Why do beta-blockers help in idiopathic dilated cardiomyopathy--frequency mismatch?
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Adrenergic beta-Antagonists↗
Biomedical subjects
C Loubeyre
Publications and source records attributed to C Loubeyre.
[Fissuration of thoracic aneurysm in Horton disease, favourable course after surgery].
The authors report another case of rupture of the thoracic aorta in Giant Cell arteritis. The progressive nature of the rupture enabled life-saving aortic replacement with a vascular prosthesis. Only one previous report of this type of operation was found in a search of the literature. The prevalence of aortitis in Giant Cell arteritis would appear to be underestimated after autopsy studies. It affects the thoracic aorta mainly in the ascending segment but sometimes involves the whole aorta. It may remain asymptomatic or be complicated by arterial occlusion, aortic regurgitation, aneurysm, dissection or rupture. Effective steroid therapy could prevent these complications.
Aged↗
[Doppler echocardiography of tricuspid insufficiency. Methods of quantification].
Evaluation of tricuspid incompetence has benefitted considerably from the development of Doppler ultrasound. In addition to direct analysis of the valves, which provides information about the mechanism involved, this method is able to provide an accurate evaluation, mainly through use of the Doppler mode. In addition to new criteria being evaluated (mainly the convergence zone of the regurgitant jet), some indices are recognised as good quantitative parameters: extension of the regurgitant jet into the right atrium, anterograde tricuspid flow, laminar nature of the regurgitant flow, analysis of the flow in the supra-hepatic veins, this is only semi-quantitative, since the calculation of the regurgitation fraction from the pulsed Doppler does not seem to be reliable; This accurate semi-quantitative evaluation is made possible by careful and consistent use of all the criteria available. The authors set out to discuss the value of the various evaluation criteria mentioned in the literature and try to define a practical approach.
Echocardiography, Doppler↗
Influence of sub-inhibitory concentrations of antibacterials on the surface properties and adhesion of Escherichia coli.
The effect of sub-inhibitory concentrations of antibacterials, including quinolones, on the surface properties of a uropathogenic strain of Escherichia coli was examined. The effect on the charge and hydrophobicity of the cell surface was assessed by means of partition between two aqueous phases, polyethylene glycol and dextran. Antibiotics at 1/8 x MIC inhibited adhesion to uroepithelial cells, and induced an increase in bacterial charge and hydrophobicity. Inhibition of adhesion correlated with increased charge, but not with hydrophobicity. The influence of magnesium on the inhibition of adhesion by sub-MICs of pefloxacin was also investigated. Loss of the anti-adhesive property of pefloxacin was observed with increasing magnesium concentrations, suggesting that quinolones should be free from magnesium to induce an inhibition of adhesion. Examination by electron microscopy showed a disappearance of fimbriae following treatment of E. coli cells with 1/8 x MIC of pefloxacin.
Anti-Bacterial Agents↗
[Preventive treatment of systemic embolic complications of atrial fibrillation].
Non-valvular atrial fibrillation multiplies the risk of presumed embolic events by a factor of four. The hemorrhagic risk of anticoagulant treatment varies considerably and its prophylactic efficacy was not tested in any randomised trial before the end of 1989. The recommendations of experts at that time recognised that data were inadequate. The publication since of four randomised trials involving 3,049 patients has provided a more objective base for management decisions, highly in favour of the anticoagulation of cases of non-isolated atrial fibrillation in the absence of contraindications.
Anticoagulants↗
[Painful left bundle-branch block during exertion].
Two new cases of exercise related left-bundle branch block are reported in this study. They should be added to the twenty established and published cases. Comparison opens the way to discussion of the mechanism of onset. Ischemia is often accused, although no exploration has been able to demonstrate its responsibility in the origin of the problem. These two cases have novel features, particularly in describing the first case of painful exercise related bundle branch block in a subject twenty-three years of age. Ischemia linked to epicardial coronary lesions cannot be held responsible, but the possibility of micro-circulatory ischemia is suggested.
Adult↗
[Paroxysmal supraventricular tachycardia induced by deglutition].
The authors report the case of a 43-year-old man with runs of tachycardia, sometimes atrial and sometimes by reentry, induced by atrial extrasystoles provoked by ewallowing. This rare condition, 21 descriptions of which are referred to, raises the problem of the inducing mechanism, with discussion of the role of mechanical stimulus played by the alimentary bolus or of a reflex of ortho- or parasympathetic origin. The discussion includes a detailed review of this condition and its treatment. The prognosis is always excellent but symptomatic discomfort may be considerable. Spontaneous recovery is possible, as in the case described here.
Adult↗
Effect of pefloxacin on microorganism: host cell interaction.
Recent evidence indicates that certain antibiotics affect bacterial adherence and phagocyte-micro-organism interactions. These interactions are important in the early stages of bacterial pathogenesis, that is, attachment to mucosal surfaces and invasion. Among the antibiotics of interest in this field are the fluoroquinolones. Sub-MICs of pefloxacin can alter the ability of Gram-positive cocci (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative bacilli (Escherichia coli) to adhere to different eukaryotic cells (uroepithelial and buccal cells) and to fibrin-platelet matrices. The mechanism by which pefloxacin reduces adhesion is not completely understood. However in the case of Esch. coli, the inhibition of haemagglutination and adherence corresponds to: (1) a decrease in production of fimbriae; (2) changes in the composition of outer membrane proteins; and (3) an effect on partition coefficient (carried out with the PEG/dextran system) which can be attributed to changes in electric and/or hydrophobic properties of the Esch. coli surface. The first step of phagocytosis is represented by adherence of opsonized bacteria to the membrane receptors of phagocytes. Consequently, the action of pefloxacin on phagocytosis is also of importance. Pretreatment of bacteria (Staph. aureus, Ent. faecalis, Esch. coli and Legionella pneumophila) with 1/4 the MIC of pefloxacin leads to an increase in uptake of the different strains by phagocytes (polymorphonuclear leucocytes and macrophages). Exposure of the phagocytes to 10 mg/l of pefloxacin enhances phagocytosis of strains that have not been pretreated. Finally, entry of antibiotics into phagocytic cells is a prerequisite for activity against intracellular organisms. The concentration of pefloxacin by polymorphs and macrophages is high (intracellular concentration/extracellular concentration = 5-10). Such findings correlate well with the intracellular activity of pefloxacin, demonstrated with guinea pig macrophages and different bacteria (Staph. aureus, L. pneumophila).
Bacterial Adhesion↗
[Effect of sub-inhibitory concentrations of cefixime on the morphology, hemagglutination and adhesiveness of urinary strains of Escherichia coli].
The treatment of urinary tract infections is one of the indications of cefixime, a new oral cephem. The aim of the present work was to study the in vitro effect of cefixime sub- and infra-MICs on the morphology, haemagglutination and adhesiveness to epithelial cells of three uropathogenic Escherichia coli strains pretreated with sub-MICs (1/2 to 1/64 the MIC) of cefixime during growth phase (37 degrees C for 18 h). This treatment led to morphological alterations of the bacteria with filament formation. The E. coli strains showed different haemagglutination profiles (MS; MS-MR; MR). In the presence of cefixime sub-MICs (1/2 to 1/32 the MIC), MR E. coli showed a markedly altered capacity for haemagglutination (using guinea pig, human P1 and p erythrocytes). Adhesiveness was studied with human buccal cells for MS adhesins and human urothelial cells for MR adhesins. A significant decrease of adherence (70-90 per cent) was observed after pretreatment of E. coli strains with cefixime (up to 1/32 the MIC). Compared with other antibiotics active against E. coli, such as nalidixic acid, norfloxacin and ampicillin, the effect of 1/8 the MIC of cefixime on adhesiveness, was more pronounced. These results demonstrate that sub-MICs of cefixime induce a marked reduction in adhesiveness of E. coli. This property might potentiate the effectiveness of cefixime in the treatment of urinary tract infections due to E. coli.
Animals↗
Right atrial thrombi: percutaneous mechanical thrombectomy.
The current therapeutic options for right atrial thrombi-surgical embolectomy and thrombolysis-are associated with high mortality and such patients often have contraindications to these therapeutic options. The purpose of this study was to evaluate the feasibility of endovascular right atrial embolectomy. Two patients with contraindications to thrombolysis and surgery were treated by a femoral approach. A catheter was placed in the right atrium, under fluoroscopic control, and a basket device was used to trap the thrombus. The location and extent of the thrombus was established before the procedure by transesophageal echocardiography (TEE) and the procedure was performed with TEE and fluoroscopy. Thrombi were withdrawn in the basket into the inferior vena cava (IVC) and a filter was inserted by a jugular approach and positioned in the IVC, just above the thrombi. The basket was removed leaving the thrombus below the filter. One patient died immediately after the procedure. In conclusion, endovascular extraction of right atrial thrombi may represent a potential therapeutic alternative, particularly in patients with contraindications to thrombolysis and surgery.
Aged↗
Alcohol-free pastis and hypokalaemia.
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Alcoholism↗