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Biomedical subjects

J Werner

Publications and source records attributed to J Werner.

279 records · Page 16Linked to original sources
PubMedDate not supplied

Assessment of the temperature distribution during hyperthermia treatment by isolated extremity perfusion.

A finite-element model of the human leg is developed for the assessment of temperature distribution during hyperthermia treatment by isolated extremity perfusion with a heart-lung-machine. The simulation comprises the true geometry, adequate perfusion models for the different parts of the extremity circulation in normal and tumour tissue, and the numerical procedure for the solution of the partial differential heat balance equation used. The simulation is validated using both experimental physiological and clinical data, and predicts temperature distributions and courses for various modifications of the hyperthermia procedure. It is concluded that the homogeneous temperature required in combination with chemotherapy can be achieved by isolated extremity perfusion, if a good thermal insulation is applied. If temperatures >42 degrees C are required, an additional external heat source (microwaves or ultrasound) is necessary. Although these sources may produce high absorption rates, combination with extremity perfusion is useful in reducing higher temperature gradients and the danger of locally lower temperatures.

Chemotherapy, Cancer, Regional Perfusion↗
PubMedDate not supplied

Do black-box models of thermoregulation still have any research value? Contribution of system-theoretical models to the analysis of thermoregulation.

The aims and the usefulness of modelling the thermoregulatory system are outlined by demonstrating applications and results of simulation on different levels of complexity. It is shown that both very simple one-loop models and complex models based on spatially distributed parameters have contributed to a better understanding of the system, but that current issues primarily require the latter type. However, mathematical modelling must be performed in conjunction with experimental studies and must be adapted to the amount of basic physiological data. Future fields of modelling are the adaptive mechanisms and the interactions of systems.

Animals↗
PubMedDate not supplied

Dynamics and specificity of influenza virus antibodies as well as IgE values in serum and nasal fluid after repeated local application of live bivalent influenza vaccine.

A long term study with bivalent live influenza vaccine was carried out in 18 subjects with no previous history of egg protein hypersensitivity. Experimental conditions included a nine-fold vaccination schedule with collection of serum and nasal fluid. The parameters studied were determination of serum and local antibody formation as well as the demonstration of specific IgE antibodies in serum and nasal fluid. HI antibody response was observed in 100% of the vaccinees against vaccine related strains but not to antigenically remote isolates. NI antibodies could be demonstrated in serums and to some extent in nasal fluids. Special attention was given to induction of specific IgE antibodies to egg protein, however no indication for a vaccine induced sensitization could be detected when total and specific IgE concentrations of serum and nasal fluid were determined.

Administration, Oral↗
PubMedDate not supplied

Neuraminidase antibodies in serum and nasal washings after immunization by means of live and killed whole virion, split virion and subunit (HA and N) influenza vaccines.

Anti-neuraminidase antibody (ANAB) formation was determined in serum and nasal washing fluids pre- and post-vaccination in 278 adult healthy volunteers vaccinated with different types of current experimental and conventional influenza vaccines. The best systemic ANAB formation expressed as conversion rate (CR) was observed with the subunit vaccine "Sandovac" (CR = 90%) followed by the split virion vaccine "Begrivac S" (CR = 66%), the whole virion vaccine "Alorbat" (CR = 65%) and the live attenuated vaccine "Alice" (CR = 58%). The best local ANAB formation was obtained with live attenuated vaccines (CR = 47-50%) followed by "Begrivac S" (CR = 34%) and "Alorbat" (CR = 17%). The subunit vaccine, unfortunately, could not be tested for ANAB formation. On the basis of this data the optimal method of immunization against influenza would consist of simultaneous topical and parenteral application of live attenuated and inactivated subunit or split vaccine.

Administration, Intranasal↗
PubMedDate not supplied

Hallux varus--surgical correction and review of the literature.

Acquired hallux varus may follow correction of hallux abducto valgus by the modified McBride procedure. The authors discuss correction of both acquired and congenital hallux varus and show pre- and postoperative illustrations of both types.

Foot Deformities, Acquired↗
PubMedDate not supplied

Conflicts of thermal adaptation and fever--a cybernetic approach based on physiological experiments.

Cold adaptation aims primarily at a better economy, i.e., preservation of energy often at the cost of a lower mean body temperature during cold stress, whereas heat adaptation whether achieved by exposure to a hot environment or by endogenous heat produced by muscle exercise, often brings about a higher efficiency of control, i.e., a lower mean body temperature during heat stress, at the cost of a higher water loss. While cold adaptation is beneficial in a cold environment, it may constitute a detrimental factor for exposure to a hot environment, mainly because of morphological adaptation. Heat adaptation may be maladaptive for cold exposure, mainly because of functional adaptation. Heat adaptation clearly is best suited to avoid higher body temperatures in fever, no matter which environmental conditions prevail. On the other hand, cold adaptation is detrimental for coping with fever in hot environment. Yet, in the cold, preceding cold adaptation may, because of reduced metabolic heat production, result in lower febrile increase of body temperature. Apparently controversial effects and results may be analyzed in the framework of a cybernetic approach to the main mechanisms of thermal adaptation and fever. Morphological adaptations alter the properties of the heat transfer characteristics of the body ("passive system"), whereas functional adaptation and fever concern the subsystems of control, namely sensors, integrative centers and effectors. In a closed control-loop the two types of adaptation have totally different consequences. It is shown that the experimental results are consistent with the predictions of such an approach.

Acclimatization↗