Spiky: An ImageJ Plugin for Data Analysis of Functional Cardiac and Cardiomyocyte Studies.

Introduction And Objective: Nowadays, investigations of heart physiology and pathophysiology rely more and more upon image analysis, whether for the detection and characterization of events in single cells or for the mapping of events and their characteristics across an entire tissue. These investigations require extensive skills in image analysis and/or expensive software, and their reproducibility may be a concern. Our objective was to build a robust, reliable and open-source software tool to quantify excitation-contraction related experimental data at multiple scales, from single isolated cells to the whole heart.

SarConfoCal: simultaneous sarcomere length and cytoplasmic calcium measurements for laser scanning confocal microscopy images.

Summary: Simultaneous recordings of myocytes contractility and their cytoplasmic calcium concentration allow powerful studies, particularly on heart failure and other cardiac dysfunctions. Such studies require dedicated and expensive experimental devices that are difficult to use. Thus we propose SarConfoCal, the first and only software to simultaneously analyse both cytoplasmic calcium variations (from fluorescence signal) and myocytes contractility (from sarcomere length measurement) on laser scanning confocal microscopy images.

SarcOptiM for ImageJ: high-frequency online sarcomere length computing on stimulated cardiomyocytes.

Accurate measurement of cardiomyocyte contraction is a critical issue for scientists working on cardiac physiology and physiopathology of diseases implying contraction impairment. Cardiomyocytes contraction can be quantified by measuring sarcomere length, but few tools are available for this, and none is freely distributed. We developed a plug-in (SarcOptiM) for the ImageJ/Fiji image analysis platform developed by the National Institutes of Health.

Automatic quantitative analysis of t-tubule organization in cardiac myocytes using ImageJ.

The transverse tubule system in mammalian striated muscle is highly organized and contributes to optimal and homogeneous contraction. Diverse pathologies such as heart failure and atrial fibrillation include disorganization of t-tubules and contractile dysfunction. Few tools are available for the quantification of the organization of the t-tubule system.

Enhanced expression of lmb gene encoding laminin-binding protein in Streptococcus agalactiae strains harboring IS1548 in scpB-lmb intergenic region.

Group B streptococcus (GBS) is the main cause of neonatal sepsis and meningitis. Bacterial surface proteins play a major role in GBS binding to and invasion of different host surfaces. The scpB and lmb genes, coding for fibronectin-binding and laminin-binding surface proteins, are present in almost all human GBS isolates.

Altered heart rate control in transgenic mice carrying the KCNJ6 gene of the human chromosome 21.

Congenital heart defects (CHD) are common in Down syndrome (DS, trisomy 21). Recently, cardiac sympathetic-parasympathetic imbalance has also been documented in DS adults free of any CHD. The KCNJ6 gene located on human chromosome 21 encodes for the Kir3.

Roles of PKA, PI3K, and cPLA2 in the NO-mediated negative inotropic effect of beta2-adrenoceptor agonists in guinea pig right papillary muscles.

Although beta(2)-adrenoceptors represent 15-25% of beta-adrenoceptors in the guinea pig heart, their functionality is controversial. We assessed the inotropic effects of beta(2)-adrenoceptor partial agonists in right papillary muscles. Salbutamol induced a small but significant concentration-dependent negative inotropic effect (NIE, -5% at 60 nM) followed by a moderate positive inotropic effect (+36% at 6 microM) due to activation of beta(1)-adrenoceptors.

Evaluation of the ability of Streptococcus agalactiae strains isolated from genital and neonatal specimens to bind to human fibrinogen and correlation with characteristics of the fbsA and fbsB genes.

The ability of 111 Streptococcus agalactiae strains to bind to human fibrinogen was quantified. We correlated the percentages of bacteria that bound to immobilized fibrinogen with fibrinogen-binding (fbs) gene characteristics of strains and with clinical origin, serotypes, and phylogenetic positions of strains. Percentages varied from 0.

Antimony-induced cardiomyopathy in guinea-pig and protection by L-carnitine.

Antimony (Sb) is the mainstay for the treatment of Leishmaniasis. It has serious, often lethal, cardiovascular side effects. The objective of this study was to examine the effects of Sb treatment upon the electrocardiogram (ECG), myocyte contractility (assessed by monitoring sarcomere length during field stimulation), whole-cell action potential (AP) and calcium current (I(Ca)) of the guinea-pig and to evaluate L-carnitine as a cardioprotective agent.

Caffeine-induced immobilization of gating charges in isolated guinea-pig ventricular heart cells.

The effects of 10 mM caffeine (CAF) on intramembrane charge movements (ICM) were studied in isolated guinea-pig ventricular heart cells with the whole-cell patch-clamp technique. In the presence of CAF, the properties (voltage dependence, maximum Q(ON) [Q(max)], availability with voltage) of Q(ON) charge activated from -110 mV were barely affected. Following a 100 ms prepulse to -50 mV to decrease the participation of charges originating from Na channels, the voltage dependence of Q(ON) was shifted by 5 mV (negative component) and by 10 mV (positive component) towards negative potentials, and Q(max) was depressed by 16.