Comparison of fracture resistance of endodontically treated teeth restored with different aesthetic post and core systems under all ceramic restoration luted with two types of cements.

Context: Fracture of endodontically treated teeth is a grave sequela that a clinician should seriously ponder. Suitable selection of restorative materials is a requisite for long-term clinical success. Aims: To compare the fracture resistance of endodontically treated teeth restored with three different posts luted using two different cements under all ceramic crowns. Settings and Design: This in vitro study was conducted in the Department of Prosthodontics, Government Dental College, Kottayam, Kerala, India. Methods and Material: Thirty endodontically treated single-rooted mandibular premolars in which post spaces were prepared and divided into three different groups. Group 1 (n = 10): zirconia post group. Group 2 (n = 10): quartz fibre post group. Group 3 (n = 10): glass fibre post group. Each group is sub-divided into two based on the luting system: resin-modified glass ionomer cement (RMGIC) or dual-cure resin cement (DCRC). The fracture resistance testing was performed in a universal testing machine with a crosshead speed of 0.5 mm/min. Statistical Analysis Used: The mean fracture resistance were analysed using independent sample Student t-test and one-way ANOVA. Results: : Within the zirconia post group, the mean fracture resistance was higher in DCRC sub-group compared to the RMGIC sub-group and the difference was statistically significant (p = 0.017). The difference in fracture resistance between three different post systems was not found to be statistically significant with respect to both the luting systems. Conclusions: It was observed that when zirconia post is used, the mean fracture resistance was higher in dual-cure resin group compared to the resin-modified GIC group.

Nanomedicine in the Diagnosis and Treatment of Atherosclerosis-A Systematic Review.

BACKGROUND: Atherosclerosis is a chronic inflammatory condition causing very high morbidity and mortality. It is characterized by accumulation of plaques within arteries. Nanomedicine is an emerging field of medicine utilizing nanotechnology for advanced imaging and therapy. Nanomedicine has led to significant developments in the field of cardiovascular diseases, including atherosclerosis. Many nanoformulations have been developed with anti-atherosclerotic effects. Nanomedicine tools have been used in the imaging of atherosclerosis. Various nanocarriers have been employed for successful localization in atherosclerotic lesions. The biggest challenge for such delivery vehicles has been localization to atherosclerosis lesions. Several strategies have been employed to overcome these defects. Strategies have also been developed for stabilization of atherosclerotic lesions. CONCLUSION: Nanotechnology is also an important tool for the development of novel biomarkers. At the same time there are also potential limitations. Toxicity, lack of translation from preclinical phase to clinical development, and the inability to address the chronic phase of atherosclerosis are the most important among them. Future toxicity studies shall enlighten us further on this exciting research area.

Attitude of bachelor of dental surgery students and interns toward teaching-learning process in Government Dental College, Kottayam, Kerala, India.

INTRODUCTION: The educational environment affects the academic performance of students. One of the most widely utilized tools for measuring the educational environment is Dundee Ready Education Environment Measure (DREEM). The objective of the study was to assess the attitude toward study environment, as measured using DREEM questionnaire, and to find out the differences in perception of various batches of dental students. MATERIALS AND METHODS: All Bachelor of Dental Surgery students from Government Dental College, Kottayam, Kerala, India, were included in the study. They were given the well-established DREEM questionnaire. A total of 234 students took part in the study, belonging to 2009, 2010, 2011, 2012, 2013, and 2014 batches. DREEM subcategories were analyzed for significance using analysis of variance. The significance of DREEM score across the different batches was further analyzed using post hoc test. RESULTS: Overall, DREEM score was positive (111.14), but there is need for improvement. Individual questions also were given positive score for most questions. The maximum score was obtained for 3rd year students. Similar results are obtained for three of the five subcategories of DREEM. CONCLUSION: The total DREEM score was positive (111.14). The total score as well as the scores for the subcategories was highest in 3rd year dental students. The increase might be due to the excitement of clinical exposure for the first time in 3rd year students.

Probing structural selectivity of synthetic heparin binding to Stabilin protein receptors.

As one of the most widely used drugs worldwide, heparin is an essential anticoagulant required for surgery, dialysis, treatment of thrombosis, cancer, and general circulatory management. Stabilin-2 is a scavenger clearance receptor with high expression in the sinusoidal endothelium of liver. It is believed that Stabilin-2 is the primary receptor for the clearance of unfractionated and low molecular weight heparins in the liver. Here, we identify the modifications and length of the heparin polymer that are required for binding and endocytosis by both human Stabilin receptors: Stabilin-2 and its homolog Stabilin-1 (also found in liver endothelium). Using enzymatically synthesized (35)S-labeled heparan sulfate oligomers, we identified that sulfation of the 3-OH position of N-sulfated glucosamine (GlcNS) is the most beneficial modification for binding and endocytosis via both Stabilin receptors. In addition, our data suggest that a decasaccharide is the minimal size for binding to the Stabilin receptors. These findings define the physical parameters of the heparin structure required for efficient clearance from blood circulation. These results will also aid in the design of synthetic heparins with desired clearance rates.

In vivo liver endocytosis followed by purification of liver cells by liver perfusion.

The liver is the metabolic center of the mammalian body and serves as a filter for the blood. The basic architecture of the liver is illustrated in figure 1 in which more than 85% of the liver mass is composed of hepatocytes and the remaining 15% of the cellular mass is composed of Kupffer cells (KCs), stellate cells (HSCs), and sinusoidal endothelial cells (SECs). SECs form the blood vessel walls within the liver and contain specialized morphology called fenestrae within in the cytoplasm. Fenestration of the cytoplasm is the appearance of holes (˜100 µm) within the cells so that the SECs act as a sieve in which most chylomicrons, chylomicron remnants and macromolecules, but not cells, pass through to the hepatocytes and HSCs (1) (Fig. 1). Due to the lack of a basement membrane, the gap between the SECs and hepatocytes form the Space of Disse. HSCs occupy this space and play a prominent role in regulation and response to injury, storage of retinoic acid and immunoregulation of the liver (2). SECs are among the most endocytically active cells of the body displaying an array of scavenger receptors on their cell surface (3). These include SR-A, Stabilin-1 and Stabilin-2. Generally, small colloidal particles less than 230 nm and macromolecules in buffer phase are taken up by SECs, whereas, large particles and cellular debris is endocytosed (phagocytosed) by KCs (4). Thus, the bulk clearance of extracellular material such as the glycosaminoglycans from blood is largely dependent on the health and endocytic functions of SECs (5,6). For example, an increase in blood hyaluronan levels is indicative of liver disease ranging from mild to more severe forms (7). With the exception of one report (8), there are no immortalized SEC cell lines in existence. Even this immortalized cell line is de-differentiated in that it does not express scavenger receptors that are present on primary SECs (our data, not shown). All cell biological studies must be performed on primary cells obtained freshly from the animal. Unfortunately, SECs dedifferentiate under standard culture conditions and must be used within 1 or 2 days upon isolation from the animal. Differentiation of SECs is marked by the expression of Stabilin-2 or HARE receptor (9) , CD31, and the presence of cytoplasmic fenestration (1). Differentiation of SECs can be extended by the addition of VEGF in culture media or by culturing cells in hepatocyte conditioned medium (10,11). In this report, we will demonstrate the endocytic activity of SECs in the intact organ using radio-labeled heparin for hyaluronan for the SEC-specific Stabilin-2 receptor. We will then purify hepatocytes and SECs from the perfused liver to measure endocytosis.

Air-liquid interfaces of aqueous solutions containing ammonium and sulfate: spectroscopic and molecular dynamics studies.

Investigations of the air-liquid interface of aqueous salt solutions containing ammonium (NH(4)(+)) and sulfate (SO(4)(2-)) ions were carried out using molecular dynamics simulations and vibrational sum frequency generation spectroscopy. The molecular dynamics simulations show that the predominant effect of SO(4)(2-) ions, which are strongly repelled from the surface, is to increase the thickness of the interfacial region. The vibrational spectra reported are in the O-H stretching region of liquid water. Isotropic Raman and ATR-FTIR (attenuated total reflection Fourier transform infrared) spectroscopies were used to study the effect of ammonium and sulfate ions on the bulk structure of water, whereas surface sum frequency generation spectroscopy was used to study the effect of these ions on the interfacial structure of water. Analysis of the interfacial and bulk vibrational spectra reveal that aqueous solutions containing SO(4)(2-) perturb the interfacial water structure differently than the bulk and, consistent with the molecular dynamics simulations, reveal an increase in the thickness of the interfacial region.

Dispersed fluorescence spectroscopy of primary and secondary alkoxy radicals.

Dispersed fluorescence (DF) spectra of 1-propoxy, 1-butoxy, 2-propoxy, and 2-butoxy radicals have been observed under supersonic jet cooling conditions by pumping different vibronic bands of the B-X laser induced fluorescence excitation spectrum. The DF spectra were recorded for both conformers of 1-propoxy, three conformers of the possible five of 1-butoxy, the one possible conformer of 2-propoxy, and two conformers of the possible three of 2-butoxy. Analysis of the spectra yields the energy separations of the vibrationless levels of the ground X and low-lying A electronic state as well as their vibrational frequencies. In all cases, the vibrational structure of the DF spectra is dominated by a CO stretch progression yielding the nuCO stretching frequency for the X state and in most cases for the A state. In addition to the experimental work, quantum chemical calculations were carried out to aid the assignment of the vibrational levels of the X state and for some conformers the A state as well. Geometry optimizations of the different conformers of the isomers were performed and their energy differences in the ground states were determined. The results of the calculation of the energy separations of the close-lying X and A states of the different conformations are provided for comparison with the experimental observations.