Epitope load identifies kidney transplant recipients at risk of allosensitization following minimization of immunosuppression

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Central Role of Subthreshold Currents in Myotonia

It is generally thought that muscle excitability is almost exclusively controlled by currents responsible for generation of action potentials. We propose that smaller ion channel currents that contribute to setting the resting potential and to subthreshold fluctuations in membrane potential can also modulate excitability in important ways. These channels open at voltages more negative than the action potential threshold and are thus termed subthreshold currents. As subthreshold currents are orders of magnitude smaller than the currents responsible for the action potential, they are hard to identify and easily overlooked. Discovery of their importance in regulation of excitability opens new avenues for improved therapy for muscle channelopathies and diseases of the neuromuscular junction. ANN NEUROL 2020;87:175–183     

From files to SAF: 3D endodontic treatment is possible at last

3D cleaning, shaping and obturation of root canals has always been the desired goal of endodontic treatment which in many cases is difficult to attain. The introduction of NiTi rotary files made a major change in endodontic practice, making treatment easier, safer and faster. Nevertheless, after 16 years of intensive development, most of these instruments still share several drawbacks, the major one being the inability to three-dimensionally clean and shape oval root canals. The Self-Adjusting File (SAF) System was designed to overcome many of the current drawbacks of rotary file systems. It is based on a hollow, highly compressible file that adapts itself three-dimensionally to the shape of a given root canal, including its cross section. The file is operated with vibratory in-and-out motion, with continuous irrigation delivered by a peristaltic pump through the hollow file. A uniform layer of dentin is removed from the whole circumference of the root canal, thus achieving the main goals of root canal treatment while preserving the remaining root dentin. The 3D scrubbing effect of the file, combined with the always fresh irrigant, result in unprecedentedly clean canals which facilitate in turn better obturation. More effective disinfection of flat-oval root canals is another goal which is simultaneously attained. The safety of the root-canal treatment is also greatly enhanced by the high mechanical stability of the SAF and by using a new concept of no-pressure irrigation. The SAF System gets the operator much closer to the long-desired goal of 3D root-canal treatment.     

Epithelial-connective tissue interaction on the tooth surface: An in vitro model

In the present study, and in vitro system was developed and designed to examine the interaction between gingival fibroblasts (GF) and epithelial cells (EC) on the tooth surface. Porcine roots were cut transversely into 300 microns-thick root slices (RS). Gingival explants were placed on the upper RS surface and cultured in a defined medium permissive for the growth of EC. After 4 or 6 days, RS yielding EC were transferred onto confluent cultures of GF and further co-cultured for either 4 or 8 d. Cultures were then fixed and examined by SEM. The upper RS surfaces and the upper half of their peripheral aspect were covered by EC. The lower half of the peripheral RS surfaces were populated by GF originating from the confluent culture of GF. EC and GF made contact at approximately the middle of the side of the root slice. In cultures of epithelial components grown in defined medium for either 4 or 6 d and harvested 4 d after assembling the system, the EC-GF junction was located 117 +/- 45 and 271 +/- 82 microns, respectively from the upper RS aspect. Extending the co-culture period did not affect the EC-GF junction location. These results indicate that GF-EC contact stops the migration of these cells on root surfaces in vitro. The described system should be valuable for studying cellular events that may affect the formation of a new dentogingival junction following surgical periodontal therapy.