Influence of Light Intensity on Surface Free Energy and Dentin Bond Strength of Core Build-up Resins

Objective

We examined the influence of light intensity on surface free energy characteristics and dentin bond strength of dual-cure direct core build-up resin systems.

Methods

Two commercially available dual-cure direct core build-up resin systems, Clearfil DC Core Automix with Clearfil Bond SE One and UniFil Core EM with Self-Etching Bond, were studied. Bovine mandibular incisors were mounted in acrylic resin and the facial dentin surfaces were wet ground on 600-grit silicon carbide paper. Adhesives were applied to dentin surfaces and cured with light intensities of 0 (no irradiation), 200, 400, and 600 mW/cm2. The surface free energy of the adhesives (five samples per group) was determined by measuring the contact angles of three test liquids placed on the cured adhesives. To determine the strength of the dentin bond, the core build-up resin pastes were condensed into the mold on the adhesive-treated dentin surfaces according to the methods described for the surface free energy measurement. The resin pastes were cured with the same light intensities as those used for the adhesives. Ten specimens per group were stored in water maintained at 37°C for 24 hours, after which they were shear tested at a crosshead speed of 1.0 mm/minute in a universal testing machine. Two-way analysis of variance (ANOVA) and a Tukey-Kramer test were performed, with the significance level set at 0.05.

Results

The surface free energies of the adhesive-treated dentin surfaces decreased with an increase in the light intensity of the curing unit. Two-way ANOVA revealed that the type of core build-up system and the light intensity significantly influence the bond strength, although there was no significant interaction between the two factors. The highest bond strengths were achieved when the resin pastes were cured with the strongest light intensity for all the core build-up systems. When polymerized with a light intensity of 200 mW/cm2 or less, significantly lower bond strengths were observed.

Conclusions

The data suggest that the dentin bond strength of core build-up systems are still affected by the light intensity of the curing unit, which is based on the surface free energy of the adhesives. On the basis of the results and limitations of the test conditions used in this study, it appears that a light intensity of >400 mW/cm2 may be required for achieving the optimal dentin bond strength.

Phase II trial of combination therapy of gemcitabine plus anti-angiogenic vaccination of elpamotide in patients with advanced or recurrent biliary tract cancer

Background Elpamotide is an HLA-A*24:02-restricted epitope peptide of vascular endothelial growth factor receptor 2 (VEGFR-2) and induces cytotoxic T lymphocytes (CTLs) against VEGFR-2/KDR. Given the high expression of VEGFR-2 in biliary tract cancer, combination chemoimmunotherapy with elpamotide and gemcitabine holds promise as a new therapy. Patients and Methods Patients with unresectable advanced or recurrent biliary tract cancer were included in this single-arm phase II trial, with the primary endpoint of overall survival. Survival analysis was performed in comparison with historical control data. The patients concurrently received gemcitabine once a week for 3 weeks (the fourth week was skipped) and elpamotide once a week for 4 weeks. Results Fifty-five patients were registered, of which 54 received the regimen and were included in the full analysis set as well as the safety analysis set. Median survival was 10.1 months, which was longer than the historical control, and the 1-year survival rate was 44.4 %. Of these patients, injection site reactions were observed in 64.8 %, in whom median survival was significantly longer (14.8 months) compared to those with no injection site reactions (5.7 months). The response rate was 18.5 %, and all who responded exhibited injection site reactions. Serious adverse reactions were observed in five patients (9 %), and there were no treatment-related deaths. Conclusion Gemcitabine and elpamotide combination therapy was tolerable and had a moderate antitumor effect. For future development of therapies, it will be necessary to optimize the target population for which therapeutic effects could be expected.

Mechanical Properties and Simulated Wear of Provisional Resin Materials

The purpose of this study was to determine flexural properties and erosive wear behavior of provisional resin materials. Three bis-acryl base provisional resins-1) Protemp Plus (PP), 2) Integrity (IG), 3) Luxatemp Automix Plus (LX)-and a conventional poly(methylmethacrylate) (PMMA) resin, UniFast III (UF), were evaluated. A resin composite, Z100 Restorative (Z1), was included as a benchmark material. Six specimens for each of the four materials were used to determine flexural strength and elastic modulus according to ISO Standard 4049. Twelve specimens for each material were used to examine wear using a generalized wear simulation model. The test materials were each subjected to wear challenges of 25,000, 50,000, 100,000, and 200,000 cycles in a Leinfelder-Suzuki (Alabama) wear simulator. The materials were placed in custom cylinder-shaped stainless-steel fixtures, and wear was generated using a cylindrical-shaped flat-ended stainless-steel antagonist in a slurry of nonplasticized PMMA beads. Wear (mean facet depth [μm] and volume loss [mm(3)]) was determined using a noncontact profilometer (Proscan 2100) with Proscan and AnSur 3D software. The laboratory data were evaluated using two-way analysis of variance (ANOVA; factors: 1) material and 2) cycles) followed by Tukey HSD post hoc test (α=0.05). The flexural strength ranged from 68.2 to 150.6 MPa, and the elastic modulus ranged from 2.0 to 15.9 GPa. All of the bis-acryl provisional resins (PP, IG, and LX) demonstrated significantly higher values than the PMMA resin (UF) in flexural strength and elastic modulus (p<0.05). However, there was no significant difference (p>0.05) in flexural properties among three bis-acryl base provisional resins (PP, IG, and LX). Z1 demonstrated significantly (p<0.05) higher flexural strength and elastic modulus than the other materials tested. The results for mean facet wear depth (μm) and standard deviations (SD) for 200,000 cycles were as follows: PP, 22.4 (5.0); IG, 51.0 (6.5); LX, 63.7 (4.5); UF, 70.5 (8.0); and Z1, 7.6 (1.2). Volume loss (mm(3)) and SDs for 200,000 cycles were as follows: PP, 0.311 (0.049); IG, 0.737 (0.074); LX, 0.919 (0.053); UF, 1.046 (0.127); and Z1, 0.111 (0.017). The two-way ANOVA showed a significant difference among materials (p<0.001) and number of cycles for both facet depth and volume loss. The post hoc test revealed differences (p<0.05) in wear values among the tested materials examined in this study. The findings provide valuable information regarding the flexural properties and the relative wear behavior of the provisional resins examined in this study.

Combined vascular resection and reconstruction during hepatobiliary and pancreatic cancer surgery

Prospective studies needed at high-volume centres

Current and emerging MR imaging techniques for the diagnosis and management of CSF flow disorders: a review of phase-contrast and time-spatial labeling inversion pulse

This article provides an overview of phase-contrast and time-spatial labeling inversion pulse MR imaging techniques to assess CSF movement in the CNS under normal and pathophysiologic situations. Phase-contrast can quantitatively measure stroke volume in selected regions, notably the aqueduct of Sylvius, synchronized to the heartbeat. Judicious fine-tuning of the technique is needed to achieve maximal temporal resolution, and it has limited visualization of CSF motion in many CNS regions. Phase-contrast is frequently used to evaluate those patients with suspected normal pressure hydrocephalus and a Chiari I malformation. Correlation with successful treatment outcome has been problematic. Time-spatial labeling inversion pulse, with a high signal-to-noise ratio, assesses linear and turbulent motion of CSF anywhere in the CNS. Time-spatial labeling inversion pulse can qualitatively visualize whether CSF flows between 2 compartments and determine whether there is flow through the aqueduct of Sylvius or a new surgically created stoma. Cine images reveal CSF linear and turbulent flow patterns.

Risk factors for hepatocellular carcinoma in hepatitis C patients with normal alanine aminotransferase treated with pegylated interferon and ribavirin

Pegylated interferon (Peg-IFN) plus ribavirin combination therapy is effective in patients with hepatitis C virus (HCV) infection and normal alanine aminotransferase levels (NALT). However, it remains unclear whether the risk of hepatocellular carcinoma (HCC) incidence is actually reduced in virological responders. In this study, HCC incidence was examined for 809 patients with NALT (ALT ≤ 40 IU/mL) treated with Peg-IFN alpha-2b and ribavirin for a mean observation period of 36.2 ± 16.5 months. The risk factors for HCC incidence were analysed by Kaplan-Meier method and Cox proportional hazards model. On multivariate analysis among NALT patients, the risk of HCC incidence was significantly reduced in patients with sustained virological response (SVR) or relapse compared with those showing nonresponse (NR) (SVR vs NR, hazard ratio (HR): 0.16, P = 0.009, relapse vs NR, HR: 0.11, P = 0.037). Other risk factors were older age (≥65 years vs <60 years, HR: 6.0, P = 0.032, 60-64 vs <60 years, HR: 3.2, P = 0.212) and male gender (HR: 3.9, P = 0.031). Among 176 patients with PNALT (ALT ≤ 30 IU/mL), only one patient developed HCC and no significant risk factors associated with HCC development were found. In conclusion, antiviral therapy for NALT patients with HCV infection can lower the HCC incidence in responders, particularly for aged and male patients. The indication of antiviral therapy for PNALT (ALT ≤ 30 IU/mL) patients should be carefully determined.

Effect of Pre-reacted Glass-ionomer Filler Extraction Solution on Demineralization of Bovine Enamel

Objective

To determine the effect of pre-reacted glass-ionomer (PRG) filler extraction solution on the demineralization of bovine enamel by measuring changes in the ultrasound transmission velocity.

Methods

The specimens were prepared by cutting bovine teeth into enamel blocks. The specimens were immersed in buffered lactic acid solution for 10 minutes twice a day, and then stored in artificial saliva. Other specimens were stored in PRG filler extraction solution for 10 minutes, followed by 10-minute immersion in the buffered lactic acid solution twice a day. The propagation time of longitudinal ultrasonic waves was measured by a pulser receiver. Six specimens were used for each condition, and analyses of variance followed by Tukey tests (α=0.05) were done.

Results

No changes in sonic velocity were found for specimens stored in the PRG filler extraction solution, indicating that the PRG extraction solution had an effect on inhibiting the demineralization of bovine enamel.

Conclusions

The results obtained with the use of an ultrasound measurement technique suggested that PRG filler extraction solution has the ability to prevent demineralization of enamel.

Proposal to modify the International Union Against Cancer staging system for perihilar cholangiocarcinomas

BACKGROUND

The International Union Against Cancer (UICC) staging system for perihilar cholangiocarcinoma changed in 2009. The aim of this study was to validate and optimize the UICC system for these tumours.

METHODS

This retrospective study was conducted in eight Japanese hospitals between 2001 and 2010. Perihilar cholangiocarcinoma was defined as a cholangiocarcinoma that involves the hilar bile duct, independent of the presence or absence of a liver mass component. The stratification ability of the UICC tumour node metastasis (TNM) system was compared with that of a modified system.

RESULTS

Of 1352 patients, 35.9, 44.8 and 12.6 per cent had Bismuth type IV tumours, nodal metastasis (N1) and distant metastasis (M1) respectively. T4 tumours (43.2 per cent) and stage IVA (T4 Nany M0; 36.3 per cent) disease were most common. Survival was not significantly different between patients with T3 versus T4 tumours (P = 0.284). Survival for patients with stage IVA disease was comparable to that for patients with stage IIIB tumours (T1-3 N1 M0) (P = 0.426). Vascular invasion, pancreatic invasion, positive margin, N1 and M1 status were identified as independent predictors of survival. When Bismuth type IV tumours were removed from the T4 determinants and N1 tumours grouped together, the modified grouping had a higher linear trend χ2 and likelihood ratio χ2 compared with the original system (245.6 versus 170.3 respectively and 255.8 versus 209.3 respectively).

CONCLUSION

The present data suggest that minimal modification with removal of Bismuth type IV tumours from the T4 determinants and bundling of N1 disease may enhance the prognostic ability of the UICC system. However, this requires validation on an independent data set.

Abstract P3-13-08: A phase I study of weekly nab-paclitaxel in combination with S-1 in patients with metastatic breast cancer

Background: S-1 is an oral, fixed dose combination product comprised of tegafur, a fluoropyrimidine prodrug of 5-fluorouracil (5-FU), and modulators of 5-FU metabolism, 5-chloro-2.4-dihydrooxypyridine and oteracil potassium. S-1 is designed to provide oral delivery of 5-FU, a pyrimidine analog antimetabolite antineoplastic agent, while reducing the rate of degradation of 5-FU and its conversion in the gastrointestinal tract to its toxic phosphorylated metabolite. S-1 is active in breast cancer and a variety of solid tumors. nab™-Paclitaxel (nab-P) is a treatment option in metastatic breast cancer (MBC) (approved 260 mg/m2 q3w dosing schedule), and high activity of nab-P with single-agent weekly administration at 100 mg/m2 has been investigated in MBC as well as other disease states. Since these two agents differed in their mechanisms of action and toxicity profiles, we sought to test their combined activity in a phase I study of nab-P/S-1 for HER2-negative MBC. The primary objectives of this study was to determine the maximum tolerated dose (MTD) and recommended dose (RD) of nab-P/S-1 in patients with HER-2 negative MBC. The secondary objective of this study was to evaluate pharmacokinetic (PK) parameters of both agents.

Methods: Patients received treatment on 3 week cycles. S-1 was administered orally at a twice-daily dose of 65 mg/m2 (dose level 1 and 2b) or 80 mg/m2 (dose level 2a and 3) for 14 days and nab-P was administered as a 30-minute IV infusion at a dose of 100 mg/m2 on days 1 and 8 (dose level 1 and 2b) or 100 mg/m2 on days 1, 8 and 15 (dose level 2a and 3).

Results: Fifteen patients were enrolled in this study; nab-P/S-1 was given as first-line chemotherapy for MBC in 9 patients, and as second-line therapy subsequent to an anthracycline-containing therapy in 6 patients. At dose level 3, one patient experienced a DLT. The observed DLT was delay of initiation of next cycle, G4 neutropenia had not recovered to G1/G0 in a period defined on the protocol. No cases of febrile neutropenia were observed. Judged from the status of dose reduction and the extension of drug holidays (cycle start delay), and the occurrence of non-severe adverse events after 2 cycles, the dose level was not increased above level 3. Seven patients were able to be treated 10 cycles or more. Additionally, three patients were able to be treated 20 cycles or more. Among of the 12 patients who had a measurable lesion which was evaluable by RECISTv1.1, the overall response rate was 50%, with 1 CR, 5 PR, 4 SD, and 1 PD. Pharmacokinetics of Paclitaxel and 5-FU in the combination therapy were comparable to those after single-agent administration of nab-P and S-1, respectively.

Conclusion: Based on the results of this study, the RD was determined to be dose level 3 (S-1 80 mg/m2 twice daily plus nab-P 100 mg/m2 on days 1, 8, and 15). Since this combination therapy was generally well tolerated even with prolonged treatment, it is suggested that this combination therapy may be a promising treatment regimen in HER-2 negative MBC and merits further evaluation.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-13-08.

Downregulation of miRNA-31 induces taxane resistance in ovarian cancer cells through increase of receptor tyrosine kinase MET

Ovarian cancer is one of the most aggressive female reproductive tract tumors. Paclitaxel (PTX) is widely used for the treatment of ovarian cancer. However, ovarian cancers often acquire chemotherapeutic resistance to this agent. We investigated the mechanism of chemoresistance by analysis of microRNAs using the ovarian cancer cell line KFr13 and its PTX-resistant derivative (KFr13Tx). We found that miR-31 was downregulated in KFr13Tx cells, and that re-introduction of miR31 re-sensitized them to PTX both in vitro and in vivo. miR-31 was found to bind to the 3′-UTR of mRNA of MET, and the decrease in MET correlated to higher sensitivity to PTX. Furthermore, co-treatment of KFr13Tx cells with MET inhibitors sensitized the tumor cells to PTX both in vitro and in vivo. In addition, lower levels of miR31 and higher expression of MET in human ovarian cancer specimens were significantly correlated with PTX chemoresistance and poor prognosis. This study demonstrated miR31-dependent regulation of MET for chemoresistance of ovarian cancer, raising the possibility that combination therapy with a MET inhibitor and PTX will increase PTX efficacy.

Chylous ascites after hepatopancreatobiliary surgery

Background

Postoperative chylous ascites following abdominal surgery is uncommon. It potentially induces malnutrition and immunodeficiency, contributing to increased mortality. In the field of hepatopancreatobiliary (HPB) surgery, no large studies have been conducted that focused on postoperative chylous ascites. The aim of this study was to determine the incidence, risk factors and management of chylous ascites following HPB surgery, with particular emphasis on pancreatic resection.

Methods

Consecutive patients who had HPB surgery between 2000 and 2011 at a single institution were reviewed retrospectively. Chyle leak was defined as 100 ml/day or more of milky, amylase-free peritoneal fluid with a triglyceride concentration of 110 mg/dl or above. Risk factors for chylous ascites associated with pancreatic resection and the clinical efficacy of octreotide in treating chylous ascites were evaluated.

Results

Of 2002 consecutive patients who underwent HPB surgery during the study period, 21 (1·0 per cent) developed chylous ascites. Chylous ascites occurred relatively frequently in patients who had a pancreatic resection, such as pancreaticoduodenectomy (3·3 per cent) or distal pancreatectomy (3·8 per cent). Multivariable analysis revealed that manipulation of the para-aortic area (P &lt; 0·001), retroperitoneal invasion (P = 0·031) and early enteral feeding after operation (P &lt; 0·001) were independent risk factors for chylous ascites following pancreatic resection. Octreotide treatment decreased drainage output of chylous ascites on day 1 after initiation of treatment (P = 0·002).

Conclusion

Chylous ascites is a rare complication following HPB surgery. It is more common after pancreatic resection. Treatment with octreotide combined with total parenteral nutrition is recommended.

Activation of the human multidrug resistance-1 (mdr1) gene promoter in response to inhibitors of DNA topoisomerases

The multidrug resistance (MDR1) gene encodes a Mr 170,000 energy-dependent membrane efflux pump termed P-glycoprotein, and the P-glycoprotein is often expressed in various human tumors before and after cancer chemotherapy. In this study, we have established a human cancer KB cell line (Kst-6) which stably expressed the CAT gene (pMDRCAT1) driven by the human MDR1 promoter. Exposure to inhibitors of DNA topoisomerase I (camptothecin: CPT-11) and II (etoposide: VP-16 and teniposide: VM-26) could efficiently induce CAT activities in both time- and dose-dependent manners. However, CAT activity could not be significantly induced when treated with an ATP-antagoist, novobiocin. Northern blot analysis showed about 5-fold increase in CAT mRNA levels in Kst-6 cells treated with CPT-11 or VP-16, but not with novobiocin. Proximal MDR1 promoter-binding activities of transacting factor were augmented in nuclear extracts from KB cells treated with CPT-11, VM-26, and VP-16.

Annexin V decreases PS-mediated macrophage efferocytosis and deteriorates elastase-induced pulmonary emphysema in mice

Efferocytosis is believed to be a key regulator for lung inflammation in chronic obstructive pulmonary disease. In this study we pharmacologically inhibited efferocytosis with annexin V and attempted to determine its impact on the progression of pulmonary emphysema in mouse. We first demonstrated in vitro and in vivo efferocytosis experiments using annexin V, an inhibitor for phosphatidylserine-mediated efferocytosis. We then inhibited efferocytosis in porcine pancreatic elastase (PPE)-treated mice. PPE-treated mice were instilled annexin V intranasally starting from day 8 until day 20. Mean linear intercept (Lm) was measured, and cell apoptosis was assessed in lung specimen obtained on day 21. Cell profile, apoptosis, and mRNA expression of matrix metalloproteinases (MMPs) and growth factors were evaluated in bronchoalveolar lavage (BAL) cells on day 15. Annexin V attenuated macrophage efferocytosis both in vitro and in vivo. PPE-treated mice had a significant higher Lm, and annexin V further increased that by 32%. More number of macrophages was found in BAL fluid in this group. Interestingly, cell apoptosis was not increased by annexin V treatment both in lung specimens and BAL fluid, but macrophages from mice treated with both PPE and annexin V expressed higher MMP-2 mRNA levels and had a trend for higher MMP-12 mRNA expression. mRNA expression of keratinocyte growth factor tended to be downregulated. We showed that inhibited efferocytosis with annexin V worsened elastase-induced pulmonary emphysema in mice, which was, at least partly, attributed to a lack of phenotypic change in macrophages toward anti-inflammatory one.