The use of sealants for the infiltration of proximal enamel lesions could be a promising alternative to the common strategies of remineralization and operative treatment. The aim of the present study was to compare the progression of sealed initial enamel lesions after exposure to a demineralizing solution in vitro. In each of 54 bovine enamel specimens three subsurface lesions were created. Two of the lesions were etched with phosphoric acid and sealed with either a fissure sealant or with various adhesives (1–5) for 15 s or 30 s, respectively, whereas one lesion remained as the untreated control. Subsequently, half of each specimen was covered with nail varnish (baseline) and the other half was reexposed to a demineralizing solution for 14 days (experimental). The specimens were cut perpendicularly to the surface, infiltrated with a low-viscosity fluorescent resin and observed with a confocal laser scanning microscope (CLSM). For lesions sealed with the fissure sealant and adhesives 1–3, the progression of lesion depth (0–31 µm) was significantly decreased (p < 0.01; paired t test) compared with the untreated control (57 µm). For the fissure sealant and adhesives 1 and 3 extended penetration times (30 s) resulted in significantly reduced lesion progression compared to 15 s. It can be concluded that filling of the pores in initial enamel lesions with the fissure sealant and adhesives 1–3 can inhibit further demineralization in vitro.
The penetration of adhesives into initial enamel demineralization seems to be a promising approach to providing a non-operative treatment regimen for carious lesions. SUMMARYThis study compared the progression of sealed initial enamel lesions penetrated with a fissure sealant (Helioseal, Vivadent) or various adhesives (Heliobond, Excite, Vivadent; Resulcin, Merz; Solobond M, Voco; Prompt L-Pop, 3M-ESPE) after exposure to a demineralizing solution, in vitro. From 27 bovine teeth, 54 enamel specimens were prepared and covered with nail varnish (control), thus obtaining three windows for treatment. After demineralization (pH 5.0; 14 days), two of the windows (A, B) were etched with phosphoric acid (20%; 5 seconds); whereas, the third area served as the control (C). The specimens were divided randomly into six groups (n=9), and the material was applied (90 seconds) either once (A) or twice (B). Light-curing followed each application. Half of the area of each specimen window was then covered with nail varnish, and the samples were again stored in the demineralizing solution (pH 5.0; 14 days). The specimens were cut perpendicular to the surface, and both enamel slabs were studied after infiltration using a fluorescent, low viscous resin (VIRIN) and confocal microscopy (CLSM). Lesion depths were calculated (ImageJ) from the surface to that point in the lesion where the grey values clearly changed to a darker grey. After demineralization, mean lesion depths (SD) (14 days) were measured at 105 (21) µm. The second demineralization led to a mean progression of the lesion depths of 52 (31)
Hepatic fat accumulation and changes in lipid composition are hallmarks of nonalcoholic fatty liver disease (NAFLD). As an experimental approach for treatment of NAFLD, we synthesized the bile acid-phospholipid conjugate ursodeoxycholyl lysophosphatidylethanolamide (UDCA-LPE). Previous work demonstrated profound hepatoprotective properties of the conjugate in vitro and in vivo. Here we investigated the effects of UDCA-LPE in two nutritional mouse models of NAFLD. C57BL/6 mice were fed a high-fat diet (HFD) for 28 weeks, resulting in steatosis with hyperlipidemia. In a second model, mice received a methionin-choline-deficient (MCD) diet for up to 11 weeks, which induced advanced nonalcoholic steatohepatitis (NASH). Establishment of liver injury was followed by intraperitoneal injections of 30 mg/kg UDCA-LPE three times a week for different time periods. UDCA-LPE ameliorated both HFDand MCD-induced increases in alanine aminotransferase (ALT) values near to normalization. As for metabolic parameters, UDCA-LPE reduced elevated serum triglyceride and cholesterol values in HFD mice. Liver histology showed improvement of steatosis in HFD and MCD mice concomitant with reductions in hepatic triglyceride and cholesterol levels. Additionally, the conjugate lowered serum caspase-8 activity in both models and decreased lipid hydroperoxides in MCD mice. Abundance of proinflammatory lysophosphatidylcholine (LPC), which was detectable in both HFD and MCD mice, was reduced by UDCA-LPE. Quantitative reverse transcriptase-polymerase chain reaction qRT-PCR of liver specimens revealed that UDCA-LPE strongly down-regulated inflammatory genes and modified the expression of genes involved in lipid metabolism. Conclusion: The current study demonstrates that UDCA-LPE improves hepatic injury at different stages of NAFLD. By concurrently lowering hepatic lipid overloading as well as susceptibility of hepatocytes toward inflammatory stimuli, the conjugate may be able to ameliorate disease progression. Thus, UDCA-LPE represents a promising compound suitable for the treatment of NAFLD. (HEPATOLOGY 2012;55:1369-1378
Purpose Hip prosthesis is one of the most common types of metal implants and can cause significant artifacts in computed tomography (CT) examinations. The purpose of this work was to develop a projection-based method for reducing metal artifacts caused by hip prostheses in multislice helical CT. Method and Materials The proposed method is based on a novel concept, reformatted projection, which is formed by combining the projection data at the same view angle over the full longitudinal scan range. Detection and segmentation of the metal were performed on each reformatted projection image. Two dimensional interpolation based on Delaunay triangulation was used to fill voids left after removal of the metal in the reformatted projection. The corrected data were then reconstructed using a commercially available algorithm. The main advantage of this method is that both the detection of the metal objects and the interpolations are performed on complete reformatted projections with the entire metal region present, which is particularly useful for long hip prostheses. Twenty clinical abdominal/pelvis exams with hip prostheses were corrected and clinically evaluated. Results The overall image quality and the conspicuity in some critical organs were significantly improved compared with the uncorrected images: overall quality (P = 0.0024); bladder base (P = 0.0027), and rectum (P = 0.0078). The average noise level in the bladder base was reduced from 86.7 HU to 36.2 HU. In 17 of 20 cases, the radiologists preferred either coronal (13) or axial (4) views of the corrected images. Conclusions A novel method for reducing metal artifact in multislice helical CT was developed. Initial clinical results showed that the proposed method can effectively reduce the artifacts caused by metal implants for the cases of unilateral and bilateral hip prothesis.
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