Development of acute burn shock in unresuscitated guinea pigs.

Conscious guinea pigs were used to study the development of burn shock as a function of the size of thermal injury to the body surface. Scale burns equivalent to 0 (control, n = 18), 15.7 +/- 0.8% (n = 11), 24.6 +/- 0.5% (n = 10), and 43.4 +/- 1.5% (n = 10) of total body surface area were obtained by use of a template device, while the animals were deeply anesthetized with methoxyflurane. Circulatory function was assessed without further anesthetic restraint before and at 1, 2, 4, 6, 8, and 24 hr after burn. Values from control guinea pigs varied little during the observation period. Hemodynamic functions of burned guinea pigs were abnormal, and both the magnitude and duration of dysfunction generally depended upon the size of injury. Burn shock was characterized by hemo-concentration, hypothermia, tachycardia (bradycardia in the 43.4% group), minimal adjustments in systemic blood pressure, hyperkalemia, normonatremia (hyponatremia in the 43.4% group) arterial acidemia, and decreased respiratory rate. Circulatory functions of the 15.7% and 24.6% groups returned toward control levels during 8 hr after burn. Severe shock persisted in the 43.4% group, which experienced 70% mortality by 24 hr. These experiments characterize the guinea pig as a reproducible small animal model for studying different severities of burn shock unencumbered by secondary influences associated with general anesthesia.

Effect of dextranase on plaque formation and caries development in the rat.

Plaque formation and caries development were studied in 0-M rats fed Diet 2000 and infected with S. mutans 6715 and fecal flora from older caries-active rats. Merck dextranase, Beckman dextranase or Beckman glucanase 447 were administered singly or in combination to groups of 12 rats either as an addition to the diet or as a "mouthwash" twice daily, 5 per week. All enzymes studied were associated with significant inhibition of both plaque formation and caries development, especially on the buccal and lingual surfaces.

Clinical study of an amine fluoride gel and acidulated phosphate fluoride gel.

This study compared caries inhibition in children by an amine fluoride and an acidulated phosphate fluoride when administered in a topically applied gel. In addition, the effects of applying amine fluoride daily and weekly were compared. Four hundred and sixty-eight children, ages 6 to 13, were randomly assigned to one of five treatment groups and received a total of five, 5-minute treatments. The treatment and interval between each of the five treatments were as follows:(A)acidulated phosphate fluoride daily, (B) amine fluoride daily, (C) amine fluoride weekly, (D) placebo daily, and (E) placebo weekly. When the children were examined for total Decayed, Missing, and Filled Surfaces (DMFS) increments 2 years later, no significant differences were observed. However, when the data were examined for effects of DMFS for specific tooth surface, significant restriction (61%) of occlusal increment was shown in the group which was treated with amine fluoride daily for 5 consecutive days as compared with the control group.