Melatonin alters the excitability of mouse cerebellar granule neurons by inhibiting voltage-gated sodium, potassium, and calcium channels.

Besides its role in the circadian rhythm, the pineal gland hormone melatonin (MLT) also possesses antiepileptogenic, antineoplastic, and cardioprotective properties, among others. The dosages necessary to elicit beneficial effects in these diseases often far surpass physiological concentrations. Although even high doses of MLT are considered to be largely harmless to humans, the possible side effects of pharmacological concentrations are so far not well investigated. In the present study, we report that pharmacological doses of MLT (3 mM) strongly altered the electrophysiological characteristics of cultured primary mouse cerebellar granule cells (CGCs). Using whole-cell patch clamp and ratiometric Ca2+ imaging, we observed that pharmacological concentrations of MLT inhibited several types of voltage-gated Na+ , K+ , and Ca2+ channels in CGCs independently of known MLT-receptors, altering the character and pattern of elicited action potentials (APs) significantly, quickly and reversibly. Specifically, MLT reduced AP frequency, afterhyperpolarization, and rheobase, whereas AP amplitude and threshold potential remained unchanged. The altered biophysical profile of the cells could constitute a possible mechanism underlying the proposed beneficial effects of MLT in brain-related disorders, such as epilepsy. On the other hand, it suggests potential adverse effects of pharmacological MLT concentrations on neurons, which should be considered when using MLT as a pharmacological compound.

Telltale termination of an A-on-V tachycardia with two blocked atrial activations: What is the mechanism?

The termination of tachycardia may provide important clues toward the mechanism of the tachycardia and that close vigilance may clinch the diagnosis before proceeding to other pacing maneuvers.

Value of point-of-care neutrophil gelatinase associated lipocalin in early diagnosis of acute kidney injury in patients with left ventricular systolic dysfunction after coronary angiography.

BACKGROUND: Increased neutrophil gelatinase-associated lipocalin (NGAL) levels are associated with toxic or ischemic renal injury. OBJECTIVE: This study aimed to assess the usefulness of serial NGAL measurements with a point-of-care assay in patients with left ventricular systolic dysfunction (LVSD) for earlier detection of contrast-induced nephropathy (CIN). MATERIALS AND METHODS: A total of 84 patients with LVSD patients referred for coronary angiography were consecutively enrolled in the study. The study population was divided into two groups as the CIN and the non-CIN groups according to the CIN's determination. The serum creatinine levels were calculated 24 h before the procedure and at the 48th and 72nd h after the cardiac catheterization. The plasma NGAL concentration was measured before and at 4 and 24 h after the cardiac catheterization. RESULTS: Baseline and serial NGAL levels were significantly higher in patients with CIN compared to the patients without CIN. NGAL 24th h levels after the index procedure were found to be an independent and significant predictor of CIN in multivariate analysis. CONCLUSIONS: Serial point-of-care NGAL measurements might help earlier detection of CIN in patients with heart failure after coronary angiography.

Parasitic copepod (Lernanthropus kroyeri) on caged sea bass (Dicentrarchus labrax): An estimation of abundance and internal infestation pressure.

Infestation by parasitic copepods is a substantial problem in the cage culture of European sea bass (Dicentrarchus labrax). The Copepoda parasite, Lernanthropus kroyeri (Lernanthropidae), is one of the threats to the mariculture of sea bass. In the present study, we evaluated the data of abundance for L. kroyeri pre-adults and adult males (PAAM) and ovigerous adult females (AFo ) to estimate the internal infection pressure (IIP) in the same cage environment. The sea bass infested by L. kroyeri was collected from grow-out sea cages located in Gulluk Bay (Turkey) in September and October 2019. Mean fish weight and length of sea bass were 75.79 ± 1.66 g and 21.40 ± 0.56 cm, respectively. The fixed lag method was used to predict the abundance of L. kroyeri adult females. The overall prevalence of L. kroyeri was 60%. The mean abundance of PAAM and AFo varied from 0.8 ± 0.24 to 2.5 ± 0.67 and 2.9 ± 0.40 to 4.3 ± 0.55, respectively. The abundance of AF was strongly correlated with PAAM. The pattern of AFo and PAAM was interpreted as an indication of the continuous infestation of L. kroyeri on sea bass. Our results showed that the correlation of AFo abundance for five consecutive weeks was significant, representing the main determinative factor for the continuity of the parasitic load. In our approach, internal infestation pressure is the quantitative estimation of the potential infective copepodids, which are mainly characterized by AF abundance and the prevalence. We predicted that the internal infestation pressure could be high, even exceeding the 50.000 × 106 potential infective copepodids for one sea cage with the fish density of 20 sea bass/m3 .

Unusual response to His-refractory atrial premature complex: What is the mechanism?

A 32-year-old woman underwent radiofrequency catheter ablation of narrow QRS tachycardia that was terminated with intravenous adenosine.

Association between atrial septal aneurysm and arrhythmias.

Objective. This study aimed to assess the association of atrial septal aneurysm (ASA) with cardiac arrhythmias by comparing patients with ASA with a control group with non-ASA, matched for age and gender. Methods. 641 patients with ASA who fulfilled the inclusion criteria were enrolled into the study. The control group consisted of 641 patients without ASA. Patients underwent physical, electrocardiographic and transthoracic echocardiographic examinations. Additional examinations such as transesophageal echocardiography, 24-h rhythm Holter monitoring, and electrophysiological study were performed when clinically needed. Results. There were no differences between the groups in respect to baseline demographic, clinical parameters and echocardiographic parameters except ischemic stroke and smoking status. Percentages of patients suffering from atrial premature complex (APC), ventricular premature complex (VPC), supraventricular tachycardia (SVT) and paroxysmal atrial fibrillation (AF) were higher in ASA patients compared to non-ASA patients. In addition, these parameters were independently associated with the presence of ASA in logistic regression analysis. Conclusions. Certain types of arrhythmias such as APC, VPC, SVT and paroxysmal AF have been shown to be independently associated with the presence of ASA.

Atrial fibrillation associated with carbon monoxide poisoning.

Carbon monoxide intoxication occurs usually via inhalation of carbon monoxide that is emitted as a result of a fire, furnace, space heater, generator, motor vehicle. A 37-year-old male patient was admitted to the emergency department at about 5:00 a.m., with complaints of nausea, vomiting and headache. He was accompanied by his wife and children. His venous blood gas measures were: pH was 7.29, partial pressure of carbon dioxide (pCO2) was 42 mmHg, partial pressure of oxygen (pO2) was 28 mmHg, carboxyhemoglobin (COHb) was 12.7% (reference interval: 0.5%-2.5%) and oxygen saturation was 52.4%. Electro-cardiogram (ECG) examination showed that the patient was not in sinus rhythm but had atrial fibrillation. After three hours the laboratory examination was repeated: Troponin was 1.2 pg/ml and in the arterial blood gas COHb was 3%. The examination of the findings on the monitor showed that the sinus rhythm was re-established. The repeated ECG examination confirmed the conversion to sinus rhythm. He was monitored with the normobaric oxygen administration.

Combination of change in hematological parameters with exercise stress test to predict coronary artery disease.

OBJECTIVE: Treadmill exercise stress testing for identifying patients with a higher likelihood of coronary artery disease (CAD) before elective coronary angiography is recommended in the current guidelines. In this study, we aimed to evaluate the changes in the hematological parameters before and after exercise stress test in relation with the presence of CAD. METHODS: A total of 113 patients with chest pain who underwent treadmill exercise testing and coronary angiography were included in this study. RESULTS: Neutrophil count (4.38±0.99 vs 5.19±0.93, P<.001), and neutrophil to lymphocyte ratio (NLR) (2.04±0.63 vs 2.41±0.78, P<.001) were significantly elevated after treadmill exercise test in all the patients. Increase in the NLR after exercise test was significantly higher in patients with positive exercise test (n=68) than negative exercise test (n=45) (0.49±0.58 vs 0.19±0.44, P=.016). The sensitivity and specificity of treadmill exercise testing according to coronary angiography was 79% and 64%, respectively. A cut-off point of 0.2 for the change in the NLR in addition to positive treadmill exercise testing had 91% sensitivity and 92% specificity in predicting significant coronary artery stenosis (AUC:0.913, 95% CI: 0.805-1.000, P<.001). CONCLUSIONS: Neutrophil to lymphocyte ratio is an important inflammatory marker that can contribute to treadmill ECG testing in predicting CAD.

Subclinical right ventricular dysfunction in intermittent and persistent mildly asthmatic children on tissue Doppler echocardiography and serum NT-proBNP: Observational study.

BACKGROUND: Bronchial asthma may lead to pulmonary hypertension, right ventricular (RV) dysfunction, and cor pulmonale due to elevated afterload on the RV later in life. The aim of this study was to determine whether serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) might serve as a biomarker for detecting subclinical RV dysfunction using echocardiography during the early stages of bronchial asthma. METHODS: Sixty-eight pediatric patients with asthma (asthma group) and 69 age- and sex-matched healthy children (control group) were enrolled. The study was conducted in a tertiary woman and child diseases education and research hospital from January 2013 to December 2013. RV function (2-D and tissue-Doppler echocardiography), pulmonary function (spirometry) and serum NT-proBNP concentration were evaluated. RESULTS: Mean age was 10.5 ± 2.8 years in the asthma group and 10.2 ± 2.7 years in the control group (P = 0.522). RV diastolic function was significantly decreased in the asthma group (ratio of tricuspid lateral annular early diastolic peak velocity to tricuspid lateral annular late diastolic peak velocity [E'/A'], 1.29 ± 0.68 vs 1.74 ± 0.89, P = 0.001). RV myocardial performance index was significantly higher in the asthma group than in the control group (0.28 ± 0.06 vs 0.24 ± 0.07, respectively; P = 0.003). Finally, serum NT-proBNP concentration was significantly higher in the asthma group than in the control group (292.3 ± 142.2 pg/mL vs 208.2 ± 70.1 pg/mL, respectively; P = 0.003). CONCLUSION: Increased serum NT-proBNP is associated with subclinical RV dysfunction in asthmatic children. RV function is significantly affected in children with bronchial asthma.