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Biomedical subjects

P Bürgel

Publications and source records attributed to P Bürgel.

5 recordsLinked to original sources
PubMed2005

The self-adjusting crown (SAC).

When previously using Cerec 3D, the occlusal surface could be designed according to morphologically functional aspects with the aid of a bite registration (static and/or dynamic). In addition, different tooth databases could be used for the design of crowns. However, the relevant design suggestion had then to be manually aligned onto the functional registration by the user. The new Cerec 3D software version R 2005 now promises the automatic adjustment of crown proposals in alignment with the corresponding functional registration. In this case, the crown design selected from the tooth databases is adjusted to the morphology of the functional registration and is therefore modified until light contact points are still present. The procedure of the "self-adjusting crown" is demonstrated by reference to a clinical case. As the name "self-adjusting crown" indicates, this automatic tool is possible only in restorations which have a single-segment preparation margin (crowns).

Adult↗
PubMed1977

The influence of age and drugs on the thermoregulatory behaviour of rats.

A method is described which allows to measure thermoregulatory effective conditioned behaviour in rats. This method makes it possible to vary the preset ambient temperature (Ta) in a wide range. The results only deal with subnormal Ta (normal housing temperature 23 degrees C). Rats are able to acquire a conditioned behaviour additional to inborn behaviour which is adequate to contribute to thermal homoeostasis. Exposed to -4 degrees C adult animals adjusted their mean Ta to +4 degrees C, old animals to +8 degrees C. A dose of 40 micromol/kg Phentolamine caused adult rats to adjust mean temperature to +9 degrees C, old rats to +13.5 degrees C. But even this increased behavioural activity did not prevent the hypothermic effect of the drug totally. Core temperature in adult animals dropped by 0.8 degrees C, in old animals by 1.4 degrees C.

Aging↗
PubMed1976

[A method for determination of thermally motivated behavior (author's transl)].

Constant body temperature in homeothermic organisms results from autonomic and behavioral thermoregulatory reactions. The input variables for thermally motivated behavior are temperatures of the skin and of the hypothalamus. Our aim was to determine the behavioral side of thermoregulatory reactions under the influence of drugs interfering with normal body temperature. Initial experiments were made with phentolamine, which at an ambient temperature of + 4 degrees C causes a dose dependent hypothermia. Rats were trained in a cold box to press a lever and were rewarded by a certain amount of warm air. Trained rats were able to raise the temperature in the box from -4 degrees C up to + 4 degrees C at a response rate of 0.5 min. Treated with phentolamine (3.7-15 mg/kg) these rats increased the rate of lever pressing dose dependently, i.e. they increased their ambient temperature. The hypothermic effect of the drug was therby reduced to a certain extent. Using this method it can be determined whether a drug influences body temperature at the level of autonomic reactions or at that of thermally motivated behavior or at those of both.

Animals↗