A comparison of a forced-air warming system to traditional thermal support for rodent microenvironments.

Thermal homeostasis is important for the well-being of laboratory rodents during experimental investigations involving chemical restraint. Anaesthesia-induced hypothermia may alter physiological processes, prolong recovery times, or result in death. Therefore, active warming may be needed to prevent excess heat loss from the rodent to the environment. Three methods of active warming were evaluated in typical rodent procedural areas and recovery cages: a forced-air warming system, infra-red heat emitter and circulating-water blanket. The first experiment involved recording the temperature of the immediate environment of the three devices, with and/or without the accompanying plastic drape, to simulate a surgical situation. In the second experiment, temperatures were recorded within cages that simulated a recovery situation with the same modalities. Forced-air warmer blankets (FAWB) were either wrapped around or placed underneath standard polycarbonate rodent cages and the results were compared with cage temperatures warmed by the heat emitter and circulating-water blanket. Temperatures were recorded at 0, 20, 40, and 60 min for each warming treatment, to determine mean temperature (+/- SEM) and the magnitude of increase (+/- SEM) between 0 and 60 min. All three devices showed an increase in temperature, but the FAWB with a plastic drape heated the procedural area microenvironment (Experiment 1) quickly and to a final temperature of 38.6 degrees C (101.5 degrees F) at 60 min, compared with 25 degrees C (77 degrees F) for the heat emitter and 28 degrees C (82.4 degrees F) for the circulating-water blanket. The magnitude of increase was significantly different for each treatment, but the FAWB with a plastic drape climbed 16.3 degrees C (29.3 degrees F) in 60 min. In Experiment 2, the FAWB wrapped around a cage, covered with a plastic drape, heated recovery cages to 32.5 degrees C (90.5 degrees F) compared to the heat emitter 26.4 degrees C (79.5 degrees F) and circulating-water blanket with drape 26.3 degrees C (79.3 degrees F). The magnitude of increase in the microenvironmental temperature was significantly higher for the FAWB, with the plastic drape wrapped around the recovery cage, compared to the other treatments. In both experiments, forced-air warming proved superior to the more traditional thermal support treatments in heating the microenvironments quickly and to an optimum ambient temperature. Forced-air warming devices should be considered when thermal support is required for rodent procedural areas and recovery cages.

The relationship of daily sperm production with number of Sertoli cells and testicular size in adult horses: role of primitive spermatogonia.

The number of Sertoli cells is important in spermatogenesis as noted by significant correlations between the number of Sertoli cells and the number of germ cells observed as early as type B2 spermatogonia in the horse. However, the stage within spermatocytogenesis at which these relationships first occur is unclear. The relationships between the number of Sertoli cells and parenchymal weight and the number of germ cells during the mitosis of spermatogenesis were determined in 184 adult horses to identify the developmental stage (that is, the earliest germ cell) at which significant relationships are established. The total numbers of all types of A spermatogonia and of specific subtypes (A1, A2, A3, B1 or B2) of spermatogonia were correlated with the number of Sertoli cells and with parenchymal weight. The number of each cell type was calculated using stereology. The number of Sertoli cells was correlated (P < 0.01) with parenchymal weight (r = 0.85) and with daily sperm production (r = 0.83), and parenchymal weight was correlated (P < 0.01) with daily sperm production (r = 0.89). The number of Sertoli cells was correlated (P < 0.01) with the number of type A (r = 0.81) and A1 (r = 0.74) spermatogonia. Parenchymal weight was correlated with the number of type A (r = 0.80) spermatogonia and with the number of A1 (r = 0.67) spermatogonia.(ABSTRACT TRUNCATED AT 250 WORDS)