The tooth as a monitor of cholestatic liver disease in rats.

OBJECTIVE: Measure, noninvasively, the deposition of bilirubin in the tooth by using DIAGNOdent and correlate it to liver dysfunction. STUDY DESIGN: After confirming the capacity of DIAGNOdent to measure varying bile concentrations in plaster blocks, a cholestatic liver disease model was studied to detect increasing bilirubin impregnation in the teeth of rats. Wistar-EPM rats (n = 50) were divided into three groups: (1) BDL: rats submitted to bile duct ligation (BDL); (2) Naïve: rats without procedure; and (3) Sham: rats submitted to laparotomy without BDL (n = 10/period/group). The rats' teeth were monitored with the use of DIAGNOdent before the procedure and at days 10 and 50 following surgery. Serum bilirubin was also monitored. RESULTS: Tests in vitro showed that DIAGNOdent detected bile in plaster blocks according to its concentration. BDL promoted progressive liver dysfunction, with death occurring approximately 50 days later. DIAGNOdent values obtained on teeth showed correlation with the progression of serum hyperbilirubinemia. CONCLUSIONS: The tooth was found to be a good tissue for noninvasively monitoring the progression of bilirubinemia in cholestatic liver disease in rats by using DIAGNOdent.

A hybrid material assembled by anthocyanins from açaí fruit intercalated between niobium lamellar oxide.

Organic-inorganic hybrid materials can be prepared dispersing organic species into well-defined inorganic nanoblocks. This paper describes the immobilization of natural dyes from the extract of the Brazilian açaí-fruit into two types of layered hexaniobate precursors derived from H(2)K(2)Nb(6)O(17): (i) colloidal dispersion of niobate exfoliated nanoparticles and (ii) niobate pre-intercalated with tetraethylammonium cations (TEA(+)). The restacking of exfoliated particles in the presence of açaí anthocyanins promotes their intercalation and produces stacked layers showing large basal spacing (ca. 50 A). The TEA(+) pre-intercalated niobate provides particles with lower content of dye species than the exfoliated precursor but with higher degree of organization and regularity according to X-ray diffraction data and images obtained by electron microscopies. Vibrational (FTIR and Raman) and (13)C NMR spectroscopies indicate the presence of flavylium cations in the hybrid materials and spectral profiles characteristic of glycosylated anthocyanidins. According to thermal analysis results, the purplish hybrids materials are more stable than the free açaí-dyes. One hybrid sample was heated under air up to 170 degrees C and maintained at this temperature for 240 min. No weight loss events were observed and the sample retained its original color, indicating that the intercalation of anthocyanin into hexaniobate increases its thermal stability. Considering the structural, chemical, optical and thermal properties of the synthesized hybrid materials, they might be good candidates to be investigated for future specialized applications.