Biomedical subjects

Thomas Trautmann

Publications and source records attributed to Thomas Trautmann.

4 recordsLinked to original sources

PubMed2006

Optimizing the experimental environment for dog telemetry studies.

INTRODUCTION: The objective of this study was to test the influence of housing conditions on hemodynamics during cardiovascular general pharmacological studies. Our goal was to optimize both the quality of the data through an optimization of the physiological conditions, as well as to ensure the dog's well-being in general pharmacological studies. METHODS: Two groups of four dogs were equipped with radiotelemetry transmitters and continuously monitored in two different housing models. Model I consisted of 4 cages, two on each site of a corridor. Model II consisted of 4 cages positioned in a row, where the bordering cages were not separated with a metal plate. The physiological status of the dogs in the different housing models was based on the frequency of vocalizations and the average resting heart rate, as well as video monitoring. RESULTS: The housing arrangement during the study had a remarkable effect on the hemodynamics measured. The hemodynamic parameters were best when the dogs were housed with their usual run mate. In this setting, they have impressively low average heart rates of about 60 bpm during the entire study, was associated with fewer vocalizations. DISCUSSION: This study demonstrated that the quality of the acquired cardiovascular data for conscious dogs is dependent on the pen configuration and group make-up during a study.

Animals↗

PubMed2005

Airborne system for fast measurements of upwelling and downwelling spectral actinic flux densities.

An airborne system for fast measurements of spectral actinic flux densities in the wavelength range 305-700 nm is introduced. The system is called the Actinic Flux Density Meter (AFDM). The AFDM utilizes the diode array technique and measures downwelling and upwelling spectral actinic flux densities separately with a time resolution of less than 1 s. For airborne measurements this means a spatial resolution of approximately 60 m, assuming an average aircraft velocity of 60 m/s. Thus the AFDM resolves fast changes in the actinic radiation field, which are of special importance for conditions of inhomogeneous clouds or surface reflection. Laboratory characterization measurements of the AFDM are presented, and a method to correct the nonideal angular response of the optical inlets is introduced. Furthermore, exemplar field data sampled simultaneously with spectral irradiance measurements are shown. The horizontal variability of the measured spectra of actinic flux density is quantified, and profile measurements for overcast situations are presented. Finally, the effects of clouds on the spectral actinic flux density are discussed.

Journal Article↗

PubMed2004

Modeling of the signals of an optical particle counter for real nonspherical particles.

An optical particle counter (OPC) was exposed to atmospheric particles of diameters of 200, 300, and 400 nm. The OPC data were combined with the results of single-particle analysis with a transmission electron microscope (TEM) on samples taken in parallel with the OPC measurements. With a T-matrix-based optical model the measured OPC spectra of scattered light pulses could be approximated with good precision. With an algorithm that simulated the response of the OPC to a given population of model particles derived from the TEM results, average absorption properties of different particle types were retrieved. For mobility sizes of 400 nm, higher light absorption was retrieved with the optical model for soot aggregates than for the rest of the morphological particle types. At smaller mobility sizes no compositional information could be derived from the model particles derived from the TEM data. Despite the limited success of the new methodology applied to the present experiment the results encourage the use of OPCs in combination with electrical mobility analyzers to derive more than aerosol-size distributions. With state-of-the-art pulse-height analysis the light-scattering pulses could be resolved with much finer resolution than in the instrument used.

Aerosols↗

PubMedDate not supplied

A novel propellant-free inhalation drug delivery system for cardiovascular drug safety evaluation in conscious dogs.

INTRODUCTION: Estimation of possible cardiovascular side effects belongs to the safety assessment of every drug candidate. This paper describes a new strategy for treating conscious labrador dogs with drugs by inhalation using a specially designed mask and a novel inhaler device. METHODS: Labrador dogs (male or female) were used that had transducers implanted for the measurement of left ventricular and descending aortic blood pressures and an ECG for use together with a telemetry system. Administration by inhalation was achieved using a novel delivery device. The Respimat device is a propellant-free inhaler to deliver aerosols from solutions. The new system was evaluated using Formoterol with four dogs using a 4 x 4 Latin square design. Three doses of Formoterol (0.6, 1.2, and 2.4 microg/kg, dissolved in 60% ethanol) were administered by inhalation together with a vehicle (60% ethanol) treatment by applying three inhalations, each consisting of 10 microl solution. RESULTS: Formoterol increased HR, QRS-interval, QT-interval, and LVPdP/dtmax and dose-dependently decreased systolic and diastolic BP. This effect lasted up to 14 h. DISCUSSION: Drug administration by inhalation in the conscious labrador dog using the Respimat is a useful new model for safety pharmacology studies of new drug candidates that are intended to be given by inhalation in the clinic.

Administration, Inhalation↗