Tolerable infusion rate of citrate based on clinical signs and the electrocardiogram in conscious dogs.

BACKGROUND & AIMS: The possible clinical significance of the toxic effects of citrate has not yet been fully clarified. This study was therefore conducted to confirm the toxicity and determine the tolerable infusion rate of citrate administered by rapid intravenous infusion to conscious dogs. METHODS: Citrate solutions were infused via the cephalic vein of 4 conscious dogs at 0.33, 0.67, or 1.33mmol/kg/h up to 1.33mmol/kg. Clinical signs and the electrocardiogram were observed during and after infusion. Serum citrate and ionized calcium levels were also measured. RESULTS: Although the mean citrate level increased in accordance with the infusion rate, the calcium level decreased. No significant changes in clinical signs or the electrocardiogram were observed during infusion at 0.33mmol/kg/h despite an increase in the serum citrate level to 1.22+/-0.11mmol/l (pre-infusion value: 0.38+/-0.01mmol/l) and a decrease in the serum calcium level to 1.28+/-0.03mmol/l (pre-infusion value: 1.50+/-0.05mmol/l). Vomiting and QTc prolongation were observed at 0.67mmol/kg/h or higher. Salivation and tachycardia were observed at 1.33mmol/kg/h. CONCLUSIONS: Based on clinical signs and the electrocardiogram, the tolerable infusion rate of citrate in conscious dogs is concluded to be 0.33mmol/kg/h.

Effects of housing conditions on the development of wet skin lesions in the NOA mouse.

The effects of housing on the onset time and prevalence of wet skin lesions were investigated in NOA mice, which spontaneously develop these lesions at a high rate. Wet skin lesions developed earliest in mice that were housed individually. For mice that were housed in groups, the lesions developed earlier in mice with non-littermate group housing than in mice with littermate group housing. The prevalence of lesions was in the following order: individual housing > non-littermate group housing > littermate group housing. These results suggest that socio-psychological factors are involved in the etiology of wet skin lesions in the NOA mouse. Under individual housing conditions, two other novel characters of the NOA mouse were also observed, specifically, development of dry skin and wet skin lesions at the tail root. These characteristics developed early and with high prevalence and were easily observed on external examination. Therefore, these novel characteristics observed in NOA mice are potential markers of the psychological state of the animals.

Development of dry skin in the NOA mouse under individual housing conditions: a potentially useful animal model for evaluating moisturizing effects.

In a previous study, we reported the development of grossly observable dry skin in all of the Naruto Research Institute Otsuka Atrichia (NOA) mice that were housed individually. In the present study, dermal physiological function tests were conducted and the usefulness of this dry skin model for evaluating the efficacy of topical moisturizers was assessed. As a result, we have confirmed a marked reduction in the water content of the stratum corneum in these animals. Therefore, the development of dry skin in the NOA mouse strain under individual housing conditions may be expected to serve as a useful animal model for evaluating topical moisturizers. Specifically, the water content of the stratum corneum was restored in proportion to the oil content of the ointment base used to treat the animals, and the moisturizing effects of urea were confirmed in animals treated with urea-containing ointment. In addition, when the animals that had been housed individually were returned to group housing conditions, the water content of the stratum corneum was restored, with a corresponding improvement in dry skin. This finding suggests that socio-psychological factors are involved in the etiology of dry skin in individually housed NOA mice.