A report on the clinical use of bonding systems for coronal restorations produced from CAD/CAM resin blocks.

Computer-aided design and manufacturing (CAD/CAM) resin-produced restorations were approved by a health insurance system in Japan from the year 2014. In this study, we investigated the use of CAD/CAM resin blocks in Japan since 2014, and the clinical use of adhesive systems for CAD/CAM resin-produced restorations in dentistry. Our findings indicated a rise in the clinical application of these products; however, some studies have reported instances of debonding and fracture of the restorations. CAD/CAM resin blocks were implemented in the health insurance system in Japan as an alternative for alloys due to the continuous rise in the prices of gold and palladium. Thus, in order to reduce the number of failures in CAD/CAM resin-produced restorations due to debonding and fracture, the integration of these restorations with the tooth structures is of utmost importance.

Muscle weakness and impaired motor coordination in hyperpolarization-activated cyclic nucleotide-gated potassium channel 1-deficient rats.

Hyperpolarization-activated cyclic nucleotide-gated potassium channel 1 (HCN1) contribute to spontaneous rhythmic activity in different tissues, including the heart and brain. Deficiency in HCN1 function is associated with sick sinus syndrome in mice and epilepsy in humans. We recently developed Hcn1-deficient rats and found that they exhibit absence epilepsy. While rearing Hcn1-deficient rats, we noticed loose muscle tension and abnormal gait. We therefore evaluated the muscle strength and motor functions of Hcn1-deficient rats. When subjected to the wire hang test, Hcn1-deficient rats fell down more easily than control F344 rats. Grip strength of Hcn1-deficient rats was significantly smaller than F344 rats. In the inclined plane test, they exhibited a smaller maximum angle. In the rotarod test, the latency to fall was shorter for Hcn1-deficient rats than F344 rats. In the footprint analysis, Hcn1-deficient rats exhibited smaller step length and wider step width than F344 rats. Instead of poor motor coordination ability and muscle weakness, Hcn1-deficient rats exhibited normal electromyograms, muscle histology, and deep tendon reflex. These findings suggest that HCN1 channels contribute to motor coordination and muscle strength, and that the muscle weakness of Hcn1-deficient rats results from the involvement not of the peripheral but of the central nervous system.

Concept and clinical application of the resin-coating technique for indirect restorations.

The resin-coating technique is one of the successful bonding techniques used for the indirect restorations. The dentin surfaces exposed after cavity preparation are coated with a thin film of a coating material or a dentin bonding system combined with a flowable composite resin. Resin coating can minimize pulp irritation and improve the bond strength between a resin cement and tooth structures. The technique can also be applied to endodontically treated teeth, resulting in prevention of coronal leakage of the restorations. Application of a resin coating to root surface provides the additional benefit of preventing root caries in elderly patients. Therefore, the coating materials have the potential to reinforce sound tooth ("Super Tooth" formation), leading to preservation of maximum tooth structures.

Characteristics of low polymerization shrinkage flowable resin composites in newly-developed cavity base materials for bulk filling technique.

The purpose of this study was to evaluate polymerization shrinkage and other physical properties of newly-developed cavity base materials for bulk filling technique, with the brand name BULK BASE (BBS). Polymerization shrinkage was measured according to ISO/FDIS 17304. BBS showed the significantly lowest polymerization shrinkage and significantly higher depth of cure than conventional flowable resin composites (p<0.05). The Knoop hardness, flexural strength and elastic modulus of that were significantly lower than conventional flowable resin composites (p<0.05). BBS had the significantly greatest filler content (p<0.05). SEM images of the surface showed failure of fillers. The lowest polymerization shrinkage was due to the incorporation of a new type of low shrinkage monomer, which has urethane moieties. There were no clear correlations between inorganic filler contents and polymerization shrinkage, flexural strength and elastic modulus. In conclusion, the low polymerization shrinkage of BBS will be useful for cavity treatment in dental clinics.

Microbicidal activities of low frequency atmospheric pressure plasma jets on oral pathogens.

Research using low frequency atmospheric pressure plasma jets (LF jet) is becoming increasingly more common. We carried out experiments to evaluate the sterilizing effects of this technology on oral pathogenic microorganisms (S.mutans, C.albicans and E. faecalis) and to determine its potential for clinical application. We performed the direct exposure test on a solid surface, indirect exposure test on a liquid phase, and ROS (reactive oxygen species) inhibitory test. The results showed the LF jet had microbicidal effects on oral pathogens, and that the ROS influenced this sterilization effect. The experiments of this study revealed that LF jet had a sterilizing effect on oral pathogenic microorganisms present in both the solid and liquid phases. The sterilizing mechanism was considered to be related to the effect of superoxide anion radicals. These results indicate that LF jets may represent a novel technology that can be applied to the field of clinical dentistry.

Calcitonin induces connective tissue growth factor through ERK1/2 signaling in renal tubular cells.

Calcitonin (CT), a polypeptide hormone, plays important roles in a variety of physiological processes. CT has been used clinically to treat osteoporosis and humoral hypercalcemia of malignancy. In order to clarify the pharmacological effects of CT in the kidney, we identified potential downstream genes induced by CT in the renal cells. Using a cDNA subtraction hybridization method, we identified connective tissue growth factor (CTGF) as a CT-induced gene in the porcine renal cell line, LLC-PK1. Furthermore, we found that CT-mediated induction of the gene was not inhibited by cycloheximide, which suggests that CTGF gene was not induced by an increased synthesis of regulating proteins. Therefore, CTGF is an immediate early gene. We further demonstrated that the regulation of CTGF gene expression by CT involved the ERK1/2 pathway, because PD98059, a MEK1 inhibitor, partially inhibited the mRNA expression of CTGF induced by CT. CT-induced CTGF protein expression was also observed in vivo. Our present findings suggest that CT induces the transcription of CTGF through ERK1/2 phosphorylation. We also identified twelve other genes induced by CT that, like CTGF, were related to wound healing. These results suggest that CT may have an effect on renal differentiation and wound healing in the kidney.

Microtensile bond strength of porcelain laminate veneers bonded to fluorosed teeth.

PURPOSE: The aim of this study was to evaluate the microtensile bond strengths (MTBSs) of porcelain laminate veneers bonded to normal and fluorosed teeth. MATERIALS AND METHOD: Forty human incisors, including 20 normal and 20 moderately fluorosed teeth [Thylstrup Fejerskov Index (TFI) = 4 to 6], were collected. The labial surfaces of the teeth were ground up to 1 mm and polished with #600 silicon carbide abrasive paper. The surfaces were bonded to 1-mm-thick ceramic slices (5 x 5 mm(2)) previously made (VitaVM7) using one of two ceramic cement systems (RelyX or Clapearl) following the manufacturers' instructions. A resin composite was added on top of the ceramic slices and built up to 5-mm thickness to serve as grips. The specimens were stored in water (37 degrees C) for 24 hours, and beams of adhesive interface with a surface area of approximately 1.25 mm(2) were obtained. Then the beams were subjected to MTBS tests at a crosshead speed of 1.0 mm/min. The data were analyzed with two-way ANOVA. RESULTS: The results of the MTBS test (MPa) were 20.55 +/- 5.83 (RelyX/fluorosed), 20.16 +/- 4.61 (RelyX/normal), 18.74 +/- 2.88 (Clapearl/fluorosed), and 21.06 +/- 4.99 (Clapearl/normal). There were no significant differences in the MTBSs among the four groups (p > 0.05). CONCLUSIONS: The MTBSs of ceramic cement systems used were not influenced by the moderately fluorosed teeth.

Influence of cyclic loading on fiber post and composite resin core.

From a selection of four kinds of post and core systems, including a fiber post and composite resin core, the purpose of this study was to determine the most effective system for the restoration of endodontically treated teeth with 0 mm of coronal tooth structure. For experimental abutment teeth, typical human maxillary central incisor teeth were modeled using bovine mandibular incisor teeth. By means of a static loading test, the four restoration systems were evaluated and compared in terms of failure load and failure mode. Further, by means of a cyclic loading test, these systems were assessed in terms of durability. For fiber post and composite resin core, it excelled from the standpoints of failure load and failure mode, and fared favorably too in durability after cyclic loading test. For composite resin post-and-core, it also showed excellent results for both failure load and failure mode in static loading test, but durability significantly decreased with cyclic loading. Taken together, the fiber post and composite resin core was found to be most effective from the standpoints of failure load, failure mode, and durability.

Phylogeography of wild musk shrew (Suncus murinus) populations in Asia based on blood protein/enzyme variation.

The musk shrew (Suncus murinus) is an insectivore species that inhabits tropical and subtropical Asia widely. To clarify the genetic relationship among wild musk shrew populations, we examined the electrophoretic variants of biparentally inherited genetic markers at 10 loci coding for eight blood proteins/enzymes in a total of 639 animals and compared the results obtained from the mitochondrial DNA data. The principal-component analysis performed using the allele frequency data revealed that the 17 populations could be divided into two major groups, a South Asian group and a Southeast Asian group that includes several island populations bound by Myanmar. The degrees of genetic divergence among populations were higher within the Southeast Asian group than within the South Asian group. This finding was incongruent with the mtDNA diversity. Analysis conducted at the individual level showed that a shrew from the central region in Myanmar that carries a South Asian type of mtDNA showed the electrophoretic variants specific to the Southeast Asian group, suggesting that this region is a contact zone between the two major groups.

Deletion of the kinase domain from death-associated protein kinase enhances spatial memory in mice.

Death-associated protein kinase (DAPK) is a Ca2+/calmodulin-dependent serine/threonine kinase that is thought to mediate apoptosis. DAPK is highly expressed in hippocampal neurons which are essential elements for memory formation. To examine if DAPK is implicated in spatial learning and memory, both wild-type and DAPK-mutant mice were subjected to Morris water maze tests. DAPK-mutant mice were generated by deleting 74 amino acids from the catalytic kinase domain of DAPK, and were used to investigate roles of the DAPK kinase domain in regulating spatial memory. Both mutant and wild-type mice were able to learn the water maze tasks to locate a hidden escape platform. In the first probe test, mutant mice showed a more precise memory for platform position compared to wild-type mice. In the reversal training in which the platform was located opposite from the original position, DAPK-mutant mice exhibited superior spatial learning compared to wild-type mice. DAPK-mutant mice also showed a more precise memory than their wild-type littermates in the probe trial of reversal test. Thus, the present results revealed crucial implications of DAPK in regulating spatial memory in mice.

Reduced prepulse inhibition of startle in STAT6-deficient mice.

To determine the role of STAT6 transcription factors in brain function, we performed a battery of mouse behavioral analyses of STAT6-deficient mice. We recently showed that STAT6-deficient mice displayed increased locomotor activities and had reduced levels of dopamine transporter (DAT) expression in the striatum. To further examine the behavioral effects of STAT6 deficiency, we subjected STAT6-deficient mice to behavior task testing prepulse inhibition (PPI) of the auditory startle response. In acoustic prepulse conditions, STAT6-deficient mice displayed significantly lower levels of PPI in acoustic startle than did wild-type mice, indicating their sensorimotor gating deficits. Thus, STAT6 transcription factors may be crucially implicated in sensorimotor gating by modulating the expression of several genes, including DAT in brain neurons.

Deletion of the kinase domain from death-associated protein kinase attenuates p53 expression in chronic obstructive uropathy.

Death-associated protein kinase (DAPK) is a Ca(2+)/calmodulin-dependent serine/threonine kinase that is thought to mediate apoptosis. We previously showed that the kinase domain of DAPK is crucial for the induction of renal tubular cell apoptosis in chronic obstructive uropathy (COU) caused by a unilateral ureteral ligation. Here, we used DAPK-mutant mice, generated by the deletion of 74 amino acids from the catalytic kinase domain, to investigate the role of the DAPK kinase domain in regulating the p53 level following COU. The p53 expression levels in obstructed kidneys of wild-type and mutant mice were determined during the course of COU. Western blot analysis revealed that the p53 protein levels were significantly increased at 5 days after a ureteral ligation. This increase in the p53 level was significantly attenuated in mutant kidneys compared to wild-type kidneys. The obstructed kidneys of DAPK-mutant mice showed a significantly lower number of p53-expressing renal tubule cells than wild-type mice. These results are consistent with the hypothesis that DAPK stabilizes p53 protein in response to apoptosis-inducing stimuli. Thus, the present results suggest that the DAPK kinase domain is crucial for stabilizing p53 protein in renal tubular cell apoptosis in a mouse model of COU.

Semaphorin 4A induces growth cone collapse of hippocampal neurons in a Rho/Rho-kinase-dependent manner.

Semaphorins are a family of secreted and membrane-bound proteins, known to control axonal pathfinding. It was recently demonstrated that Semaphorin 4A (Sema4A) is crucially involved in immune cell activation. However, the role of Sema4A in the nervous system has not yet been clarified. To examine if Sema4A can function as a chemo-repulsive cue to growth cones of developing hippocampal neurons, a growth cone collapse assay with recombinant Sema4A was performed in primary hippocampal neurons cultured from E17 mice. In these primary hippocampal neurons, Sema4A induced a significant growth cone collapse as compared with the culture without Sema4A. The Sema4A-induced growth cone collapse could be blocked by Y-27632, a Rho-kinase inhibitor. Furthermore, immunocytochemical analysis with antibodies against Sema4A demonstrated the binding of recombinant Sema4A to the growth cones of hippocampal neurons. Thus, our data indicated that Sema4A could function as a chemo-repulsive cue by activating a receptor whose signal is transmitted to Rho-kinase and induced growth cone collapse of hippocampal neurons.

Down-regulation of dopamine transporter and abnormal behavior in STAT6-deficient mice.

To determine the role of STAT6 transcription factors in brain function, we performed a battery of mouse behavioral analyses of STAT6-deficient mice and made comparisons with wild-type mice. STAT6-deficient mice were significantly more hyperactive in the final two blocks of an open field test, indicating abnormal habituation in completing the task. Two learning tasks, a water maze and a passive avoidance test, were mastered by STAT6-deficient mice as effectively as the wild-type. RT-PCR analysis suggested that the levels of dopamine transporter (DAT) mRNA may be lower in the midbrain of the mutant. In agreement with the finding, subsequent Western blotting and immunohistochemical analysis demonstrated lower levels of DAT protein in the mutant striatum. These results lead to the proposal that, in addition to being a pivotal transcription factor in the immune system, STAT6 may be crucially implicated in mouse behavior by modulating the expression of neuronal genes such as DAT.

Direct in vivo protein transduction into a specific restricted brain area in rats.

Attempts at protein transduction into specific restricted brain areas have remained unsuccessful. We attempted targeted, direct in vivo protein transduction by microinjecting beta-galactosidase (beta-gal) with hemagglutinating virus of Japan envelope (HVJ-E) vector into the rat nucleus tractus solitarius (NTS). The medulla oblongata including the NTS was removed 6h post-injection and cryostat sections were histochemically stained to detect beta-gal enzymatic activity. beta-gal-positive cells were present in these sections as was beta-gal activity determined by colorimetric analysis. beta-gal-positive cells were not present in the rats microinjected only beta-gal protein without HVJ-E vector. Our findings suggest that direct in vivo protein transduction into specific restricted brain areas is possible. The type of targeted delivery system we present may have wide applications in the administration of therapeutic proteins to the central nervous system.

Hypotensive effect of des-acyl ghrelin at nucleus tractus solitarii of rat.

Ghrelin is a gut-brain peptide and its endocrine activities are mediated by GH secretagogue receptor (GHSR)-1a. Des-acyl ghrelin does not activate GHSR-1a and is devoid of endocrine activities. While the microinjection of ghrelin into rat nucleus tractus solitarii (NTS) elicited hypotensive effects, this was not the case upon injection into GHSR-expressing rostral ventrolateral medulla or caudal ventrolateral medulla. To make clear the reason of the discrepancy between receptor distribution and neuronal responses, we examined the cardiovascular response of rats microinjected with des-acyl ghrelin into NTS. Intra-NTS injection of des-acyl ghrelin significantly reduced mean arterial pressure and heart rate. The hypotensive and bradycardic activity evoked by des-acyl ghrelin was not significantly different from that of native ghrelin. These results suggest that des-acyl ghrelin contribute to the regulation of cardiovascular control and that a receptor other than GHSR-1a exists in NTS.

STAT6 deficiency inhibits tubulointerstitial fibrosis in obstructive nephropathy.

To elucidate the contribution of signal transducer and activator of transcription (STAT) 6 to the pathophysiology of chronic renal injury, STAT6-/- mice were subjected to unilateral ureteral ligation together with wild-type control mice. STAT6-/- kidneys had more apoptotic cells and a greater influx of F4/80-positive cells than wild-type kidneys following ureteral obstruction. There was a much larger alpha-smooth muscle actin-positive area in STAT6-/- kidneys than in wild-type kidneys after ureteral ligation. However, renal fibrosis, as quantified by Masson-Trichrome staining, was not significantly exaggerated in STAT6-/- kidneys compared with wild-type kidneys. The accumulation of collagen I was significantly less in STAT6-/- kidneys than in wild-type kidneys. These observations indicate that the STAT6 signal transduction pathway exerts a protective role on renal cell apoptosis in chronic obstructive uropathy. Our findings also suggest that the STAT6 pathway may have a promotive effect on renal fibrosis by activating collagen synthesis following ureteral obstruction.

The kinase domain of death-associated protein kinase is inhibitory for tubulointerstitial fibrosis in chronic obstructive nephropathy.

Death-associated protein kinase (DAPK) is a Ca2+/calmodulin-dependent serine/threonine kinase that is thought to mediate apoptosis. We have shown that the kinase domain of DAPK is crucial for the induction of renal tubular cell apoptosis in chronic obstructive uropathy (COU) created by unilateral ureteral ligation. DAPK-mutant mice, generated by deletion of 74 amino acids from the catalytic kinase domain, were used to investigate the role of the DAPK kinase domain in renal fibrosis following COU. Interstitial collagen and alpha-smooth muscle actin (alpha-SMA) expressions in situ were compared between obstructed kidneys in wild-type and mutant mice. As a result, tubulointerstitial fibrosis, as quantified by interstitial collagen expression, was significantly augmented in mutant kidneys compared with wild-type kidneys following COU. Furthermore, deletion of the kinase domain from DAPK significantly increased the appearance of alpha-SMA-positive myofibroblasts in the renal interstitium during COU. Thus, our results suggest that the kinase domain deleted by gene targeting plays a suppressive role for the development of renal fibrosis through inhibition of the tubular epithelial-to-mesenchymal transition in a mouse model of COU.

Deletion of the kinase domain in death-associated protein kinase attenuates tubular cell apoptosis in renal ischemia-reperfusion injury.

Death-associated protein kinase (DAPK) is a calcium/calmodulin-dependent serine/threonine kinase localized to renal tubular epithelial cells. To elucidate the contribution of DAPK activity to apoptosis in renal ischemia-reperfusion (IR) injury, wild-type (WT) mice and DAPK-mutant mice, which express a DAPK deletion mutant that lacks a portion of the kinase domain, were subjected to renal pedicle clamping and reperfusion. After IR, DAPK activity was elevated in WT kidneys but not in mutant kidneys (1785.7 +/- 54.1 pmol/min/mg versus 160.7 +/- 60.6 pmol/min/mg). Furthermore, there were more TUNEL-positive nuclei and activated caspase 3-positive cells in WT kidneys than in mutant kidneys after IR (24.0 +/- 5.9 nuclei or 9.4 +/- 0.6 cells per high-power field [HPF] versus 6.3 +/- 2.2 nuclei or 4.4 +/- 0.7 cells/HPF at 40 h after ischemia). In addition, the increase in p53-positive tubule cells after IR was greater in WT kidney than in mutant kidneys (9.9 +/- 1.4 cells/HPF versus 0.8 +/- 0.4 cells/HPF), which is consistent with the theory that DAPK activity stabilizes p53 protein. Finally, serum creatinine levels after IR were higher in WT mice than in mutant mice (2.54 +/- 0.34 mg/dl versus 0.87 +/- 0.24 mg/dl at 40 h after ischemia). Thus, these results indicate that deletion of the kinase domain from DAPK molecule can attenuate tubular cell apoptosis and renal dysfunction after IR injury.

Death-associated protein kinase localization to human renal tubule cells, and increased expression of chronic obstructive uropathy in rats.

BACKGROUND: Death-associated protein kinase (DAP kinase) is a Ca2+/calmodulin-dependent serine/threonine kinase implicated as a positive apoptosis mediator. However, little is known about DAP kinase involvement with apoptosis in renal diseases. METHODS: In order to determine whether DAP kinase has a role in renal cell apoptosis in kidney diseases, we performed an immunohistochemical study using a monoclonal antibody to DAP kinase. Firstly, by examining the cellular distribution of DAP kinase in normal human renal tissues and cultured proximal tubule cells. We then used western blotting and immunohistochemical analysis to examine directly whether DAP kinase protein levels could be modulated in rat kidneys with chronic obstructive uropathy created by unilateral ureteric ligation. RESULTS: Immunohistochemistry of normal human kidney tissues showed that DAP kinase was exclusively localized in the cytoplasm of renal tubule cells. Expression analysis of DAP kinase using cultured cells confirmed DAP kinase mRNA and protein presence in human renal tubule cells. Immunocytochemical analysis directly visualized DAP kinase in the cytoplasm of the renal tubule cells in culture. Finally, DAP kinase was found up-regulated in renal tubule cells of rat kidneys with chronic obstructive uropathy. CONCLUSIONS: Our study demonstrates that DAP kinase is localized to renal tubule cells, implying a crucial role for DAP kinase in renal tubular cell apoptosis in progressive renal diseases.