Effects of maltitol and xylitol chewing-gums on parameters involved in dental caries development

AIM

The effects on plaque parameters of sugar free chewing-gums (CG) sweetened with either maltitol or xylitol were assessed to better understand the role polyols can play in dental caries prevention.

MATERIALS AND METHODS

A double-blind, parallel, randomised, controlled study was conducted in China. Subjects (N = 258, age = 13 to 15 years-old) were divided into 4 groups: 2 receiving polyols CG, containing respectively maltitol or xylitol, a group receiving gum base (placebo) and a negative control group not receiving any gum. CG were chewed for 30 days. This corresponds to a 10 g consumption of polyol per day. Plaque parameters (growth, pH, bacteria and insoluble glucans) were evaluated throughout the experimental period.

RESULTS

All parameters studied were significantly modified with gum base compared to no-gum: plaque pH increased; plaque growth, bacteria (S. mutans, S. sobrinus, A. viscosus and Lactobacillus) and insoluble glucans decreased. Maltitol and xylitol CG led similarly to a higher plaque pH (AUC, p⋜0.05) on short (at baseline after the first CG consumption) and long term (after 4 weeks of daily CG consumption), with or without saliva stimulation compared to both control and placebo groups. They led to a decrease in plaque growth (p=0.02) over the experimental period compared to controls. Moreover, they significantly reduced the concentration of 4 cariogenic bacteria species (p⋜0.05) in dental plaque compared to gum base.

CONCLUSION

Sugar free CG sweetened with either maltitol or xylitol can similarly reduce plaque acidogenicity compared to gum base through a decrease in oral bacteria presence. The use of a gum base placebo allowed to isolate effects on parameters involved in dental caries development specific to maltitol and xylitol, and to show these effects were similar.

Abstract 5032: Elucidating the role of CXCR4 in Ewing sarcoma

Background: Ewing sarcoma (ES) is the second most common malignant bone tumor in pediatric patients. While intensification of chemotherapy has improved the outlook for patients with localized disease, little progress has been made for those with metastatic or relapsed disease. Prognosis for these patients remains dismal with fewer than 20% surviving. Moving forward, we need to develop molecularly targeted therapy for patients with high-risk disease. The mechanisms underlying metastatic relapse in ES remain unknown but gene encoding the chemokine receptor CXCR4 has been shown to be upregulated in metastatic ES. The CXCL12-CXCR4 axis contributes to tumor metastasis in other sarcomas but its function in ES is not yet known.

Objective: In the current study we are investigating whether CXCR4 is a mediator of ES cell metastasis and may be useful as a biomarker of high-risk disease.

Results: Using qRT-PCR and flow cytometry we have shown that expression of CXCR4 transcript and protein varies significantly across ES cell lines. Importantly, the frequency of CXCR4+ cells and CXCR4 expression levels were found to be highly dynamic and were altered under different experimental conditions. Specifically, both serum deprivation and hypoxia induced upregulation of CXCR4 in TC32, TC71, and A673 ES cells. CXCR4+ cell frequency was found to be consistently highest in TC32 where the frequency ranged from 35% in ambient conditions to 62% in serum deprivation. When sorted into CXCR4+ and CXCR4- populations TC32 populations returned to their baseline state of 40% CXCR4+ cells within 3 weeks indicating that CXCR4+ cells can change into CXCR4- cells and vice versa. Interestingly, CXCR4 transcript was identified to be increased in slowly proliferating (PKH-dye-retaining) TC71 and A673 cells compared to more rapidly dividing counterparts. These data implicate CXCR4 as a potential marker of putative cancer stem cells. Finally, initial immunohistochemical studies have demonstrated highly variable patterns of CXCR4 expression in primary ES tumor samples.

Summary: ES cells express CXCR4 both in primary tumors and in cultured cell lines. However, the expression is both variable and highly dynamic. Specifically, we have found that ES cells can switch back and forth between CXCR4- and CXCR4+ states in response to environmental cues including serum deprivation and hypoxia. Ongoing work is now testing the hypothesis that CXCR4+ ES cells are more migratory than CXCR4- cells and may thus be a source of metastasis. To further test this hypothesis we are using correlative studies of clinically annotated tumor microarrays to determine if a high frequency of CXCR4+ cells at diagnosis is associated with an increased risk of metastatic relapse.

Citation Format: Melanie A. Krook, Lauren A. Nicholls, Natashay J. Bailey, Amy Han, Chris Scannell, Dafydd Thomas, Elizabeth R. Lawlor. Elucidating the role of CXCR4 in Ewing sarcoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5032. doi:10.1158/1538-7445.AM2013-5032

Abstract P6-07-40: Initial Neutrophil-to-Lymphocyte ratio in primary breast cancer patients: a simple and useful biomarker as prognostic factor

Background: Increasing neutrophil/lymphocyte ratios (NLR) on preoperative blood tests have been associated with worse survival of patients with colorectal, gastric, hepatocellular, pancreatic and lung cancer. However the utility of NLR to predict mortality in breast cancer patients has not been studied. The aim of our study was to determine whether the NLR is predictive of disease specific mortality in breast cancer and subtype-adjusted prognostic effect in breast cancer patients.

Methods: We retrospectively identified all the patients with primary breast cancer diagnosed at Yonsei University Wonju Medical School between January 2000 and June 2011 who underwent primary surgery and completed all phase of their treatment. Breast cancer with infiltrating ductal histology was included and divided into 4 subtypes: Luminal A, Luminal B, Her2-enriched, and basal type. Each immunohistochemical characteristics are as followings: Luminal A: ER and/or PgR positive and negative Her2, Luminal B: ER and/or PgR positive with positive HER2, Her2-enriched: negative ER and PR with positive Her2, and triple negative as basal.

Results: Patients with NLR≥2.5 showed significantly lower 5-year, 10-year breast cancer specific survival than patients with NLR<2.5. (5-year survival; 88.6% vs. 96.4%, p = 0.009, 10-year survival; 84.3% vs. 92.2%, p = 0.006). Cox proportional multivariate hazard model for cancer-specific mortality showed that patients with NLR≥2.5 has hazard ratio 4.71 with 95% confidence interval 1.77–12.53. Further analysis was done according to stratified patients' subgroup with intrinsic subtype. In Luminal A subtype, patients with NLR≥2.5 showed higher mortality rate(p = 0.014), while NLR≥2.5 failed to show statistical significance in the other subtype such as Luminal B, Her2 enriched, and triple negative subtype.

Conclusion: Increased preoperative NLR is a significant prognostic factor in breast cancer specific survival and relevant in Luminal A subtype. This study shows that NLR could be a useful prognostic factor for breast cancer specific survival. And this study suggests that different factors could contribute as prognostic factor to each subtype, such as NLR was significant prognostic factor in Luminal A, while we couldn't find increased NLR is significant in other subtypes.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-07-40.

Abstract 4492: Targeting Ras-mutated tumors with novel multiplex PI3K inhibitors

Background: The simultaneous dysregulation of both PI3K and Ras-MAPK pathways is characteristic of some of the most aggressive forms of human cancer (e.g. tumors with Ras mutations). It has been demonstrated in preclinical studies that effective treatment of Ras-mutated tumors requires blockade of both pathways. Therefore, the ability to achieve this outcome with a single agent holds great clinical promise. One key function of the PI3K and Ras-MAPK pathways is the regulation of protein translation. Both pathways converge to regulate eIF-4E, a key factor in cap-dependent translation of mRNAs encoding critical proteins involved in tumorigenesis and tumor cell survival (e.g. c-Myc and Mcl-1). The PI3K pathway activates eIF-4E via mTOR-mediated phosphorylation and suppression of 4E-BP1, a negative regulator of eIF-4E; the Ras-MAPK pathway modulates eIF4E function through phosphorylation by MNK. It has recently been demonstrated that MNK expression and MNK-dependent phosphorylation of eIF-4E on Ser209 are required for Ras-induced oncogenic transformation, and for tumor development and progression in vivo. Using a combination of rational drug design and conditional lethal screening, we discovered a novel lead series of small molecule inhibitors with multiplex activities against PI3K, mTOR and MNK. Aspects of the preclinical characterization of these novel multiplex PI3K inhibitors will be presented.

Methods and Results: Multiplex PI3K inhibitors are potent inhibitors of tumor cell proliferation and this anti-proliferative activity is independent of the presence of oncogenic mutations (e.g. Ras, PI3K, B-Raf or EGFR). Multiplex PI3K inhibitors effectively induced cell killing of tumor cell lines, including those with Ras mutations, at concentrations ranging from 100 nM to single digit μM, and are superior to either PI3K or MEK inhibitors used alone or in combination. Mechanistically, multiplex PI3K inhibitors inhibit the phosphorylation of AKT, 4E-BP1, ribosomal S6 and eIF-4E, inhibit the expression of c-Myc and Mcl-1 proteins, and induce caspase activity. In human tumor xenograft efficacy studies, multiplex PI3K inhibitors demonstrated robust in vivo anti-tumor activity. The levels of key pharmacodynamic endpoints (phosphorylated AKT, 4E-BP1, ribosomal S6 and eIF-4E) were significantly reduced in treated tumors, consistent with the proposed mechanism of action.

Conclusion: Newly-discovered novel multiplex PI3K inhibitors are capable of simultaneously targeting both PI3K and Ras-MAPK pathways and exhibit potent anti-tumor activity in Ras-mutated tumors. These inhibitors warrant further investigation for development as a potentially novel class of anti-cancer drugs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4492. doi:10.1158/1538-7445.AM2011-4492

Tissue Transglutaminase (TG2)-Induced Inflammation in Initiation, Progression, and Pathogenesis of Pancreatic Cancer

Pancreatic cancer (PC) is among the deadliest cancers, with a median survival of six months. It is generally believed that infiltrating PC arises through the progression of early grade pancreatic intraepithelial lesions (PanINs). In one model of the disease, the K-ras mutation is an early molecular event during progression of pancreatic cancer; it is followed by the accumulation of additional genetic abnormalities. This model has been supported by animal studies in which activated K-ras and p53 mutations produced metastatic pancreatic ductal adenocarcinoma in mice. According to this model, oncogenic K-ras induces PanIN formation but fails to promote the invasive stage. However, when these mice are subjected to caerulein treatment, which induces a chronic pancreatitis-like state and inflammatory response, PanINs rapidly progress to invasive carcinoma. These results are consistent with epidemiologic studies showing that patients with chronic pancreatitis have a much higher risk of developing PC. In line with these observations, recent studies have revealed elevated expression of the pro-inflammatory protein tissue transglutaminase (TG2) in early PanINs, and its expression increases even more as the disease progresses. In this review we discuss the implications of increased TG2 expression in initiation, progression, and pathogenesis of pancreatic cancer.

Abstract 4491: Novel multiplex PI3-kinase inhibitors potently inhibit Ras-mutated tumors via suppression of eIF-4E-mediated protein translation

Background: The PI3K pathway is a target of significant interest for cancer drug development due to its prominent role in cancer cell growth and survival. However, PI3K pathway inhibition alone has limited efficacy in the presence of oncogenic Ras mutations, which are found in approximately one-third of all human tumors. In preclinical models, efficacy in Ras-mutated tumors has required the inhibition of both PI3K and other Ras-activated pathways. One key function of these pathways is to regulate eIF-4E, a central factor in cap-dependent translation of critical proteins involved in growth and survival (e.g., c-myc and Mcl-1), and anti-tumor activity has been associated with the selective inhibition of translation of these proteins. Simultaneous inhibition of PI3K and other Ras-activated pathways that converge on eIF-4E-mediated protein translation represents an attractive strategy for oncology drug development.

Methods and Results: Using rational drug design, we identified a novel chemical series of small molecules that possess potent activity against PI3K and additional Ras-regulated kinases implicated in protein translation. The anti-tumor activity of these multiplex PI3K inhibitors was assessed against a panel of 30 human tumor cell lines comprised of various genetic backgrounds and histotypes. Multiplex PI3K inhibitors demonstrated broad and potent anti-proliferative activity in all cell lines tested (EC50: 10 nM - 500 nM) and induced cell death in Ras-mutated cell lines (e.g., PANC-1, HCT116 and A549). Mechanistically, these multiplex PI3K inhibitors induced caspase activity, inhibited the phosphorylation of AKT, 4E-BP1, ribosomal S6 and eIF-4E, and inhibited the expression of c-myc and Mcl-1 proteins. In contrast, PI3K-selective inhibitors were partially cytostatic in Ras-mutated tumor cell lines, inhibiting cell proliferation by at most 60-90%. PI3K-selective inhibitors also failed to induce significant increases in caspase activity, inhibit eIF-4E phosphorylation, or inhibit c-myc and Mcl-1 expression.

Conclusion: We have discovered novel multiplex PI3K inhibitors that demonstrate potent anti-tumor activity in Ras-mutant tumors via inhibition of eIF-4E-mediated protein translation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4491.

Effects of the addition of electrolyte on liquid infiltration in a hydrophobic nanoporous silica gel

In this letter, we report the experimental results of pressure induced infiltration in the hydrophobic nanopores of a silica gel. The infiltration pressure increases with the prolonged surface treatment time, whereas the infiltration volume is not dependent on the surface coverage. When temperature increases, if the liquid phase is pure water, the infiltration pressure would decrease, which is in agreement with the classic contact angle measurement results at large solid surfaces. As an electrolyte is added, however, the variation in infiltration pressure is negligible over a broad temperature range.

Upper sphincter function during transient lower oesophageal sphincter relaxation (tLOSR); it is mainly about microburps

Transient lower oesophageal sphincter relaxations (tLOSRs) are both a dominant mechanism of reflux and an element of the belch reflex. This study aimed to analyse the interplay between reflux and upper oesophageal sphincter (UOS) activity during meal-induced tLOSRs. Fifteen normal subjects were studied with a solid-state high-resolution manometry assembly positioned to record from the hypopharynx to the stomach and a catheter pH electrode 5 cm above the LOS. Subjects ate a 1000-calorie high-fat meal and were monitored for 120 min in a sitting posture. The relationship among tLOSRs, common cavities, pressure changes within the oesophagus and UOS contractile activity were analysed. A total of 218 tLOSRs occurred among the 15 subjects. The majority (79%) were coupled with UOS relaxation and 84% (145/173) of these occurred in association with a common cavity. Upper oesophageal sphincter relaxation was usually preceded by a pressure change in the oesophagus; however, some relaxations (16%) occurred without a discernable increase in pressure or before the pressure increase began. Acid reflux did not appear to play a role in determining UOS response to tLOSRs. The majority of post-prandial tLOSRs were associated with brief periods of UOS relaxation, likely permissive of gas venting (microburps). Intraoesophageal pressure changes likely modulate this UOS response; however, an anticipatory characteristic was evident in some subjects. Whether or not GORD patients with extra-oesophageal symptoms exhibit an exaggeration of the UOS relaxation response during reflux is yet to be determined.

Use of army weapons and private firearms for suicide and homicide in the region of Basel, Switzerland

OBJECTIVES

Switzerland has one of the highest rates of firearm suicides in the world. International studies show a positive correlation between the rate of households with guns and femicides with guns. Because its defense system requires a militia to keep personal firearms at home, Switzerland has a high rate of households with a gun.

METHODS

Records of suicides in the region of Basel between 1992 and 1996 were reviewed. Suicides with either army weapons or private firearms and suicides by other means were compared. Methods and types of homicides that occurred in the region at the same time were also analyzed.

FINDINGS

Firearm suicides were clearly the most frequent means of suicide. They were also used in 30.0% of domestic homicides, although other means were used at similar rates. Firearms for suicide were mainly used by men, especially army weapons. These men were younger, professionally better qualified, and fewer had ever been treated in one of the local state psychiatric services.

DISCUSSION

The use of firearms for suicide, rather than homicide, and particularly of army weapons by young, well-educated men, requires more attention in debates and informed policy regarding access to firearms and suicide prevention in Switzerland.

Clinical Approach to the Patient With Alopecia

Hair loss, or alopecia, is a common patient complaint and a source of significant psychological and physical distress. The majority of common hair loss disorders can be accurately diagnosed in the outpatient setting with a systematic evaluation of the patient. This review will present a clinical approach to the patient with alopecia by describing the history, clinical findings, and diagnosis of various hair loss disorders.