Assessment of Specific Biomarkers' Profile and Structural, Functional Parameters of the Left Ventricle in Patients With Lymphomas Undergoing Antitumor Therapy.

AIM: To evaluate the dynamics of specific biomarkers for cardiotoxicity, endothelial dysfunction, fibrosis, systemic inflammation, and morpho-functional alterations in the left ventricular (LV) myocardium in patients with newly diagnosed lymphomas during 6 courses of polychemotherapy (PCT). MATERIAL AND METHODS: The study included 30 patients with newly diagnosed lymphomas. All patients were evaluated for laboratory markers of cardiotoxicity at baseline and after 6 courses of chemotherapy (6 months), including N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitivity troponin I (hsTnI), endothelin-1 (ET-1), circulating cardiac biomarker ST-2, high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), and LV structural and functional echocardiographic (EchoCG) parameters. RESULTS: The changes in NT-proBNP and hsTnI concentrations during 6 courses of PCT were not statistically significant. Comparison of the baseline values with those after 6 courses of PCT showed increases in the median concentrations of ET-1 (3.38 and 5.5 pg/ml, respectively; p=0.438) and ST-2 (12.21 and 26.75 ng/ml, respectively; p=0.687). Markers of systemic inflammation were significantly decreased after 6 courses of PCT: the median CRP decreased from 15.2 to 0.72 mg/ml (p=0.006), and the median IL-6 decreased from 12.2 to 5.1 pg/ml (p=0.034). EchoCG data revealed a statistically significant impairment of the LV diastolic function parameters (E/A; E/e' lateral; E/e' average; left atrial volume index; isovolumic relaxation time). A moderate direct correlation was found between the ET-1 concentration and the isovolumic relaxation time at baseline and after 6 courses of PCT, respectively (r1 = 0.387, p=0.047 and r2 = 0.391, p=0.035). No changes in the LV systolic function were observed. CONCLUSION: The study showed that patients with lymphoproliferative diseases had no signs of cardiotoxicity during PCT according to the accepted criteria. This study described and highlighted for the first time the interrelation of endothelial dysfunction, profibrotic status, and LV diastolic dysfunction as manifestations of cardiovascular toxicity in patients with lymphoproliferative diseases. It is advisable to supplement the integrated strategies for the prevention and monitoring of PCT cardiovascular toxicity with a thorough evaluation of instrumental parameters of diastolic dysfunction for timely initiation/correction of cardioprotective therapy.

The effects of inspiratory muscle training on biomarkers of muscle damage in recovered COVID-19 patients after weaning from mechanical ventilation.

Background: COVID-19 patients experience respiratory muscle damage, leading to reduced respiratory function and functional capacity often requiring mechanical ventilation which further increases susceptibility to muscle weakness. Inspiratory muscle training (IMT) may help mitigate this damage and improve respiratory function and functional capacity. Methods: We studied the effects of IMT on muscle damage biomarkers, respiratory function, and functional capacity in COVID-19 recovered young adults, successfully weaned from mechanical ventilation. Participants were randomly allocated to either an IMT (n = 11) or control (CON; n = 11) intervention for 4 weeks. The IMT group performed 30 dynamic inspiratory efforts twice daily, at 50% of their maximal inspiratory mouth pressure (PMmax) while the CON group performed 60 inspiratory efforts at 10% of pMmax daily. Serum was collected at baseline, week two, and week four to measure creatine kinase muscle-type (CKM), fast skeletal troponin-I (sTnI) and slow sTnI. Results: Time × group interaction effects were observed for CKM and slow sTnI, but not for fast sTnI. Both were lower at two and 4 weeks for the IMT compared to the CON group, respectively. Time × group interaction effects were observed for forced expiratory volume in 1s, forced vital capacity, PMmax and right- and left-hand grip strength. These were higher for the IMT compared to the CON group. Conclusion: Four weeks of IMT decreased muscle damage biomarkers and increased respiratory function and grip strength in recovered COVID-19 patients after weaning from mechanical ventilation.

Validation and correlation of high-sensitive troponin I and troponin T in the emergency department.

BACKGROUND: Troponin elevation is frequently observed in various scenarios in the Emergency Department (ED), yet there is a paucity of studies investigating simultaneously measured high-sensitivity cardiac troponin T (hs-cTnT) and troponin I (hs-cTnI) within a diverse cohort in a clinical setting. METHODS: All patients who underwent troponin testing at a single center were eligible for this study. Only patients with simultaneous samples with hs-cTnI (Siemens) and hs-cTnT (Roche) were included, regardless of chief complaint. RESULTS: Analysis of 1987 samples from 1134 patients showed a significant correlation between hs-cTnT and hs-cTnI (r = 0.86, p < 0.01). Of these samples, 65% exceeded the upper reference limit (URL) for hs-cTnT, and 30% for hs-cTnI with 39% who exhibited elevated hs-cTnT levels alongside normal hs-cTnI levels. The area under the curve (AUC) for acute myocardial infarction (AMI) for the index visit was 0.80 (95% CI; 0.75-0.85) for hs-cTnT and 0.87 (95% CI; 0.83-0.91) for hs-cTnI. Sensitivity and specificity were 91% and 39% for hs-cTnT, and 80% and 80% for hs-cTnI. Positive predictive value (PPV) and negative predictive value (NPV) was 9.3% and 98.5% for hs-cTnT respectively, corresponding for hs-cTnI was 21.3% and 98.3% respectively. Hazard ratios for 1-year mortality were 1.52 (95% CI; 1.40-1.66) for hs-cTnT and 1.26 (95% CI; 1.18-1.34) for hs-cTnI. CONCLUSION: Elevated troponins above the URL were very common in this diverse cohort, particularly for hs-cTnT, which was twice as frequent compared to hs-cTnI, resulting in low specificity and PPV for AMI.

Robust Luminescent Pyrene-Based Metal-Organic Framework Hydrogel as a pH-Responsive Fluorescence Emitter for Sensitive Immunoassay of Cardiac Troponin I.

Despite many luminescent advantages including outstanding absorption coefficient and high quantum yield, pyrene and its derivatives have been suffering from a dramatic aggregation-caused quenching (ACQ) effect. Although the dramatic ACQ effect of pyrene-based fluorophores has been restrained in pyrene-doped metal-organic frameworks (MOFs), the low loading of fluorescent (FL) units substantially impedes the improved luminescent behaviors. Herein, pyrene-based MOFs hydrogel was synthesized with a high loading of pyrene as the unique organic linker blocks instead of a dopant in MOFs. The gel matrix contributed to rigidifying the location of the FL emitters and achieving intensive FL emission and high luminescent stability and therefore efficiently overcoming the ACQ effect. Furthermore, the protonation of pyrene in the MOFs hydrogel remarkably decreased the luminescent intensity, which endowed the FL hydrogel with highly pH-responsive activity in the broad range (pH 4-10). Interestingly, glucose oxidase was immobilized into ZIF-8 as a highly efficient luminescent quencher, which contributed to catalyzing the form of gluconic acid and thus drastically quenching the FL signal of the MOFs hydrogel. Furthermore, the emitter-quencher pair of pyrene-based MOFs hydrogel and glucose oxidase was successfully employed to develop an ultrasensitive FL immunoassay platform for cardiac troponin I (as a model analyte). The limit of detection for cardiac troponin I was 5.2 pg/mL (3σ). The proof-of-principle study demonstrated the thrilling auxiliary effect of tailorable MOFs hydrogel on boosting the feasibility of aqueous insoluble FL chromophores for trace analysis.

ST-Segment Alterations in the Electrocardiogram of Acute Pulmonary Thromboembolism: A Rabbit Model.

In this study, we investigated the mechanism underlying electrocardiogram (ECG) alterations in a rabbit model of acute pulmonary thromboembolism (PTE). Twelve healthy adult New Zealand white rabbits were used, with eight in the experimental group (PTE group) and four in the control group. After developing the rabbit model of acute PTE, ECG and coronary angiography were performed. HE staining was conducted on the right and left ventricular tissues, and polymerase chain reaction (PCR) was used to determine brain natriuretic peptide (BNP), tumor necrosis factor-alpha (TNF-?), and Troponin I (TNI) mRNA expression in the myocardium. There were considerable changes in the ST segment of the ECG in the PTE group. Coronary angiography revealed the absence of spasm, stenosis, and occlusion. In the plasma of the PTE group, the levels of D-dimer, BNP, TNF-?, and TNI were significantly elevated, and these changes were statistically significant (P<0.05). PCR analysis of ventricular myocardial tissue indicated significantly higher levels of BNP, TNF-?, and TNI mRNA in the PTE group than in the control group. These differences were statistically significant (P<0.05). The ST-T variations on the ECG of rabbits with acute PTE correlate strongly with the temporary changes in right heart volume caused by acute PTE. Keywords: Animal model of pulmonary embolism, B-type natriuretic peptide, Electrocardiogram, Pulmonary thromboembolism, Troponin I, Tumor necrosis factor-alpha.

Perioperative Change of High-Sensitive Cardiac Troponin I Concentration in Cats According to Three Different Anaesthesia Protocols.

BACKGROUND: Cardiac troponin I, a particular biomarker, is released into the bloodstream in response to myocardial injury. OBJECTIVES: To evaluate perioperative changes in high-sensitivity cardiac troponin I (hs-cTnI) concentration during ovariohysterectomy in cats undergoing three different anaesthesia protocols. METHODS:  Twenty-one female mixed-breed cats owned by clients aged (2.2 ± 0.7 years) and weight (3.2 ± 0.5 kg) were included in our study. The cats were divided into three groups: propofol-isoflurane (PI) group (n = 7), xylazine-ketamine (XK) group (n = 7) and xylazine-isoflurane (XI) group (n = 7). After pre-anaesthetic propofol (6 mg/kg IV) was administered to cats in Group PI, a mask was placed, and anaesthesia was maintained with 3.0% isoflurane in oxygen. Cats in Group XK underwent general anesthetization with xylazine hydrochloride (2 mg/kg IM) and, 10 min later, ketamine hydrochloride (10 mg/kg IM). Cats in Group XI were administered xylazine hydrochloride (2 mg/kg IM), and then anaesthesia (3.0% isoflurane and oxygen) was continued with a mask. Blood samples were collected from all cats; preoperatively and postoperatively at 0 and 12 h (Pre-, Post-0 h and Post-12 h, respectively). Serum hs-cTnI concentrations were measured with the Advia Centaur TnI-Ultra. RESULTS: In all 21 cats, hs-cTnI concentration increased at Post-0 h and 12 h measurement points compared to Pre-. In the XK group, hs-cTnI concentrations exhibited a significant increase at the Post-0 h (51.30 ng/L) and Post-12 h (157.70 ng/L) time points compared to Pre- (6.70 ng/L) (p < 0.05). CONCLUSIONS: The XK group increased the concentration of hs-cTnI more than other protocols. In the PI group, the increase in hs-cTnI concentrations at Post-0 and 12 h increased less than the other two groups (p < 0.05). The PI group was found to induce less myocardial damage.

Significance of an Early Repeat Troponin Measurement Upon Presentation to the Hospital for Acute Heart Failure.

BACKGROUND: Higher cardiac troponin is associated with worse outcomes in patients with acute heart failure. The significance of repeat measurements over hours remains unclear. We assessed whether a repeat measurement and the Δ between measurements of high-sensitivity cardiac troponin I (hs-cTnI) were associated with outcomes in hypervolemic patients with acute heart failure without acute coronary syndrome. METHODS AND RESULTS: We analyzed 582 individuals from AKINESIS (Acute Kidney Injury Neutrophil Gelatinase-Associated Lipocalin Evaluation of Symptomatic Heart Failure Study) with hs-cTnI measured ≤12 hours from admission and repeated ≤6 hours thereafter. Associations between hs-cTnI levels and their Δ with short-term (death, intensive care unit admission, receipt of inotropes, or positive pressure ventilation during hospitalization) and long-term (death or heart failure readmission within 1 year) outcomes were assessed. The average age was 69±13 years, 62% were men, 65% were White, 46% had coronary artery disease, and 22% had chest pain. Median hs-cTnI levels were 27 (interquartile range [IQR], 13-62) ng/L initially and 28 (IQR, 14-68) ng/L subsequently, with a Δ of 0 [IQR, -2 to 4] ng/L over 3.4±1 hours. Only the second measurement was associated with short-term outcomes (odds ratio, 1.14 per 2-fold higher [95% CI, 1.02-1.28]). Both individual measurements and the Δ were associated with long-term outcomes (hazard ratios, 1.09, 1.12, and 1.16 for first, second, and Δ, respectively). Associated risk for the first and second measurements were not constant over the year but highest early after being measured and decreased over 1 year. CONCLUSIONS: Repeat measurements of hs-cTnI over hours can identify individuals with acute heart failure without acute coronary syndrome at risk for short- and long-term outcomes.

Preliminary study on heart response and locomotor parameters in Donkeys (Equus asinus) during exercise using fitness tracker (Equimetre).

The welfare of donkeys remains a compelling subject for researchers, with limited literature available on the response of the donkey cardiovascular system during strenuous exercise. The study aimed to address two primary objectives. Firstly, to assess the reliability of wearable devices in detecting heart rate (HR) and ECG readings. Secondly, to determine HR, locomotor and cardiac troponin 1 (cTnI) levels in donkeys during exercise. A total of seven donkeys were outfitted with two systems for ECG measurements, namely Equimetre and the Standard base apex, to enable a comparison between the two. Additionally, fifteen apparently healthy donkeys equipped with Equimetre were divided into two groups: the race group (R), consisting of donkeys trained for racing, and the non-race group (NR), comprising donkeys used for regular riding. The results indicated a level of agreement between the two devices in intervals R-R (P = < 0.0001), S-T (P = 0.0002), Q-T(P = 0.0003), P-R (P = 0.0037), segment P-R (P = 0.0023) and HR (P = < 0.0001) at rest. This suggested that Equimetre can provide a level of accepted ECG reading in donkey. No significant difference in heart response and locomotor parameters between donkey groups, although this finding needs further studies to verify it and to understand the dynamics of donkey. This study demonstrates the feasibility of Equimetre in detection HR and present initial data of heart response and locomotor in donkeys during exercise.

Half-Life and Clearance of Cardiac Troponin I and Troponin T in Humans.

BACKGROUND: Cardiac troponin (cTn) is key in diagnosing myocardial infarction (MI). After MI, the clinically observed half-life of cTn has been reported to be 7 to 20 hours, but this estimate reflects the combined elimination and simultaneous release of cTn from cardiomyocytes. More precise timing of myocardial injuries necessitates separation of these 2 components. We used a novel method for determination of isolated cTn elimination kinetics in humans. METHODS: Patients with MI were included within 24 hours after revascularization and underwent plasmapheresis to obtain plasma with a high cTn concentration. After at least 3 weeks, patients returned for an autologous plasma retransfusion followed by blood sampling for 8 hours. cTn was measured with 5 different high-sensitivity cTn assays. RESULTS: Of 25 included patients, 20 participants (mean age, 64.5 years; SD, 8.2 years; 4 women [20%]) received a retransfusion after a median of 5.8 weeks (interquartile range, 5.0-6.9 weeks) after MI. After retransfusion of a median of 620 mL (range, 180-679 mL) autologous plasma, the concentration of cTn in participants' blood increased 4 to 445 times above the upper reference level of the 5 high-sensitivity cTn assays. The median elimination half-life ranged from 134.1 minutes (95% CI, 117.8-168.0) for the Elecsys high-sensitivity cTnT assay to 239.7 minutes (95% CI, 153.7-295.1) for the Vitros high-sensitivity cTnI assay. The median clearance of cTnI ranged from 40.3 mL/min (95% CI, 32.0-44.9) to 52.7 mL/min (95% CI, 42.2-57.8). The clearance of cTnT was 77.0 mL/min (95% CI, 45.2-95.0). CONCLUSIONS: This novel method showed that the elimination half-life of cTnI and cTnT was 5 to 16 hours shorter than previously reported. This indicates a considerably longer duration of cardiomyocyte cTn release after MI than previously thought. Improved knowledge of timing of myocardial injury may call for changes in the management of MI and other disorders with myocardial injury.

Functional cardiac consequences of ß-adrenergic stress-induced injury in a model of Duchenne muscular dystrophy.

Cardiomyopathy is the leading cause of death in Duchenne muscular dystrophy (DMD); however, in the mdx mouse model of DMD, the cardiac phenotype differs from that seen in DMD-associated cardiomyopathy. Although some have used pharmacologic stress to stimulate injury and enhance cardiac pathology in the mdx model, many methods lead to high mortality with variable cardiac outcomes, and do not recapitulate the structural and functional cardiac changes seen in human disease. Here, we describe a simple and effective method to enhance the cardiac phenotype model in mdx mice using advanced 2D and 4D high-frequency ultrasound to monitor cardiac dysfunction progression in vivo. mdx and wild-type mice received daily low-dose (2 mg/kg/day) isoproterenol injections for 10 days. Histopathological assessment showed that isoproterenol treatment increased myocyte injury, elevated serum cardiac troponin I levels and enhanced fibrosis in mdx mice. Ultrasound revealed reduced ventricular function, decreased wall thickness, increased volumes and diminished cardiac reserve in mdx compared to wild-type mice. Our findings highlight the utility of challenging mdx mice with low-dose isoproterenol as a valuable model for exploring therapies targeting DMD-associated cardiac pathologies.

Association Between High Sensitivity Troponin I and NTproBNP With Rejection and Graft Loss in Pediatric Heart Transplant Recipients.

BACKGROUND: Troponin I is a blood biomarker of cardiac injury and levels measured using a high-sensitivity assay after pediatric heart transplantation (HT) have not been described. We sought to assess the association between high-sensitivity troponin I (hsTnI) and N-terminal pro-B-type natriuretic peptide (NTproBNP) with treated acute rejection (AR) and graft loss in pediatric heart transplant (HT) recipients. METHODS: Serum was collected and banked from pediatric HT recipients prior to cardiac catheterization. Patients with samples drawn within 365 days post-HT were included and followed for up to 5 years. Generalized linear mixed-effect models examined the association between hsTnI and treated AR using a random intercept per patient. Cox proportional hazards models tested the association between maximal hsTnI and NT-proBNP and death/graft loss. RESULTS: HsTnI and NTproBNP values decline in the weeks following HT, after which these biomarkers stabilize. HsTnI was higher in AR versus no AR (6.2 vs. 3.5 ng/L, p < 0.001); doubling of hsTnI increased the odds of AR by 33% (p = 0.004). HsTnI showed moderate discrimination for AR with an AUC of 0.811 (95% CI 0.76, 0.87) and a NPV of 96.4% (95% CI 93.0, 98.1). Elevation in NT-proBNP was not associated with AR. In multivariable Cox modeling, a doubling of maximal NT-proBNP was associated with graft loss (HR 8.96, p = 0.014). CONCLUSIONS: In this pediatric HT cohort, HsTnI was moderately discriminative for AR and higher maximal NT-proBNP was associated with graft loss. HsTnI may add value in pediatric HT non-invasive AR surveillance, and elevated NTproBNP could suggest an increased risk of graft loss.

Deep learning assisted quantitative detection of cardiac troponin I in hierarchical dendritic copper-nickel nanostructure lateral flow immunoassay.

The rising demand for point-of-care testing (POCT) in disease diagnosis has made LFIA sensors based on dendritic metal thin film (HD-nanometal) and background fluorescence technology essential for rapid and accurate disease marker detection, thanks to their integrated design, high sensitivity, and cost-effectiveness. However, their unique 3D nanostructures cause significant fluorescence variation, challenging traditional image processing methods in segmenting weak fluorescence regions. This paper develops a deep learning method to efficiently segment target regions in HD-nanometal LFIA sensor images, improving quantitative detection accuracy. We propose an improved UNet++ network with attention and residual modules, accurately segmenting varying fluorescence intensities, especially weak ones. We evaluated the method using IoU and Dice coefficients, comparing it with UNet, Deeplabv3, and UNet++. We used an HD-nanoCu-Ni LFIA sensor for cardiac troponin I (cTnI) as a case study to validate the method's practicality. The proposed method achieved a 96.3% IoU, outperforming other networks. The R2 between characteristic quantity and cTnI concentration reached 0.994, confirming the method's accuracy and reliability. This enhances POCT accuracy and provides a reference for future fluorescence immunochromatography expansion.

[Clinical analysis of maternal autoantibody-mediated complete left bundle branch block in 9 children].

Objective: To analyze the clinical characteristics, treatment, and outcomes of children with complete left bundle branch block (CLBBB) mediated by maternal autoantibodies. Methods: A retrospective analysis was conducted on nine children diagnosed with maternal autoantibody-mediated CLBBB, treated at Beijing Anzhen Hospital and Fujian Provincial Hospital from March 2015 to August 2023. Their clinical characteristics, electrocardiographic and echocardiographic findings before and after treatment were reviewed. Paired sample t-test was used for inter-group comparison. Results: Among the mothers, 6 had positive antinuclear antibodies (ANA), 5 had anti-Sjogren syndrome antigen A antibodies, and 3 had anti-Ro-52 antibodies. The cohort included one female and eight male children, diagnosed with CLBBB at the age of 1 (2, 13) months. The positive autoantibodies in the infants, consisted with maternal antibodies, were detected within the first 3 months of life among 3 cases. Treatments included anti-heart failure therapy, myocardial nutritional support, intravenous immunoglobulin (IVIG) and glucocorticoids. Before treatment, the levels of troponin I (0.175 (0.060, 10.270) µg/L) and N-terminal pro-B-type natriuretic peptide (420 (327, 12 865) ng/L) were elevated, which normalized in most cases after treatment. Post-treatment, the QRS duration significantly shortened compared to pre-treatment ((137±15) vs.(169±25) ms, t=3.76, P<0.001), and the QTc interval significantly decreased ((433±41) vs. (514±27) ms, t=4.95, P=0.001). Before treatment, varying degrees of mitral and tricuspid regurgitation and marked interventricular septal dyskinesia were observed in echocardiography. After treatment, valve regurgitation and ventricular septum motion significantly improved, with a marked increase in left ventricular ejection fraction ((51±13)% vs. (27±6)%, t=-6.66, P<0.001). Conclusions: Maternal autoantibody-mediated CLBBB in children presents with chronic heart failure in infancy. Early treatment with anti-heart failure medications, IVIG and glucocorticoids can improve clinical symptoms.

Risk scores and coronary artery disease in patients with suspected acute coronary syndrome and intermediate cardiac troponin concentrations.

BACKGROUND: Guidelines recommend the use of risk scores to select patients for further investigation after myocardial infarction has been ruled out but their utility to identify those with coronary artery disease is uncertain. METHODS: In a prospective cohort study, patients with intermediate high-sensitivity cardiac troponin I concentrations (5 ng/L to sex-specific 99th percentile) in whom myocardial infarction was ruled out were enrolled and underwent coronary CT angiography (CCTA) after hospital discharge. History, ECG, Age, Risk factors, Troponin (HEART), Emergency Department Assessment of Chest Pain Score (EDACS), Global Registry of Acute Coronary Event (GRACE), Thrombolysis In Myocardial Infarction (TIMI), Systematic COronary Risk Evaluation 2 and Pooled Cohort Equation risk scores were calculated and the odds ratio (OR) and diagnostic performance for obstructive coronary artery disease were determined using established thresholds. RESULTS: Of 167 patients enrolled (64±12 years, 28% female), 29.9% (50/167) had obstructive coronary artery disease. The odds of having obstructive disease were increased for all scores with the lowest and highest increase observed for an EDACS score ≥16 (OR 2.2 (1.1-4.6)) and a TIMI risk score ≥1 (OR 12.9 (3.0-56.0)), respectively. The positive predictive value (PPV) was low for all scores but was highest for a GRACE score >88 identifying 39% as high risk with a PPV of 41.9% (30.4-54.2%). The negative predictive value (NPV) varied from 77.3% to 95.2% but was highest for a TIMI score of 0 identifying 26% as low risk with an NPV of 95.2% (87.2-100%). CONCLUSIONS: In patients with intermediate cardiac troponin concentrations in whom myocardial infarction has been excluded, clinical risk scores can help identify patients with and without coronary artery disease, although the performance of established risk thresholds is suboptimal for utilisation in clinical practice. TRIAL REGISTRATION NUMBER: NCT04549805.

A Fluorescent Lateral Flow Immunoassay for the Detection of Skeletal Muscle Troponin I in Serum for Muscle Injury Monitoring at the Point of Care.

Exercise-induced muscle injury is one of the most common types of sports injuries. Skeletal muscle troponin I (skTnI) serves as an ideal biomarker in assessing such injuries, facilitating timely detection and evaluation. In this study, we develop a fluorescent sandwich lateral flow immunoassay (LFIA) combined with a desktop analyzer for rapid detection of skTnI. Through optimizing the reaction system, the assay achieves a satisfying detection performance, reaching a limit of detection (LOD) of 0.5 ng/mL with a turnaround time of 15 min. The proposed detection platform offers portability, ease of use, and high sensitivity, which facilitates the monitoring of exercise-induced muscle injuries at the point of care. This feature is particularly advantageous for end users, enabling timely detection of sports-related injuries and ultimately enhancing prognosis and sports life.

Influence of Anticoagulants on the Dissociation of Cardiac Troponin Complex in Blood Samples.

Immunodetection of cardiac isoforms of troponin I (cTnI) and troponin T (cTnT) in blood samples is widely used for the diagnosis of acute myocardial infarction. The cardiac troponin complex (ITC-complex), comprising cTnI, cTnT, and troponin C (TnC), makes up a large portion of troponins released into the bloodstream after the necrosis of cardiomyocytes. However, the stability of the ITC-complex has not been fully investigated. This study aimed to investigate the stability of the ITC-complex in blood samples. A native ITC-complex was incubated in buffer solutions, serum, and citrate, heparin, or EDTA plasma at various temperatures. Western blotting and gel filtration were performed, and troponins were detected using specific monoclonal antibodies. The ITC-complex dissociated at 37 °C in buffers with or without anticoagulants, in citrate, heparin, and EDTA plasmas, and in serum, into a binary cTnI-TnC complex (IC-complex) and free cTnT. In plasma containing heparin and EDTA, the IC-complex further dissociated into free TnC and cTnI. No dissociation was found at 4 °C or at room temperature (RT) in all matrices within 24 h except for EDTA plasma. After incubation at 37 °C in EDTA plasma and serum, dissociation was accompanied by proteolytic degradation of both cTnI and cTnT. The presence of anti-troponin autoantibodies in the sample impeded dissociation of the ITC-complex. The ITC-complex dissociates in vitro to form the IC-complex and free cTnT at 37 °C but is mostly stable at 4 °C or RT. Further dissociation of the IC-complex occurs at 37 °C in plasmas containing heparin and EDTA.

Acute Myocardial Injury in Spontaneous Intracerebral Hemorrhage: A Secondary Observational Analysis of the FAST Trial.

BACKGROUND: Acute myocardial injury is associated with poor outcomes in patients with acute ischemic stroke, but its prognostic significance in patients with spontaneous intracerebral hemorrhage remains unclear. We investigated whether acute myocardial injury and the direction of the cardiac troponin I (cTnI) change (rising versus falling) affect post-intracerebral hemorrhage outcomes. METHODS AND RESULTS: We re-analyzed the FAST (Factor-Seven-for-Acute-Hemorrhagic-Stroke) trial. Acute myocardial injury was defined as at least 1 cTnI value above the upper reference limit with a rise/fall of >20%. Logistic regression tested for associations (1) between acute myocardial injury (presence versus absence) and poor outcome (modified Rankin Scale 4-6) and mortality at 15 and 90 days; (2) among 3 groups (rising versus falling versus no acute myocardial injury) and outcomes. Among the 841 FAST participants, 785 patients were included. Acute myocardial injury was detected in 29% (n=227); 170 had rising cTnI. At 15 and 90 days, respectively, those with acute myocardial injury had higher odds of poor outcome (adjusted odds ratio) ([aOR] 2.3 [95% CI, 1.3-3.9]); and adjusted odds ratio 2.5 [95% CI, 1.6-3.9];, and higher odds of mortality (adjusted odds ratio 2.4 [95% CI, 1.4-4.3]; and adjusted odds ratio 2.2 [CI, 1.3-3.6]) than patients without. There was no interaction between FAST group assignment and myocardial injury, and associations between myocardial injury and outcomes were consistent across group assignments. Rising cTnI was associated with the highest risk of poor outcomes and mortality. CONCLUSIONS: In this secondary analysis of the FAST trial, acute myocardial injury was common and associated with poor outcomes. The direction of the cTnI change might provide additional risk stratification after intracerebral hemorrhage.

Minimal effects after a massive intravenous terbutaline overdose in a child.

A 22-kg female in early childhood with a history of reactive airway disease presented to a paediatric emergency department with acute shortness of breath, tachypnoea and wheezing. Despite treatment with albuterol and corticosteroids, her bronchospasm persisted, prompting the administration of terbutaline. The patient received 220 mcg (10 mcg/kg) terbutaline intravenously, followed immediately by an inadvertent supratherapeutic intravenous dose of 10 000 mcg (454.5 mcg/kg). The patient's laboratory results obtained minutes after the medication error were notable for: potassium, 3.1 mmol/L, lactate, 2.6 mmol/L and troponin I, 0.30 ng/mL (normal <0.03 ng/mL). Over the next 48 hours, serial serum troponin values decreased. The patient was discharged home approximately 72 hours after the initial presentation and she remained well based on follow-up calls over the next several months. Given the timing and trend of troponin concentrations, we do not believe the terbutaline overdose to be responsible for the myocardial injury.