No abstract

BACKGROUND: Chromium(III) is generally thought to be an essential trace element that allows for proper glucose metabolism. However, chromium(III) picolinate, Cr(pic) 3 , a popular dietary supplement form of chromium, has been shown to be capable of generating hydroxyl radicals and oxidative DNA damage in rats. The cation1 , Cr3, has been studied as an alternative supplemental source of chromium. It has been shown to increase insulin sensitivity and lower glycated hemoglobin levels in rats, making it attractive as a potential therapeutic treatment for gestational diabetes. To date, no studies have been published regarding the safety of Cr3 supplementation to a developing fetus. METHODS: From gestation days (GD) 6-17, mated CD-1 female mice were fed diets delivering either 25 mg Cr/kg/day as Cr(pic) 3 , 3.3 or 26 mg Cr/kg/day as Cr3, or the diet only to determine if Cr3 could cause developmental toxicity. Dams were sacrificed on GD 17, and their litters were examined for adverse effects. RESULTS: No signs of maternal toxicity were observed. No decrease in fetal weight or significantly increased incidence of skeletal defects was observed in the Cr3 or Cr(pic) 3 exposed fetuses compared to the controls. CONCLUSION: Maternal exposure to either Cr(pic) 3 or Cr3 at the dosages employed did not appear to cause deleterious effects to the developing offspring in mice. Birth Defects Res (Part B) 83:27-31, 2008.

At the highest dosages employed, maternal exposure to P(NIPAAm-co-AAm) was associated with decreased fetal weight. However, as the estimated human exposure levels for persons using this system would be some 1,500-fold lower than the lowest dosage administered in this study, the authors feel that this oligomer was not shown to pose a biologically significant risk at relevant human dosages.

A thermosensitive grafted hydrogel was investigated for heating-activated drug release. The hydrogel was created by grafting oligomers of N-isopropylacrylamide-co-acrylamide (AAm) to a poly(2-hydroxyethyl methacrylate), or PHEMA, hydrogel. N-Isopropylacrylamide-co-AAm oligomers were synthesized with a range of compositions to raise the lower critical solution temperature (LCST) above physiological temperature. PHEMA hydrogels with these thermosensitive grafts were synthesized by free-radical solution polymerization, using an acrylated version of the oligomers. The oligomers were characterized for their molecular weight, LCSTs, and rate of response to a change in temperature. With the flexibility in tuning their properties by varying reaction parameters, these oligomers present possibilities in several fields, including drug delivery. The impact of cross-linking agent type and the amount and presence of grafts on the polymer network structure was found by determining the hydrogel mesh sizes. PHEMA gels cross-linked with methylenebisacrylamide had larger mesh sizes than those crosslinked with ethylene glycol dimethacrylate. Increasing amounts of cross-linking agent decreased mesh sizes. LCSTs exhibited by oligomers were slightly lower than those exhibited by polymer gels of the same composition. The grafting reaction was found to have only a slight impact on the hydrogel mesh size.