Isolation and in vitro antibacterial activity of astilbin, the bioactive flavanone from the leaves of Harungana madagascariensis Lam. ex Poir. (Hypericaceae).

Harungana madagascariensis is well known for its topical antibacterial properties used in the elaboration of a lot of skin hygiene products. The aim of this study was, on the one hand, to evaluate the in vitro antibacterial activities of aqueous, ethanolic and ethyl acetate crude extracts of Harungana madagascariensis leaves against bacterial strains representative of skin microflora and, on the other hand, to determine the chemical structure of the active compound. Only the ethyl acetate leaf extract presented important antibacterial activity.

Estimation of atrial fibrillatory wave from single-lead atrial fibrillation electrocardiograms using principal component analysis concepts.

A new method for the assessment of the atrial fibrillatory wave (AFW) from the ECG is presented. This methodology is suitable for signals registered from Holter systems, where the reduced number of leads is insufficient to exploit the spatial information of the ECG. The temporal dependence of the bio-electrical activity were exploited using principal component analysis.

Analysis of the extension of Q-waves after infarction with body surface map: relationship with infarct size.

Aims: We aimed to characterize the extension of Q-waves after a first ST-segment elevation myocardial infarction using body surface map (BSM) and its relationship with infarct size quantified with cardiovascular magnetic resonance imaging (CMR).

Methods And Results: Thirty-five patients were studied 6 months after a first ST-segment elevation myocardial infarction (23 anterior, 12 inferior). All cases had single-vessel disease and an open artery.

Modification of ventricular fibrillation activation patterns induced by local stretching.

Introduction: We hypothesize that local modifications in electrophysiological properties, when confined to zones of limited extent, induce few changes in the global activation process during ventricular fibrillation (VF). To test this hypothesis, we produced local electrophysiological modifications by stretching a circumscribed zone of the left ventricular wall in an experimental model of VF.

Methods And Results: In 23 Langendorff-perfused rabbit hearts frequency, time-frequency and time-domain techniques were used to analyze the VF recordings obtained with two epicardial multiple electrodes before, during, and after local stretching produced with a left intraventricular device.

[Study of post-infarction coronary perfusion using quantitative analysis of myocardial echocardiography with intravenous injection of contrast].

Introduction And Objectives: After a myocardial infarction, damage to the microcirculation indicates a worse prognosis. We compared the usefulness of the quantitative analysis of myocardial contrast echocardiography with intravenous injection of contrast (MCE-iv) with intracoronary injection (MCE-ic) for analyzing coronary perfusion.

Patients And Method: We studied 42 patients with a first ST-elevation myocardial infarction, single-vessel disease and a patent artery (TIMI 3, stenosis < 50%).

Spatiotemporal blind source separation approach to atrial activity estimation in atrial tachyarrhythmias.

The analysis and characterization of atrial tachyarrhythmias requires, in a previous step, the extraction of the atrial activity (AA) free from ventricular activity and other artefacts. This contribution adopts the blind source separation (BSS) approach to AA estimation from multilead electrocardiograms (ECGs). Previously proposed BSS methods for AA extraction--e.

Vitamins C and E reverse effect of herbicide-induced toxicity on human epidermal cells HaCaT: a biochemometric approach.

The purpose of this study was to investigate and compare the cytotoxicity of glyphosate alone or included in Roundup 3 plus modulated by the cytoprotective effects of additional antioxidants such as Vitamin C and Vitamin E on the human keratinocytes cell line HaCaT. An experimental design which allows to minimize the number of experiments was carried out to determine the optimal conditions for cytoprotection against herbicide-induced toxicity. It was shown that HaCaT cell line provides a useful model to study components with toxicity or antioxidant activity.

Polymorphism in plasmodium falciparum drug transporter proteins and reversal of in vitro chloroquine resistance by a 9,10-dihydroethanoanthracene derivative.

BG958 reverses resistance in chloroquine-resistant isolates from different countries. Five mutations in the Plasmodium falciparum crt (pfcrt) gene resulting in the amino acid changes K76T, M74I, N75E, A220S, and R371I are systematically identified in resistance-reversed Asian, African, and Brazilian parasites which possess the pfcrt (CIET) haplotype. In combination with BG958, the activity of chloroquine is increased in parasites with the N86Y mutation in pfmdr1.

Treatment of silica effluents: ultrafiltration or coagulation-decantation.

In the electronics industry, the preparation of silicon plates generates effluents that contain a great amount of colloidal silica. Two processes--decantation and ultrafiltration--are studied with in view the treatment of the effluents released by the firm Rockwood Electronic Materials. The feasibility of each of the two processes is studied separately and their operating parameters optimized.

Atrial activity extraction for atrial fibrillation analysis using blind source separation.

This contribution addresses the extraction of atrial activity (AA) from real electrocardiogram (ECG) recordings of atrial fibrillation (AF). We show the appropriateness of independent component analysis (ICA) to tackle this biomedical challenge when regarded as a blind source separation (BSS) problem. ICA is a statistical tool able to reconstruct the unobservable independent sources of bioelectric activity which generate, through instantaneous linear mixing, a measurable set of signals.

Dihydroethanoanthracene derivatives as in vitro malarial chloroquine resistance reversal agents.

The ability of four 9,10-dihydroethanoanthracene derivatives (BG920, BG932, BG958, and BG996), as well as verapamil and promethazine, to reverse chloroquine resistance was assessed against 24 chloroquine-resistant and 10 chloroquine-susceptible strains of Plasmodium falciparum from different countries. The 9,10-dihydroethanoanthracene derivatives clearly increase chloroquine susceptibility only in chloroquine-resistant isolates.

Short report: High prevalence of multidrug-resistant Plasmodium falciparum malaria in the French territory of Mayotte.

A drug-resistance survey was conducted in the French territory of Mayotte in the Comorian Islands in the Indian Ocean where malaria is endemic. A high prevalence of resistant Plasmodium falciparum parasites was observed, not only to chloroquine (88%) and pyrimethamine (99%), but more surprisingly to quinine (17%), mefloquine (9%), and amodiaquine (24%). This leaves few treatment alternatives other than artemisine-mefloquine combinations.

[Iron chelation in antimalarial therapy].

Rapid development of significant resistance to antimalarial drugs has been a major force driving research to identify and develop new compounds. A number of iron(III)-chelating compounds designed for purposes other than treating malaria have in vitro antimalarial activity stemming from iron deprivation or toxic effects related to free radical release. Several of the iron(III) chelators have been effective in animal models of plasmodial infection.

Significance of the morphological patterns of electrograms recorded during ventricular fibrillation: an experimental study.

Mapping techniques are used to study the significance of the morphological patterns of the electrograms (EGMs) obtained during VF in an experimental model. In 24 isolated rabbit heart preparations recordings were made of activation during VF using a multiple electrode (121 unipolar electrodes) positioned on the lateral wall of the left ventricle. Three types of activation maps were selected: (A) with functional block of an activation front; (B) with epicardial breakthrough; and (C) with a single broad wavefront without block lines.

Concentration of sodium ion as the determining factor for the association of dansyl amino acids with the teicoplanin molecule in reversed-phase liquid chromatography.

The mechanism of the binding of D,L dansyl amino acids to teicoplanin was investigated. Na+ was used as an indicator of the interactions between the solutes and teicoplanin. The number (n) of sodium ions, Na+, excluded from the solute-teicoplanin interface when analyte transfer occurred was determined.

[Study on the inhibitory activity, in vitro, of baicalein and baicalin against skin fungi and bacteria].

In this paper, we concentrated in examining, in vitro, the antiseptic activity of the baicalein and baicalin upon the seventeen pathogenic skin fungal and sixteen skin bacterial strains, these two flavonic compounds were known principally as the biosubstances of a traditional Chinese medicinal plant: Scutellaria baicalensis. In agar media, the baicalein possessed potent specific activity against the pathogenic yeasts with MICs of 70-100 micrograms/ml; But in the same condition, no inhibitory effect was observed upon dermatophytes and filamentous imperfect fungi for baicalein, and upon all used strains for baicalin. According to the antibacterial test of baicalein, a high efficacy was achieved against certain causative specie of axillary and foot's odour such as Micrococcus sedentarius, Staphylococcus epidermidis, S.

Effects of acute reduction of temperature on ventricular fibrillation activation patterns.

Because of its electrophysiological effects, hypothermia can influence the mechanisms that intervene in the sustaining of ventricular fibrillation. We hypothesized that a rapid and profound reduction of myocardial temperature impedes the maintenance of ventricular fibrillation, leading to termination of the arrhythmia. High-resolution epicardial mapping (series 1; n = 11) and transmural recordings of ventricular activation (series 2; n = 10) were used to analyze ventricular fibrillation modification during rapid myocardial cooling in Langendorff-perfused rabbit hearts.

[Effects of myocardial stretching on excitation frequencies determined by spectral analysis during ventricular fibrillation].

Introduction And Objectives: The aim of this study was to analyze the effects of myocardial stretching on excitation frequencies, as determined by spectral analysis, during ventricular fibrillation.

Methods: In 12 isolated rabbit heart preparations, ventricular activation during ventricular fibrillation was recorded with multiple electrodes. Recordings were obtained before, during and after ventricular dilatation produced with an intraventricular balloon.

Triazine-human serum albumin association: thermodynamic approach and sodium effect.

Human serum albumin (HSA) serves as a carrier protein to transport triazine herbicides to molecular targets. In this paper, a theoretical treatment was developed to describe the HSA-triazine herbicides association. A determination of the association constant, K, as well as the degree of complexation n(c) (the percent of complex guest) was carried out.

Role of the Na+ ion on phenol derivatives/hydroxypropyl-beta-cyclodextrin complex formation on porous graphitic carbon phase.

The reversed-phase liquid chromatography retention of phenol derivatives was investigated over a concentration range of sodium chloride (0-10(-2) M) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) (0-35x10(-3) M) using a porous graphitic carbon (PGC) stationary phase and a methanol/water mixture (50:50 (v/v)) as the mobile phase. A theoretical treatment was developed to investigate the effect of the sodium chloride and hydroxypropyl-beta-cyclodextrin on the equilibrium between the solutes with the PGC surface and the aqueous medium, respectively. The thermodynamic parameter variations were calculated using van't Hoff plots.

Supercoiled circular DNA and protein retention in non-equilibrium chromatography temperature and velocity dependence: testimony of a transition.

Non-equilibrium chromatography (NEC) is a chromatographic mode for the rapid separation of polymers. The retention behavior of various proteins (human, chicken, bovine serum albumin) and supercoiled circular double-stranded DNA (plasmids) was investigated using a phosphate buffer as a mobile phase at different velocities and column temperatures with a C1 column with very low-packing particle diameter as a stationary phase. It was shown that the two factors (temperature and velocity) constituted important parameters in the retention mechanism of plasmids and proteins in NEC.

Solute complexation degree with human serum albumin: biochromatographic approach.

A mathematical model was developed for the study of the D,L-dansylamino acid retention mechanism in reversed-phase liquid chromatography using a C18 column as a stationary phase and human serum albumin (HSA) as an eluent modifier. The solute retention factor is dependent on the HSA concentration in the eluent as well as the binding constant of the guest-HSA complex. A determination of the degree of complexation n(c) (the percent of the complexed guest) could be carried out.