Human Digital Meissner Corpuscles Display Immunoreactivity for the Multifunctional Ion Channels Trpc6 and Trpv4.

Ion channels are at the basis of the sensory processes including mechanosensing. Some members of the transient receptor potential (TRP) ion channel superfamily have been proposed as mechanosensors, but their putative role in mechanotransduction is controversial. Among them there are TRP canonical 6 (TRPC6) and TRP vanilloid 4 (TRPV4) ion channels, which are known to cooperate in mechanical hyperalgesia. Here, we investigated the occurrence, distribution, and possible colocalization of TRPC6 and TRPV4 in human digital Meissner sensory corpuscles using immunohistochemistry and double immunofluorescence (associate with markers for specific corpuscular constituents). TRPC6 immunoreactivity was restricted to the axon of Meissner corpuscles, whereas TRPV4 was detected in the axon but also in the lamellar cells. Moreover, axonal colocalization of TRPV4 and TRPC6 was found in the digital Meissner corpuscles. Present results demonstrate for the first time the occurrence and colocalization of two ion channels candidates to mechanosensors in human cutaneous mechanoreceptors. The functional significance of these ion channels in that place remains to be clarified, but should be related to different properties of mechanosensitivity. Anat Rec, 300:1022-1031, 2017. © 2016 Wiley Periodicals, Inc.

Pacinian Corpuscles in a Cervical Chondrocutaneous Remnant: A Case Report and Update of Pacinian Corpuscles.

Cervical chondrocutaneous remnants are congenital, benign, and rare neck masses. We present here for the first time the immunohistochemical profile of Pacinian corpuscles present in cervical chondrocutaneous remnants, removed, and localized in the territory of the second branchial arch from a 5-year-old girl. We have performed immunohistochemistry to analyze these sensory corpuscles using a battery of antibodies including markers for each corpuscle constituent. The central axon was immunoreactive for neurofilaments, neuron-specific enolase, and neural cell adhesion molecule; the Schwann-related cells forming the inner core displayed immunoreactivity for S100 protein, vimentin, and neural cell adhesion molecule; the outer core and the capsule were positive for vimentin, epithelial membrane antigen, and glucose transporter 1. These results are discussed in topographical differences. Moreover, a brief update about the structure, protein composition, and development of Pacinian corpuscles was performed.

A comparison of two soldering techniques on the misfit of bar-retained implant-supported overdentures.

PURPOSE: This study was conducted to measure and compare the effect of the soldering method (torch soldering or ceramic furnace soldering) used for soldering bars to bar-retained, implant-supported overdentures on the fit between the bar gold cylinder and implant transgingival abutment. MATERIALS AND METHODS: Thirty-two overdenture implant bars were manufactured and screw retained into two Bränemark implants, which were attached to a cow rib. The bars were randomly distributed in two groups: a torch-soldering group and a porcelain-furnace soldering group. Then all bars were cut and soldered using a torch and a ceramic furnace. The fit between the bar gold cylinders and implant transgingival abutments was measured with a light microscope on the opposite side to the screw tightening side before and after the bar soldering procedure. The data obtained were statistically processed for paired and independent data. RESULTS: The average misfit for all bars before soldering was 33.83 to 54.04 µm. After cutting and soldering the bars, the misfit increased up to a range of 71.74 to 78.79 µm. Both before and after the soldering procedure, the bars soldered using a torch showed a higher misfit when compared to the bars soldered using a porcelain furnace. After the soldering procedure, the misfit was slightly lower on the left side of the bars, which had been soldered using a ceramic furnace. CONCLUSIONS: According to our data, the soldering of bars using the torch or furnace oven soldering techniques does not improve the misfit of one-piece cast bars on two implants. The lower misfit was obtained using the porcelain furnace soldering technique.

Stress distribution in the abutment and retention screw of a single implant supporting a prosthesis with platform switching.

PURPOSE: Three-dimensional finite element analysis was conducted to evaluate and compare the stress distribution in the abutment and retention screw of implant-supported single crowns with platform switching and with a conventional platform under vertical and oblique loading. MATERIALS AND METHODS: Two finite element models were created simulating an osseointegrated implant (4 × 10 mm, platform 4.1 mm) embedded in jawbone. One model simulated a 4-mm-diameter abutment connection (conventional model) and the other represented a 3.8-mm-diameter abutment connection (platform-switched model). A crown with a cobalt-chromium framework and feldspathic porcelain veneering was applied to the titanium abutment. Static vertical and oblique loads were applied to the crown, with a maximum load of 150 N. RESULTS: In both models, the highest stress values occurred in the abutment during vertical and oblique loading. Nevertheless, the von Mises stresses in the abutment and the retention screw were lower in the platform-switched model than in the conventional model. During axial loading, the abutment and screw supported slightly less stress in the conventional model than in the platform-switched model. Increases in the angle of force application caused a progressive increase in stresses in the abutment and screw in both models. The maximum stress was distributed at the margin and transgingival area of the abutment and on two-thirds of the flat area and the first threads of the retention screw in both models. CONCLUSIONS: Platform switching reduced the stress values on the abutment and retention screw of a single-unit prosthesis during oblique loading. Regardless of whether platform switching was employed, the stress on the abutment and screw gradually increased as the loading direction changed from vertical to 45 degrees oblique. The locations and distributions of stresses were similar in both models.