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Biomedical subjects

P Binder

Publications and source records attributed to P Binder.

At least 19 recordsLinked to original sources
PubMed2002

Exploration of a rich variety of breather modes in Josephson ladders.

We report on systematic measurements of localized rotational modes in Josephson junction arrays. These modes, also known as rotobreathers, persist under the action of uniform bias force. In contrast to previous experiments, here we focus on systems with strong coupling between rotators. In ladders with either open or periodic boundary conditions, we observe a very rich variety of stable dynamic states including symmetric, asymmetric, combined, hybrid, coupled, and truncated modes. The switching scenarios between different states are discussed in detail.

Journal Article↗
PubMed2001

Observation of breather resonances in Josephson ladders.

We report experimental observation of resonances excited by nonlinear localized states (rotobreathers) in Josephson junction ladders. The rotobreathers are found to persist in a frequency range that allows for their resonant interaction with linear electromagnetic modes in the ladders. This interaction leads to nearly constant voltage steps on the current-voltage characteristics. We also present numerical simulations that agree well with experimental data and confirm the resonant interaction between breathers and linear waves. Resonances occur at the base frequency as well as higher harmonics of the linear modes. The observed substructures on the resonances are attributed to the cavity modes for the ladders. Both experimental and simulated current-voltage characteristics show good quantitative agreement with an analytically calculated dispersion relation for linear electromagnetic modes.

Journal Article↗
PubMed2001

Effective combination therapy for invasive pneumococcal pneumonia with ampicillin and intravenous immunoglobulins in a mouse model.

Intranasal immunotherapy for Streptococcus pneumoniae invasive pneumonia with polyvalent immunoglobulins (IVIG) was effective in mice against pneumonia but failed to prevent bacteremia. The combination of subcurative doses of IVIG and of ampicillin was fully protective. Such an approach, successfully applied in the preantibiotic era, offers new perspectives for modern therapies.

Ampicillin↗
PubMed2001

[Perceived health survey of 3,800 French adolescents: methodological aspects].

An epidemiological survey was carried out by a local association network and was developed in partnership with regional and national institutions. The survey on well-being and health was conducted over an 18-month period in the French department of Charente. The purpose of the research was to test the hypothesis that "the change in context that is experienced by adolescents at the end of junior high school and at the beginning of high school leads to an increase in risky behaviours". To this end, the survey questioned 3,800 young people on a random basis, mixing those from different grades, those participating in vocational training and apprenticeships, and those from public and private schools. The accomplishment of this survey was made possible thanks to the motivation of a pre-existing strong local network organised and linked to education professionals, the technical contribution of the region's health observatory who conducted the statistical analysis of the data, and the assistance of Unit 472 of the French Institute of Health and Medical Research who provided scientific supervision and advice. The high participation rate and quality of the data (comparable with and even better than some existing studies) demonstrate that it is possible for local associations to carry out effective epidemiological surveys based on the needs keenly felt by the workers themselves, within the scope of a reasonable budget and in a short time span without sacrificing the precision demanded by the scientific method.

Adolescent↗
PubMed2000

Relative spatial position of a snake neurotoxin and the reduced disulfide bond alpha (Cys192-Cys193) at the alpha gamma interface of the nicotinic acetylcholine receptor.

We determined the distances separating five functionally important residues (Gln(10), Lys(27), Trp(29), Arg(33), and Lys(47)) of a three-fingered snake neurotoxin from the reduced disulfide bond alpha(Cys(192)-Cys(193)) located at the alphagamma interface of the Torpedo nicotinic acetylcholine receptor. Each toxin position was substituted individually for a cysteine, which was then linked to a maleimido moiety through three different spacers, varying in length from 10 to 22 A. We estimated the coupling efficiency between the 15 toxin derivatives and the reduced cystine alpha(192-193) by gel densitometry of Coomassie Blue-stained gels. A nearly quantitative coupling was observed between alphaCys(192) and/or alphaCys(193) and all probes introduced at the tip of the first (position 10) and second (position 33) loops of Naja nigricollis alpha-neurotoxin. These data sufficed to locate the reactive thiolate in a "croissant-shaped" volume comprised between the first two loops of the toxin. The volume was further restrained by taking into account the absence or partial coupling of the other derivatives. Altogether, the data suggest that alphaCys(192) and/or alphaCys(193), at the alphagamma interface of a muscular-type acetylcholine receptor, is (are) located in a volume located between 11.5 and 15.5 A from the alpha-carbons at positions 10 and 33 of the toxin, under the tip of the toxin first loop and close to the second one.

Acetylcholine↗
PubMed2000

Observation of breathers in Josephson ladders.

We report on the observation of spatially localized excitations in a ladder of small Josephson junctions. The excitations are whirling states which persist under a spatially homogeneous force due to the bias current. These states of the ladder are visualized using a low temperature scanning laser microscopy. We also compute breather solutions with high accuracy in corresponding model equations. The stability analysis of these solutions is used to interpret the measured patterns in the I-V characteristics.

Journal Article↗
PubMed2000

Diversity of discrete breathers observed in a josephson ladder

We generate and observe discrete rotobreathers in Josephson junction ladders with open boundaries. Rotobreathers are localized excitations that persist under the action of a spatially uniform force. We find a rich variety of stable dynamic states including pure symmetric, pure asymmetric, and mixed states. The parameter range where the discrete breathers are observed in our experiment is limited by retrapping due to dissipation.

Journal Article↗
PubMed1999

Biomedical research: its mission within the French Military Medical Service.

The French Military Medical Service is organized as a distinct corps to support Army, Navy, and Air Force operations. This complex mission is accomplished through five operational components: (1) direct medical support of the force units; (2) hospital nursing and expertise; (3) biomedical research; (4) biomedical training; and (5) medical supply. Additionally, the French Military Medical Service is committed to humanitarian and civil medical support. Advanced biomedical research, particularly on infectious diseases and treatment of injuries, is actively pursued. Fundamental and applied research is needed to anticipate potential threats and improve medical support and care of French forces. The importance of biomedical research was recognized as necessary to develop technological improvements in rescue operations and to provide the military command with scientifically based advice. Biomedical military research has often been the engine of progress in medicine and surgery. Chief among those developments has been a special emphasis on infectious diseases and wound treatment.

Communicable Diseases↗
PubMed1998

Effective prophylaxis of influenza A virus pneumonia in mice by topical passive immunotherapy with polyvalent human immunoglobulins or F(ab')2 fragments.

The effectiveness of polyvalent plasma-derived human immunoglobulins (IVIG) in passive immunotherapy of influenza virus pneumonia was assessed, using the Strain Scotland (A/Scotland/74 (H3N2)) adapted to BALB/c mice by repeated lung passages. Haemagglutinin antibodies in two batches of IVIG at 10 mg/ml had a titre of 1/16. Intravenous injection of 1000-5000 microg of IVIG, 3 h after infection, gave 60-70% protection, whereas intranasal injection of 25-50 microg protected 90% of mice infected with a lethal dose of influenza virus. F(ab')2 fragments were at least as protective as intact IVIG, suggesting that complement or Fcgamma receptor-bearing cells were not required. Topical passive immunotherapy with IVIG or F(ab')2 gave protection up to 8 h after infection, but not at 24 h, suggesting that anti-influenza A antibodies in IVIG, delivered locally, are only effective at early stages of the infectious process. The potential value of topical administration of IVIG or F(ab')2 fragments for influenza A pneumonia prophylaxis was further demonstrated by the protective effects of their intranasal administration 24 h before challenge.

Animals↗
PubMed1996

Passive and active immunotherapy for experimental pneumococcal pneumonia by polyvalent human immunoglobulin or F(ab')2 fragments administered intranasally.

Experimental pneumococcal pneumonia in leukopenic BALB/c mice enabled evaluation of passive immunotherapy with human polyvalent intravenous immune globulin (IVIG) given intravenously or intranasally and with F(ab')2 fragments administered intranasally. For intravenous and intranasal IVIG, the respective effective doses were < 5 but > 0.5 mg/kg and < 250 but > 2.5 micrograms/kg. For F(ab')2 fragments, the effective dose was < 500 but > 2.5 micrograms/kg. Assessment of the acquired immune responses of passively protected mice and convalescing controls 3 weeks after primary infection showed that antibody responses to whole bacteria were serotype-specific in all mice. Mice protected with IVIG and F(ab')2 fragments had more antibodies to pneumolysin than did controls. In addition, treated mice acquired greater resistance to reinfection than untreated survivors. Thus, local passive immunotherapy may be an effective means of treating pneumococcal pneumonia and may promote acquired resistance to reinfection.

Administration, Intranasal↗
PubMed1994

Cytotoxicity of sulphur mustard on a human keratinocyte cell line: direct effects compared to conditioned-medium effects.

Direct toxic effects of sulphur mustard (SM) were compared to SM-conditioned medium effects in a human keratinocyte cell line. Cytotoxicity was evaluated by measurement of cell viability with the Neutral Red uptake assay. Culture directly exposed to SM exhibited cytotoxic dose-response curves after 24, 48 or 72 h. Inhibitory concentration 50 (IC50) appeared to be more than 10 times lower after 72 h than the corresponding value after 24 h. In contrast, no cytotoxic activity was observed in media which were collected 4 h or 24 h after SM exposure. Cell viability was unchanged even if observation was extended to 48 h. Results suggested that SM cytotoxicity was not due to potential mediators secreted by human keratinocytes.

Cell Line↗