Protein analysis through Western blot of cells excised individually from human brain and muscle tissue.

Comparing protein levels from single cells in tissue has not been achieved through Western blot. Laser capture microdissection allows for the ability to excise single cells from sectioned tissue and compile an aggregate of cells in lysis buffer. In this study we analyzed proteins from cells excised individually from brain and muscle tissue through Western blot. After we excised individual neurons from the substantia nigra of the brain, the accumulated surface area of the individual cells was 120,000, 24,000, 360,000, 480,000, 600,000 µm2. We used an optimized Western blot protocol to probe for tyrosine hydroxylase in this cell pool. We also took 360,000 µm2 of astrocytes (1700 cells) and analyzed the specificity of the method. In muscle we were able to analyze the proteins of the five complexes of the electron transport chain through Western blot from 200 human cells. With this method, we demonstrate the ability to compare cell-specific protein levels in the brain and muscle and describe for the first time how to visualize proteins through Western blot from cells captured individually.

Wear of posterior metal-free polymer crowns after 2 years.

The objective of this study was to evaluate the clinical wear behaviour of posterior, metal-free polymer crowns and to compare it with that of metal-ceramic crowns. After randomization, a total of 120 single crowns were set in posterior teeth. These 120 crowns were divided into three groups: 40 polymer crowns with a glass-fibre framework (group 1), 40 polymer crowns without framework stabilization (group 2) and 40 metal-ceramic crowns (control group). Wear was measured by use of gypsum replicas and a 3D laser scanner at baseline and after 2 years. Statistical analysis was performed by use of a mixed-effects regression model. The mean total wear of posterior single crowns was -19.0 mum (+/- 18.5 microm) in group 1, -24.3 microm (+/- 31.5 microm) in group 2 and -7.0 microm (+/- 8.8 microm) in the control group. Statistical analysis revealed the mean total wear of the polymer crowns in groups 1 (P < or = 0.01) and 2 (P < or = 0.01) was significantly greater than in the control group. No significant difference was detected between groups 1 and 2 (P = 0.58). Age, gender and opposing teeth had no significant effect on wear behaviour.

Digital enhancement of radiographs for assessment of interproximal dental caries.

OBJECTIVES: Evaluation of a particular digital caries image-enhancing mode (filter) for its effect on the validity of measurements of caries lesion depth. METHODS: Standardized radiographs of 44 extracted teeth exhibiting interproximal caries lesions were obtained. Six radiographs were obtained of each tooth and digitized. Four radiographs were made using D-speed film with and without soft tissue scattering equivalent (STSE) at normal exposure time (0.32 s) and underexposed (0.16 s). Two were made using E-speed film with STSE normally (0.16 s) and underexposed (0.08 s). On each of the 264 radiographs, 4 independent examiners measured the central depth (CD) of 1 carious lesion per tooth both on the unchanged radiographic image and after use of the filter. Histometric CD assessments provided a gold standard for comparison with the radiographic measurements (validity). Repeated measures ANOVA was calculated for validity in relation to examiner, lesion type, filter, film type, exposure time and STSE. RESULTS: The lesion type was identified to statistically significantly influence the validity of CD measurements. Examiner in combination with defect type (P<0.001), filter (P = 0.017), exposure (P = 0.027) and film type (P = 0.044) had an additional albeit small effect. CONCLUSIONS: The lesion type significantly influenced the validity of CD measurements: enamel lesions were less underestimated than dentin lesions.