Beta-blocker use in patients with acute myocardial infarction treated by hospitalists.

It is well recognized that the administration of beta blockers to patients after myocardial infarction improves survival. This retrospective cohort and prospective study sought to define the usage of a large hospitalist group and enhance this usage by education and the utilization of a uniform discharge summary. All patients with a discharge diagnosis of acute myocardial infarction were included for analysis.

A comparative study on methods of optimal sample preparation for the analysis of oligonucleotides by matrix-assisted laser desorption/ionization mass spectrometry.

Metal adducts (e.g., Na+ and K+) significantly hinder the analysis of oligonucleotides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS).

Measurement of the ADP:ATP ratio in human leukaemic cell lines can be used as an indicator of cell viability, necrosis and apoptosis.

In this study the relative levels of ADP and ATP have been measured in cells undergoing apoptosis. Using HL60, CEM7, Jurkat and U937 cell lines and cytotoxic agents known to induce apoptosis, there was a significant correlation (P<0.01 for all models) between the ADP:ATP ratio and the degree of apoptosis measured by TUNEL and estimation of the sub G(0) fraction by propidium iodide staining and flow cytometry.

Glenoid version in children with obstetric brachial plexus palsy.

Glenoid version in a group of 29 children with obstetric brachial plexus paralysis and posterior dislocation of the shoulder was studied by using computed axial tomography (CT). The CT scan in most patients was done before an open release and reduction of the shoulder. A comparison was made between the normal and affected sides in regard to glenoid version and structure.

False-positive behavior with the dP/dt sensing pacemaker: a rare complication of a physiological sensor.

As with "nonphysiological" devices, sensors that directly measure physiological variables have the potential to measure unexpected signals and for the physiological parameter being measured to respond in an unexpected manner. We present the case of a dP/dt sensing pacing system that functioned normally for 2 months and then developed upper rate behavior due to the sensing of a high frequency artifact on the pressure recording. Our case and others cited reinforce the need for future physiological rate responsive pacemakers to incorporate a second sensor to provide for backup rate response in cases of inappropriate rate response.

Human low density lipoprotein receptor fragment. Successful refolding of a functionally active ligand-binding domain produced in Escherichia coli.

The low density lipoprotein (LDL) receptor plays a key role in cholesterol homeostasis, mediating cellular uptake of lipoprotein particles by high affinity binding to its ligands, apolipoprotein (apo) B-100 and apoE. The ligand-binding domain of the LDL receptor contains 7 cysteine-rich repeats of approximately 40 amino acids; each repeat contains 6 cysteines, which form 3 intra-repeat disulfide bonds. As a first step toward determining the structure of the LDL receptor, both free and bound to its ligands, we produced in Escherichia coli a soluble fragment containing the ligand-binding domain (residues 1-292) as a thrombin-cleavable, heat-stable thioredoxin fusion.

Phase II trial of tirapazamine combined with cisplatin in chemotherapy of advanced malignant melanoma.

Purpose: A phase II study was undertaken to determine the efficacy of tirapazamine (TPZ) combined with cisplatin (cDDP) in patients with metastatic melanoma.

Patients And Methods: Between June 1994 and November 1995, 48 patients with metastatic melanoma were treated with TPZ (260 mg/m2, administered intravenously over two hours) followed in one-hour by cDDP (75 mg/m2 over one hour) every 21 days. Sixteen patients had received prior chemotherapy, and 13 of these had failed to respond to prior cDDP.

Reprogramming pacemakers enhances longevity and is cost-effective.

Background: Historically, the majority of pulse generators implanted in the United States remain at the nominal programmed settings from the time of implant. While these nominal settings typically allow a sufficient safety margin to prevent later loss of capture with potential chronic threshold rise, the pulse generator with significant use would not be expected to last longer than that predicted by the manufacturer. However, improvements in lead technology have resulted in significantly lower chronic capture thresholds, which would permit lower programmable output settings while still allowing acceptable safety margins.

Novel mechanism for defective receptor binding of apolipoprotein E2 in type III hyperlipoproteinemia.

The defective binding of apolipoprotein (apo) E2 to lipoprotein receptors, an underlying cause of type III hyperlipoproteinemia, results from replacement of Arg 158 with Cys, disrupting the naturally occurring salt bridge between Asp 154 and Arg 158. A new bond between Asp 154 and Arg 150 is formed, shifting Arg 150 out of the receptor binding region. Elimination of the 154-150 salt bridge by site-directed mutagenesis of Asp 154 to Ala restored the receptor binding activity to near normal levels.

Defibrillator twiddler's syndrome causing device failure in a subpectoral transvenous system.

Twiddler's syndrome is well described as a complication of cardiac pacing. Defibrillator twiddler's syndrome has been recently reported with abdominal implantations of epicardial and transvenous defibrillator systems. We report a case of a patient with a transvenous defibrillator system implanted with the pulse generator placed in the subpectoral plane.

Effects of atrial fibrillation and atrial flutter on the signal-averaged electrocardiogram.

In conclusion, atrial flutter can create significant errors in the automated time-domain analysis of the SAECG that are only apparent when the study is repeated in sinus rhythm, thus lowering the predictive accuracy of the technique in patients with atrial flutter. Atrial fibrillation rarely creates problems with time-domain analysis of the SAECG. These findings suggest that, unless the performance of a specific signal-averaging device has been evaluated in patients with atrial flutter and found to have acceptable error rates, patients with atrial flutter should not have SAECGs performed for postinfarction risk assessment.

P wave morphology during atrial pacing along the atrioventricular ring. ECG localization of the site of origin of retrograde atrial activation.

P wave morphology during atrial pacing along the atrioventricular (AV) ring was evaluated to develop electrocardiographic (ECG) criteria for identifying the site of origin of the atrial activation wave during reentrant supraventricular tachycardia. Because P wave morphology changes as the pattern of atrial activation changes, the P wave should show characteristic morphologies during reentrant supraventricular tachycardia with use of either accessory AV pathways or the AV node for retrograde atrial activation. In 14 patients, 12-lead ECGs were recorded during bipolar atrial pacing at sites in the coronary sinus vein (along the mitral annulus) and along the atrial endocardium of the tricuspid annulus.

Diagnosis and management of the infected total knee arthroplasty.

While infection in TKA is a relatively infrequent complication, it can be devastating in terms of morbidity and cost. Prevention of infection begins with patient selection. Prior knee sepsis surgery, rheumatoid arthritis, and poor general health may lead to an increased rate of infection.

Quantification of lumbar nerve root decompression using somatosensory-evoked potentials.

Intraoperative somatosensory-evoked potential (SSEP) data were collected prospectively in a consecutive series of patients with an acute lumbar herniated nucleus pulposus (HNP). Each patient underwent an open limited diskectomy, hemilaminotomy, and partial foraminotomy. The sequence of diskectomy and bony decompression was randomized, and the extent of foraminotomy was standardized.

Radiofrequency catheter ablation for management of symptomatic ventricular ectopic activity.

Objectives: This study assessed the useful role of intracardiac mapping and radiofrequency catheter ablation in eliminating drug-refractory monomorphic ventricular ectopic beats in severely symptomatic patients.

Background: Ventricular ectopic activity is commonly encountered in clinical practice. Usually, it is not associated with life-threatening consequences in the absence of significant structural heart disease.

Protein synthesis is required for laminin-induced expression of the 67-kDa laminin receptor and its 37-kDa precursor.

The high affinity 67-kDa laminin receptor (67LR) is highly expressed in metastatically active human cancers. A 37-kDa polypeptide has been identified as its precursor (37LRP). Antibodies raised against 37LRP-derived synthetic peptides were used in immunogold electron microscopy and immunoblot studies to assess the effect of laminin on expression of the 67LR and the 37LRP.

Human apolipoprotein E. Role of arginine 61 in mediating the lipoprotein preferences of the E3 and E4 isoforms.

Human apolipoprotein (apo) E4 (arginine at residue 112) preferentially associates with very low density lipoproteins (VLDL), and apoE3 (cysteine at 112) associates with high density lipoproteins. It has been postulated that the amino-terminal domain, which contains residue 112, influences the lipoprotein preference by interacting with the carboxyl-terminal domain, which contains the lipid-binding region. To delineate the region in the carboxyl-terminal domain mediating lipoprotein binding and involved in isoform preference, we produced truncated apoE3 and apoE4 variants (terminating at residues 251, 260, 266, or 272) in Escherichia coli and assessed them for lipoprotein association.

A volume-activated taurine channel in skate hepatocytes: membrane polarity and role of intracellular ATP.

Osmoregulation in isolated hepatocytes and perfused livers of the little skate (Raja erinacea), an osmoconforming marine elasmobranch, is mediated in part by the uptake or release of the intracellular osmolyte taurine. To further characterize the efflux mechanism, [14C]taurine release and Na(+)-independent uptake were assessed after cell swelling in hypotonic media containing 0.1-100 mM taurine.

Chronic atrial fibrillation and stroke in paced patients with sick sinus syndrome. Relevance of clinical characteristics and pacing modalities.

Background: The goal of the report was to study the long-term incidence and the independent predictors for chronic atrial fibrillation and stroke in 507 paced patients with sick sinus syndrome, adjusting for differences in baseline clinical variables with multivariate analysis.

Methods And Results: From 1980 to 1989, we implanted 376 dual-chamber, 19 atrial, and 112 ventricular pacemakers to treat patients with sick sinus syndrome. After a maximum follow-up of 134 months (mean: 59 +/- 38 months for chronic atrial fibrillation, 65 +/- 37 months for stroke), actuarial incidence of chronic atrial fibrillation was 7% at 1 year, 16% at 5 years, and 28% at 10 years.

Initial experience with the maze procedure for atrial fibrillation.

From January 1991 until May 1992, a total of 14 patients (mean age 48 years) underwent the maze procedure for refractory atrial fibrillation (mean duration, 7 years; mean number of antiarrhythmic medications, six). Three patients had had embolic events, one patient had had a cardiac arrest from flecainide, one had pulmonary fibrosis from amiodarone, and six of ten who were employed were temporarily disabled. Two patients underwent successful mitral valve repair in which the maze procedure was added as a secondary goal of the operation.

Salvage trial of trimetrexate-leucovorin for the treatment of cerebral toxoplasmosis in patients with AIDS.

The clinical efficacy of trimetrexate, a dihydrofolate reductase inhibitor with potent in vitro antitoxoplasma activity, was assessed in 9 sulfonamide-intolerant patients with AIDS and biopsy-proven cerebral toxoplasmosis. The 9 patients were treated for 28-149 days with trimetrexate (30-280 mg/m2/day) plus leucovorin (20-90 mg/m2 every 6 h). Radiographic responses were documented in 8 patients, and clinical responses in 5 patients.

The Maze procedure: surgical therapy for refractory atrial fibrillation.

Although atrial fibrillation is well tolerated by most patients, in some patients the consequences may be severe. The Maze procedure is a new open-heart operation that creates a carefully designed maze of incisions in the atrial myocardium; this maze then acts as an electrical conduit to channel atrial impulses from the sinoatrial node to the atrioventricular node. The Maze procedure has been shown to restore sinus rhythm and atrial systole (thus reducing the risk of thromboembolism), improve hemodynamics, alleviate palpitations, and eliminate the need for antiarrhythmic and anticoagulant drugs.