John D. Gallagher

The Heart Rhythm Society (HRS)/American Society of Anesthesiologists (ASA) Expert Consensus Statement on the Perioperative Management of Patients with Implantable Defibrillators, Pacemakers and Arrhythmia Monitors: Facilities and Patient Management: Executive Summary: This document was developed as a joint project with the American Society of Anesthesiologists (ASA), and in collaboration with the American Heart Association (AHA), and the Society of Thoracic Surgeons (STS)

a t C r a t a R The Heart Rhythm Society (HRS)/American Society of Anesthesiologists (ASA) Expert Consensus Statement on the Perioperative Management of Patients with Implantable Defibrillators, Pacemakers and Arrhythmia Monitors: Facilities and Patient Management This document was developed as a joint project with the American Society of Anesthesiologists (ASA), and in collaboration with the American Heart Association (AHA), and the Society of Thoracic Surgeons (STS)

Practice advisory for the perioperative management of patients with cardiac rhythm management devices: Pacemakers and implantable cardioverter- defibrillators - A report by the American Society of Anesthesiologists Task Force on perioperative management of patients with cardiac rhythm management devices

PRACTICE advisories are systematically developed reports that are intended to assist decision making in areas of patient care. Advisories provide a synthesis and analysis of expert opinion, clinical feasibility data, open forum commentary, and consensus surveys. Advisories are not intended as standards, guidelines, or absolute requirements. They may be adopted, modified, or rejected according to clinical needs and constraints. The use of practice advisories cannot guarantee any specific outcome. Practice advisories summarize the state of the literature and report opinions derived from a synthesis of task force members, expert consultants, open forums, and public commentary. Practice advisories are not supported by scientific literature to the same degree as standards or guidelines because of the lack of sufficient numbers of adequately controlled studies. Practice advisories are subject to periodic revision as warranted by the evolution of medical knowledge, technology, and practice. Methodology

The Heart Rhythm Society (HRS)/American Society of Anesthesiologists (ASA) Expert Consensus Statement on the Perioperative Management of Patients with Implantable Defibrillators, Pacemakers and Arrhythmia Monitors: Facilities and Patient Management: Executive Summary

a t C r a t a R The Heart Rhythm Society (HRS)/American Society of Anesthesiologists (ASA) Expert Consensus Statement on the Perioperative Management of Patients with Implantable Defibrillators, Pacemakers and Arrhythmia Monitors: Facilities and Patient Management This document was developed as a joint project with the American Society of Anesthesiologists (ASA), and in collaboration with the American Heart Association (AHA), and the Society of Thoracic Surgeons (STS)

MERCURY SUPPRESSION OF A POTASSIUM CURRENT IN HUMAN B LYMPHOCYTES

Mercury is a recognized environmental toxin. Several organ systems are targeted by this substance and impairment of immune function is known to result from exposure to mercury. Using the patch clamp technique in the whole cell configuration on resting human B lymphocytes we have identified an outward potassium current and studied the effects of mercury on this current. We present data that demonstrate: (i) the absence of inward currents; (ii) a time and voltage dependent outward current with a threshold of -40 mV and reversal potential near EK+; (iii) blocking of this current by TEA (tetraethylammonium chloride) in a dose dependent manner; (iv) a slow time course for recovery from inactivation of this outwardly rectifying K+ current and, (v) the diminution and final block of this potassium current by mercury. These data supplement the findings from our laboratories that demonstrate inhibitory effects on B cell activation by mercury. We propose that the movement of potassium ions across the B cell membrane, an event presumed to be one of the first signals in the mitogenic process, is a target of mercury toxicity.

PRESENCE OF FUNCTIONAL NMDA RECEPTORS IN A HUMAN NEUROBLASTOMA CELL LINE

Data are presented that provide convincing evidence for the expression of structurally normal and functional NMDA receptors by acetylcholine-producing human LA-N-2 neuroblastoma cells in culture. Reverse transcription and polymerase chain reaction (RT-PCR), followed by cloning and DNA sequencing, revealed the presence in these cells of mRNA representing the key subunit, NMDAR1, of the receptor. This mRNA was further demonstrated by Northern analysis to be the same size as that described for human neurons. The neutral red cytotoxicity assay was utilized to examine the influence on these neuroblastoma cells of a 48-h incubation with either L-glutamic acid or the specific NMDA agonist N-phthalamoyl-L-glutamic acid (NPG). Cell cytotoxicity was shown by this assay to be increased through incubation with glutamate at 1 and 10 mM by 27 and 37%, and through incubation with NPG at 0.1 and 1 mM by 28 and 46%. A possible mechanism of these toxic effects was further evaluated using the whole-cell configuration of the patch-clamp technique and the specific NMDA agonists (+/-)1-aminocyclobutane-cis-1,3-dicarboxylic acid (ACDA) and NPG. Using this procedure, a voltage-dependent tetrodotoxin-sensitive inward sodium current was found to be increased (x 1.5) by L-glutamic acid and by both NMDA agonists in the presence of glycine. Another voltage-gated inward current, probably carried by calcium ions, was increased three- to fourfold. Hence, these glutamate activities observed in human LA-N-2 neuroblastoma cells appear to occur through the activation of functional NMDA receptors in much the same way as reported for neurons, and both glutamate and NMDA agonists can be toxic to these neuroblastoma cells. Our findings, therefore, suggest this cell line will provide a model suitable for investigating the mechanisms of NMDA-related long-term potentiation (LTP) in neurons and of the NMDA-related neurotoxic effects of glutamate in disease states that involve a reduction in cholinergic function.

Ionic signals in T47D human breast cancer cells

Increasing evidence that ion channels play a key role in the modulation of cellular mitogenesis led us to investigate the membranes of T47D human breast cancer cells to identify the ion currents present. We report here the results of voltage-clamp studies in the whole-cell configuration on isolated, non-synchronized single cells obtained from a ductal breast carcinoma. In these studies we identified an outward rectifying potassium current and a chloride current. The potassium current activated at potentials more positive than -40 mV, reached an average value of 1.4 nA, and did not inactivate with time. This current was sensitive to block by extracellular tetraethylammonium chloride (TEA, IC50 = 1 micro M), was insensitive to charybdotoxin (CTX, IC50 = 7.8 micro M), and was not diminished by repetitive pulses separated by 1 s. Rapid voltage-dependent inactivation of the current was demonstrated by tail current analysis. The current appeared calcium-insensitive. Application of hyperpolarizing pulses did not elicit an inward potassium rectifier current. Treatment with tetrodotoxin did not reveal the presence of an inward sodium current. The potassium current was increased by the presence of aspartate in place of chloride and in the presence of the chloride channel blocker 4,4-diisothiocyanostilbene-2,2-disulfonic acid (DIDS). We conclude that currents present in T47D breast cancer cells include a chloride current and a voltage-gated potassium outward rectifier. We suggest that the potassium current, either alone or in conjunction with potassium currents reported in different human breast cancer cell lines by others, may play a role in the modulation of the cell cycle.

Effects of cadmium on potassium currents in activated B lymphocytes

We have applied the patch clamp technique in the whole-cell configuration to study whole-cell currents in B lymphocytes under three conditions: (i) resting; (ii) interleukin-4 (IL-4)-treated; and (iii) IL-4 plus cadmium-treated murine B lymphocytes. Through these experiments we have: (i) confirmed our earlier findings and the observation of others that resting B cells express only outward currents; (ii) confirmed the presence of an inwardly rectifying K+ current elicited by treatment with the lymphokine IL-4 that was revealed in our previous study on single channel currents; (iii) demonstrated that both inward and outward rectifying K+ currents in IL-4-treated B cells are dramatically reduced by exposure to 20 microM cadmium; and (iv) determined that the activation curve of the IL-4-induced inward rectifier is shifted to more negative voltages by cadmium. We propose that one of the mechanisms by which cadmium can mediate toxicity in activated B lymphocytes is through the suppression and modulation of potassium currents, effects that may alter the timing of entry into the cell cycle.

The Heart Rhythm Society (HRS)/American Society of Anesthesiologists (ASA)

a t C r a t a R The Heart Rhythm Society (HRS)/American Society of Anesthesiologists (ASA) Expert Consensus Statement on the Perioperative Management of Patients with Implantable Defibrillators, Pacemakers and Arrhythmia Monitors: Facilities and Patient Management This document was developed as a joint project with the American Society of Anesthesiologists (ASA), and in collaboration with the American Heart Association (AHA), and the Society of Thoracic Surgeons (STS)