Prevalence of the Brugada sign in idiopathic ventricular fibrillation and healthy controls.

Objective: To determine the prevalence of the Brugada sign (right bundle branch block with ST elevation in V1-V3) in idiopathic ventricular fibrillation and in an age matched healthy population.

Design: ECGs from 39 consecutive patients with idiopathic ventricular fibrillation and 592 healthy controls were reviewed. They were classified as definite, questionable, and no Brugada sign (according to predetermined criteria) by four investigators blinded to the subjects' status.

Structure-activity studies on gossypol in tumor cell lines.

Gossypol [(2,2'-binaphthalene)-8,8'-dicarboxaldehyde-1,1',6,6',7,7'-hexahydroxy-5,5'-diisopropyl-3,3'-dimethyl] 1a is a naturally occurring compound extracted from the cotton plant and has been extensively studied as an oral male contraceptive. Its favorable toxicity profile, and the more recent demonstration of anti-tumor activity in animals and humans, prompted us to investigate the role of the aldehyde groups in a structure-activity study in cultured tumor cells. Four racemic compounds were evaluated: gossypol 1a, gossypolone 2, the bis Schiff's base of L-phenylalanine methyl ester with gossypol (bis Schiff's base) 1c and apogossypol 1b.

Arrhythmias in the congenital long QT syndrome: how often is torsade de pointes pause dependent?

Objective: To determine the frequency and predictors of pause dependent torsade de pointes among patients with the congenital long QT syndrome and spontaneous ventricular tachyarrhythmias.

Design: The literature on the "congenital long QT" was reviewed. Articles with illustrations demonstrating the onset of spontaneous polymorphic ventricular arrhythmias in the absence of arrhythmogenic drugs were included.

Systemic treatments for metastatic cutaneous melanoma.

Background: Systemic therapies for metastatic cutaneous melanoma, the most aggressive of all skin cancers, remain disappointing. Few lasting remissions are achieved and the therapeutic aim remains one of palliation. Many agents are used alone or in combination with varying degrees of toxicity and cost.

Glomerular basement membrane anionic sites in adriamycin nephropathy: effect of saline loading and nitric oxide modulation.

Background: In previous studies we found that experimental Adriamycin (ADR) nephropathy is associated with the loss of glomerular basement membrane (GBM) anionic sites provided by heparan sulfate proteoglycans. Chronic saline loading in normal rats resulted in a similar effect on the GBM anionic sites. The L-arginine-nitric oxide synthase-nitric oxide system is involved in the pathogenesis of experimental chronic renal failure.

Simplified "ATP test" for noninvasive diagnosis of dual AV nodal physiology and assessment of results of slow pathway ablation in patients with AV nodal reentrant tachycardia.

Introduction: We recently reported that administration of adenosine triphosphate (ATP) during sinus rhythm identifies dual AV nodal physiology (DAVNP) in 76% of patients with inducible sustained AV nodal reentrant tachycardia (AVNRT) at electrophysiologic (EP) study. In that report, however, the ATP test was considered positive for DAVNP only when the results were reproducible at a given dose of ATP. The aim of the present study was to assess the value of a simplified ATP test for noninvasive diagnosis of DAVNP and abolition or modification of the slow pathway (SP) after radiofrequency ablation (RFA) in patients with inducible sustained AVNRT.

Electric injury, part III: cardiac monitoring indications, the pregnant patient, and lightning.

A number of publications have presented recommendations for prolonged cardiac monitoring after electric injury. These recommendations are combined in this article to make criteria for monitoring that agree with the recommendations of most studies. It is generally agreed that cardiac monitoring is not needed unless there is an abnormal electrocardiogram or other suggestion of acute problems.

Alterations in proteolytic activity at low pH and its association with invasion: a theoretical model.

The extracellular pH (pHe) of solid tumours is often lower than in normal tissues, with median pH values of about 7.0 in tumours and 7.5 in normal tissue.

Electric injury, Part II: Specific injuries.

Electric injury can cause disruption of cardiac rhythm and breathing, burns, fractures, dislocations, rhabdomyolysis, eye and ear injury, oral and gastrointestinal injury, vascular damage, disseminated intravascular coagulation, peripheral and spinal cord injury, and Reflex Sympathetic Dystrophy. Secondary trauma from falls, fires, flying debris, and inhalation injury can complicate the clinical picture. Diagnostic and treatment considerations for electric injuries are described in this article, which is the second part of a three-part series on electric injuries.

Electric injury, part I: treatment priorities, subtle diagnostic factors, and burns.

Patients with electric injury present a significant challenge. Possible mechanisms of injury include electrical disruption of cardiac rhythm and breathing, burns of several types, and inhalation of gases from fires. Mechanical trauma may come from electric arc blast, explosion of gases, falls, and strong muscle contractions.

Effects of electrophysiologic-guided therapy with Class IA antiarrhythmic drugs on the long-term outcome of patients with idiopathic ventricular fibrillation with or without the Brugada syndrome.

Introduction: Implantation of a implantable cardioverter defibrillator (ICD) is viewed universally as the "gold standard" therapy for patients with idiopathic ventricular fibrillation (VF). We sought to study the long-term value of electrophysiologic (EP)-guided therapy with Class IA antiarrhythmic drugs in patients with idiopathic VF with or without the Brugada syndrome.

Methods And Results: We performed EP studies in 34 consecutive patients who had idiopathic VF with (n = 5) or without (n = 29) the Brugada syndrome.

Circadian variation of symptomatic paroxysmal atrial fibrillation. Data from almost 10 000 episodes.

Aims: To determine the circadian rhythm of paroxysmal atrial fibrillation in a very large outpatient population.

Methods And Results: We reviewed all emergency telephone calls received in Shahal (a medical service covering 44 000 subscribers), from 1987 to 1997. Patients were included if new-onset atrial fibrillation was recorded.

Regioselective Reduction of NAD Models with [Cp*Rh(bpy)H] : Structure-Activity Relationships and Mechanistic Aspects in the Formation of the 1,4-NADH Derivatives.

The hydride transfer mechanism of the NAD model compound 1 to its 1,4-NADH derivative 3 [Eq. (1)] is proposed to be a consequence of the critical role of the carbonyl group of the amide to coordinate to the ring-slipped η - to η -Cp*Rh metal center of the catalyst [Cp*Rh(bpy)H] , prepared in situ from 2, while a steric effect of a substituent in the 3 position, for example, C(O)NEt , was found to totally inhibit this regioselective reduction. bpy=2,2'-bipyridine, Cp*=C Me , OTf=trifluoromethanesulfanate.

Stereo-specific cytotoxic effects of gossypol enantiomers and gossypolone in tumour cell lines.

The naturally occurring compound, gossypol, has been previously used as a male oral contraceptive, for the treatment of benign gynaecological conditions and cancer patients. Long-term daily dosing with gossypol is associated with minimal side effects and no myelosuppression. Since gossypol exhibits atropisomerism due to the restricted rotation about the 2,2' carbon bond, we have isolated the l- and d-isomers by Schiff's base formation using a chiral amine and regenerated the enantiomers by acid hydrolysis.

Catheter-induced mechanical trauma to accessory pathways during radiofrequency ablation: incidence, predictors and clinical implications.

Objectives: To evaluate the incidence, predictors and clinical implications of nonintentionally catheter-induced mechanical trauma to accessory pathways during radiofrequency ablation procedures.

Background: Data on the incidence and significance of catheter-induced trauma to accessory pathways are scarce.

Methods: Consecutive patients (n = 381) undergoing radiofrequency ablation of accessory pathways at two different institutions were closely monitored for appearance of mechanical block of accessory pathways during catheter manipulation.

Mathematical modelling of tumour acidity: regulation of intracellular pH.

Measurements of extracellular pH (pHe) in vivo have shown that the microenvironment in tumours is more acidic than in normal tissue. However, both human and animal tumour cells have been shown to have an intracellular pH (pHi) on the alkaline side of neutrality (pH 7.1-7.

A genome-based approach for the identification of essential bacterial genes.

We have used comparative genomics to identify 26 Escherichia coli open reading frames that are both of unknown function (hypothetical open reading frames or y-genes) and conserved in the compact genome of Mycoplasma genitalium. Not surprisingly, these genes are broadly conserved in the bacterial world. We used a markerless knockout strategy to screen for essential E.

Noninvasive diagnosis of dual AV node physiology in patients with AV nodal reentrant tachycardia by administration of adenosine-5'-triphosphate during sinus rhythm.

Background: Atrioventricular nodal reentry tachycardia (AVNRT) represents the most commonly encountered type of regular paroxysmal supraventricular tachycardia. This study determined whether administration of adenosine-5'-triphosphate (ATP) during sinus rhythm may be useful in the noninvasive diagnosis of dual AV nodal pathways.

Methods And Results: During electrophysiological study, we intravenously administered incremental doses of ATP (from 10 to 50 mg) during sinus rhythm to patients with spontaneous and inducible sustained AVNRT (study group, n=42) and to patients with no evidence of dual AV nodal physiology or inducible AVNRT (control group, n=21).

Prevention of torsade de pointes in the congenital long QT syndrome: use of a pause prevention pacing algorithm.

Torsade de pointes in the congenital long QT syndrome (LQTS) is often pause dependent. Thus, the main goal of pacemaker treatment in the LQTS may be the prevention of pauses that facilitate the onset of torsade de pointes. A pause prevention pacing algorithm (rate smoothing) was used for arrhythmia prevention in a 14 year old girl with congenital LQTS.

Cytotoxicity of gossypol enantiomers and its quinone metabolite gossypolone in melanoma cell lines.

The cytotoxicity of the (-)- and (+)-isomers and the quinone metabolite gossypolone prepared from the naturally occurring polyphenolic dialdehyde gossypol were compared using two human melanoma cell lines (SK-mel-19 and SK-mel-28) with a similar growth rate, one melanotic (melanin content of 69 pg/cell) and one amelanotic (melanin content of 10 pg/cell). Results from two viability assays (MTT and flow cytometry) showed that the cytotoxicity of racemic gossypol was identical for both cell lines (50% inhibition of cell growth IC50 = 22 microM). Gossypolone at equimolar concentrations was inactive in the amelanotic cell line and as potent as racemic gossypol in the melanotic cell line.

Mode of onset of malignant ventricular arrhythmias in idiopathic ventricular fibrillation.

Introduction: The mode of onset of malignant ventricular arrhythmias (ventricular tachycardia [VT] or ventricular fibrillation [VF]) has been well described in patients with organic heart disease and in patients with the long QT syndromes. Less is known about the mode of onset of VF in patients with out-of-hospital VF who have no evidence of organic heart disease or identifiable etiology.

Methods And Results: We reviewed the ECGs of all our patients with idiopathic VF.

Spatial orientation of the alpha and betac receptor chain binding sites on monomeric human interleukin-5 constructs.

Interleukin-5 (IL-5), a disulfide-linked homodimer, can be induced to fold as a biological active monomer by extending the loop between its third and fourth helices (Dickason, R. R., and Huston, D.

An interleukin 5 mutant distinguishes between two functional responses in human eosinophils.

Interleukin 5 (IL-5) is the key cytokine involved in regulating the production and many of the specialized functions of mature eosinophils including priming, adhesion, and survival. We have generated a point mutant of human IL-5, IL-5 (E12K), which is devoid of agonist activity in both a TF-1 cell proliferation assay and a human eosinophil adhesion assay. However, IL-5 (E12K) is a potent and specific antagonist of both these IL-5-dependent functional responses.

Reduction of urinary basic fibroblast growth factor using pentosan polysulphate sodium.

Objective: To evaluate the use of pentosan polysulphate sodium (PPS) to reduce the level of urinary basic fibroblast growth factor (bFGF).

Patients And Methods: Forty-one patients with a clam enterocystoplasty were randomized to receive either 200 mg three times daily of oral PPS (n = 21) or placebo (n = 20) for 6 weeks. Three patients acted as a cross-over study.