Effects of prolonged XXXX on the subcutaneous microcirculation of the hamster. I. Technique, morphology and tissue oxygenation.

@entity39 @entity3179 @entity2507 @entity519 @entity5715 @entity5723 @entity902 @entity4095 @entity130
An animal model is described allowing for direct measurements of local tissue @entity4095 , microhemodynamics and vascular density in the event of a prolonged non freezing @entity130 . The model consists of implanting a transparent skin fold chamber in the dorsal skin fold in hamsters and of inserting two permanent indwelling catheters in jugular vein and carotid artery, respectively. The microcirculation was studied using a Wild Photomacroscope for photography and a @entity902 multiwire electrode for measurements of local @entity4095 in the conscious animal. After 72 h of recovery from anesthesia and surgery, the experimental was started with the animal immobilized. The decrease of local s.c. temperature was achieved by perfusing a heat exchanger with distilled @entity2507 and @entity5723 70% (1:1) at a rate of 81/min with the heat exchanger located directly beneath the @entity5715 frame of the chamber. With this technique, a decrease in local tissue temperature from 28 degrees C to 15 degrees C could be obtained within 15 min and was kept constant for 60 min. After photography of the microcirculation and local @entity4095 -measurements, the local temperature was further reduced to 5 degrees C with 15 min. Sixty minutes later, the area exposed was slowly rewarmed from a level of 5 degrees C within 30 min. This procedure was repeated in intervals of 24 h over a period of five days. During the course of the experiments, local @entity4095 values shifted toward @entity519 or even anoxic values. Intravital microscopic observation revealed aggregate formation, @entity3179 and obstruction of capillary flow associated with pronounced tissue @entity519 after five cold exposures. This event resulted inevitably in tissue @entity39 and scar formation after seven consecutive exposures to cold. It is concluded that this model can be used to study the effects of local non freezing @entity130 in a precisely reproducible manner.
