The L-type calcium current (I(Ca)) is important in sustaining propagation during discontinuous conduction. In addition, I(Ca) is altered during discontinuous conduction, which may result in changes in the intracellular calcium transient. To study this, we have combined the ability to monitor intracellular calcium concentration ([Ca(2+)](i)) in an isolated cardiac cell using confocal scanning la...

block with intact atrioventricular conduction: electrophysiologic and pathologic correlations in three cases. Am J Cardiol 32: 783, 1973 28. Narula OS, Gann D, Samet P: Prognostic value of H-V interval. In His Bundle Electorcardiography and Clinical Electrophysiology, edited by Narula OS. Philadelphia, FA Davis Company, 1975, p 437 29. Dhingra RC, Denes P, Wu D, Wyndham CR, Amat-y-Leon F, Towne...

BACKGROUND Action potentials are the classic mechanism by which neurons convey a state of excitation throughout their length, leading, after synaptic transmission, to the activation of other neurons and consequently to network functioning. Using an in vitro integrated model, we found previously that peripheral networks in the autonomic nervous system can organise an unconventional regulatory re...

Circulating cardiac excitation was first described by George R. Mines in his seminal publication ‘On dynamic equilibrium in the heart’. Mines recognized the importance of his finding and suggested that circulating excitation may be responsible for ‘some cases of paroxysmal tachycardia as observed clinically’, and directly defined the optimal circumstances for circular excitation: ‘The circumsta...

It is generally assumed that axons use action potentials (APs) to transmit information fast and reliably to synapses. Yet, the reliability of transmission along fibers below 0.5 microm diameter, such as cortical and cerebellar axons, is unknown. Using detailed models of rodent cortical and squid axons and stochastic simulations, we show how conduction along such thin axons is affected by the pr...

BACKGROUND Bupivacaine, clindamycin, and gentamicin inhibit neuromuscular (NM) conduction. When they are combined, they may synergistically reduce the effective concentration of each to the therapeutic concentration in augmenting rocuronium-induced NM block. Thus, the aim of this study was to investigate whether combinations of the three drugs, at around their therapeutic concentrations, potent...

OBJECTIVE To establish nerve conduction parameters for carpal tunnel syndrome (CTS) electrodiagnosis in the elderly. METHOD Thirty healthy subjects (65-86 years), 9 male and 21 female, were studied. Routine median and ulnar sensory and motor nerve conduction studies, median mixed palmar latency, comparative latency techniques median to ulnar (sensory, mixed and motor lumbrical-interossei), me...

We have studied the individual and combined effects of elevated external potassium concentration (8 mM [K+], metabolic acidosis (pH = 6.8), and hypoxia at different stimulation 400 milliseconds) on Purkinje (P) and ventricular (V) conduction velocities and on Purkinje-ventricular junctional conduction delay (PVJ delay) in in vitro preparations from canine ventricles. Elevated [K+] had opposite ...

The study was undertaken to determine the differential effects of estrogen and progestin on auditory evoked responses in postmenopausal women receiving hormone replacement therapy (HRT). Forty-seven women between 45 and 70 years of age attending menopause and HRT clinic were divided into two groups. Group I included 32 women who attained natural menopause and receiving combined estrogen progest...

objective: generated acoustic trauma by suction and drill may cause sensorineural hearing loss after tympanomastoid surgery. this study was carried out to determine the relationship of sensorineural hearing loss and chronic otitis media surgery at ahvaz jundishapur university of medical sciences in iran. material and methods: this prospective study included 386 patients of chronic middle ear di...