Inter- and intra-observer variability in the echocardiographic evaluation of wall motion abnormality in patients with ST-elevation myocardial infarction or takotsubo syndrome - A novel approach.

INTRODUCTION AND OBJECTIVES: Using existing transthoracic echocardiographic indices to quantify left ventricular wall motion abnormalities (WMAs) can be difficult due to the variations in the location of the abnormalities within the left ventricle, the quality of examinations, and the inter-/intra-observer variability of available indices. This study aimed to evaluate a new approach for measuring the extent of WMA by calculating the percentage of abnormal wall motion and comparing it to the wall motion score index (WMSI). The study also sought to assess inter- and intra-observer variability. METHODS: The study included 140 echocardiograms from 54 patients presenting with ST-elevation myocardial infarction or Takotsubo syndrome. All patients underwent an echocardiographic examination according to a standard protocol and the images were used to measure the extent of akinesia (proportion akinesia, PrA), akinesia and hypokinesia (proportion akinesia/hypokinesia, PrAH), and WMSI. The inter-observer variability between the two operators was analyzed. The intra-observer analysis was performed by one observer using the same images at least 1 month after the first measurement. The agreement was analyzed using the Pearson correlation coefficient and Bland-Altman plots. RESULTS: Inter- and intra-observer variability for PrA and PrAH were low and comparable to those for WMSI. CONCLUSION: PrA and PrAH are reliable and reproducible echocardiographic methods for the evaluation of left ventricular wall motion.

Temporal electrocardiographic changes in anterior ST elevation myocardial infarction versus the Takotsubo syndrome.

Background: Electrocardiography (ECG) on admission is similar in ST elevation myocardial infarction (STEMI) and Takotsubo syndrome (TTS). ECG on admission has been extensively investigated and compared between STEMI and TTS, however, only a few studies have compared temporal ECG. Our aim was to compare ECG in anterior STEMI versus female TTS from admission to day 30. Methods: Adult patients with anterior STEMI or TTS treated at Sahlgrenska University Hospital (Gothenburg, Sweden) from December 2019 to June 2022 were prospectively enrolled. Baseline characteristics, clinical variables and ECGs from admission to day 30 were analyzed. Using a mixed effects model, we compared temporal ECG between female patients with anterior STEMI or TTS, as well as between female and male patients with anterior STEMI. Results: A total of 101 anterior STEMI patients (31 female, 70 male) and 34 TTS patients (29 female, 5 male) were included. The temporal pattern of T wave inversion was similar between female anterior STEMI and female TTS, as well as between female and male anterior STEMI. ST elevation was more common, whereas QT prolongation was less common, in anterior STEMI compared with TTS. Q wave pathology was more similar between female anterior STEMI and female TTS than between female and male anterior STEMI. Conclusions: The pattern of T wave inversion and Q wave pathology from admission to day 30 was similar in female patients with anterior STEMI and female patients with TTS. Temporal ECG in female patients with TTS may be interpreted as following a "transient ischemic" pattern.

Differences between cardiac troponin I vs. T according to the duration of myocardial ischaemia.

AIMS: Cardiac troponin T (cTnT) and troponin I (cTnI) are expressed as an obligate 1:1 complex in the myocardium. However, blood levels of cTnI often rise much higher than that of cTnT in myocardial infarction (MI), whereas cTnT is often higher in patients with stable conditions such as atrial fibrillation. Here we examine high-sensitive (hs) cTnI and hs-cTnT after different durations of experimental cardiac ischaemia. METHODS AND RESULTS: hs-cTnI, hs-cTnT, and the hs-cTnT/hs-cTnI ratio were measured in plasma samples from rats before and at 30 and 120 min after 5, 10, 15, and 30 min of myocardial ischaemia. The animals were killed after 120 min of reperfusion, and the infarct volume and volume at risk were measured. hs-cTnI, hs-cTnT, and the hs-cTnT/hs-cTnI ratio were also measured in plasma samples collected from patients with ST-elevation myocardial infarction (STEMI). hs-cTnT and hs-cTnI increased over 10-fold in all rats subjected to ischaemia. The increase of hs-cTnI and hs-cTnT after 30 min was similar, resulting in a hs-cTnI/hs-cTnT ratio around 1. The hs-cTnI/hs-cTnT ratio was also around 1 in blood samples collected at 120 min in rats subjected to 5 or 10 min of ischaemia where no localized necrosis was observed. In contrast, the hs-cTnI/hs-cTnT ratio at 2 h was 3.6-5.5 after longer ischaemia that induced cardiac necrosis. The large hs-cTnI/hs-cTnT ratio was confirmed in patients with anterior STEMI. CONCLUSION: Both hs-cTnI and hs-cTnT increased similarly after brief periods of ischaemia that did not cause overt necrosis, whereas the hs-cTnI/hs-cTnT ratio tended to increase following longer ischaemia that induced substantial necrosis. A low hs-cTnI/hs-cTnT ratio around 1 may signify non-necrotic cTn release.

The role of admission electrocardiogram in predicting outcome in patients hospitalized for COVID-19.

BACKGROUND: Abnormal electrocardiogram (ECG) has been associated with poor outcome in patients hospitalized for COVID-19. However, the independent association between admission ECG and the risk of a poor outcome remains to be established. Our aim was to determine if abnormal admission ECG predicts treatment at intensive care unit or in-hospital death within 30 days in patients hospitalized for COVID-19. METHODS: We analyzed the propensity weighted association between abnormal admission ECG and outcome in patients hospitalized for COVID-19 (March to May 2020). All adult patients hospitalized for COVID-19 at the three centers of Sahlgrenska University Hospital (Gothenburg, Sweden) were eligible for inclusion (N = 439). Patients with available admission ECG within six hours from admission were included. RESULTS: 238 patients (age 62 ± 16 years, 74% male) were included. 103 patients had normal ECG and 135 patients had abnormal ECG. 99 patients were admitted to intensive care unit or died in-hospital within 30 days. Abnormal ECG was associated with increased risk of the outcome (odds ratio 2.11 [95% confidence interval 1.21-3.66]). CONCLUSIONS: Abnormal admission ECG was associated with increased risk of treatment at intensive care unit or in-hospital death within 30 days; and could be considered a high-risk criterion in patients hospitalized for COVID-19.

ECG differences and ECG predictors in patients presenting with ST segment elevation due to myocardial infarction versus takotsubo syndrome.

Background: Previous studies comparing electrocardiogram (ECG) in Takotsubo syndrome (TS) versus ST elevation myocardial infarction (STEMI) included TS patients without ST elevation, did not consider the culprit lesion in STEMI or had groups that were unbalanced regarding sex and age. Accounting for these factors, we sought to conduct a more reliable comparison of ECG in TS with ST-elevation (STE-TS) versus STEMI. The secondary aim was to investigate if ST segment changes, T wave inversion or prolonged QT interval predicted ventricular arrhythmia or death in STE-TS and STEMI. Methods: All STE-TS patients who presented at Sahlgrenska University Hospital between 2008 and 2019 were matched by sex and age to STEMI patients. STEMI patients were subcategorized according to whether or not the culprit lesion was located in the left anterior descending artery (LAD). Baseline characteristics, in-hospital outcomes and admission ECGs were analyzed. Results: 104 STE-TS patients were sex- and age-matched with 274 STEMI patients (113 LAD-STEMI, 161 non-LAD STEMI). Admission ECG in STE-TS was more similar to LAD STEMI than non-LAD STEMI. Reciprocal ST depression was less common in STE-TS (7/104, 6.7%) compared with STEMI (112/274, 41%; p= < 0.001). The sum of all ST elevations and the sum of all ST-deviations predicted life-threatening ventricular arrhythmia (LTVA) or death in LAD STEMI but not in STE-TS. Conclusions: In conclusion, admission ECG in STE-TS was similar to LAD STEMI but reciprocal ST depression was less common in STE-TS compared with STEMI overall. ST segment changes predicted LTVA or death in STEMI but not in STE-TS.

Rapid and label-free detection of Aflatoxin-B1viamicrofluidic electrochemical biosensor based on manganese (III) oxide (Mn3O4) synthesized by co-precipitation route at room temperature.

Aflatoxin B1 (AFB1) is the most toxic mycotoxin, naturally occurring in food items, and it causes several types of lethal diseases. Therefore, a rapid and convenient detection method for AFB1 is the first step toward overcoming the effect of AFB1. The current work presents the development of an efficient microfluidic electrochemical-based biosensor using tri-manganese tetroxide nanoparticles (Mn3O4nps) for AFB1 detection. The Mn3O4nps were synthesized at room temperature through the co-precipitation route. Its phase purity, structural and morphological studies have been characterized through x-ray diffraction, Raman spectroscopy, energy-dispersive x-ray, Fourier transform infrared spectroscopy and transmission electron microscopy. The mask-less UV-lithography was carried out to fabricate the three-electrode chip and microfluidic channel of the microfluidic electrochemical biosensing system. The designed microfluidic immunosensor (BSA/Ab-AFB1/Mn3O4/ITO) was fabricated using the three-electrode chip, microfluidic channel in poly-dimethyl siloxane. The fabricated sensor exhibited the 3.4µA ml ng-1cm-2sensitivity and had the lowest lower detection limit of 0.295 pg ml-1with the detection range of 1 pg ml-1to 300 ng ml-1. Additionally, the spiked study was also performed with this immunoelectrode and a recovery rate was obtained of 108.2%.

The ratio of cardiac troponin T to troponin I may indicate non-necrotic troponin release among COVID-19 patients.

BACKGROUND: Although cardiac troponin T (cTnT) and troponin I(cTnI) are expressed to similar amount in cardiac tissue, cTnI often reach ten-times higher peak levels compared to cTnT in patients with myocardial necrosis such as in acute myocardial infarction (MI). In contrast, similar levels of cTnT and cTnI are observed in other situations such as stable atrial fibrillation and after strenuous exercise. OBJECTIVE: Examine cTnT and cTnI levels in relation to COVID-19 disease and MI. METHODS: Clinical and laboratory data from the local hospital from an observational cohort study of 27 patients admitted with COVID-19 and 15 patients with myocardial infarction (MI) that were analyzed with paired cTnT and cTnI measurement during hospital care. RESULTS: Levels of cTnI were lower than cTnT in COVID-19 patients (TnI/TnT ratio 0.3, IQR: 0.1-0.6). In contrast, levels of cTnI were 11 times higher compared to cTnT in 15 patients with MI (TnI/TnT ratio 11, IQR: 7-14). The peak cTnI/cTnT ratio among the patients with MI following successful percutaneous intervention were 14 (TnI/TnT ratio 14, IQR: 12-23). The 5 COVID-19 patient samples collected under possible necrotic events had a cTnI/cTnT ratio of 5,5 (IQR: 1,9-8,3). CONCLUSIONS: In patients with COVID-19, cTnT is often elevated to higher levels than cTnI in sharp contrast to patients with MI, indicating that the release of cardiac troponin has a different cause in COVID-19 patients.

Short- and Long-Term Clinical Outcomes for Patients With Takotsubo Syndrome and Patients With Myocardial Infarction: A Report From the Swedish Coronary Angiography and Angioplasty Registry.

Background Takotsubo syndrome (TS) is a potentially life-threatening acute cardiac syndrome with a clinical presentation similar to myocardial infarction and for which the natural history, management, and outcome remain incompletely understood. Our aim was to assess the relative short-term mortality risk of TS, ST-segment-elevation myocardial infarction (STEMI), and non-STEMI (NSTEMI) and to identify predictors of in-hospital complications and poor prognosis in patients with TS. Methods and Results This is an observational cohort study based on the data from the SCAAR (Swedish Coronary Angiography and Angioplasty Registry). We included all patients (n=117 720) who underwent coronary angiography in Sweden attributed to TS (N=2898 [2.5%]), STEMI (N=48 493 [41.2%]), or NSTEMI (N=66 329 [56.3%]) between January 2009 and February 2018. We compared patients with TS to those with NSTEMI or STEMI. The primary end point was all-cause mortality at 30 days. Secondary outcomes were acute heart failure (Killip Class ≥2) and cardiogenic shock (Killip Class 4) at the time of angiography. Patients with TS were more often women compared with patients with STEMI or NSTEMI. TS was associated with unadjusted and adjusted 30-day mortality risks lower than STEMI (adjusted hazard ratio [adjHR], 0.60; 95% CI, 0.48-0.76; P<0.001), but higher than NSTEMI (adjHR, 2.70; 95% CI, 2.14-3.41; P<0.001). Compared with STEMI, TS was associated with a similar risk of acute heart failure (adjHR, 1.26; 95% CI, 0.91-1.76; P=0.16) but a lower risk of cardiogenic shock (adjHR, 0.55; 95% CI, 0.34-0.89; P=0.02). The relative 30-day mortality risk for TS versus STEMI and NSTEMI was higher for smokers than nonsmokers (adjusted P interaction STEMI=0.01 and P interaction NSTEMI=0.01). Conclusions The 30-day mortality rate in TS was higher than in NSTEMI but lower than STEMI despite a similar risk of acute heart failure in TS and STEMI. Among patients with TS, smoking was an independent predictor of mortality.

Risk of in-hospital life-threatening ventricular arrhythmia or death after ST-elevation myocardial infarction vs. the Takotsubo syndrome.

AIMS: The risk of life-threatening ventricular arrhythmias (LTVA) has been reported to be lower in Takotsubo syndrome (TS) compared with ST-elevation myocardial infarction (STEMI). However, the extent to which these differences relate to the fact that most patients with TS are women (who have a lower risk of LTVA) and a relatively larger proportion of patients with STEMI are men is incompletely understood. We aimed to investigate the risk of LTVA or death in sex-matched and age-matched patients with TS, anterior STEMI, and non-anterior STEMI. METHODS AND RESULTS: We systematically reviewed the charts of all patients with TS who were treated at Sahlgrenska University Hospital (Gothenburg, Sweden) between 2008 and 2019. A total of 155 patients with confirmed TS (according to the European Society of Cardiology diagnostic criteria for TS) were sex-matched and age-matched 1:1:1 to patients with anterior and non-anterior STEMI. Baseline characteristics and in-hospital outcomes were recorded directly from the patient charts for all patients, and all admission electrocardiographs were analysed. The primary outcome was the composite of death or LTVA [defined as sustained ventricular tachycardia (>30 s) or ventricular fibrillation] within 72 h. The risk of LTVA or death within 72 h after admission was considerably lower in TS (2.6%) vs. anterior STEMI (14%; P = 0.002) and non-anterior STEMI (9.0%; P = 0.02), despite similar or greater risks of acute heart failure, and similar risks of cardiogenic shock. Compared with STEMI, TS was associated with a lower risk of sustained and non-sustained ventricular tachycardia and ventricular fibrillation. CONCLUSIONS: In a predominantly female age-matched and sex-matched cohort of patients with TS, anterior STEMI, and non-anterior STEMI, the adjusted risk of in-hospital LTVA or death was considerably lower in TS compared with STEMI, despite similar or greater risk of acute heart failure and similar risk of cardiogenic shock.

Restarting LDLT During COVID-19: Early Results After Restructuring.

INTRODUCTION: Living-donor liver transplantation (LDLT) has been mostly suspended and deceased-donor living transplantation activity has been considerably reduced because of coronavirus disease 2019 (COVID-19). We modified our protocols and procedures in line with COVID-19 guidelines. Since the restructuring, we have performed 20 LDLTs. Our study reports the outcomes of these cases and demonstrates the feasibility of LDLT during this pandemic. MATERIALS AND METHODS: The changes were influenced by experiences and communications from across the globe. A month-long self-imposed moratorium was spent in restructuring the program and implementing new protocols. Twenty LDLTs were performed between April 18 and September 15 using the new protocols. Our experience includes 2 simultaneous liver-kidney transplants, 1 ABO-incompatible LDLT, and 1 pediatric case (age 11 months). RESULTS: Nineteen patients recovered and 1 patient died. We maintained our postoperative immunosuppression protocol without many changes. Major complications were observed in 30% of recipients but none of the donors. One recipient was infected with COVID-19 during the postoperative period. A donor-recipient couple contracted COVID-19 after discharge from the hospital. All patients recovered from COVID-19 and liver enzymes were unaffected. CONCLUSION: This study represents a microcosm of experience in LDLT during the COVID-19 era. Outcomes of LDLT are not affected by COVID-19 per se, provided that we make necessary changes.

The Detection of Postprandial Hypoglycemia with 5-Hour Oral Glucose Tolerance Test.

INTRODUCTION: Postprandial hypoglycemia (PH) is a poorly understood phenomenon. Five-hour oral glucose tolerance test (5-OGTT) is often a useful laboratory investigation to understand and establish a diagnosis of PH. The aim of this study is to present the patterns observed during 5-OGTT performed in cases with PH in a tertiary hospital in Nepal. METHODS: 5-OGTTs were performed on 52 patients who complained symptomatic postprandial neuroglycopenic symptoms, at the Nepal Medicity hospital during the period of 2 years from 2017 to 2019. The anthropometry, medical history, serum glucose; insulin and cortisol were obtained. The homeostatic model assessment score for insulin resistance (HOMA-IR) based on fasting glucose and insulin levels were calculated. Data was analyzed using SPSS (Version 20.0). RESULTS: 21 (40.4%) patients out of 52 developed hypoglycemia [blood glucose < 55mg/dl (3.1mmol/L)], among them nine patients developed hypoglycemia at 3 hours, 11 at 4 hours and one at 5 hours post glucose load. The fasting insulin level in patients who developed hypoglycemia was 12.1 ± 5.8 µU/ml compared to the insulin level analyzed at the point of hypoglycemic episode which was 6.4 ± 1.8 µU/ml, P<0.005. CONCLUSION: The level of insulin is disproportionately high in the setting of hypoglycemia where it was expected to be nearly absent. The disturbance in physiological mechanism between insulin sensitivity and insulin secretion may be the possible cause of PH.

A decoupler-free simple paper microchip capillary electrophoresis device for simultaneous detection of dopamine, epinephrine and serotonin.

This paper demonstrates a new and simplified configuration for capillary electrophoresis-amperometric detection (CE-AD) using a paper microfluidic chip incorporating inexpensive wax printing and screen printing based methods and then used for electrophoretic separation and simultaneous in-channel amperometric detection of three clinically relevant neurochemicals in a single run without using any decouplers. Detection of neurochemicals e.g., dopamine, epinephrine and serotonin is crucial for early prediction of neurological disorders including Parkinson's, Alzheimer's, dementia, as well as progressive neuro-psychiatric conditions such as depression, anxiety, as well as certain cardiovascular diseases. The plasma concentrations of such neurochemicals are as important as those present in cerebrospinal fluid (CSF) and can be useful for rapid and convenient biosensing. However, simultaneous detection of such neurochemicals in a complex mixture such as human serum requires their separation prior to detection. With the developed microchip, separation and detection of the neurochemicals were exhibited within 650 seconds without pre-treatment and the procedure was validated with spiked fetal bovine serum samples. Beside this, the developed paper microfluidic chip has potential to be integrated in point-of-care diagnosis with onsite detection ability. Moreover, the use of a straight channel capillary, a screen-printed carbon electrode without decoupler, in-channel amperometric detection and low sample volume requirements (2 µL) are shown as additional advantages.

The selection of highly specific and selective aptamers using modified SELEX and their use in process analytical techniques for Lucentis bioproduction.

Aptamers for Lucentis were selected using 10 rounds of a modified and highly stringent SELEX process. Affinity column chromatography was used for the binding, partitioning, and elution steps, and the regeneration of ssDNA was performed via asymmetric PCR in the SELEX process. The interaction of aptamers with Lucentis was studied by means of the HADDOCK web server docking program. In addition, the secondary structures of aptamers were interrogated using the mfold web server to check common regions responsible for better affinity towards Lucentis. The two best aptamers for Lucentis (aptamers 1 and 25) were found to have dissociation constant (K d) values between 23 and 35 nM by means of thermofluorimetric and non-faradaic impedance spectroscopy (NFIS) analysis. The low dissociation constants in the nanomolar range showed the high specificities of the aptamers for Lucentis. Selectivity tests were also performed using both aptamers with different proteins in which negligible responses were obtained from interfering proteins with respect to Lucentis. Although neither of the two aptamers showed prominent responses to the interfering proteins, slightly better selectivity was shown by aptamer 1. The same aptamers were tested for their application in the detection of Lucentis in spiked and real media broth samples. For this detection test, interdigitated (IDT) gold electrodes on a glass substrate were fabricated using standard photolithography and thermal deposition techniques. NFIS measurements were used for the label-free detection of Lucentis in samples. The linear ranges of detection for aptamers 1 and 25 were found to be 22-100 nM and 40-100 nM, respectively. The LODs for aptamers 1 and 25 were calculated to be 22 nM and 40 nM, respectively, which were significantly better than the values from a HPLC-based detection method (about 240 nM). The real sample analysis results were cross-checked via a standard HPLC method, and better correlation was found between the HPLC and aptamer 1 results than the aptamer 25 results; hence, aptamer 1 can be further analyzed and tested for use in affinity column chromatography and detection-kit/chip-based PAT for Lucentis bioproduction.

Electrocardiographic predictors of adverse in-hospital outcomes in the Takotsubo syndrome.

BACKGROUND: Takotsubo syndrome (TS) is a life-threatening acute heart failure syndrome. However, little is known about risk factors for worse outcomes in TS and no high-risk ECG criteria have been defined. We sought to identify ECG predictors of life-threatening in-hospital complications in TS. METHOD AND RESULT: Using the nationwide Swedish Angiography and Angioplasty Registry (SCAAR) we obtained data on all consecutive patients undergoing coronary angiography at Sahlgrenska University Hospital between June 2008 and February 2019. For all patients with TS we conducted in-depth chart reviews to confirm the TS diagnosis. For those with confirmed TS we then evaluated all ECGs obtained during the index hospitalization. The primary endpoint was the occurrence of in-hospital major adverse cardiac event (MACE), defined as the composite of death, ventricular tachycardia or fibrillation (VT/VF), or atrioventricular block ≥2 or asystole ≫10 s. We identified 215 patients with TS (mean age 69 ±â€¯13 years; 93% women). MACE occurred in 34 patients (16%), of whom 20 had VT/VF (9,3%). Patients with MACE were less likely than those without MACE to have sinus rhythm (85% versus 96%, p = 0.025) or T-wave inversion (29% versus 51%, p = 0.025). After propensity score adjustment T-wave inversion was independently associated with lower MACE risk (adjusted odds ratio [AdjOR] 0.28, 95% confidence interval [CI] 0.10-0.76, p = 0.012) and VT/VF (AdjOR 0.24, 95% CI 0.06-0.94, p = 0.041). CONCLUSION: T-wave inversion is common in TS and is associated with lower risk of MACE, driven by a lower risk of VT/VF.

Clinical management in the takotsubo syndrome.

Introduction: Takotsubo syndrome (TS) is an increasingly recognized acute heart failure syndrome which is self-limiting in most cases but can result in life-threatening complications. TS is difficult to distinguish from acute myocardial infarction (AMI) early in the disease course and currently lacks evidence-based treatment recommendations. Areas covered: Based on the available literature this systematic review discusses the clinical management of patients with TS during (i) the diagnostic workup; (ii) acutely after establishing the TS diagnosis; and (iii) after recovery of cardiac function. Expert commentary: Since TS is self-limiting in most cases it is recommended to refrain from unnecessary treatment (the do no harm principle) when managing patients with TS. The management of patients with TS should focus on careful monitoring of ECG and hemodynamics, and on preventing and treating complications. Because catecholamine-mediated inotropic overstimulation is implicated in the pathogenesis of TS, and because inotropic drugs have been associated with worse outcomes for patients with TS, we recommend the treating physician to avoid these drugs. Instead, mechanical assist devices should be considered early for patients with TS who develop cardiogenic shock with signs of end-organ hypo-perfusion.

Surface Functionalized Prussian Blue-coated Nanostructured Nickel Oxide as a New Biosensor Platform for Catechol Detection.

An amperometric biosensor has been developed for highly efficient and sensitive detection of catechol using Prussian blue (PB)-coated nickel oxide (NiO) nanoparticles (NPs) as a matrix for the immobilization of tyrosinase enzyme. The NiO NPs were synthesized by sol-gel method using sodium dodecyl sulphate as anionic surfactant and the surface of the synthesized NiO NPs was modified with PB to enhance electrocatalytic activity and to prevent surface aggregation. After confirmation of successful synthesis of the PB-NiO NPs from transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopic (EDS) studies, the prepared NPs were deposited onto a working electrode of a commercially available screen printed carbon electrode (SPCE) substrate. The tyrosinase enzyme was covalently immobilized onto the PB-NiO deposited SPCE for selective detection and estimation of catechol through electrochemical methods via cyclic voltammetry (CV) and chronoamperometric techniques. The functionalization of tyrosinase on the electrode surface was verified by atomic force microscopy (AFM) and scanning electron microscopic (SEM) techniques and the electrochemical response studies of the proposed biosensor showed high sensitivity of 0.954 µA/µM for catechol in a wide linear range (1 - 50 µM) with low detection limit (LOD) of 0.087 µM. The developed sensor also exhibited a fast response time of 27 s and decent selectivity for catechol detection.

Correction: Highly-sensitive detection of Salmonella typhi in clinical blood samples by magnetic nanoparticle-based enrichment and in-situ measurement of isothermal amplification of nucleic acids.

[This corrects the article DOI: 10.1371/journal.pone.0194817.].

Rapid Detection Device for Salmonella typhi in Milk, Juice, Water and Calf Serum.

A limit of detection of 200 CFU/mL of Salmonella typhi spiked in various sample matrices were achieved in 30 min. The sample matrices were raw/unprocessed milk, commercially available milk, juice from packed bottles, fresh juice from carts, potable water, turbid water and calf serum. The complete protocol comprised of three steps: (a) cell lysis (b) nucleic acid amplification and (c) an in situ optical detection. The cell lysis was carried out using a simple heating based protocol, while the loop-mediated isothermal amplification of DNA was carried out by an in-house designed and fabricated system. The developed system consists of an aluminum block fitted with two cartridge heaters along with a thermocouple. The system was coupled to a light source and spectrometer for a simultaneous in situ detection. Primers specific for STY2879 gene were used to amplify the nucleic acid sequence, isolated from S. typhi cells. The protocol involves 15 min of cell lysis and DNA isolation followed by 15 min for isothermal amplification and simultaneous detection. No cross-reactivity of the primers were observed at 106 CFU/mL of Escherichia coli, Vibrio cholerae, Salmonella typhimurium, Salmonella paratyphi A, Pseudomonas aeruginosa, Bacillus cereus, Lysteria monocytogenes, Clostridium botulinum, Staphylococcus aureus and Salmonella havana. In addition, the system was able to detect S. typhi of 200 CFU/mL in a concoction of 106 CFU/mL of E. coli, 106 CFU/mL of V. cholerae, and 106 CFU/mL of hepatocyte-derived cellular carcinoma HUH7 cells. The proposed rapid diagnostic system shows a promising future in the field of food and medical diagnostics.