Can dynamic contrast-enhanced MRI evaluate VEGF expression in brain glioma? An MRI-guided stereotactic biopsy study.

PURPOSE: To investigate whether pharmacokinetic parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to evaluate vascular endothelial growth factor (VEGF) expression in brain glioma based on a point-to-point basis. MATERIALS AND METHODS: Forty-seven patients with treatment-naïve glioma received preoperative DCE-MRI before stereotactic biopsy. We histologically quantified VEGF from section of stereotactic biopsies, and co-registered biopsy locations with localized measurements of DCE-MRI parameters including volume transfer coefficient (Ktrans), reverse reflux rate constant (Kep), extracellular extravascular volume fraction (Ve) and blood plasma volume (Vp). The correlations between DCE-MRI parameters (Ktrans, Kep, Ve and Vp) and VEGF were determined using Spearman correlation coefficient. P≤.05 was considered statistically significant. RESULTS: Seventy-nine biopsy samples were obtained and graded into 45 high-grade gliomas (HGGs) and 34 low-grade gliomas (LGGs). Ktrans showed a significant positive correlation with VEGF expression in HGGs group (ρ=0.505, P<0.001) and in combined group (LGGs+HGGs) (ρ=0.549, P<0.001), but not in LGGs group (P>0.05). Kep, Ve or Vp was not correlated with VEGF even though a positive trend showed (P>0.05). CONCLUSIONS: DCE-MRI is a useful, non-invasive imaging technique for quantitative evaluation of VEGF, and its parameter Ktrans other than Kep, Ve or Vp may be used as a surrogate for VEGF expression in brain gliomas.

Fluoride or/and aluminum induced toxicity in guinea pig teeth with the low expression of dentine phosphoprotein.

This study investigated the damage and expression of dentine phosphoprotein (DPP) in guinea pig teeth by the administration of fluoride (F) or/and aluminum (Al). Fifty-two guinea pigs were divided randomly into four groups (control, F, Al, and F+Al). F (150 mg NaF/L) or/and Al (300 mg AlCl3 /L) were added in their drinking water for 90 days. The levels of F ion, dentine sialophosphoprotein (DSPP) gene, and DPP protein in incisor and molar were determined, respectively. The results showed that the concentrations of F ion in F and F+Al groups were increased significantly. F induced the mottled enamel and irregular abrasion of teeth, which might occur as a consequence of depressed DSPP mRNA and DPP protein expression. Both the gene and protein expressions showed obvious decrease induced by Al, especially by F. There were no synergistic effects between F and Al, instead, Al inhibited the toxicity of F.

Effect of dietary protein or calcium supplement on the expression of collagen I and dentine phosphoprotein of rats with dental fluorosis.

This study aims to assess the roles of dietary protein (Pr) and calcium (Ca) levels associated with excessive fluoride (F) intake and the impact of Pr, Ca, and F on expression of collagen I (COL I) and dentine phosphoprotein (DPP) in rat incisors. Seventy-two rats were randomly allotted to six groups (NC, NC + F, LPrLCa, LPrLCa + F, HPrLCa + F and LPrHCa + F). F, Pr, and Ca were orally administrated to rats for 120 days. The genes and proteins expression levels were quantified. We found that levels of COL1A1 and DSPP gene were respectively decreased by 41.9% and 43.1% in the NC + F group compared with NC group, were respectively decreased by 47.9% and 40.8% in the LPrLCa + F group compared with LPrLCa group, were respectively increased by 71.8% and 39.5% in the HPrLCa + F group and increased by 26.5% and 21.1% in the LPrHCa + F group compared with LPrLCa + F group. Meanwhile, the proteins' expression display with the genes' expression changes were consistent. This study demonstrated that the gene and protein expressions of COL I and DPP were reduced by F both in normal nutrition and malnutrition, and it was reversed by Pr and Ca supplementation, with the effect of Pr being greater than that of Ca.

Surface measurement based on chessboard-shaped 2-D Ronchi grating method.

A method for surface profile measurement using a chessboard-shaped 2-D Ronchi grating is proposed. The gradients in two orthogonal directions of the measured surface can be obtained simultaneously using a chessboard-shaped 2-D Ronchi grating, so that it is possible to reconstruct the surface profile by means of only one Ronchigram with high accuracy. The measuring principle and the design of the chessboard-shaped 2-D Ronchi grating are described. Measurements of both stationary and varying surfaces using an instrument constructed on the basis of the method were conducted with satisfactory results.