Localization and function of the renal calcium-sensing receptor

The ability to monitor changes in the ionic composition of the extracellular environment is a crucial feature that has evolved in all living organisms. The cloning and characterization of the extracellular calcium-sensing receptor (CaSR) from the mammalian parathyroid gland in the early 1990s provided the first description of a cellular, ion-sensing mechanism. This finding demonstrated how cells can detect small, physiological variations in free ionized calcium (Ca 2+) in the extracellular fluid and subsequently evoke an appropriate biological response by altering the secretion of parathyroid hormone (PTH) that acts on PTH receptors expressed in target tissues, including the kidney, intestine, and bone. Aberrant Ca 2+ sensing by the parathyroid glands, as a result of altered CaSR expression or function, is associated with impaired divalent cation homeostasis. CaSR activators that mimic the effects of Ca 2+ (calcimimetics) have been designed to treat hyperparathyroidism, and CaSR antagonists (calcilytics) are in development for the treatment of hypercalciuric disorders. The kidney expresses a CaSR that might directly contribute to the regulation of many aspects of renal function in a PTH-independent manner. This Review discusses the roles of the renal CaSR and the potential impact of pharmacological modulation of the CaSR on renal function

Chemical Investigation on Various Aromatic Compounds Polymerization in Low Pressure Helium Plasma

International audienc

New metallic nanoparticles modified adhesive used for time domain optical coherence tomography evaluation of class II direct composite restoration

Non invasive investigation in class II fillings, such as optical coherence tomography (OCT), is slowly entering in the usual dental arsenal of the direct restoration analysis. Working at more than 2 mm depth inside the samples could lead to problems related to the evaluation of the adhesive layer. At this level is difficult to point out the area with adhesive or adhesive with aerie inclusions. For this reason a new metallic Nanoparticles modified dental adhesive is used in order to increase the scattering of the normal adhesive and gain a good contrast on the OCT investigation. The validation of the results were done with SEM and EDAX procedures. In conclusion, noninvasive evaluations methods like OCT, especially OCT working in Time Domain mode, have a great capability to evaluate the interfaces between dental structure, resin fillings and dental adhesive when a metallic Nanoparticles modified adhesive is used

Time domain optical coherence tomography investigation of bone matrix interface in rat femurs

The materials used to fabricate scaffolds for tissue engineering are derived from synthetic polymers, mainly from the polyester family, or from natural materials (e.g., collagen and chitosan). The mechanical properties and the structural properties of these materials can be tailored by adjusting the molecular weight, the crystalline state, and the ratio of monomers in the copolymers. Quality control and adjustment of the scaffold manufacturing process are essential to achieve high standard scaffolds. Most scaffolds are made from highly crystalline polymers, which inevitably result in their opaque appearance. Their 3-D opaque structure prevents the observation of internal uneven surface structures of the scaffolds under normal optical instruments, such as the traditional light microscope. The inability to easily monitor the inner structure of scaffolds as well as the interface with the old bone poses a major challenge for tissue engineering: it impedes the precise control and adjustment of the parameters that affect the cell growth in response to various mimicked culture conditions. The aim of this paper is to investigate the interface between the femur rat bone and the new bone that is obtained using a method of tissue engineering that is based on different artificial matrixes inserted in previously artificially induced defects. For this study, 15 rats were used in conformity with ethical procedures. In all the femurs a round defect was induced by drilling with a 1 mm spherical Co-Cr surgical drill. The matrixes used were Bioss and 4bone. These materials were inserted into the induced defects. The femurs were investigated at 1 week, 1 month, 2 month and three month after the surgical procedures. The interfaces were examined using Time Domain (TD) Optical Coherence Tomography (OCT) combined with Confocal Microscopy (CM). The optical configuration uses two single mode directional couplers with a superluminiscent diode as the source centered at 1300 nm. The scanning procedure is similar to that used in any CM, where the fast scanning is en-face (line rate) and the scanning in depth is much slower (at the frame rate). The results showed open interfaces due to the insufficient healing process, as well as closed interfaces due to a new bone formation inside the defect. The conclusion of this study is that TD-OCT can act as a valuable tool in the investigation of the interface between the old bone and the one that has been newly induced due to the osteoinductive process. © 2013 SPIE

Confocal microscopy combined with time domain optical coherence tomography and micro computer tomography in interface evaluation of class II direct composite restoration

Class II cavities are often a challenge for dentists. There are a lot of procedures that can be used in order to fill this type of cavity and also a lot of problems concerning marginal adaptation, especially when composite materials are used. The aims of this study are to evaluate the integrity and marginal adaptation of class II direct composite fillings. There were used 32 samples for orthodontic reasons. Metallographic evaluation was used as the invasive methods. Micro computer tomography, confocal microscopy and optical coherence tomography were used as noninvasive methods. The conclusions pointed out the fact that noninvasive evaluation methods have great capability to accomplish a high quality characterization of the class II direct composite restorations

Scanning electron microscopy or optical coherence tomography for the evaluation of the glass fiber reinforced acrylic resin?

Aesthetics and strength are two major criteria for dental materials today. Objective: Easy evaluation of the bond between acrylic resin and glass fbers. Materials and methods: Pre-impregnated woven E-glass fbres (Stick® Net, Stick Tech Ltd Oy) and unidirectional pre-impregnated E-glass fbres (StickTM) were used to reinforce a conventional heat-curing denture base resin (Meliodent, Heraeus Kulzer GmbH&Co.KG) - ISO 1567:1999 (E). The samples were 12 Stick reinforced, 12 Stick net reinforced (Stick tech, Finland) and 12 were un-reinforced (control). Optical coherence tomography (OCT) investigation was performed in the Department of Applied Optics, School of Physical Sciences University of Kent, UK. SEM micrographs of the fractured specimens were taken using a SEM microscope (TESLA BS 343 A) in the Department of Materials Testing - ISIM Timisoara, Romania. The samples were in vacuum gold plated. Results: The SEM images were taken at 48× 55?, 120× 55?, 240× 55?, 480× 55? magnifcations for each sample. The OCT micrographs were taken at 670 nm and 1300 nm. The penetration depth is in micron range up to 2 mm. For each sample investigated at 670 nm, 61 de slices per stuck were taken and for each sample investigated at 1300 nm, minimum 100 slices per stuck were taken. Conclusions: Both methods are useful for the bond in between acrylic resin and glass fbers evaluation. SEM is more laborious than OCT which is able to obtain many precise images in steps up to 1 ?