Effects of Auxiliary Fiber Posts on Endodontically Treated Teeth With Flared Canals

Macro-Lock post combined with auxiliary fiber posts could increase the fracture resistance of endodontically treated roots with over-flared canals. However, an effect of the auxiliary fibers on retention strength was not observed.

Thorough QT study of the effects of vildagliptin, a dipeptidyl peptidase IV inhibitor, on cardiac repolarization and conduction in healthy volunteers

OBJECTIVE

This randomized, double-blind study evaluated the effects of vildagliptin, a dipeptidyl peptidase IV inhibitor for treating type 2 diabetes, on cardiac repolarization and conduction.

METHODS

Healthy volunteers (n = 101) were randomized (1:1:1:1 ratio) to vildagliptin 100 or 400 mg, moxifloxacin 400 mg (active control), or placebo once daily for 5 days. Electrocardiograms were recorded at baseline and day 5 for 24 hours post-dose. Placebo-adjusted mean change from baseline in QT interval, heart-rate-corrected QT intervals by Fridericia's (QTcF) or Bazett's (QTcB) formula, and PR and QRS intervals were compared at each time-point (time-matched analysis) and for values averaged across the dosing period (time-averaged analysis).

RESULTS

For time-matched analysis, mean changes in QTcF with vildagliptin were below predefined limits for QTc prolongation (mean increase <5 ms; upper 90% confidence interval [CI] < 10 ms), except for vildagliptin 100 mg at 1 and 8 hours post-dose (upper 90% CI > 10 ms). With moxifloxacin, significant QTcF prolongation occurred at most time-points, demonstrating assay sensitivity. No vildagliptin- or placebo-treated volunteer had QTcF > 450 ms. Incidences of QTcF increases ≥30 ms with vildagliptin (100 and 400 mg) and placebo were similar (4-8%) and were much lower than with moxifloxacin (39%). No QTcF increase ≥60 ms was observed with vildagliptin or placebo (versus one with moxifloxacin). Time-averaged, time-matched, and categorical analyses of QT/QTcF/QTcB showed similar results. Drug exposure analysis showed no correlation between vildagliptin plasma levels and QTc changes. Vildagliptin had no effect on PR or QRS intervals. Although this study, completed before publication of current ICH E14 guidelines, was underpowered for time-matched analysis, the results are consistent with lack of effect of vildagliptin on QTc.

CONCLUSION

Vildagliptin did not prolong QT interval or affect cardiac conduction at the highest daily therapeutic dose or a fourfold higher dose.

Synaptotagmin-7 as a positive regulator of glucose-induced glucagon-like peptide-1 secretion in mice

AIMS/HYPOTHESIS

Glucagon-like peptide-1 (GLP-1), a hormone with potent antihyperglycaemic effects, is produced and secreted from highly specialised gut endocrine L-cells. It regulates glucose homeostasis by promoting glucose-dependent insulin secretion, suppressing glucagon secretion and enhancing insulin sensitivity. Similar to islet alpha and beta cells, L-cells are electrically excitable, and express calcium channels and ATP-sensitive potassium channels. GLP-1 is also stored in secretory granules, the exocytosis of which is triggered by increased intracellular calcium levels. Although the calcium dependence of GLP-1 granule exocytosis is well established, the identities of calcium-sensing proteins in GLP-1 secretion remain elusive. Here we tested whether synaptotagmin-7, a calcium sensor in pancreatic alpha and beta cells, regulates GLP-1 secretion.

METHODS

We studied GLP-1 secretion using synaptotagmin-7 knockout (KO) mice and GLUTag cells with lentiviral-mediated synaptotagmin-7 silencing.

RESULTS

We found that synaptotagmin-7 was co-localised with GLP-1 in intestinal L-cells. GLP-1 secretion was impaired in synaptotagmin-7 KO mice when they were challenged by glucose ingestion. Lentiviral knockdown (KD) of synaptotagmin-7 in GLUTag cells led to similar reductions in GLP-1 secretion, as determined by biochemical assays and by membrane capacitance measurements. Calcium response was not altered in synaptotagmin-7 KD cells.

CONCLUSIONS/INTERPRETATION

These results demonstrate that synaptotagmin-7 functions as a positive regulator of GLP-1 secretion in intestinal L-cells and GLUTag cells, consistent with its proposed role as a calcium sensor in GLP-1 secretion.

Temporal coherence and spectral linewidth of an injection-seeded transient collisional soft x-ray laser

The temporal coherence of an injection-seeded transient 18.9 nm molybdenum soft x-ray laser was measured using a wavefront division interferometer and compared to model simulations. The seeded laser is found to have a coherence time similar to that of the unseeded amplifier, ~1 ps, but a significantly larger degree of temporal coherence. The measured coherence time for the unseeded amplifier is only a small fraction of the pulsewidth, while in the case of the seeded laser it approaches full temporal coherence. The measurements confirm that the bandwidth of the solid target amplifiers is significantly wider than that of soft x-ray lasers that use gaseous targets, an advantage for the development of sub-picosecond soft x-ray lasers.

Intestinal pseudo-obstruction syndrome in systemic lupus erythematosus

Intestinal pseudo-obstruction (IpsO) occurs in a small subgroup of patients with systemic lupus erythematosus (SLE), and has been under-recognized. The etiology and mechanisms are unclear. Herein, we report two cases. In case 1, IpsO occurred as the complication in a previously diagnosed SLE patient. In case 2, IpsO with an image-evidenced intussusception and a peripheral eosinophilia, was the initial presentation, leading to the diagnosis of SLE. In both cases, IpsO existed concomitantly with ureterohydronephrosis, and evolved into peritonitis, which we called together IpsO syndrome. However, this surgical abdomen-like syndrome had a satisfactory response to glucocorticosteroids instead of antibiotics and surgery. Physician awareness and early diagnosis could positively affect outcomes of this syndrome, avoiding unnecessary surgical intervention.

Chicken adipocyte fatty acid-binding protein knockdown affects expression of peroxisome proliferator-activated receptor γ gene during oleate-induced adipocyte differentiation

Adipocyte fatty acid-binding protein (A-FABP) is expressed in both adipose cells and macrophages. As one of the downstream genes of peroxisome proliferator-activated receptor γ (PPAR-γ), A-FABP plays an important role in the lipid metabolism of adipocytes in mammal and poultry. However, studies in A-FABP null macrophages of mice showed that A-FABP was a critical regulator of PPAR-γ and could affect the expression of PPAR-γ. The current study was designed to investigate whether the same mechanism as that in macrophages exists in chicken adipocytes. After transfection with interference and overexpression plasmids of A-FABP in chicken adipocytes for 24 h, oleate was added to the medium. Then, lipid accumulation, nonesterified fatty acids (NEFA) in the medium, and expression of lipid metabolism-related genes were detected. The results showed that in the A-FABP knockdown adipocytes, lipid accumulation was decreased at 6 h and NEFA in the medium was higher at 1 and 6 h compared with that in the control group. Moreover, gene expression levels of lipoprotein lipase, perilipin, and PPAR-γ were higher than that of the control group (P < 0.05). In the A-FABP overexpression adipocytes, lipid accumulation and expression of lipid metabolism related genes were similar to that of the control group. However, NEFA in the medium was significantly lower in the A-FABP overexpression group 1 h after adding oleate (P < 0.05). The present study suggested that the A-FABP knockdown might lead to decreased lipid accumulation and upregulated expression of PPAR-γ in chicken adipocytes.

Association of KCNJ11 with impaired glucose regulation in essential hypertension

KCNJ11 is one of the candidate genes for type 2 diabetes, confirmed by genome wide association study, but there are little data on the relationship between KCNJ11 and impaired glucose regulation in essential hypertension patients. To identify the effect of E23K and I337V in the KCNJ11 gene on susceptibility to impaired glucose regulation, we conducted a case control study in 1125 essential hypertension patients with or without impaired glucose regulation among a Han Chinese population. We also evaluated the impact of two SNPs on insulin sensitivity and glucose tolerance estimated through an oral glucose tolerance test. In our case control study, no association of E23K and I337V with impaired glucose regulation was found using any genotypic models. However, lysine carriers of E23K showed a significant association with decreased insulin (30 min) and Cederholm index, and valine carriers of I337V showed association with a lower Cederholm index. All the quantitative tests were performed by linear regression, with adjustment for gender, age, body mass index, blood pressure, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker treatment. These findings provided evidence that the KCNJ11 gene plays a role in the pathogenesis of decreased insulin sensitivity in essential hypertension patients.

Colitogenic role of tumour necrosis factor (TNF) receptors in trinitrobenzene sulphonic acid colitis: TNF-R1 ablation does not affect systemic inflammatory response

Tumour necrosis factor (TNF)-α plays a critical role in the pathogenesis of T helper type 1-mediated colitis such as Crohn's disease. However, the roles of its two receptors in mediating pathology remain largely unknown. In this study, trinitrobenzene sulphonic acid (TNBS) was used to induce colitis in TNF-receptor single or double knock-out (DKO) BALB/c mice and in wild-type counterparts. TNF-R1(-/-) mice had significantly less weight loss, reduced mortality, colon shortening and oedema, colon histological damage and lower levels of colon myeloperoxidase compared with wild-type (WT) BALB/c mice. A similar manifestation was also observed in TNF-R2(-/-) and TNF-R1(-/-) TNF-R2(-/-) (TNF-R DKO) mice. Strikingly, systemic inflammatory response (including splenomegaly and monocyte expansion) was found in WT and TNF-R1(-/-) mice after TNBS, instead of TNF-R2(-/-) and TNF-R DKO mice. Attenuated pathology of colitis in TNF-R1(-/-) or TNF-R2(-/-) mice correlated with lower amounts of interleukin (IL)-6, IL-1β, monocyte chemotactic protein (MCP)-1, IL-12p70 and interferon (IFN)-γ production in the colons. Importantly, ablation of TNF-R1 or TNF-R2 reduced the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labelling (TUNEL)-positive apoptotic epithelial cells in the affected colons compared with WT TNBS-instilled controls, which might be due to the heightened ratio of Bcl-2/Bax and reduced activity of nuclear factor (NF)-κB. These findings suggest that either TNF-R1 or TNF-R2 plays a pathogenic role in the pathology of colitis and TNF signalling via TNF-R1 or TNF-R2 alone is not sufficient for inducing mucosal damage.

IgE sequences in individuals living in an area of endemic parasitism show little mutational evidence of antigen selection

Patterns of somatic mutation in IgE genes from allergic individuals have been a focus of study for many years, but IgE sequences have never been reported from parasitized individuals. To study the role of antigen selection in the evolution of the anti-parasite response, we therefore generated 118 IgE sequences from donors living in Papua New Guinea (PNG), an area of endemic parasitism. For comparison, we also generated IgG1, IgG2, IgG3 and IgG4 sequences from these donors, as well as IgG1 sequences from Australian donors. IgE sequences had, on average, 23.0 mutations. PNG IgG sequences had average mutation levels that varied from 17.7 (IgG3) to 27.1 (IgG4). Mean mutation levels correlated significantly with the position of their genes in the constant region gene locus (IgG3 < IgG1 < IgG2 < IgG4). Interestingly, given the heavy, life-long antigen burden experienced by PNG villagers, average mutation levels in IgG sequences were little different to that seen in Australian IgG1 sequences (19.2). Patterns of mutation provide clear evidence of antigen selection in many IgG sequences. The percentage of IgG sequences that showed significant accumulations of replacement mutations in the complementarity determining regions ranged from 22% of IgG3 sequences to 39% of IgG2 sequences. By contrast, only 12% of IgE sequences had such evidence of antigen selection, and this was significantly less than in PNG IgG1, IgG2 and IgG4 subclass sequences (P < 0.01). The anti-parasite IgE response therefore has the reduced evidence of antigen selection that has previously been reported in studies of IgE sequences from allergic individuals.

Dcdc2 knockout mice display exacerbated developmental disruptions following knockdown of doublecortin

The dyslexia-associated gene DCDC2 is a member of the DCX family of genes known to play roles in neurogenesis, neuronal migration, and differentiation. Here we report the first phenotypic analysis of a Dcdc2 knockout mouse. Comparisons between Dcdc2 knockout mice and wild-type (wt) littermates revealed no significant differences in neuronal migration, neocortical lamination, neuronal cilliogenesis or dendritic differentiation. Considering previous studies showing genetic interactions and potential functional redundancy among members of the DCX family, we tested whether decreasing Dcx expression by RNAi would differentially impair neurodevelopment in Dcdc2 knockouts and wild-type mice. Consistent with this hypothesis, we found that deficits in neuronal migration, and dendritic growth caused by RNAi of Dcx were more severe in Dcdc2 knockouts than in wild-type mice with the same transfection. These results indicate that Dcdc2 is not required for neurogenesis, neuronal migration or differentiation in mice, but may have partial functional redundancy with Dcx.

Outcomes after ischemic stroke for hospitals with and without Joint Commission-certified primary stroke centers

BACKGROUND

The Joint Commission (JC) began certifying primary stroke centers (PSCs) in the United States in 2003. We assessed whether 30-day risk-standardized mortality (RSMR) and readmission (RSRR) rates differed between hospitals with and without JC-certified PSCs in 2006.

METHODS

The study cohort included all fee-for-service Medicare beneficiaries ≥65 years old discharged with a primary diagnosis of ischemic stroke (International Classification of Diseases, ninth revision, Clinical Modification 433, 434, 436) in 2006. Hierarchical linear regression models calculated hospital-level RSMRs and RSRRs, adjusting for patient demographics, comorbid conditions, and hospital referral region. Hospitals were categorized as being higher than, no different from, or lower than the national average.

RESULTS

There were 310,381 ischemic stroke discharges from 315 JC-certified PSC and 4,231 noncertified hospitals. Mean overall 30-day RSMR and RSRR were 10.9% ± 1.7% and 12.5% ± 1.4%, respectively. The RSMRs of hospitals with JC-certified PSCs were lower than in noncertified hospitals (10.7% ± 1.7% vs 11.0% ± 1.7%), but the RSRRs were comparable (12.5% ± 1.3% vs 12.4% ± 1.7%). Almost half of JC-certified PSC hospitals had RSMRs lower than the national average compared with 19% of noncertified hospitals, but 13% of JC-certified PSC hospitals had lower RSRRs vs 15% of noncertified hospitals.

CONCLUSIONS

Hospitals with JC-certified PSCs had lower RSMRs compared with noncertified hospitals in 2006; however, differences were small. Readmission rates were similar between the 2 groups. PSC certification generally identified better-performing hospitals for mortality outcomes, but some hospitals with certified PSCs may have high RSMRs and RSRRs whereas some hospitals without PSCs have low rates. Unmeasured factors may contribute to this heterogeneity.

Synthesis of one-dimensional TiO2/V2O5 branched heterostructures and their visible light photocatalytic activity towards Rhodamine B

We present the synthesis and visible-light-induced catalytic activity of one-dimensional (1D) TiO(2)/V(2)O(5) branched heterostructures. The 1D TiO(2)/V(2)O(5) heterostructures were prepared by RF reactive magnetron sputtering of V(2)O(5) onto electrospun TiO(2) nanofibers. Then, the samples were annealed at 300 °C for 2 h in air ambient to form the 1D TiO(2)/V(2)O(5) branched heterostructures. The photodecomposition rate of Rhodamine B (RhB) by the 1D TiO(2)/V(2)O(5) branched heterostructures under visible light was much faster than that of pure TiO(2) nanofibers, revealing that the visible-light-induced catalytic activity of the 1D TiO(2)/V(2)O(5) branched heterostructures was greatly improved. The enhancement of the photocatalytic activity of the 1D TiO(2)/V(2)O(5) branched heterostructures can be ascribed to the coupling with a small bandgap semiconductor material V(2)O(5), where the absorption range is extended, the photogenerated electrons and holes are highly separated and the surface charge carrier transfer rate is promoted.

Use of Haavikko's method to assess dental age in Chinese children

OBJECTIVE

To investigate the accuracy and precision of Haavikko's method in estimating dental age (DA) in healthy Chinese children, and evaluate the agreement between DA and dental age in the left mandibular quadrant (DALM), in order to simplify Haavikko's method by using only the developing teeth in the left half of the mandible.

METHOD

Six hundred and thirteen panoramic photographs of healthy Chinese children were reviewed retrospectively. DA and DALM were calculated using Haavikko's method, but DALM included only the developing teeth in the left mandible. A paired t-test was used to compare the difference between chronological age (CA) and DA, DA and DALM. Correlation coefficients were calculated. Intra-examiner and inter-examiner variation were also evaluated using Cohen's Kappa value.

RESULTS

Intra-examiner and inter-examiner Kappa values were 0.90 and 0.84 respectively, indicating a high reliability of Haavikko's method in this study group. The mean difference between DA and CA of the samples was 0.14 years. The correlation coefficient between the two was 0.93. For DA and DALM, the mean difference was 0.05 years, and the correlation coefficient was 0.99.

CONCLUSIONS

Haavikko's method has a high degree of accuracy and precision when applied in this Chinese population. DALM may be used instead of DA to estimate dental ages.