Costameres,dense plaques and podosomes: the cell matrix adhesions in cardiovascular mechanosensing

Journal of Muscle Research and Cell Motility - The stiffness of the cardiovascular environment changes during ageing and in disease and contributes to disease incidence and progression. For...     

Root canal systems in mandibular first premolars with C-shaped root configurations. Part I: Microcomputed tomography mapping of the radicular groove and associated root canal cross-sections

The purpose of this study was to investigate the morphology of the radicular grooves and root canal cross-sections in mandibular first premolars that exhibit a C-shaped root. Eighty-six mandibular first premolars with C-shaped roots were scanned from the coronal to anatomical apex using microCT80. The location, length, and depth of the radicular grooves were measured. The cross-sectional morphology of root canal systems was evaluated at 11 levels. Results were subject to the Kruskal-Wallis test. Of the 86 C-shaped roots, a total of 93 radicular grooves were noted. Most of the grooves (78.5%) were located on the mesiolingual surface of the root. The C-shaped canal could vary considerably in shape at different levels, and the incidence of two canals at the middle and apical was 21% and 80%, respectively. This study shows that radicular grooves may present relevant morphologic variations in the root canal system when the C-shaped root is present.     

Biodegradable porous calcium polyphosphate scaffolds for the three-dimensional culture of dental pulp cells

AIM: To develop a three-dimensional culture model of human dental pulp cells (DPCs) with biodegradable porous calcium polyphosphate (CPP) scaffolds. METHODOLOGY: Human DPCs were isolated from three donors. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate the cytotoxicity of CPP compared with hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP). Values were analysed using unpaired t-tests. Cells were seeded onto porous CPP scaffolds with pore sizes in the range of 200-300 microm. The nature of cellular adaptation in the three-dimensional culture model was then evaluated visually by scanning electronic microscopy (SEM) and confocal laser scanning microscopy (CLSM). The apoptotic property of cells on the scaffolds was also assessed by DNA staining with CLSM. RESULTS: The cytotoxicity assay indicated that there was no significant difference between CPP and HA for each donor's original cells (P>0.05). Calcium polyphosphate had no cytotoxic effect on DPCs, whilst SEMs showed that cells successfully adhered to CPP scaffolds and spread amongst pores. On the cell surface, fine processes and matrix secretory granules were found. Confocal laser scanning microscopy showed that cells took on a three-dimensional structure with signs of vitality. CONCLUSION: Porous CPP scaffolds are promising for the establishment of a three-dimensional culture model of DPCs.     

Identification of a C-shaped canal system in mandibular second molars-part II: the effect of bone image superimposition and intraradicular contrast medium on radiograph interpretation

The purpose of this study was to investigate the effect of image superimposition from surrounding alveolar bone and intraradicular contrast medium on radiographic interpretation of a C-shaped canal system in mandibular second molars. Thirty mandibular second molars with fused roots were collected and stored in 10% formalin solution. After being scanned by microcomputed tomography and reconstructed, the buccal-lingual radiographs of each tooth were taken with or without intraradicular contrast medium and mandibular bony plates. The number of mesial and distal canals in the coronal-to-middle canal portion and the canal number in the apical 4-mm area were recorded. The buccal-lingual and three-dimensional view of reconstructed canal images were used to evaluate the accuracy of radiograph reading. The results were subjected to the Friedman and chi-square test. The results showed that without intraradicular contrast medium, the bone superimposition could decrease the accuracy of canal recognition significantly (p < 0.001), especially in the apical area. When contrast medium was in canals, the canal reading seemed not to be affected by the bone superimposition (p > 0.05). Based on these findings, the intraradicular contrast medium could increase the accuracy of canal recognition of a C-shaped canal system in mandibular second molars despite the bone image superimposition, especially in the detection of continuous C-shaped canals and the canals in the apical area.     

Microleakage of Diaket and amalgam in root-end cavities prepared using MicroMega sonic retro-prep tips

The in vitro sealing ability of the root-canal sealer Diaket when used as a root-end filling material was compared with that of amalgam using linear microleakage of Indian ink. Eight groups of 20 extracted teeth each were formed, plus 12 control teeth as follows: 1) root-end resection of 45° bevel, root-end cavity preparation with an 008 round bur, amalgam root-end filling; 2) 45° bevel, bur, Diaket; 3) 45° bevel, using a sonic retro-prep tip, amalgam; 4) 45° bevel, sonic, Diaket; 5) no bevel, bur, amalgam; 6) no bevel, bur, Diaket; 7) no bevel, sonic, amalgam; 8) no bevel, sonic, Diaket. Root-end cavity depths of 3 mm were prepared. Specimens were immersed in Indian ink for 2 weeks. The teeth were demineralized, rendered transparent and linear dye penetration recorded. Results showed that Diaket provided a superior seal to amalgam irrespective of the root-end preparation. The degree of bevel of the resected root-end did not influence leakage. Sonic instrumentation resulted in a larger root-end cavity than with burs.     

Prevalence, location, and patency of accessory canals in the furcation region of permanent molars.

One hundred and two extracted permanent molars were debrided in 3% H2O2, sealed at the apex, and placed in a vacuum chamber. Safranin dye was introduced into the teeth that were placed in a vacuum of 525 mm of Hg. Observations were made of the external root surface to determine any staining due to patent accessory canals. Accessory canals were demonstrated in the "furcation region" in 28.4% of the total sample; 29.4% in mandibular molars, and 27.4% in maxillary molars. Of the total sample 25.5% exhibited canals in the "furcation" only, while 10.2% exhibited canals on the lateral root surface. Communication between the pulp chamber and the external surface was noted via dentinal tubules, especially when the cementum was denuded. The salient biologic and pathologic ramification of these aberrant canals were discussed along with the need to establish a differential diagnosis in order to determine the proper sequence of treatment should pulpal-periodontal disease exist.     

Mechanism of resistance to vancomycin in Enterococcus faecium D366 and Enterococcus faecalis A256.

The role of the glycopeptide-inducible proteins of Enterococcus faecium D366 (39.5 kilodaltons) and Enterococcus faecalis A256 (39 kilodaltons) in the mechanism of resistance to vancomycin and teicoplanin was examined. Crude cell walls from noninduced cells or from induced cells treated with sodium dodecyl sulfate to remove the inducible proteins were shown to bind vancomycin, in contrast to cell walls containing the cytoplasmic membrane-associated induced proteins, which did not bind vancomycin. Cytoplasmic membranes from vancomycin-induced cells did not inactivate (bind) vancomycin or teicoplanin, but they could protect the glycopeptides from being bound to the synthetic pentapeptide. This protection could be competitively abolished by D-alanyl-D-alanine. A decrease in glycopeptide binding to the pentapeptide was observed in a time-dependent fashion after treatment of the pentapeptide with the cytoplasmic membranes from induced cells. We hypothesize that the inducible proteins are responsible for glycopeptide resistance due to the binding to, and subsequent enzymatic modification of, the pentapeptide precursor of peptidoglycan, which is considered to be the natural target of glycopeptides.     

Frühmobilisation auf der Intensivstation – Sind robotergestützte Systeme die Zukunft?

Die Anaesthesiologie - Bei etwa 43?% aller Überlebenden der Intensivmedizin wird ein erworbenes Syndrom an Muskelschwäche beobachtet, welches Überleben und Lebensqualität...