Influence of Carbamide Peroxide on the Flexural Strength of Tooth-colored Restorative Materials: An In Vitro Study at Different Environmental Temperatures

The flexural strength of dental materials can be affected by carbamide peroxide. The environmental temperature can be thought to be a factor influencing the bleaching effects on dental materials.

Structures of apicomplexan calcium-dependent protein kinases reveal mechanism of activation by calcium

Calcium-dependent protein kinases (CDPKs) have pivotal roles in the calcium-signaling pathway in plants, ciliates and apicomplexan parasites and comprise a calmodulin-dependent kinase (CaMK)-like kinase domain regulated by a calcium-binding domain in the C terminus. To understand this intramolecular mechanism of activation, we solved the structures of the autoinhibited (apo) and activated (calcium-bound) conformations of CDPKs from the apicomplexan parasites Toxoplasma gondii and Cryptosporidium parvum. In the apo form, the C-terminal CDPK activation domain (CAD) resembles a calmodulin protein with an unexpected long helix in the N terminus that inhibits the kinase domain in the same manner as CaMKII. Calcium binding triggers the reorganization of the CAD into a highly intricate fold, leading to its relocation around the base of the kinase domain to a site remote from the substrate binding site. This large conformational change constitutes a distinct mechanism in calcium signal-transduction pathways.

Resolvin E1 protects the rat heart against reperfusion injury

The purpose of the present study was to assess whether resolvin E1 (RvE1), an anti-inflammatory mediator derived from eicosapentaenoic acid, would limit myocardial infarct size in the rat. The H9c2 cell line was used to assess whether RvE1 has direct protective effects on cardiomyocytes. In in vivo experiments, Male Sprague-Dawley rats underwent 30 min of ischemia/4 h of reperfusion. Before reperfusion, rats received intravenous RvE1 (0, 0.03, 0.1, or 0.3mg/kg). In in vitro experiments, H9c2 cells were incubated with RvE1 (0, 1, 10, 100, or 1000 nM). Cells were subjected to 18 h of incubation under normoxic conditions, 16 h of hypoxia, or 16 h of hypoxia and 2 h of reoxygenation. In vivo, RvE1 dose dependently reduced infarct size (30.7 +/- 1.7% of the area at risk in the control group and 29.1 +/- 1.6%, 14.7 +/- 1.3%, and 9.0 +/- 0.6% in the 0.03, 0.1, and 0.3 mg/kg groups, respectively, P < 0.001). In vitro, RvE1 increased viability and decreased apoptosis in a dose-dependent fashion in cells exposed to hypoxia or hypoxia/reoxygenation. A maximal effect was achieved at a concentration of 100 nM. RvE1 augmented phosphoinositide 3-kinase activity, attenuated caspase-3 activity, and augmented calcium-dependent nitric oxide synthase activity in cells exposed to hypoxia or hypoxia/reoxygenation. RvE1 increased Akt, ERK1/2, and endothelial nitric oxide synthase phosphorylation and attenuated the levels of activated caspase-3 and phosphorylated p38 levels. AG-1478, an EGF receptor tyrosine kinase inhibitor, blocked the protective effect of RvE1 both in vivo and in vitro and attenuated the RvE1-induced increase in Akt and ERK1/2 phosphorylation. In conclusion, RvE1, an anti-inflammatory mediator derived from eicosapentaenoic acid, has a direct protective effect on cardiomyocytes against ischemia-reperfusion injury and limits infarct size when administered intravenously before reperfusion.

Combined fluorescence and X-Ray tomography for quantitative in vivo detection of fluorophore

Initial results from a novel dual modality preclinical imager which combines non-contact fluorescence tomography (FT) and x-ray computed tomography (CT) for preclinical functional and anatomical in vivo imaging are presented. The anatomical data from CT provides a priori information to the FT reconstruction to create overlaid functional and anatomical images with accurate localization and quantification of fluorophore distribution. Phantoms with inclusions containing Indocyanine-Green (ICG), and with heterogeneous backgrounds including iodine in compartments at different concentrations for CT contrast, have been imaged with the dual modality FT/CT system. Anatomical information from attenuation maps and optical morphological information from absorption and scattering maps are used as a priori information in the FT reconstruction. Although ICG inclusions can be located without the a priori information, the recovered ICG concentration shows 75% error. When the a priori information is utilized, the ICG concentration can be recovered with only 15% error. Developing the ability to accurately quantify fluorophore concentration in anatomical regions of interest may provide a powerful tool for in vivo small animal imaging.

Percutaneous anterior transarticular screw fixation for atlantoaxial instability

We reviewed the outcome of a retrospective case series of eight patients with atlantoaxial instability who had been treated by percutaneous anterior transarticular screw fixation and grafting under image-intensifier guidance between December 2005 and June 2008.

The mean follow-up was 19 months (8 to 27). All eight patients had a solid C1–2 fusion. There were no breakages or displacement of screws. All the patients with pre-operative neck pain had immediate relief from their symptoms or considerable improvement. There were no major complications. Our preliminary clinical results suggest that percutaneous anterior transarticulation screw fixation is technically feasible, safe, useful and minimally invasive when using the appropriate instruments allied to intra-operative image intensification, and by selecting the correct puncture point, angle and depth of insertion.

The transcriptome of Populus in elevated CO reveals increased anthocyanin biosynthesis during delayed autumnal senescence

*The delay in autumnal senescence that has occurred in recent decades has been linked to rising temperatures. Here, we suggest that increasing atmospheric CO2 may partly account for delayed autumnal senescence and for the first time, through transcriptome analysis, identify gene expression changes associated with this delay. *Using a plantation of Populus x euramericana grown in elevated [CO2] (e[CO2]) with free-air CO2 enrichment (FACE) technology, we investigated the molecular and biochemical basis of this response. A Populus cDNA microarray was used to identify genes representing multiple biochemical pathways influenced by e[CO2] during senescence. Gene expression changes were confirmed through real-time quantitative PCR, and leaf biochemical assays. *Pathways for secondary metabolism and glycolysis were significantly up-regulated by e[CO2] during senescence, in particular, those related to anthocyanin biosynthesis. Expressed sequence tags (ESTs) representing the two most significantly up-regulated transcripts in e[CO2], LDOX (leucoanthocyanidin dioxgenase) and DFR (dihydroflavonol reductase), gave (e[CO2]/ambient CO(2) (a[CO2])) expression ratios of 39.6 and 19.3, respectively. *We showed that in e[CO2] there was increased autumnal leaf sugar accumulation and up-regulation of genes determining anthocyanin biosynthesis which, we propose, prolongs leaf longevity during natural autumnal senescence.

Hepatocyte nuclear factor 4alpha attenuates hepatic fibrosis in rats

BACKGROUND AND AIMS

Hepatocyte nuclear factor 4alpha (HNF4alpha) is a central transcriptional regulator of hepatocyte differentiation and function. The aim of this study was to evaluate the effect of HNF4alpha on attenuation of hepatic fibrosis.

METHODS

The adenoviruses carrying HNF4alpha gene or containing siRNA targeting HNF4alpha were injected through tail vein on two distinct hepatic fibrosis models either induced by dimethylnitrosamine or by bile duct ligation in rats. Moreover, HNF4alpha, epithelial-mesenchymal transition (EMT)-related and fibrotic markers in hepatocytes, hepatic stellate cells (HSCs) and liver tissues were detected by real time PCR, immunofluorescence or immunohistochemistry.

RESULTS

We demonstrated that decreased expression of HNF4alpha and epithelial markers accompanied by enhanced expression of mesenchymal markers occurred in fibrotic liver. More importantly, forced expression of HNF4alpha remarkably alleviated hepatic fibrosis and improved liver function with suppression of EMT in both fibrosis models. In contrast, downregulation of HNF4alpha by siRNA aggravated hepatic fibrosis and decreased the expression of E-cadherin in association with the enhanced expression of vimentin and fibroblast-specific protein-1. In vitro study revealed that HNF4alpha could suppress the EMT process of hepatocytes induced by transforming growth factor-beta1 and increase the expression of liver-specific genes. A similar phenomenon of the EMT process was observed during the activation of HSCs, which was abrogated by HNF4alpha. Additionally, HNF4alpha deactivated the myofibroblasts through inducing the mesenchymal-to-epithelial transition and inhibited their proliferation.

CONCLUSIONS

Our study suggests that HNF4alpha is critical for hepatic fibrogenesis and upregulation of HNF4alpha might present as an ideal option for the treatment of hepatic fibrosis.

Efficacy and Safety Data of Taiwan Breast Cancer Patients Enrolled in the Lapatinib Expanded Access Program (LEAP)

Background: LEAP is a single-arm, open-label, expanded access study of lapatinib in combination with capecitabine in 42 countries. The primary objective of LEAP was to provide patients with pre-approval access to lapatinib based on positive clinical data from a pivotal Phase III trial.Methods: Enrolled patients had locally advanced or HER2 positive metastatic breast cancer (MBC), progressive disease (PD, by modified RECIST) following prior therapy with anthracycline-, taxane-, and trastuzumab-containing regimens, including some patients previously treated with capecitabine, and were ineligible for ongoing lapatinib trials. Patients received lapatinib (1250 mg/day) and capecitabine (2000 mg/m2/day, days 1-14, every 21 days). Baseline characteristics, including prior therapies, were collected. Response was assessed using RECIST criteria.Results: From Mar 2007 to Sep 2008, 238 patients were enrolled at 10 centers in Taiwan. At the 11 June 2009 data cut-off, data were collected and analyzed for 166 patients. Patients received an average of 5 prior cytotoxic therapies, including trastuzumab and capecitabine.Of 166 patients, 3 (2%) had complete response, 49 (30%) had partial response, 62 (37%) had stable disease, 42 (25%) had PD, and 10 (6%) were unknown. The median duration of treatment was 5.5 mo and the median time to progression was 5.3 mo, respectively. Per protocol, only serious adverse events (SAEs) were reported. Thirty SAEs were reported for 238 patients; 6 (20%) were considered treatment-related by investigators, were not fatal, and included stomatitis (2), vomiting (2), diarrhea (1), and cellulitis (1). As of 11 June 2009, 66 (40%) patients were alive and 149 withdrew from LEAP, the majority (85%) because of progressive disease.Conclusion: Although data were collected retrospectively via case report forms, these results reflect the real world setting in Taiwan for the treatment of erbB2+ MBC patients and confirms that lapatinib, in combination with capecitabine, demonstrates efficacy in this patient population including those who are heavily pretreated.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5093.

Epidemiology of Triple Negative Breast Cancer in China

Background:The classification of tumors based on the gene expression may define intrinsic breast cancer subtypes in which the effect of risk factors could be more obvious. We sought to assess the risk factors for triple negative breast cancer on Chinese population.Methods: A retrospective study of 5761 patients was carried out from a large database of breast cancer patients undergoing surgery between January 1, 1991 and June 31, 2008 in Cancer Hospital, Fudan University, Shanghai, China. Univariate analyses were performed by chi-square test of Student's t test and multivariate analyses by logistic regression.Results: A total of 1108 women were identified as having triple negative breast cancer and were compared with the 4653 women with non-triple negative. Regardless the pathological discrepancy, women with triple negative breast cancers were significantly more likely to be younger age(P=0.001; OR=1.615, 95%CI=1.207-2.160), premenopausal (P = 0.003; OR = 1.570, 95% CI = 1.171-2.106) and parous women (P = 0.001; OR = 1.741, 95% CI = 1.269-2.387).There seems no associations with increasing risk of triple negative breast cancer for breastfeeding (P=0.126), younger age at menarche (P=0.129), first degree family history (P=0.111) and oral contraceptive usage (P=0.251).Conclusion:Based on this large population study in Chinese breast cancer patients, the risk factors for triple negative phenotype may be somewhat different from those for Western women. Therefore, a better knowledge of this issue is warranted due to it may have impact on clinical outcomes and may offer some insight into the process of carcinogenesis and therapeutic efficacy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2065.

Expression of Notch1, Jagged1 and beta-catenin and their clinicopathological significance in hepatocellular carcinoma

The Notch/Jagged signaling pathway is important for cellular differentiation and proliferation. Notch1/Jagged1 can either suppress or promote tumors depending on the cell type and context. beta-catenin, one of the mediators of the Wnt signalling pathway, represents a key element in one of the most important pathways of carcinogenesis. The aim of this study was to examine the expression of Notch1/Jagged1 and beta-catenin in hepatocellular carcinoma and to assign clinicopathological correlations. Immunohistochemical detection of Notch1/Jagged1 and beta-catenin was performed in tissue microarrays including 339 Hepatocellular carcinomas, 174 adjacent non-tumor livers and 94 normal livers. The results showed that the rate of expression was 66%, 98% and 97% for Notch1 and 36%, 85% and 92% for Jagged1 respectively in hepatocellular carcinoma, adjacent non-tumor liver and normal liver. Decreased expression of Notch1/Jagged1 was correlated significantly with Edmondson-Steiner grade. However, nuclear beta-catenin was expressed in 37% of hepatocellular carcinoma tissue, which was significantly higher than its non-tumor counterparts. Increased nuclear beta-catenin expression was correlated with HBs-Ag status and Edmondson-Steiner grade. Moreover, The positive expression of Notch1 was parallel with Jagged1 expression (r =0.235, p=0.000) and reduced Notch1 expression was associated with increased beta-catenin expression in hepatocellular carcinoma (r =-0.125, p =0.023). In conclusion, Notch1/Jagged1 were frequently low expressed in hepatocellular carcinoma and correlated with the high expression of beta-catenin suggesting that downregulation of Notch1/Jagged1 signaling may sustain tumor progression.

Negative impacts of unreported COPD exacerbations on health-related quality of life at 1 year

Unreported chronic obstructive pulmonary disease (COPD) exacerbations are common, but their intermediate-to-long-term impacts on health-related quality of life (HRQoL) are unknown. The aim of the present study was to examine the impact of unreported exacerbations on HRQoL at 1 yr. A multicentric prospective cohort study in 491 COPD patients was conducted in China. HRQoL was measured using the St George's Respiratory Questionnaire (SGRQ). Other measurements included sociodemographic, clinical, psychosocial and treatment profiles. Patients were monitored monthly for 12 months to document exacerbations (at least one symptom worsening for > or =48 h). Patients were categorised into six groups: no exacerbation, one unreported exacerbation only, more than one unreported exacerbation only, one reported exacerbation only, more than one reported exacerbation only, and both unreported and reported exacerbations. Generalised estimating equations were used to estimate the adjusted associations between exacerbations and HRQoL change. A total of 466 unreported and 410 reported exacerbations were recorded. Compared with patients with no exacerbations, the change in SGRQ total score was similar amongst patients with one unreported exacerbation (adjusted mean change 1.22 points (95% CI -4.05-6.48)), but significantly worse among patients with more than one unreported exacerbation (4.61 (95% CI 0.09-9.13)). Development and evaluation of self-management programmes emphasising early recognition of exacerbations and consequent action appear to be warranted.