Role of Protein Phosphatase 1 in Angiogenesis and Odontoblastic Differentiation of Human Dental Pulp Cells.

INTRODUCTION: The aims of this study were to examine the immunolocalization of protein phosphatase 1 (PP1) in developing mouse pulp tissue and to explore the role of PP1 in odontoblastic differentiation and in vitro angiogenesis in human dental pulp cells (HDPCs). METHODS: Immunolocalization of PP1 was assessed in developing mouse pulp tissue. Odontogenic differentiation was examined by alkaline phosphatase activity, alizarin red staining, and reverse transcriptase polymerase chain reaction. Angiogenesis was evaluated by endothelial cell migration and capillary tube formation. Signaling pathways were analyzed by Western blotting and confocal immunofluorescence. RESULTS: PP1 expression was detected in preodontoblasts, odontoblasts, dental pulp cells, and endothelial cells within pulp tissue during the crown formed, root formation, and root completion stages. PP1 messenger RNA (mRNA) and protein levels were up-regulated at the late mineralization stage during odontogenic differentiation of HDPCs. The PP1 activator C2 ceramide increased alkaline phosphatase activity, mineralized nodule formation, and mRNA expression of dentin matrix protein 1 and dentin sialophosphoprotein. In contrast, knockdown by PP1 small interfering RNA inhibited odontoblastic differentiation. Moreover, PP1 activator up-regulated mRNA expression of angiogenic genes in HDPCs and increased the migration and capillary tube formation of endothelial cells, whereas PP1 small interfering RNA showed opposite effects. C2 ceramide increased levels of bone morphogenetic protein 2, phosphorylation of Smad 1/5/8, and mRNA expression of runt-related transcription factor 2 and osterix. CONCLUSIONS: This study provides the first evidence that PP1 might be a potent regulator of developing pulp tissue in vivo and odontoblastic differentiation and angiogenesis in HDPCs in vitro and may have clinical implications for pulp/dentin regeneration or reparative dentinogenesis.

The Efficacy of a Novel Tissue Grasper-Clips Technique for Large Perforations of the Sigmoid Colon in an Experimental Animal Model (Video).

BACKGROUND: The incidence of iatrogenic colonic perforation has been gradually increasing. In particular, sigmoid colon perforations are difficult to handle because of excess mobility. AIM: The aim of this study was to evaluate the efficacy of the twin grasper-clips technique for large perforations of the sigmoid colon. METHODS: This study was designed as a prospective, randomized, experimental study using ex vivo porcine colorectal specimens. Thirty standardized and variable artificial perforations were closed in the hemoclip group (hemoclips) and twin grasper group (hemoclips with a novel tissue grasper). We counted the number of hemoclips used per case to assess the cost and efficacy of the procedure. RESULTS: In the hemoclip group (n = 15), among the 20-, 25-, and 30-mm defects, the mean number of clips (4.8 ± 0.8, 6.0 ± 1.6, and 8.4 ± 2.1, respectively, p = 0.011) and closure time (7.6 ± 0.5, 9.9 ± 3.3, and 13.9 ± 4.1 min, respectively, p = 0.020) differed significantly. In the twin grasper group (n = 15), among the 20-, 25-, and 30-mm defects, the mean number of clips (4.0 ± 1.0, 5.0 ± 0.7, and 5.4 ± 1.1, respectively, p = 0.101) and closure time (7.7 ± 0.6, 8.3 ± 1.9, and 9.1 ± 2.7 min, respectively, p = 0.506) did not differ significantly. In 30-mm defects, the mean number of hemoclips used per case and total closure time were significantly lower in the twin grasper group than the hemoclip group. CONCLUSIONS: The twin grasper-clips technique seems to reduce the use of hemoclips and to result in more effective and rapid closure than does the conventional technique in large perforations of the ex vivo porcine sigmoid colon.

Usefulness of the Forrest Classification to Predict Artificial Ulcer Rebleeding during Second-Look Endoscopy after Endoscopic Submucosal Dissection.

BACKGROUND/AIMS: Delayed post-endoscopic submucosal dissection (ESD) bleeding (DPEB) is difficult to predict and there is controversy regarding the usefulness of prophylactic hemostasis during second-look endoscopy. This study evaluated the risk factors related to DPEB, the relationship between clinical outcomes and the Forrest classification, and the results of prophylactic hemostasis during second-look endoscopy. METHODS: Second-look endoscopy was performed on the day after ESD to check for recent hemorrhage or potential bleeding and the presence of artificial ulcers in all patients. RESULTS: DPEB occurred in 42 of 581 patients (7.2%). Multivariate analysis determined that a specimen size ≥40 mm (odds ratio [OR], 3.03; p=0.003), and a high-risk Forrest classification (Forrest Ib+IIa+IIb; OR, 6.88; p<0.001) were risk factors for DPEB. DPEB was significantly more likely in patients classified with Forrest Ib (OR, 24.35; p<0.001), IIa (OR, 12.91; p<0.001), or IIb (OR, 8.31; p<0.001) ulcers compared with Forrest III ulcers. There was no statistically significant difference between the prophylactic hemostasis and non-hemostasis groups (Forrest Ib, p=0.938; IIa, p=0.438; IIb, p=0.397; IIc, p=0.773) during second-look endoscopy. CONCLUSIONS: The Forrest classification of artificial gastric ulcers during second-look endoscopy seems to be a useful tool for predicting delayed bleeding. However, routine prophylactic hemostasis during second-look endoscopy seemed to not be useful for preventing DPEB.

Effect of a sintering process on the electrical properties of SnO2 gas sensors.

SnO2 is a widely used sensor material that exhibits high sensitivity. It is known for its complex sensing characteristics, and its microstructure is an important parameter related to electrical properties and mechanical rigidity. Understanding of its microstructural effects is therefore essential to examine sensing mechanisms that may apply to industrial devices. In this work, the effect of a sintering process on the electrical properties is investigated. The sintering temperature and the relative density were chosen as process variables. The grain size of the specimen increased as the sintering temperature increased, whereas the relative density did not change. The apparent activation energy for conduction varied as the compacting pressure and the sintering conditions changed. Samples with a high density and large particle size showed low activation energy for conduction and low sensitivity at 375 degrees C. In an attempt to improve the properties, the powder was heat-treated at 1000 degrees C for 10 hours before compacting and sintering. The samples with heat-treated powder showed a slight decrease in the activation energy depending on the density and comparable sensitivity compared to non-treated powder at a high density. Pre-treatment of powder can be a simple means of thermal stability under high operating temperatures.

Spontaneous osteonecrosis of the knee involving both the medial femoral condyle and the medial tibial plateau: report of three cases.

Spontaneous osteonecrosis of the knee (SPONK) usually involves a single condyle or plateau. The medial femoral condyle (MFC) is most often involved and spontaneous osteonecrosis of the medial tibial plateau (MTP) is a rare condition, representing only 2% of all necroses reported in the knee. SPONK involving both the MFC and the MTP is extremely rare. SPONK occurring in either the MFC or the MTP individually might extend to the corresponding side of the knee in the advanced end-stage; however, in that situation, significant degenerative changes would exist and it might be difficult to differentiate end-stage SPONK form severe osteoarthritis. SPONK affecting both the MFC and the MTP without significant secondary osteoarthritic changes has not been reported, even though it is difficult to know which occurs first. We have cared for three patients with histologically proven osteonecrosis of the MFC and MTP and report their radiologic features.

Healthcare architects' professional autonomy: interview case studies.

The purpose of this project was to understand the nature of an architect's professional power. The central questions were: (1) What is the impact of specialized knowledge on the professional autonomy of architects in general? and (2) What are the relationships between task complexity, specialized knowledge, and the professional autonomy of healthcare architects in particular? To answer these questions, this research utilized interviews and focus groups. Focus groups provided in-depth knowledge on a sub-question: How do real-world situations restrict or reinforce the professional autonomy of healthcare architects? The interviews on this sub-question were project-specific to help gain an understanding of the impact that healthcare design complexity and research utilization have on practice and professional autonomy. Two main relationships were discovered from the interviews and focus groups. One was the relationship between the context of healthcare design complexity and the culture of healthcare design practice. The other was the relationship between changing professional attitudes and the consequences of changes in the profession.