his blood chemistry. The electrocardiogram disclosed sinus tachycardia. Aggressive treatment with fluids, activated charcoal, penicillin G and silibinin were started. The patient was sent to hemodialysis because of anuria. During follow-up, biochemical parameters and clinical findings improved. The patient was discharged from the hospital following the arrangement of hemodialysis schedule because of the chronic renal failure. False elevations of cardiac markers may confuse the clinicians in differential diagnosis of myocardial infarction in ED. In our patient, amatoxins that have bound the actin filaments within myocardiocytes or renal cells and/or its effects as circulating anti-troponin antibodies might result in elevation of cardiac markers. Elevated cardiac enzyme levels without any acute coronary syndrome are probable in mushroom poisoning cases involving amatoxin ingestion.

Perioperative creatine phosphokinase (CPK) and troponin I trends after elective hip surgery

BACKGROUND

Perioperative myocardial infarction (MI) is an important risk factor for cardiac morbidity and mortality after hip surgery. On the basis of the limitations of creatine kinase cardiac muscle isoenzyme (CK-MB) in the perioperative setting, and the high specificity of troponin I, we hypothesized that troponin I would be effective at detecting perioperative MI more frequently than CK-MB would be, after hip surgery.

METHODS

A prospective study of the serum levels of creatine phosphokinase (CPK), its isoenzyme CK-MB, and troponin I, in 90 patients with risk factors for coronary artery disease, undergoing hip surgery is reported. We measured these cardiac markers in the postoperative period for 5 days, after hemiarthroplasty, total hip arthroplasty, and hip intramedullary nailing.

RESULTS

We found increased levels of creatine phosphokinase and CK-MB, after all the types of operation, with maximum levels reached on the first postoperative day and the levels were more pronounced after total hip arthroplasty. False-elevated CK-MB index >6% without MI was evidenced in 43.3% of patients. Troponin I levels were elevated >3.1 ng/mL only in the patients who suffered MI postoperatively. All the patients who suffered MI had both CK-MB index and troponin I levels elevated. Also, we found high correlation between maximum CK-MB levels and size of implants, which means that reaming and its heating effect may be responsible for false-elevated CK-MB levels, except direct muscle damage caused by surgical incision.

CONCLUSION

CK-MB index and troponin I have the same sensitivity, but troponin I is more specific than CK-MB index in detecting MI after hip surgery.

Potential value for new diagnostic markers in the early recognition of acute coronary syndromes

The diagnostic approach to acute coronary syndromes (ACS) remains one of the most difficult and controversial challenges facing emergency physicians. In recent years, cardiac troponins have emerged as the biochemical "gold standard" for diagnosis of patients with acute chest pain, enhancing our ability to recognize ACS. Early diagnosis and treatment of myocardial ischemia improve patient outcomes, but conventional markers are often nondiagnostic at the time of arrival at the emergency department. Promising new biomarkers, which appear earlier after the onset of ischemia, are being studied and integrated into clinical practice. Some are markers of myocyte necrosis, but others, including ischemia-modified albumin and natriuretic peptides, detect myocardial ischemia and myocardial dysfunction. The aim of the present article is to review the diagnostic approach to ACS, focusing on recent literature describing novel biochemical markers. If ongoing and future studies confirm their role in probability-based models risk assessment, a new era in the diagnostic approach to ACS may be dawning.

Plasmonic technology: novel approach to ultrasensitive immunoassays

At the Center for Fluorescence Spectroscopy, we have taken advantage of the favorable properties of surface plasmon-coupled emission (SPCE) to improve fluorescence-based immunoassays. SPCE occurs when excited fluorophores near conducting metallic structures efficiently couple to surface plasmons. These surface plasmons, appearing as free electron oscillations in the metallic layer, produce electromagnetic radiation that preserves the spectral properties of fluorophores but is highly polarized and directional. SPCE immunoassays provide several advantages over other fluorescence-based methods. This review explains new approaches to fluorescence immunoassays, including our own use of SPCE for simultaneous detection of more than one fluorescent marker and performance of immunoassays in the presence of an optically dense medium, such as whole blood.

Myoglobin immunoassay utilizing directional surface plasmon-coupled emission

We described an immunoassay for the cardiac marker myoglobin on a thin silver mirror surface using surface plasmon-coupled emission (SPCE). SPCE occurs for fluorophores in proximity (within approximately 200 nm) of a thin metal film (in our case, silver) and results in a highly directional radiation through a glass substrate at a well-defined angle from the normal axis. We used the effect of SPCE to develop a myoglobin immunoassay on the silver mirror surface deposited on a glass substrate. Binding of the labeled anti-myoglobin antibodies led to the enhanced fluorescence emission at a specific angle of 72 degrees . The directional and enhanced directional fluorescence emission enables detection of myoglobin over a wide range of concentrations from subnormal to the elevated level of this cardiac marker. Utilizing SPCE allowed us also to demonstrate significant background suppression (from serum or whole blood) in the myoglobin immunoassay. We expect SPCE to become a powerful technique for performing immunoassays for many biomarkers in surface-bound assays.

Early interleukin-1 receptor antagonist elevation in patients with acute myocardial infarction

OBJECTIVES

We sought to evaluate interleukin-1 receptor antagonist (IL-1Ra) levels in patients with ST-segment elevation acute myocardial infarction (AMI) upon emergency department (ED) admission in order to assess the sensitivity of such a determination by comparison with common markers of myocardial necrosis.

BACKGROUND

Inflammatory markers are elevated in patients with unstable coronary syndromes, but IL-1Ra levels during the early phases of AMI have not been previously investigated.

METHODS

Levels of IL-1Ra were measured in 44 consecutive patients with AMI and compared with creatine kinase (CK), CK-MB, troponin I, myoglobin, and C-reactive protein (CRP).

RESULTS

Upon admission, 82% of patients had elevated (>230 pg/ml) IL-1Ra levels, compared with 41% of patients with raised CK (p = 0.001), CK-MB (45%, p = 0.002), troponin I (57%, p = 0.027), myoglobin (48%, p = 0.004), and CRP (57%, p = 0.019) levels. The IL-1Ra values were significantly higher in patients with heralded AMI than in those without pre-infarction angina (671 vs. 320 pg/ml, p = 0.013). The sensitivity of IL-1Ra determination increased to 86% when chest pain duration was < or =3 h and to 91% if heralded infarction occurred.

CONCLUSIONS

Our study indicates that, unlike markers of necrosis, an increase of IL-1Ra levels occurs early in patients with AMI, is more significant in those with heralded infarction and symptom onset < or =3 h, and precedes the release of markers of necrosis. Thus, IL-1Ra determination may be an important early adjuvant toward the diagnosis of AMI in the ED.