BACKGROUND Surface microhardness is a physical property which access the effect of chemical and physical agents on hard tissues of teeth, and a useful way to examine the resistance of fluoride treated enamel against caries. The purpose of this study was to evaluate microhardness of enamel following pH-cycling through demineralization and remineralization using suspensions of dentifrices with di...

The effects of breathing CO continuously at high altitude on the mean electrical axis of the heart, hematocrit ratio and body weight were studied in laboratory rats. Laboratory rats were exposed for 6 weeks to: 100 or 500 ppm CO; 15,000 feet stimulated high altitude (SHA); or 100 or 500 ppm CO at SHA. SHA decreased body weight significantly; CO and CO-SHA interaction had no significant effect o...

B6C3F1 mice were treated with 0, 100, 500, 1500, or 6000 ppm di(2-ethylhexyl)phthalate (DEHP) in the diet for up to 104 weeks. Blood and urine were analyzed at Weeks 26, 52, 78, and 104 from 10 animals per sex per group. Body weights and food consumption were measured weekly for the first 16 weeks, then monthly thereafter. Survival was reduced for mice receiving 6000 ppm DEHP. Overall weight ga...

Three experiments were conducted to evaluate the effect of feeding pharmacological concentrations of zinc (Zn), from organic and inorganic sources, on growth performance, plasma and tissue Zn accumulation, and Zn excretion of nursery pigs. Blood from all pigs was collected for plasma Zn determination on d 14 in Exp. 1, d 7 and 28 in Exp. 2, and d 15 in Exp. 3. In Exp. 1, 2, and 3, 90, 100, and ...

OBJECTIVE This study evaluated the effects of three post-brushing mouthwashes containing 0 ppm F, 225 ppm F, and 500 ppm F, respectively, on salivary fluoride retention after brushing with 1450 ppm fluoride (as NaF) toothpaste and rinsing with water immediately after brushing. METHODS In this three-phase, randomized, cross-over study, an ion-specific electrode was used to measure salivary F l...

To assess the effects of chronic administration of tamoxifen (TAM) and toremifene (TOR) on genetic damage related to carcinogenesis, we measured DNA adduct formation by (32)P-postlabeling in liver, kidney, and uterus of Fischer rats given TAM or TOR in the diet for 18 months. TAM induced high levels of DNA adducts in the liver in a dose-dependent manner. The total adduct levels were 3000 +/- 87...

Effects of supplemental dietary Zn levels of 0, 50, 500 and 5,000 ppm on the mineral concentration in milk of first- and second-parity sows were evaluated. Colostrum from sows fed 5,000 ppm of supplemental Zn contained less Cu and P than colostrum from sows on the other treatments. Calcium was reduced in the colostrum from sows fed 0 or 5,000 ppm Zn. Copper was reduced and Zn increased in milk ...

This study investigated if the use of the pesticides cyprodinil and fludioxonil produced an inhibitory effect on the bovine liver catalase (CAT) activity. It was documented that the activity of the enzyme decreased with increasing concentrations of cyprodinil and fludioxonil from 0 to 500 ppm. At pesticide concentrations of 250 and 500 ppm, the activity of CAT remained unchanged and passed to a...

First, the developmental toxic potential of n-butyl acetate (BA) was examined in SpragueDawley rats following whole body inhalation exposure, 6 h day-1, from day 6 to 20 of gestation, at concentrations of 0, 500, 1000, 2000 and 3000 ppm. Maternal toxicity was evidenced by significant decreases in body weight gain at 2000 and 3000 ppm, and by reduced food consumption at 1000 ppm and higher conce...

Two 28-d randomized complete block design experiments were conducted to evaluate the effects of concentrations and sources of Zn on growth performance of nursery pigs. Seven stations participated in Exp. 1, which evaluated the efficacy of replacing 2,500 ppm of Zn from ZnO with 125, 250, or 500 ppm of Zn from Zn methionine. A control diet with 125 ppm of supplemental Zn was included at all stat...