Transient repolarization alterations dominate the initial phase of an acute anterior infarction — a vectorcardiography study

Objective

To study effects of ischemia-reperfusion on ventricular electrophysiology in humans by three-dimensional electrocardiography.

Methods

Fifty-seven patients with first-time acute anterior ST elevation myocardial infarction were monitored from admission and > 24 h after symptom onset with continuous vectorcardiography (VCG; modified Frank orthogonal leads). Global ventricular depolarization and repolarization (VR) measures were compared at maximum vs. minimum ST vector magnitude (STVM) (median 208; 111–303 vs. 362; 165–1359 min after symptom onset).

Results

At maximum vs. minimum STVM the Tarea (overall VR dispersion) almost tripled (118 vs. 41 μVs; p < 0.0001), the T-loop bulginess was 90% greater (Tavplan 0.91 vs 0.48 μV; p < 0.0001), and Tpeak-end/QT was 39% larger (0.32 vs 0.23; p < 0.0001). QRSarea (overall dispersion of depolarization) was 12% larger at maximum STVM, while QRS duration was 10% longer at minimum STVM.

Conclusions

Ischemia-reperfusion was accompanied by profound and transient alterations of VR dispersion, while changes in depolarization were modest and delayed.     

Protein A is the von Willebrand factor binding protein on Staphylococcus aureus

Endovascular infection is a highly critical complication of invasive Staphylococcus aureus disease. For colonization, staphylococci must first adhere to adhesive endovascular foci. Von Willebrand factor (vWF) is a large, multimeric glycoprotein mediating platelet adhesion at sites of endothelial damage. Earlier it was demonstrated that vWF binds to and promotes the surface adhesion of S. aureus, prompting this effort to identify the vWF adhesin. In Western ligand assays of S. aureus lysates, staphylococcal protein A (SPA) was recognized by purified vWF. Surface plasmon resonance demonstrated the binding of soluble vWF to immobilized recombinant protein A with a K(d) of 1.49 x 10(-8) mol/L. Using flow cytometry, the binding of fluorescein isothiocyanate-labeled vWF to S. aureus was found to be saturable and inhibitable by unlabeled vWF, antiprotein-A antibodies, or IgG. Isogenic Deltaspa::Tc(r) mutants were constructed by the insertion of a tetracycline resistance cassette into spa using allelic replacement, and it exhibited decreased binding of soluble vWF and decreased adhesion to vWF-adsorbed surfaces. The interaction was restored on complementation of the mutants with spa-containing plasmid pSPA7235. In conclusion, protein A confers interaction of S. aureus with soluble and immobilized vWF in a newly discovered function characterizing protein A as a novel member of the staphylococcal surface protein adhesin superfamily and suggesting its potential role in the pathogenesis of endovascular staphylococcal disease.     

International Collaborative Effort (ICE) on birthweight; plurality; and perinatal and infant mortality. I: Methods of data collection and analysis

This paper describes the collection and analysis of data by a group of international collaborators (International Collaborative Effort on Perinatal and Infant Mortality) interested in comparative studies on birthweight distributions and reproductive outcome. This is the first of a series of reports on the results of these studies. It gives an account of the countries or states involved, and the collection and characteristics of the data. The countries and states included sixteen of the United States, plus England and Wales, Denmark, Bavaria and North Rhine-Westphalia from the Federal Republic of Germany, Israel, Japan, Norway, Scotland, and Sweden. The data comprised birthweight distributions in 500-gram groups for all births and for singletons separately, for livebirths, stillbirths, first week deaths and, where available, late neonatal and infant deaths, from 1970 up to 1985.     

Athletic activity after total joint replacement

Total hip and knee replacement surgery is a successful treatment for the arthritic hip and knee ensuring proven pain relief and return of function. Younger, more active patients who have greater expectations and higher demands are receiving hip and knee replacements. With current surgical techniques and implant designs, athletic participation should be limited to low impact, low demand, and low duration activity. Future advancesin bearing surfaces may allow for higher demand activities.     

Physical activity, symptoms of chest pain and dyspnea in patients with ischemic heart disease in relation to age before and two years after coronary artery bypass grafting

BACKGROUND: To describe limitation of physical activity, cause of limitation of physical activity and symptoms of dyspnea and chest pain in relation to age before and 2 years after coronary artery bypass grafting (CABG). METHODS: All patients from Western Sweden who underwent CABG without concomitant procedures during 3 years in 1989-1991 answered questionnaires before, and 2 years after the operation. Patients were divided into 3 age groups of equal size i.e. 32-59 years, 60-67 years and > or = 68 years. RESULTS: In total, 2121 patients participated in the evaluation. The overall 2 year mortality in the 3 age groups was 3.8%, 6.8% and 12.2% (p<0.001). Limitation of physical activity was significantly associated with age prior to surgery but not thereafter. Improvement in physical activity, following CABG, was significant in all age groups. The proportion of patients being free of dyspnea increased markedly regardless of age. The number of chest pain attacks was associated with age after CABG, i.e. fewer attacks in the elderly, but such an association was not found prior to surgery. Improvement in number of chest pain attacks was more marked in the elderly. CONCLUSIONS: Physical activity improved similarly in all age groups after CABG. Attacks of chest pain, although significantly reduced in all age groups, seemed more effectively reduced in the elderly.     

Tea tree oil

Tea tree oil is a popular ingredient in many over-the-counter healthcare and cosmetic products. With the explosion of the natural and alternative medicine industry, more and more people are using products containing tea tree oil. This article reviews basic information about tea tree oil and contact allergy, including sources of tea tree oil, chemical composition, potential cross reactions, reported cases of allergic contact dermatitis, allergenic compounds in tea tree oil, practical patch testing information, and preventive measures.     

Na,K-ATPase alpha 2 inhibition alters calcium responses in optic nerve astrocytes

Experiments were conducted to test the effect of 1 microM ouabain, an Na,K-ATPase inhibitor, on capacitative calcium entry (CCE) and calcium responses elicited by ATP in rat optic nerve astrocytes. In the rat, 1 microM ouabain is sufficient to inhibit the alpha2 Na,K-ATPase, but not the alpha1. Immortalized astrocytes derived from Na,K-ATPase alpha2 homozygous knockout (KO) mice and wild-type (WT) littermates were also used. Cytosolic calcium and sodium concentrations were measured using Fura-2 and SBFI, respectively. The magnitude of the increase in cytosolic calcium concentration during CCE was significantly greater in rat astrocytes exposed to 1 microM ouabain. To measure calcium release from stores, cells were exposed to ATP in the absence of extracellular calcium. In astrocytes exposed to 1 microM ouabain, a significantly greater calcium response to ATP was observed. 1 microM ouabain was shown to inhibit ATP hydrolysis in membrane material containing Na,K-ATPase alpha2 and alpha1 isoforms (rat muscle) but not in membranes containing only Na,K-ATPase alpha1 (rat kidney). In intact astrocytes, 1 microM ouabain did not alter the cell-wide cytosolic sodium concentration. In mouse Na,K-ATPase alpha2 KO astrocytes, the calcium increase during CCE was significantly higher than in WT cells, as was the magnitude of the calcium response to ATP. In KO astrocytes, but not WT, the cytosolic calcium increase during CCE was insensitive to 1 microM ouabain. Taken together, the results suggest that selective inhibition of the Na,K-ATPase alpha2 isoform has the potential to change calcium signaling and CCE.     

Reemergence of sexual dysfunction in patients with major depressive disorder: double-blind comparison of nefazodone and sertraline

BACKGROUND: Several different classes of antidepressants have been associated with sexual adverse effects. This double-blind, randomized trial compared the effects of nefazodone and sertraline on reemergence of sexual dysfunction in depressed patients who had experienced sexual dysfunction as a result of sertraline treatment. Depressive symptoms were also monitored. METHOD: One hundred five patients with DSM-III-R major depressive episode who were experiencing sexual dysfunction attributable to sertraline (100 mg/day) were screened for entry. Eligible patients entered a 1-week washout period that was followed by a 7- to 10-day single-blind placebo phase. Patients without symptoms of sexual dysfunction at the end of the single-blind placebo phase were randomly assigned to receive double-blind treatment with either nefazodone (400 mg/day) or sertraline (100 mg/day) for 8 weeks. RESULTS: Nearly 3 times more sertraline-treated patients (76%; 25/33) experienced reemergence of sexual dysfunction (ejaculatory and/or orgasmic difficulty) than did nefazodone-treated patients (26%; 10/39) (p < .001). In addition, patients treated with nefazodone were more satisfied with their sexual functioning than were patients treated with sertraline. Both treatment groups demonstrated a similar and sustained improvement in depressive symptoms. Both drugs were well tolerated, and the overall incidence of adverse reactions was similar for both treatment groups; however, 9 sertraline-treated patients (26%) discontinued because of adverse events compared with 5 nefazodone-treated patients (12%). Of the patients discontinuing therapy for adverse events, 5 of the sertraline-treated patients did so because of sexual dysfunction reported as an adverse event, whereas only 1 of the nefazodone-treated patients discontinued therapy secondary to sexual dysfunction. CONCLUSION: In this sample of patients with major depression who had recovered from sexual dysfunction induced by treatment with sertraline, nefazodone treatment resulted in significantly less reemergence of sexual dysfunction than did renewed treatment with sertraline and provided continued antidepressant activity.