Previous scientific data suggests that enterovirus infections, especially those caused by coxsackieviruses have a role in the pathogenesis of type 1 diabetes. One mechanism by which viral infection could initiate or accelerate diabetogenic process in humans is ‘molecular mimicry’, induction of antiviral immune responses which cross-react with self-epitopes in insulin producing β-cells. This stu...

Experiments were performed on the hearts of open-chest anesthetized dogs and on isolated rabbit hearts. Intracellular microelectrodes and bipolar surface electrodes were used for recording from and for stimulating the atria, AV node, bundle of His, bundle branches and ventricles. Atrial or ventricular premature beats which were usually blocked or delayed within the AV node were facilitated when...

THE ELECTROPHYSIOLOGIC EFFECTS of adenosine and other adenine derivatives were first described by Drury and Szent-Gyorgyi in 1929.' These investigators clearly demonstrated that intravenous administration of adenosine produced a decrease in sinus rate and transient atrioventricular (AV) block. Adenosine is a mediator of many physiologic phenomena and most of the interest in its effects on the c...

This study 1) compares the negative chronotropic and dromotropic actions of adenosine in guinea pig, rat, and rabbit hearts; 2) investigates the mechanism(s) for the different responses; and 3) determines the physiological implications. Isolated perfused hearts were instrumented for measurement of atrial rate and atrioventricular (AV) nodal conduction time. Differences in metabolism of adenosin...

Introduction: Developmental changes in atrioventricular nodal conduction time and refractoriness have been shown in several studies. Prevalence of atrioventricular nodal reentrant tachycardia (AVNRT) is clearly age-dependent. The purpose of this study was to determine developmental changes of basic and frequency-dependent electrophysiological properties of the atrioventricular node (AV-node)...

A total of 60 nulliparous crossbred rabbit females were, a posteriori, divided into 2 experimental groups according to their natural “decision” to conceive or not at day 11 post first parturition (L: solelylactating or LP: lactating-pregnant). This design allowed us to study the evolution of body reserves around first parturition and its influence on the future reproductive success of rabbit fe...

The phenomenon of atrioventricular (AV) nodal "facilitation," described in traditional "black box"-functional studies, implies enhanced AV nodal dromotropic function. We investigated the role of atrial prematurities in the modulation of the nodal cellular responses in the mechanism of AV nodal facilitation. Atrial and His (H) bundle electrograms and microelectrode recordings from proximal AV no...

Objectives: Dual pathways have a determinant role in the occurrence of atrio nodal tachyarrhythmia (AVNRT). The aim of present study is to determine the role of slow pathway (SP) in the concealment zone and protective role of AV node during atrial fibrillation (AF). Material &Methods: In 7 isolated nodal rabbit preparation zone of concealment and concealed conduction is quantified by Specif...