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Biomedical subjects

J Brendel

Publications and source records attributed to J Brendel.

6 recordsLinked to original sources
PubMed2000

Quantum cryptography using entangled photons in energy-time bell states

We present a setup for quantum cryptography based on photon pairs in energy-time Bell states and show its feasibility in a laboratory experiment. Our scheme combines the advantages of using photon pairs instead of faint laser pulses and the possibility to preserve energy-time entanglement over long distances. Moreover, using four-dimensional energy-time states, no fast random change of bases is required in our setup: Nature itself decides whether to measure in the energy or in the time base, thus rendering eavesdropper attacks based on "photon number splitting" less efficient.

Journal Article↗
PubMed1995

Cardiovascular actions of the furoxan CAS 1609, a novel nitric oxide donor.

1. This study examines the cardiovascular effects of CAS 1609 (4-hydroxymethyl-furoxan-3-carboxamide) in vitro as well as in vivo in various animal models. 2. CAS 1609 relaxed guinea-pig pulmonary artery strips without endothelium with IC50-values of 0.9 microM (phenylephrine contracted) and 15 microM (KCl-depolarized). This effect was inhibited by oxyhaemoglobin. In these arteries CAS 1609 significantly increased (+192%) guanosine 3':5'-cyclic monophosphate levels, which indicates that the compound acts as a donor of nitric oxide (NO). 3. In the anaesthetized pig, CAS 1609 (0.3-1.0 mg kg-1, i.d.) significantly lowered blood pressure and left ventricular end-diastolic pressure. Left ventricular contractility was slightly reduced and heart rate remained almost unchanged. 4. In anaesthetized dogs, i.v. or i.d. administration of CAS 1609 (0.3-3.0 mg kg-1) decreased, in a dose-related fashion, preload and afterload of the heart, cardiac output, left ventricular work and myocardial oxygen consumption. This haemodynamic profile is similar to that of known NO-donors. 5. In anaesthetized dogs with acute heart failure due to intracoronary injection of microspheres, CAS 1609 (0.3 mg kg-1, i.v.) improved the haemodynamic condition and reduced mortality by 80%. 6. In conscious dogs, oral treatment with a dose of 0.5 mg kg-1 given twice daily at 07 h 00 min and 19 h 00 min (each dose had a duration of action > or = 12 h) for 5 days showed no signs of tolerance to the haemodynamic effects of the drug. 7. All these data indicate that CAS 1609 is a potent, long-lasting orally active donor of NO, devoid of tolerance development.

Administration, Oral↗
PubMed1991

Studies of desensitization and cross-desensitization to immunologic and nonimmunologic stimuli that evoke contraction and histamine release in superfused guinea pig trachea.

This study examined the possibility that there is cross-desensitization between immunologic and nonimmunologic stimuli that evoke contraction and histamine release (HR) in the isolated guinea pig trachea. Compound 48/80 and D-tubocurarine were found to cause homologous and heterologous desensitization for both contraction and HR from superfused trachea. Specific antigen challenge of trachea obtained from animals sensitized with either IgG1 (ovalbumin [OA]) or IgE (oxazalone-human serum albumin [OX-HSA]) also resulted in homologous desensitization for both contraction and HR. However, in experiments with animals sensitized with both IgG1 and IgE antibodies, prechallenge with OA resulted in cross-desensitization to OX-HSA, whereas the reverse sequence was ineffective in eliciting this phenomenon. This may be related to the type of desensitization produced by each antigen (specific versus nonspecific) or to heterogeneity of mast cells in the tissue. Prechallenge of the trachea with compound 48/80 or D-tubocurarine failed to alter subsequent effects of antigen after active sensitization with OA or passive sensitization with either IgG1 or IgE antibodies. Small but statistically significant decreases in tracheal responses to D-tubocurarine were observed after antigen prechallenge to active both IgG1 and IgE antibodies. This is the first study to demonstrate a cross-desensitization between compound 48/80 and D-tubocurarine and the first to examine cross-desensitization with IgG1 and IgE antibodies in the guinea pig trachea. The overall conclusion is that there is no major overlap in the desensitization mechanisms between immunologic and nonimmunologic stimuli in the guinea pig trachea.

Animals↗
PubMed1984

Isolation of guinea pig basophils using anti-leukocyte antibody and density gradient centrifugation on Percoll.

Peripheral blood basophils were isolated from guinea pigs using a 2-step procedure. Initial enrichment of basophils was achieved by treating leukocyte preparations obtained from whole blood with antibody to contaminating granulocytes and mononuclear cells. Basophil populations of 82% purity (mean; range 65-99%) were obtained by subsequent application of the antibody treated preparation to discontinuous Percoll gradients. The isolated basophils were viable and shown to be functional by histamine release upon stimulation with various secretogogues.

Animals↗